xref: /linux/drivers/i2c/busses/i2c-mlxbf.c (revision 03c11eb3b16dc0058589751dfd91f254be2be613)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Mellanox BlueField I2C bus driver
4  *
5  *  Copyright (C) 2020 Mellanox Technologies, Ltd.
6  */
7 
8 #include <linux/acpi.h>
9 #include <linux/bitfield.h>
10 #include <linux/delay.h>
11 #include <linux/err.h>
12 #include <linux/interrupt.h>
13 #include <linux/i2c.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/mutex.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/string.h>
21 
22 /* Defines what functionality is present. */
23 #define MLXBF_I2C_FUNC_SMBUS_BLOCK \
24 	(I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL)
25 
26 #define MLXBF_I2C_FUNC_SMBUS_DEFAULT \
27 	(I2C_FUNC_SMBUS_BYTE      | I2C_FUNC_SMBUS_BYTE_DATA | \
28 	 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_I2C_BLOCK | \
29 	 I2C_FUNC_SMBUS_PROC_CALL)
30 
31 #define MLXBF_I2C_FUNC_ALL \
32 	(MLXBF_I2C_FUNC_SMBUS_DEFAULT | MLXBF_I2C_FUNC_SMBUS_BLOCK | \
33 	 I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SLAVE)
34 
35 /* Shared resources info in BlueField platforms. */
36 
37 #define MLXBF_I2C_COALESCE_TYU_ADDR    0x02801300
38 #define MLXBF_I2C_COALESCE_TYU_SIZE    0x010
39 
40 #define MLXBF_I2C_GPIO_TYU_ADDR        0x02802000
41 #define MLXBF_I2C_GPIO_TYU_SIZE        0x100
42 
43 #define MLXBF_I2C_COREPLL_TYU_ADDR     0x02800358
44 #define MLXBF_I2C_COREPLL_TYU_SIZE     0x008
45 
46 #define MLXBF_I2C_COREPLL_YU_ADDR      0x02800c30
47 #define MLXBF_I2C_COREPLL_YU_SIZE      0x00c
48 
49 #define MLXBF_I2C_COREPLL_RSH_YU_ADDR  0x13409824
50 #define MLXBF_I2C_COREPLL_RSH_YU_SIZE  0x00c
51 
52 #define MLXBF_I2C_SHARED_RES_MAX       3
53 
54 /*
55  * Note that the following SMBus, CAUSE, GPIO and PLL register addresses
56  * refer to their respective offsets relative to the corresponding
57  * memory-mapped region whose addresses are specified in either the DT or
58  * the ACPI tables or above.
59  */
60 
61 /*
62  * SMBus Master core clock frequency. Timing configurations are
63  * strongly dependent on the core clock frequency of the SMBus
64  * Master. Default value is set to 400MHz.
65  */
66 #define MLXBF_I2C_TYU_PLL_OUT_FREQ  (400 * 1000 * 1000)
67 /* Reference clock for Bluefield - 156 MHz. */
68 #define MLXBF_I2C_PLL_IN_FREQ       156250000ULL
69 
70 /* Constant used to determine the PLL frequency. */
71 #define MLNXBF_I2C_COREPLL_CONST    16384ULL
72 
73 #define MLXBF_I2C_FREQUENCY_1GHZ  1000000000ULL
74 
75 /* PLL registers. */
76 #define MLXBF_I2C_CORE_PLL_REG1         0x4
77 #define MLXBF_I2C_CORE_PLL_REG2         0x8
78 
79 /* OR cause register. */
80 #define MLXBF_I2C_CAUSE_OR_EVTEN0    0x14
81 #define MLXBF_I2C_CAUSE_OR_CLEAR     0x18
82 
83 /* Arbiter Cause Register. */
84 #define MLXBF_I2C_CAUSE_ARBITER      0x1c
85 
86 /*
87  * Cause Status flags. Note that those bits might be considered
88  * as interrupt enabled bits.
89  */
90 
91 /* Transaction ended with STOP. */
92 #define MLXBF_I2C_CAUSE_TRANSACTION_ENDED  BIT(0)
93 /* Master arbitration lost. */
94 #define MLXBF_I2C_CAUSE_M_ARBITRATION_LOST BIT(1)
95 /* Unexpected start detected. */
96 #define MLXBF_I2C_CAUSE_UNEXPECTED_START   BIT(2)
97 /* Unexpected stop detected. */
98 #define MLXBF_I2C_CAUSE_UNEXPECTED_STOP    BIT(3)
99 /* Wait for transfer continuation. */
100 #define MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA   BIT(4)
101 /* Failed to generate STOP. */
102 #define MLXBF_I2C_CAUSE_PUT_STOP_FAILED    BIT(5)
103 /* Failed to generate START. */
104 #define MLXBF_I2C_CAUSE_PUT_START_FAILED   BIT(6)
105 /* Clock toggle completed. */
106 #define MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE    BIT(7)
107 /* Transfer timeout occurred. */
108 #define MLXBF_I2C_CAUSE_M_FW_TIMEOUT       BIT(8)
109 /* Master busy bit reset. */
110 #define MLXBF_I2C_CAUSE_M_GW_BUSY_FALL     BIT(9)
111 
112 #define MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK     GENMASK(9, 0)
113 
114 #define MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR \
115 	(MLXBF_I2C_CAUSE_M_ARBITRATION_LOST | \
116 	 MLXBF_I2C_CAUSE_UNEXPECTED_START | \
117 	 MLXBF_I2C_CAUSE_UNEXPECTED_STOP | \
118 	 MLXBF_I2C_CAUSE_PUT_STOP_FAILED | \
119 	 MLXBF_I2C_CAUSE_PUT_START_FAILED | \
120 	 MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE | \
121 	 MLXBF_I2C_CAUSE_M_FW_TIMEOUT)
122 
123 /*
124  * Slave cause status flags. Note that those bits might be considered
125  * as interrupt enabled bits.
126  */
127 
128 /* Write transaction received successfully. */
129 #define MLXBF_I2C_CAUSE_WRITE_SUCCESS         BIT(0)
130 /* Read transaction received, waiting for response. */
131 #define MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE BIT(13)
132 /* Slave busy bit reset. */
133 #define MLXBF_I2C_CAUSE_S_GW_BUSY_FALL        BIT(18)
134 
135 /* Cause coalesce registers. */
136 #define MLXBF_I2C_CAUSE_COALESCE_0        0x00
137 
138 #define MLXBF_I2C_CAUSE_TYU_SLAVE_BIT   3
139 #define MLXBF_I2C_CAUSE_YU_SLAVE_BIT    1
140 
141 /* Functional enable register. */
142 #define MLXBF_I2C_GPIO_0_FUNC_EN_0    0x28
143 /* Force OE enable register. */
144 #define MLXBF_I2C_GPIO_0_FORCE_OE_EN  0x30
145 /*
146  * Note that Smbus GWs are on GPIOs 30:25. Two pins are used to control
147  * SDA/SCL lines:
148  *
149  *  SMBUS GW0 -> bits[26:25]
150  *  SMBUS GW1 -> bits[28:27]
151  *  SMBUS GW2 -> bits[30:29]
152  */
153 #define MLXBF_I2C_GPIO_SMBUS_GW_PINS(num) (25 + ((num) << 1))
154 
155 /* Note that gw_id can be 0,1 or 2. */
156 #define MLXBF_I2C_GPIO_SMBUS_GW_MASK(num) \
157 	(0xffffffff & (~(0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num))))
158 
159 #define MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(num, val) \
160 	((val) & MLXBF_I2C_GPIO_SMBUS_GW_MASK(num))
161 
162 #define MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(num, val) \
163 	((val) | (0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num)))
164 
165 /*
166  * Defines SMBus operating frequency and core clock frequency.
167  * According to ADB files, default values are compliant to 100KHz SMBus
168  * @ 400MHz core clock. The driver should be able to calculate core
169  * frequency based on PLL parameters.
170  */
171 #define MLXBF_I2C_COREPLL_FREQ          MLXBF_I2C_TYU_PLL_OUT_FREQ
172 
173 /* Core PLL TYU configuration. */
174 #define MLXBF_I2C_COREPLL_CORE_F_TYU_MASK   GENMASK(15, 3)
175 #define MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK  GENMASK(19, 16)
176 #define MLXBF_I2C_COREPLL_CORE_R_TYU_MASK   GENMASK(25, 20)
177 
178 /* Core PLL YU configuration. */
179 #define MLXBF_I2C_COREPLL_CORE_F_YU_MASK    GENMASK(25, 0)
180 #define MLXBF_I2C_COREPLL_CORE_OD_YU_MASK   GENMASK(3, 0)
181 #define MLXBF_I2C_COREPLL_CORE_R_YU_MASK    GENMASK(31, 26)
182 
183 /* SMBus timing parameters. */
184 #define MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH    0x00
185 #define MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE     0x04
186 #define MLXBF_I2C_SMBUS_TIMER_THOLD               0x08
187 #define MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP   0x0c
188 #define MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA         0x10
189 #define MLXBF_I2C_SMBUS_THIGH_MAX_TBUF            0x14
190 #define MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT           0x18
191 
192 #define MLXBF_I2C_SHIFT_0   0
193 #define MLXBF_I2C_SHIFT_8   8
194 #define MLXBF_I2C_SHIFT_16  16
195 #define MLXBF_I2C_SHIFT_24  24
196 
197 #define MLXBF_I2C_MASK_8    GENMASK(7, 0)
198 #define MLXBF_I2C_MASK_16   GENMASK(15, 0)
199 
200 #define MLXBF_I2C_MST_ADDR_OFFSET         0x200
201 
202 /* SMBus Master GW. */
203 #define MLXBF_I2C_SMBUS_MASTER_GW         0x0
204 /* Number of bytes received and sent. */
205 #define MLXBF_I2C_YU_SMBUS_RS_BYTES       0x100
206 #define MLXBF_I2C_RSH_YU_SMBUS_RS_BYTES   0x10c
207 /* Packet error check (PEC) value. */
208 #define MLXBF_I2C_SMBUS_MASTER_PEC        0x104
209 /* Status bits (ACK/NACK/FW Timeout). */
210 #define MLXBF_I2C_SMBUS_MASTER_STATUS     0x108
211 /* SMbus Master Finite State Machine. */
212 #define MLXBF_I2C_YU_SMBUS_MASTER_FSM     0x110
213 #define MLXBF_I2C_RSH_YU_SMBUS_MASTER_FSM 0x100
214 
215 /* SMBus master GW control bits offset in MLXBF_I2C_SMBUS_MASTER_GW[31:3]. */
216 #define MLXBF_I2C_MASTER_LOCK_BIT         BIT(31) /* Lock bit. */
217 #define MLXBF_I2C_MASTER_BUSY_BIT         BIT(30) /* Busy bit. */
218 #define MLXBF_I2C_MASTER_START_BIT        BIT(29) /* Control start. */
219 #define MLXBF_I2C_MASTER_CTL_WRITE_BIT    BIT(28) /* Control write phase. */
220 #define MLXBF_I2C_MASTER_CTL_READ_BIT     BIT(19) /* Control read phase. */
221 #define MLXBF_I2C_MASTER_STOP_BIT         BIT(3)  /* Control stop. */
222 
223 #define MLXBF_I2C_MASTER_ENABLE \
224 	(MLXBF_I2C_MASTER_LOCK_BIT | MLXBF_I2C_MASTER_BUSY_BIT | \
225 	 MLXBF_I2C_MASTER_START_BIT | MLXBF_I2C_MASTER_STOP_BIT)
226 
227 #define MLXBF_I2C_MASTER_ENABLE_WRITE \
228 	(MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_WRITE_BIT)
229 
230 #define MLXBF_I2C_MASTER_ENABLE_READ \
231 	(MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_READ_BIT)
232 
233 #define MLXBF_I2C_MASTER_WRITE_SHIFT      21 /* Control write bytes */
234 #define MLXBF_I2C_MASTER_SEND_PEC_SHIFT   20 /* Send PEC byte when set to 1 */
235 #define MLXBF_I2C_MASTER_PARSE_EXP_SHIFT  11 /* Control parse expected bytes */
236 #define MLXBF_I2C_MASTER_SLV_ADDR_SHIFT   12 /* Slave address */
237 #define MLXBF_I2C_MASTER_READ_SHIFT       4  /* Control read bytes */
238 
239 /* SMBus master GW Data descriptor. */
240 #define MLXBF_I2C_MASTER_DATA_DESC_ADDR   0x80
241 #define MLXBF_I2C_MASTER_DATA_DESC_SIZE   0x80 /* Size in bytes. */
242 
243 /* Maximum bytes to read/write per SMBus transaction. */
244 #define MLXBF_I2C_MASTER_DATA_R_LENGTH  MLXBF_I2C_MASTER_DATA_DESC_SIZE
245 #define MLXBF_I2C_MASTER_DATA_W_LENGTH (MLXBF_I2C_MASTER_DATA_DESC_SIZE - 1)
246 
247 /* All bytes were transmitted. */
248 #define MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE      BIT(0)
249 /* NACK received. */
250 #define MLXBF_I2C_SMBUS_STATUS_NACK_RCV           BIT(1)
251 /* Slave's byte count >128 bytes. */
252 #define MLXBF_I2C_SMBUS_STATUS_READ_ERR           BIT(2)
253 /* Timeout occurred. */
254 #define MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT         BIT(3)
255 
256 #define MLXBF_I2C_SMBUS_MASTER_STATUS_MASK        GENMASK(3, 0)
257 
258 #define MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR \
259 	(MLXBF_I2C_SMBUS_STATUS_NACK_RCV | \
260 	 MLXBF_I2C_SMBUS_STATUS_READ_ERR | \
261 	 MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT)
262 
263 #define MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK      BIT(31)
264 #define MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK  BIT(15)
265 
266 #define MLXBF_I2C_SLV_ADDR_OFFSET             0x400
267 
268 /* SMBus slave GW. */
269 #define MLXBF_I2C_SMBUS_SLAVE_GW              0x0
270 /* Number of bytes received and sent from/to master. */
271 #define MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES 0x100
272 /* Packet error check (PEC) value. */
273 #define MLXBF_I2C_SMBUS_SLAVE_PEC             0x104
274 /* SMBus slave Finite State Machine (FSM). */
275 #define MLXBF_I2C_SMBUS_SLAVE_FSM             0x110
276 /*
277  * Should be set when all raised causes handled, and cleared by HW on
278  * every new cause.
279  */
280 #define MLXBF_I2C_SMBUS_SLAVE_READY           0x12c
281 
282 /* SMBus slave GW control bits offset in MLXBF_I2C_SMBUS_SLAVE_GW[31:19]. */
283 #define MLXBF_I2C_SLAVE_BUSY_BIT         BIT(30) /* Busy bit. */
284 #define MLXBF_I2C_SLAVE_WRITE_BIT        BIT(29) /* Control write enable. */
285 
286 #define MLXBF_I2C_SLAVE_ENABLE \
287 	(MLXBF_I2C_SLAVE_BUSY_BIT | MLXBF_I2C_SLAVE_WRITE_BIT)
288 
289 #define MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT 22 /* Number of bytes to write. */
290 #define MLXBF_I2C_SLAVE_SEND_PEC_SHIFT    21 /* Send PEC byte shift. */
291 
292 /* SMBus slave GW Data descriptor. */
293 #define MLXBF_I2C_SLAVE_DATA_DESC_ADDR   0x80
294 #define MLXBF_I2C_SLAVE_DATA_DESC_SIZE   0x80 /* Size in bytes. */
295 
296 /* SMbus slave configuration registers. */
297 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG        0x114
298 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT        16
299 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT     BIT(7)
300 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK       GENMASK(6, 0)
301 
302 /*
303  * Timeout is given in microsends. Note also that timeout handling is not
304  * exact.
305  */
306 #define MLXBF_I2C_SMBUS_TIMEOUT   (300 * 1000) /* 300ms */
307 #define MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT (300 * 1000) /* 300ms */
308 
309 /* Polling frequency in microseconds. */
310 #define MLXBF_I2C_POLL_FREQ_IN_USEC        200
311 
312 #define MLXBF_I2C_SMBUS_OP_CNT_1   1
313 #define MLXBF_I2C_SMBUS_OP_CNT_2   2
314 #define MLXBF_I2C_SMBUS_OP_CNT_3   3
315 #define MLXBF_I2C_SMBUS_MAX_OP_CNT MLXBF_I2C_SMBUS_OP_CNT_3
316 
317 /* Helper macro to define an I2C resource parameters. */
318 #define MLXBF_I2C_RES_PARAMS(addr, size, str) \
319 	{ \
320 		.start = (addr), \
321 		.end = (addr) + (size) - 1, \
322 		.name = (str) \
323 	}
324 
325 enum {
326 	MLXBF_I2C_TIMING_100KHZ = 100000,
327 	MLXBF_I2C_TIMING_400KHZ = 400000,
328 	MLXBF_I2C_TIMING_1000KHZ = 1000000,
329 };
330 
331 enum {
332 	MLXBF_I2C_F_READ = BIT(0),
333 	MLXBF_I2C_F_WRITE = BIT(1),
334 	MLXBF_I2C_F_NORESTART = BIT(3),
335 	MLXBF_I2C_F_SMBUS_OPERATION = BIT(4),
336 	MLXBF_I2C_F_SMBUS_BLOCK = BIT(5),
337 	MLXBF_I2C_F_SMBUS_PEC = BIT(6),
338 	MLXBF_I2C_F_SMBUS_PROCESS_CALL = BIT(7),
339 };
340 
341 /* Mellanox BlueField chip type. */
342 enum mlxbf_i2c_chip_type {
343 	MLXBF_I2C_CHIP_TYPE_1, /* Mellanox BlueField-1 chip. */
344 	MLXBF_I2C_CHIP_TYPE_2, /* Mellanox BlueField-2 chip. */
345 	MLXBF_I2C_CHIP_TYPE_3 /* Mellanox BlueField-3 chip. */
346 };
347 
348 /* List of chip resources that are being accessed by the driver. */
349 enum {
350 	MLXBF_I2C_SMBUS_RES,
351 	MLXBF_I2C_MST_CAUSE_RES,
352 	MLXBF_I2C_SLV_CAUSE_RES,
353 	MLXBF_I2C_COALESCE_RES,
354 	MLXBF_I2C_SMBUS_TIMER_RES,
355 	MLXBF_I2C_SMBUS_MST_RES,
356 	MLXBF_I2C_SMBUS_SLV_RES,
357 	MLXBF_I2C_COREPLL_RES,
358 	MLXBF_I2C_GPIO_RES,
359 	MLXBF_I2C_END_RES
360 };
361 
362 /* Encapsulates timing parameters. */
363 struct mlxbf_i2c_timings {
364 	u16 scl_high;		/* Clock high period. */
365 	u16 scl_low;		/* Clock low period. */
366 	u8 sda_rise;		/* Data rise time. */
367 	u8 sda_fall;		/* Data fall time. */
368 	u8 scl_rise;		/* Clock rise time. */
369 	u8 scl_fall;		/* Clock fall time. */
370 	u16 hold_start;		/* Hold time after (REPEATED) START. */
371 	u16 hold_data;		/* Data hold time. */
372 	u16 setup_start;	/* REPEATED START condition setup time. */
373 	u16 setup_stop;		/* STOP condition setup time. */
374 	u16 setup_data;		/* Data setup time. */
375 	u16 pad;		/* Padding. */
376 	u16 buf;		/* Bus free time between STOP and START. */
377 	u16 thigh_max;		/* Thigh max. */
378 	u32 timeout;		/* Detect clock low timeout. */
379 };
380 
381 struct mlxbf_i2c_smbus_operation {
382 	u32 flags;
383 	u32 length; /* Buffer length in bytes. */
384 	u8 *buffer;
385 };
386 
387 struct mlxbf_i2c_smbus_request {
388 	u8 slave;
389 	u8 operation_cnt;
390 	struct mlxbf_i2c_smbus_operation operation[MLXBF_I2C_SMBUS_MAX_OP_CNT];
391 };
392 
393 struct mlxbf_i2c_resource {
394 	void __iomem *io;
395 	struct resource *params;
396 	struct mutex *lock; /* Mutex to protect mlxbf_i2c_resource. */
397 	u8 type;
398 };
399 
400 struct mlxbf_i2c_chip_info {
401 	enum mlxbf_i2c_chip_type type;
402 	/* Chip shared resources that are being used by the I2C controller. */
403 	struct mlxbf_i2c_resource *shared_res[MLXBF_I2C_SHARED_RES_MAX];
404 
405 	/* Callback to calculate the core PLL frequency. */
406 	u64 (*calculate_freq)(struct mlxbf_i2c_resource *corepll_res);
407 
408 	/* Registers' address offset */
409 	u32 smbus_master_rs_bytes_off;
410 	u32 smbus_master_fsm_off;
411 };
412 
413 struct mlxbf_i2c_priv {
414 	const struct mlxbf_i2c_chip_info *chip;
415 	struct i2c_adapter adap;
416 	struct mlxbf_i2c_resource *smbus;
417 	struct mlxbf_i2c_resource *timer;
418 	struct mlxbf_i2c_resource *mst;
419 	struct mlxbf_i2c_resource *slv;
420 	struct mlxbf_i2c_resource *mst_cause;
421 	struct mlxbf_i2c_resource *slv_cause;
422 	struct mlxbf_i2c_resource *coalesce;
423 	u64 frequency; /* Core frequency in Hz. */
424 	int bus; /* Physical bus identifier. */
425 	int irq;
426 	struct i2c_client *slave[MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT];
427 	u32 resource_version;
428 };
429 
430 /* Core PLL frequency. */
431 static u64 mlxbf_i2c_corepll_frequency;
432 
433 static struct resource mlxbf_i2c_coalesce_tyu_params =
434 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COALESCE_TYU_ADDR,
435 				     MLXBF_I2C_COALESCE_TYU_SIZE,
436 				     "COALESCE_MEM");
437 static struct resource mlxbf_i2c_corepll_tyu_params =
438 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_TYU_ADDR,
439 				     MLXBF_I2C_COREPLL_TYU_SIZE,
440 				     "COREPLL_MEM");
441 static struct resource mlxbf_i2c_corepll_yu_params =
442 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_YU_ADDR,
443 				     MLXBF_I2C_COREPLL_YU_SIZE,
444 				     "COREPLL_MEM");
445 static struct resource mlxbf_i2c_corepll_rsh_yu_params =
446 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_RSH_YU_ADDR,
447 				     MLXBF_I2C_COREPLL_RSH_YU_SIZE,
448 				     "COREPLL_MEM");
449 static struct resource mlxbf_i2c_gpio_tyu_params =
450 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_GPIO_TYU_ADDR,
451 				     MLXBF_I2C_GPIO_TYU_SIZE,
452 				     "GPIO_MEM");
453 
454 static struct mutex mlxbf_i2c_coalesce_lock;
455 static struct mutex mlxbf_i2c_corepll_lock;
456 static struct mutex mlxbf_i2c_gpio_lock;
457 
458 static struct mlxbf_i2c_resource mlxbf_i2c_coalesce_res[] = {
459 	[MLXBF_I2C_CHIP_TYPE_1] = {
460 		.params = &mlxbf_i2c_coalesce_tyu_params,
461 		.lock = &mlxbf_i2c_coalesce_lock,
462 		.type = MLXBF_I2C_COALESCE_RES
463 	},
464 	{}
465 };
466 
467 static struct mlxbf_i2c_resource mlxbf_i2c_corepll_res[] = {
468 	[MLXBF_I2C_CHIP_TYPE_1] = {
469 		.params = &mlxbf_i2c_corepll_tyu_params,
470 		.lock = &mlxbf_i2c_corepll_lock,
471 		.type = MLXBF_I2C_COREPLL_RES
472 	},
473 	[MLXBF_I2C_CHIP_TYPE_2] = {
474 		.params = &mlxbf_i2c_corepll_yu_params,
475 		.lock = &mlxbf_i2c_corepll_lock,
476 		.type = MLXBF_I2C_COREPLL_RES,
477 	},
478 	[MLXBF_I2C_CHIP_TYPE_3] = {
479 		.params = &mlxbf_i2c_corepll_rsh_yu_params,
480 		.lock = &mlxbf_i2c_corepll_lock,
481 		.type = MLXBF_I2C_COREPLL_RES,
482 	}
483 };
484 
485 static struct mlxbf_i2c_resource mlxbf_i2c_gpio_res[] = {
486 	[MLXBF_I2C_CHIP_TYPE_1] = {
487 		.params = &mlxbf_i2c_gpio_tyu_params,
488 		.lock = &mlxbf_i2c_gpio_lock,
489 		.type = MLXBF_I2C_GPIO_RES
490 	},
491 	{}
492 };
493 
494 static u8 mlxbf_i2c_bus_count;
495 
496 static struct mutex mlxbf_i2c_bus_lock;
497 
498 /*
499  * Function to poll a set of bits at a specific address; it checks whether
500  * the bits are equal to zero when eq_zero is set to 'true', and not equal
501  * to zero when eq_zero is set to 'false'.
502  * Note that the timeout is given in microseconds.
503  */
mlxbf_i2c_poll(void __iomem * io,u32 addr,u32 mask,bool eq_zero,u32 timeout)504 static u32 mlxbf_i2c_poll(void __iomem *io, u32 addr, u32 mask,
505 			    bool eq_zero, u32  timeout)
506 {
507 	u32 bits;
508 
509 	timeout = (timeout / MLXBF_I2C_POLL_FREQ_IN_USEC) + 1;
510 
511 	do {
512 		bits = readl(io + addr) & mask;
513 		if (eq_zero ? bits == 0 : bits != 0)
514 			return eq_zero ? 1 : bits;
515 		udelay(MLXBF_I2C_POLL_FREQ_IN_USEC);
516 	} while (timeout-- != 0);
517 
518 	return 0;
519 }
520 
521 /*
522  * SW must make sure that the SMBus Master GW is idle before starting
523  * a transaction. Accordingly, this function polls the Master FSM stop
524  * bit; it returns false when the bit is asserted, true if not.
525  */
mlxbf_i2c_smbus_master_wait_for_idle(struct mlxbf_i2c_priv * priv)526 static bool mlxbf_i2c_smbus_master_wait_for_idle(struct mlxbf_i2c_priv *priv)
527 {
528 	u32 mask = MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK;
529 	u32 addr = priv->chip->smbus_master_fsm_off;
530 	u32 timeout = MLXBF_I2C_SMBUS_TIMEOUT;
531 
532 	if (mlxbf_i2c_poll(priv->mst->io, addr, mask, true, timeout))
533 		return true;
534 
535 	return false;
536 }
537 
538 /*
539  * wait for the lock to be released before acquiring it.
540  */
mlxbf_i2c_smbus_master_lock(struct mlxbf_i2c_priv * priv)541 static bool mlxbf_i2c_smbus_master_lock(struct mlxbf_i2c_priv *priv)
542 {
543 	if (mlxbf_i2c_poll(priv->mst->io, MLXBF_I2C_SMBUS_MASTER_GW,
544 			   MLXBF_I2C_MASTER_LOCK_BIT, true,
545 			   MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT))
546 		return true;
547 
548 	return false;
549 }
550 
mlxbf_i2c_smbus_master_unlock(struct mlxbf_i2c_priv * priv)551 static void mlxbf_i2c_smbus_master_unlock(struct mlxbf_i2c_priv *priv)
552 {
553 	/* Clear the gw to clear the lock */
554 	writel(0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
555 }
556 
mlxbf_i2c_smbus_transaction_success(u32 master_status,u32 cause_status)557 static bool mlxbf_i2c_smbus_transaction_success(u32 master_status,
558 						u32 cause_status)
559 {
560 	/*
561 	 * When transaction ended with STOP, all bytes were transmitted,
562 	 * and no NACK received, then the transaction ended successfully.
563 	 * On the other hand, when the GW is configured with the stop bit
564 	 * de-asserted then the SMBus expects the following GW configuration
565 	 * for transfer continuation.
566 	 */
567 	if ((cause_status & MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA) ||
568 	    ((cause_status & MLXBF_I2C_CAUSE_TRANSACTION_ENDED) &&
569 	     (master_status & MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE) &&
570 	     !(master_status & MLXBF_I2C_SMBUS_STATUS_NACK_RCV)))
571 		return true;
572 
573 	return false;
574 }
575 
576 /*
577  * Poll SMBus master status and return transaction status,
578  * i.e. whether succeeded or failed. I2C and SMBus fault codes
579  * are returned as negative numbers from most calls, with zero
580  * or some positive number indicating a non-fault return.
581  */
mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv * priv)582 static int mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv *priv)
583 {
584 	u32 master_status_bits;
585 	u32 cause_status_bits;
586 
587 	/*
588 	 * GW busy bit is raised by the driver and cleared by the HW
589 	 * when the transaction is completed. The busy bit is a good
590 	 * indicator of transaction status. So poll the busy bit, and
591 	 * then read the cause and master status bits to determine if
592 	 * errors occurred during the transaction.
593 	 */
594 	mlxbf_i2c_poll(priv->mst->io, MLXBF_I2C_SMBUS_MASTER_GW,
595 			 MLXBF_I2C_MASTER_BUSY_BIT, true,
596 			 MLXBF_I2C_SMBUS_TIMEOUT);
597 
598 	/* Read cause status bits. */
599 	cause_status_bits = readl(priv->mst_cause->io +
600 					MLXBF_I2C_CAUSE_ARBITER);
601 	cause_status_bits &= MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK;
602 
603 	/*
604 	 * Parse both Cause and Master GW bits, then return transaction status.
605 	 */
606 
607 	master_status_bits = readl(priv->mst->io +
608 					MLXBF_I2C_SMBUS_MASTER_STATUS);
609 	master_status_bits &= MLXBF_I2C_SMBUS_MASTER_STATUS_MASK;
610 
611 	if (mlxbf_i2c_smbus_transaction_success(master_status_bits,
612 						cause_status_bits))
613 		return 0;
614 
615 	/*
616 	 * In case of timeout on GW busy, the ISR will clear busy bit but
617 	 * transaction ended bits cause will not be set so the transaction
618 	 * fails. Then, we must check Master GW status bits.
619 	 */
620 	if ((master_status_bits & MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR) &&
621 	    (cause_status_bits & (MLXBF_I2C_CAUSE_TRANSACTION_ENDED |
622 				  MLXBF_I2C_CAUSE_M_GW_BUSY_FALL)))
623 		return -EIO;
624 
625 	if (cause_status_bits & MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR)
626 		return -EAGAIN;
627 
628 	return -ETIMEDOUT;
629 }
630 
mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv * priv,const u8 * data,u8 length,u32 addr,bool is_master)631 static void mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv *priv,
632 				       const u8 *data, u8 length, u32 addr,
633 				       bool is_master)
634 {
635 	u8 offset, aligned_length;
636 	u32 data32;
637 
638 	aligned_length = round_up(length, 4);
639 
640 	/*
641 	 * Copy data bytes from 4-byte aligned source buffer.
642 	 * Data copied to the Master GW Data Descriptor MUST be shifted
643 	 * left so the data starts at the MSB of the descriptor registers
644 	 * as required by the underlying hardware. Enable byte swapping
645 	 * when writing data bytes to the 32 * 32-bit HW Data registers
646 	 * a.k.a Master GW Data Descriptor.
647 	 */
648 	for (offset = 0; offset < aligned_length; offset += sizeof(u32)) {
649 		data32 = *((u32 *)(data + offset));
650 		if (is_master)
651 			iowrite32be(data32, priv->mst->io + addr + offset);
652 		else
653 			iowrite32be(data32, priv->slv->io + addr + offset);
654 	}
655 }
656 
mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv * priv,u8 * data,u8 length,u32 addr,bool is_master)657 static void mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv *priv,
658 				      u8 *data, u8 length, u32 addr,
659 				      bool is_master)
660 {
661 	u32 data32, mask;
662 	u8 byte, offset;
663 
664 	mask = sizeof(u32) - 1;
665 
666 	/*
667 	 * Data bytes in the Master GW Data Descriptor are shifted left
668 	 * so the data starts at the MSB of the descriptor registers as
669 	 * set by the underlying hardware. Enable byte swapping while
670 	 * reading data bytes from the 32 * 32-bit HW Data registers
671 	 * a.k.a Master GW Data Descriptor.
672 	 */
673 
674 	for (offset = 0; offset < (length & ~mask); offset += sizeof(u32)) {
675 		if (is_master)
676 			data32 = ioread32be(priv->mst->io + addr + offset);
677 		else
678 			data32 = ioread32be(priv->slv->io + addr + offset);
679 		*((u32 *)(data + offset)) = data32;
680 	}
681 
682 	if (!(length & mask))
683 		return;
684 
685 	if (is_master)
686 		data32 = ioread32be(priv->mst->io + addr + offset);
687 	else
688 		data32 = ioread32be(priv->slv->io + addr + offset);
689 
690 	for (byte = 0; byte < (length & mask); byte++) {
691 		data[offset + byte] = data32 & GENMASK(7, 0);
692 		data32 = ror32(data32, MLXBF_I2C_SHIFT_8);
693 	}
694 }
695 
mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv * priv,u8 slave,u8 len,u8 block_en,u8 pec_en,bool read)696 static int mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv *priv, u8 slave,
697 				  u8 len, u8 block_en, u8 pec_en, bool read)
698 {
699 	u32 command;
700 
701 	/* Set Master GW control word. */
702 	if (read) {
703 		command = MLXBF_I2C_MASTER_ENABLE_READ;
704 		command |= rol32(len, MLXBF_I2C_MASTER_READ_SHIFT);
705 	} else {
706 		command = MLXBF_I2C_MASTER_ENABLE_WRITE;
707 		command |= rol32(len, MLXBF_I2C_MASTER_WRITE_SHIFT);
708 	}
709 	command |= rol32(slave, MLXBF_I2C_MASTER_SLV_ADDR_SHIFT);
710 	command |= rol32(block_en, MLXBF_I2C_MASTER_PARSE_EXP_SHIFT);
711 	command |= rol32(pec_en, MLXBF_I2C_MASTER_SEND_PEC_SHIFT);
712 
713 	/* Clear status bits. */
714 	writel(0x0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_STATUS);
715 	/* Set the cause data. */
716 	writel(~0x0, priv->mst_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
717 	/* Zero PEC byte. */
718 	writel(0x0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_PEC);
719 	/* Zero byte count. */
720 	writel(0x0, priv->mst->io + priv->chip->smbus_master_rs_bytes_off);
721 
722 	/* GW activation. */
723 	writel(command, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
724 
725 	/*
726 	 * Poll master status and check status bits. An ACK is sent when
727 	 * completing writing data to the bus (Master 'byte_count_done' bit
728 	 * is set to 1).
729 	 */
730 	return mlxbf_i2c_smbus_check_status(priv);
731 }
732 
733 static int
mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv * priv,struct mlxbf_i2c_smbus_request * request)734 mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
735 				  struct mlxbf_i2c_smbus_request *request)
736 {
737 	u8 data_desc[MLXBF_I2C_MASTER_DATA_DESC_SIZE] = { 0 };
738 	u8 op_idx, data_idx, data_len, write_len, read_len;
739 	struct mlxbf_i2c_smbus_operation *operation;
740 	u8 read_en, write_en, block_en, pec_en;
741 	u8 slave, flags, addr;
742 	u8 *read_buf;
743 	int ret = 0;
744 
745 	if (request->operation_cnt > MLXBF_I2C_SMBUS_MAX_OP_CNT)
746 		return -EINVAL;
747 
748 	read_buf = NULL;
749 	data_idx = 0;
750 	read_en = 0;
751 	write_en = 0;
752 	write_len = 0;
753 	read_len = 0;
754 	block_en = 0;
755 	pec_en = 0;
756 	slave = request->slave & GENMASK(6, 0);
757 	addr = slave << 1;
758 
759 	/*
760 	 * Try to acquire the smbus gw lock before any reads of the GW register since
761 	 * a read sets the lock.
762 	 */
763 	if (WARN_ON(!mlxbf_i2c_smbus_master_lock(priv)))
764 		return -EBUSY;
765 
766 	/* Check whether the HW is idle */
767 	if (WARN_ON(!mlxbf_i2c_smbus_master_wait_for_idle(priv))) {
768 		ret = -EBUSY;
769 		goto out_unlock;
770 	}
771 
772 	/* Set first byte. */
773 	data_desc[data_idx++] = addr;
774 
775 	for (op_idx = 0; op_idx < request->operation_cnt; op_idx++) {
776 		operation = &request->operation[op_idx];
777 		flags = operation->flags;
778 
779 		/*
780 		 * Note that read and write operations might be handled by a
781 		 * single command. If the MLXBF_I2C_F_SMBUS_OPERATION is set
782 		 * then write command byte and set the optional SMBus specific
783 		 * bits such as block_en and pec_en. These bits MUST be
784 		 * submitted by the first operation only.
785 		 */
786 		if (op_idx == 0 && flags & MLXBF_I2C_F_SMBUS_OPERATION) {
787 			block_en = flags & MLXBF_I2C_F_SMBUS_BLOCK;
788 			pec_en = flags & MLXBF_I2C_F_SMBUS_PEC;
789 		}
790 
791 		if (flags & MLXBF_I2C_F_WRITE) {
792 			write_en = 1;
793 			write_len += operation->length;
794 			if (data_idx + operation->length >
795 					MLXBF_I2C_MASTER_DATA_DESC_SIZE) {
796 				ret = -ENOBUFS;
797 				goto out_unlock;
798 			}
799 			memcpy(data_desc + data_idx,
800 			       operation->buffer, operation->length);
801 			data_idx += operation->length;
802 		}
803 		/*
804 		 * We assume that read operations are performed only once per
805 		 * SMBus transaction. *TBD* protect this statement so it won't
806 		 * be executed twice? or return an error if we try to read more
807 		 * than once?
808 		 */
809 		if (flags & MLXBF_I2C_F_READ) {
810 			read_en = 1;
811 			/* Subtract 1 as required by HW. */
812 			read_len = operation->length - 1;
813 			read_buf = operation->buffer;
814 		}
815 	}
816 
817 	/* Set Master GW data descriptor. */
818 	data_len = write_len + 1; /* Add one byte of the slave address. */
819 	/*
820 	 * Note that data_len cannot be 0. Indeed, the slave address byte
821 	 * must be written to the data registers.
822 	 */
823 	mlxbf_i2c_smbus_write_data(priv, (const u8 *)data_desc, data_len,
824 				   MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
825 
826 	if (write_en) {
827 		ret = mlxbf_i2c_smbus_enable(priv, slave, write_len, block_en,
828 					 pec_en, 0);
829 		if (ret)
830 			goto out_unlock;
831 	}
832 
833 	if (read_en) {
834 		/* Write slave address to Master GW data descriptor. */
835 		mlxbf_i2c_smbus_write_data(priv, (const u8 *)&addr, 1,
836 					   MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
837 		ret = mlxbf_i2c_smbus_enable(priv, slave, read_len, block_en,
838 					 pec_en, 1);
839 		if (!ret) {
840 			/* Get Master GW data descriptor. */
841 			mlxbf_i2c_smbus_read_data(priv, data_desc, read_len + 1,
842 					     MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
843 
844 			/* Get data from Master GW data descriptor. */
845 			memcpy(read_buf, data_desc, read_len + 1);
846 		}
847 
848 		/*
849 		 * After a read operation the SMBus FSM ps (present state)
850 		 * needs to be 'manually' reset. This should be removed in
851 		 * next tag integration.
852 		 */
853 		writel(MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK,
854 			priv->mst->io + priv->chip->smbus_master_fsm_off);
855 	}
856 
857 out_unlock:
858 	mlxbf_i2c_smbus_master_unlock(priv);
859 
860 	return ret;
861 }
862 
863 /* I2C SMBus protocols. */
864 
865 static void
mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request * request,u8 read)866 mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request *request,
867 			      u8 read)
868 {
869 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1;
870 
871 	request->operation[0].length = 0;
872 	request->operation[0].flags = MLXBF_I2C_F_WRITE;
873 	request->operation[0].flags |= read ? MLXBF_I2C_F_READ : 0;
874 }
875 
mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request * request,u8 * data,bool read,bool pec_check)876 static void mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request *request,
877 				      u8 *data, bool read, bool pec_check)
878 {
879 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1;
880 
881 	request->operation[0].length = 1;
882 	request->operation[0].length += pec_check;
883 
884 	request->operation[0].flags = MLXBF_I2C_F_SMBUS_OPERATION;
885 	request->operation[0].flags |= read ?
886 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
887 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
888 
889 	request->operation[0].buffer = data;
890 }
891 
892 static void
mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool read,bool pec_check)893 mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request *request,
894 			       u8 *command, u8 *data, bool read, bool pec_check)
895 {
896 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
897 
898 	request->operation[0].length = 1;
899 	request->operation[0].flags =
900 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
901 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
902 	request->operation[0].buffer = command;
903 
904 	request->operation[1].length = 1;
905 	request->operation[1].length += pec_check;
906 	request->operation[1].flags = read ?
907 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
908 	request->operation[1].buffer = data;
909 }
910 
911 static void
mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool read,bool pec_check)912 mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request *request,
913 			       u8 *command, u8 *data, bool read, bool pec_check)
914 {
915 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
916 
917 	request->operation[0].length = 1;
918 	request->operation[0].flags =
919 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
920 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
921 	request->operation[0].buffer = command;
922 
923 	request->operation[1].length = 2;
924 	request->operation[1].length += pec_check;
925 	request->operation[1].flags = read ?
926 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
927 	request->operation[1].buffer = data;
928 }
929 
930 static void
mlxbf_i2c_smbus_i2c_block_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,u8 * data_len,bool read,bool pec_check)931 mlxbf_i2c_smbus_i2c_block_func(struct mlxbf_i2c_smbus_request *request,
932 			       u8 *command, u8 *data, u8 *data_len, bool read,
933 			       bool pec_check)
934 {
935 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
936 
937 	request->operation[0].length = 1;
938 	request->operation[0].flags =
939 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
940 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
941 	request->operation[0].buffer = command;
942 
943 	/*
944 	 * As specified in the standard, the max number of bytes to read/write
945 	 * per block operation is 32 bytes. In Golan code, the controller can
946 	 * read up to 128 bytes and write up to 127 bytes.
947 	 */
948 	request->operation[1].length =
949 	    (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
950 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
951 	request->operation[1].flags = read ?
952 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
953 	/*
954 	 * Skip the first data byte, which corresponds to the number of bytes
955 	 * to read/write.
956 	 */
957 	request->operation[1].buffer = data + 1;
958 
959 	*data_len = request->operation[1].length;
960 
961 	/* Set the number of byte to read. This will be used by userspace. */
962 	if (read)
963 		data[0] = *data_len;
964 }
965 
mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,u8 * data_len,bool read,bool pec_check)966 static void mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request *request,
967 				       u8 *command, u8 *data, u8 *data_len,
968 				       bool read, bool pec_check)
969 {
970 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
971 
972 	request->operation[0].length = 1;
973 	request->operation[0].flags =
974 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
975 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
976 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
977 	request->operation[0].buffer = command;
978 
979 	request->operation[1].length =
980 	    (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
981 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
982 	request->operation[1].flags = read ?
983 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
984 	request->operation[1].buffer = data + 1;
985 
986 	*data_len = request->operation[1].length;
987 
988 	/* Set the number of bytes to read. This will be used by userspace. */
989 	if (read)
990 		data[0] = *data_len;
991 }
992 
993 static void
mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool pec_check)994 mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request *request,
995 				  u8 *command, u8 *data, bool pec_check)
996 {
997 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3;
998 
999 	request->operation[0].length = 1;
1000 	request->operation[0].flags =
1001 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
1002 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
1003 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
1004 	request->operation[0].buffer = command;
1005 
1006 	request->operation[1].length = 2;
1007 	request->operation[1].flags = MLXBF_I2C_F_WRITE;
1008 	request->operation[1].buffer = data;
1009 
1010 	request->operation[2].length = 3;
1011 	request->operation[2].flags = MLXBF_I2C_F_READ;
1012 	request->operation[2].buffer = data;
1013 }
1014 
1015 static void
mlxbf_i2c_smbus_blk_process_call_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,u8 * data_len,bool pec_check)1016 mlxbf_i2c_smbus_blk_process_call_func(struct mlxbf_i2c_smbus_request *request,
1017 				      u8 *command, u8 *data, u8 *data_len,
1018 				      bool pec_check)
1019 {
1020 	u32 length;
1021 
1022 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3;
1023 
1024 	request->operation[0].length = 1;
1025 	request->operation[0].flags =
1026 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
1027 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
1028 	request->operation[0].flags |= (pec_check) ? MLXBF_I2C_F_SMBUS_PEC : 0;
1029 	request->operation[0].buffer = command;
1030 
1031 	length = (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
1032 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
1033 
1034 	request->operation[1].length = length - pec_check;
1035 	request->operation[1].flags = MLXBF_I2C_F_WRITE;
1036 	request->operation[1].buffer = data;
1037 
1038 	request->operation[2].length = length;
1039 	request->operation[2].flags = MLXBF_I2C_F_READ;
1040 	request->operation[2].buffer = data;
1041 
1042 	*data_len = length; /* including PEC byte. */
1043 }
1044 
1045 /* Initialization functions. */
1046 
mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv * priv,u8 type)1047 static bool mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv *priv, u8 type)
1048 {
1049 	return priv->chip->type == type;
1050 }
1051 
1052 static struct mlxbf_i2c_resource *
mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv * priv,u8 type)1053 mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv *priv, u8 type)
1054 {
1055 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1056 	struct mlxbf_i2c_resource *res;
1057 	u8 res_idx = 0;
1058 
1059 	for (res_idx = 0; res_idx < MLXBF_I2C_SHARED_RES_MAX; res_idx++) {
1060 		res = chip->shared_res[res_idx];
1061 		if (res && res->type == type)
1062 			return res;
1063 	}
1064 
1065 	return NULL;
1066 }
1067 
mlxbf_i2c_init_resource(struct platform_device * pdev,struct mlxbf_i2c_resource ** res,u8 type)1068 static int mlxbf_i2c_init_resource(struct platform_device *pdev,
1069 				   struct mlxbf_i2c_resource **res,
1070 				   u8 type)
1071 {
1072 	struct mlxbf_i2c_resource *tmp_res;
1073 	struct device *dev = &pdev->dev;
1074 
1075 	if (!res || *res || type >= MLXBF_I2C_END_RES)
1076 		return -EINVAL;
1077 
1078 	tmp_res = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource),
1079 			       GFP_KERNEL);
1080 	if (!tmp_res)
1081 		return -ENOMEM;
1082 
1083 	tmp_res->io = devm_platform_get_and_ioremap_resource(pdev, type, &tmp_res->params);
1084 	if (IS_ERR(tmp_res->io)) {
1085 		devm_kfree(dev, tmp_res);
1086 		return PTR_ERR(tmp_res->io);
1087 	}
1088 
1089 	tmp_res->type = type;
1090 
1091 	*res = tmp_res;
1092 
1093 	return 0;
1094 }
1095 
mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv * priv,u64 nanoseconds,bool minimum)1096 static u32 mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv *priv, u64 nanoseconds,
1097 			       bool minimum)
1098 {
1099 	u64 frequency;
1100 	u32 ticks;
1101 
1102 	/*
1103 	 * Compute ticks as follow:
1104 	 *
1105 	 *           Ticks
1106 	 * Time = --------- x 10^9    =>    Ticks = Time x Frequency x 10^-9
1107 	 *         Frequency
1108 	 */
1109 	frequency = priv->frequency;
1110 	ticks = (nanoseconds * frequency) / MLXBF_I2C_FREQUENCY_1GHZ;
1111 	/*
1112 	 * The number of ticks is rounded down and if minimum is equal to 1
1113 	 * then add one tick.
1114 	 */
1115 	if (minimum)
1116 		ticks++;
1117 
1118 	return ticks;
1119 }
1120 
mlxbf_i2c_set_timer(struct mlxbf_i2c_priv * priv,u64 nsec,bool opt,u32 mask,u8 shift)1121 static u32 mlxbf_i2c_set_timer(struct mlxbf_i2c_priv *priv, u64 nsec, bool opt,
1122 			       u32 mask, u8 shift)
1123 {
1124 	u32 val = (mlxbf_i2c_get_ticks(priv, nsec, opt) & mask) << shift;
1125 
1126 	return val;
1127 }
1128 
mlxbf_i2c_set_timings(struct mlxbf_i2c_priv * priv,const struct mlxbf_i2c_timings * timings)1129 static void mlxbf_i2c_set_timings(struct mlxbf_i2c_priv *priv,
1130 				  const struct mlxbf_i2c_timings *timings)
1131 {
1132 	u32 timer;
1133 
1134 	timer = mlxbf_i2c_set_timer(priv, timings->scl_high,
1135 				    false, MLXBF_I2C_MASK_16,
1136 				    MLXBF_I2C_SHIFT_0);
1137 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_low,
1138 				     false, MLXBF_I2C_MASK_16,
1139 				     MLXBF_I2C_SHIFT_16);
1140 	writel(timer, priv->timer->io +
1141 		MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH);
1142 
1143 	timer = mlxbf_i2c_set_timer(priv, timings->sda_rise, false,
1144 				    MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_0);
1145 	timer |= mlxbf_i2c_set_timer(priv, timings->sda_fall, false,
1146 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_8);
1147 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_rise, false,
1148 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_16);
1149 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_fall, false,
1150 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_24);
1151 	writel(timer, priv->timer->io +
1152 		MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE);
1153 
1154 	timer = mlxbf_i2c_set_timer(priv, timings->hold_start, true,
1155 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1156 	timer |= mlxbf_i2c_set_timer(priv, timings->hold_data, true,
1157 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1158 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_TIMER_THOLD);
1159 
1160 	timer = mlxbf_i2c_set_timer(priv, timings->setup_start, true,
1161 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1162 	timer |= mlxbf_i2c_set_timer(priv, timings->setup_stop, true,
1163 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1164 	writel(timer, priv->timer->io +
1165 		MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP);
1166 
1167 	timer = mlxbf_i2c_set_timer(priv, timings->setup_data, true,
1168 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1169 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA);
1170 
1171 	timer = mlxbf_i2c_set_timer(priv, timings->buf, false,
1172 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1173 	timer |= mlxbf_i2c_set_timer(priv, timings->thigh_max, false,
1174 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1175 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_THIGH_MAX_TBUF);
1176 
1177 	timer = timings->timeout;
1178 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT);
1179 }
1180 
1181 enum mlxbf_i2c_timings_config {
1182 	MLXBF_I2C_TIMING_CONFIG_100KHZ,
1183 	MLXBF_I2C_TIMING_CONFIG_400KHZ,
1184 	MLXBF_I2C_TIMING_CONFIG_1000KHZ,
1185 };
1186 
1187 /*
1188  * Note that the mlxbf_i2c_timings->timeout value is not related to the
1189  * bus frequency, it is impacted by the time it takes the driver to
1190  * complete data transmission before transaction abort.
1191  */
1192 static const struct mlxbf_i2c_timings mlxbf_i2c_timings[] = {
1193 	[MLXBF_I2C_TIMING_CONFIG_100KHZ] = {
1194 		.scl_high = 4810,
1195 		.scl_low = 5000,
1196 		.hold_start = 4000,
1197 		.setup_start = 4800,
1198 		.setup_stop = 4000,
1199 		.setup_data = 250,
1200 		.sda_rise = 50,
1201 		.sda_fall = 50,
1202 		.scl_rise = 50,
1203 		.scl_fall = 50,
1204 		.hold_data = 300,
1205 		.buf = 20000,
1206 		.thigh_max = 5000,
1207 		.timeout = 106500
1208 	},
1209 	[MLXBF_I2C_TIMING_CONFIG_400KHZ] = {
1210 		.scl_high = 1011,
1211 		.scl_low = 1300,
1212 		.hold_start = 600,
1213 		.setup_start = 700,
1214 		.setup_stop = 600,
1215 		.setup_data = 100,
1216 		.sda_rise = 50,
1217 		.sda_fall = 50,
1218 		.scl_rise = 50,
1219 		.scl_fall = 50,
1220 		.hold_data = 300,
1221 		.buf = 20000,
1222 		.thigh_max = 5000,
1223 		.timeout = 106500
1224 	},
1225 	[MLXBF_I2C_TIMING_CONFIG_1000KHZ] = {
1226 		.scl_high = 600,
1227 		.scl_low = 1300,
1228 		.hold_start = 600,
1229 		.setup_start = 600,
1230 		.setup_stop = 600,
1231 		.setup_data = 100,
1232 		.sda_rise = 50,
1233 		.sda_fall = 50,
1234 		.scl_rise = 50,
1235 		.scl_fall = 50,
1236 		.hold_data = 300,
1237 		.buf = 20000,
1238 		.thigh_max = 5000,
1239 		.timeout = 106500
1240 	}
1241 };
1242 
mlxbf_i2c_init_timings(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1243 static int mlxbf_i2c_init_timings(struct platform_device *pdev,
1244 				  struct mlxbf_i2c_priv *priv)
1245 {
1246 	enum mlxbf_i2c_timings_config config_idx;
1247 	struct device *dev = &pdev->dev;
1248 	u32 config_khz;
1249 
1250 	int ret;
1251 
1252 	ret = device_property_read_u32(dev, "clock-frequency", &config_khz);
1253 	if (ret < 0)
1254 		config_khz = I2C_MAX_STANDARD_MODE_FREQ;
1255 
1256 	switch (config_khz) {
1257 	default:
1258 		/* Default settings is 100 KHz. */
1259 		pr_warn("Illegal value %d: defaulting to 100 KHz\n",
1260 			config_khz);
1261 		fallthrough;
1262 	case I2C_MAX_STANDARD_MODE_FREQ:
1263 		config_idx = MLXBF_I2C_TIMING_CONFIG_100KHZ;
1264 		break;
1265 
1266 	case I2C_MAX_FAST_MODE_FREQ:
1267 		config_idx = MLXBF_I2C_TIMING_CONFIG_400KHZ;
1268 		break;
1269 
1270 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
1271 		config_idx = MLXBF_I2C_TIMING_CONFIG_1000KHZ;
1272 		break;
1273 	}
1274 
1275 	mlxbf_i2c_set_timings(priv, &mlxbf_i2c_timings[config_idx]);
1276 
1277 	return 0;
1278 }
1279 
mlxbf_i2c_get_gpio(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1280 static int mlxbf_i2c_get_gpio(struct platform_device *pdev,
1281 			      struct mlxbf_i2c_priv *priv)
1282 {
1283 	struct mlxbf_i2c_resource *gpio_res;
1284 	struct device *dev = &pdev->dev;
1285 	struct resource	*params;
1286 	resource_size_t size;
1287 
1288 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1289 	if (!gpio_res)
1290 		return -EPERM;
1291 
1292 	/*
1293 	 * The GPIO region in TYU space is shared among I2C busses.
1294 	 * This function MUST be serialized to avoid racing when
1295 	 * claiming the memory region and/or setting up the GPIO.
1296 	 */
1297 	lockdep_assert_held(gpio_res->lock);
1298 
1299 	/* Check whether the memory map exist. */
1300 	if (gpio_res->io)
1301 		return 0;
1302 
1303 	params = gpio_res->params;
1304 	size = resource_size(params);
1305 
1306 	if (!devm_request_mem_region(dev, params->start, size, params->name))
1307 		return -EFAULT;
1308 
1309 	gpio_res->io = devm_ioremap(dev, params->start, size);
1310 	if (!gpio_res->io) {
1311 		devm_release_mem_region(dev, params->start, size);
1312 		return -ENOMEM;
1313 	}
1314 
1315 	return 0;
1316 }
1317 
mlxbf_i2c_release_gpio(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1318 static int mlxbf_i2c_release_gpio(struct platform_device *pdev,
1319 				  struct mlxbf_i2c_priv *priv)
1320 {
1321 	struct mlxbf_i2c_resource *gpio_res;
1322 	struct device *dev = &pdev->dev;
1323 	struct resource	*params;
1324 
1325 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1326 	if (!gpio_res)
1327 		return 0;
1328 
1329 	mutex_lock(gpio_res->lock);
1330 
1331 	if (gpio_res->io) {
1332 		/* Release the GPIO resource. */
1333 		params = gpio_res->params;
1334 		devm_iounmap(dev, gpio_res->io);
1335 		devm_release_mem_region(dev, params->start,
1336 					resource_size(params));
1337 	}
1338 
1339 	mutex_unlock(gpio_res->lock);
1340 
1341 	return 0;
1342 }
1343 
mlxbf_i2c_get_corepll(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1344 static int mlxbf_i2c_get_corepll(struct platform_device *pdev,
1345 				 struct mlxbf_i2c_priv *priv)
1346 {
1347 	struct mlxbf_i2c_resource *corepll_res;
1348 	struct device *dev = &pdev->dev;
1349 	struct resource *params;
1350 	resource_size_t size;
1351 
1352 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1353 						    MLXBF_I2C_COREPLL_RES);
1354 	if (!corepll_res)
1355 		return -EPERM;
1356 
1357 	/*
1358 	 * The COREPLL region in TYU space is shared among I2C busses.
1359 	 * This function MUST be serialized to avoid racing when
1360 	 * claiming the memory region.
1361 	 */
1362 	lockdep_assert_held(corepll_res->lock);
1363 
1364 	/* Check whether the memory map exist. */
1365 	if (corepll_res->io)
1366 		return 0;
1367 
1368 	params = corepll_res->params;
1369 	size = resource_size(params);
1370 
1371 	if (!devm_request_mem_region(dev, params->start, size, params->name))
1372 		return -EFAULT;
1373 
1374 	corepll_res->io = devm_ioremap(dev, params->start, size);
1375 	if (!corepll_res->io) {
1376 		devm_release_mem_region(dev, params->start, size);
1377 		return -ENOMEM;
1378 	}
1379 
1380 	return 0;
1381 }
1382 
mlxbf_i2c_release_corepll(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1383 static int mlxbf_i2c_release_corepll(struct platform_device *pdev,
1384 				     struct mlxbf_i2c_priv *priv)
1385 {
1386 	struct mlxbf_i2c_resource *corepll_res;
1387 	struct device *dev = &pdev->dev;
1388 	struct resource *params;
1389 
1390 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1391 						    MLXBF_I2C_COREPLL_RES);
1392 
1393 	mutex_lock(corepll_res->lock);
1394 
1395 	if (corepll_res->io) {
1396 		/* Release the CorePLL resource. */
1397 		params = corepll_res->params;
1398 		devm_iounmap(dev, corepll_res->io);
1399 		devm_release_mem_region(dev, params->start,
1400 					resource_size(params));
1401 	}
1402 
1403 	mutex_unlock(corepll_res->lock);
1404 
1405 	return 0;
1406 }
1407 
mlxbf_i2c_init_master(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1408 static int mlxbf_i2c_init_master(struct platform_device *pdev,
1409 				 struct mlxbf_i2c_priv *priv)
1410 {
1411 	struct mlxbf_i2c_resource *gpio_res;
1412 	struct device *dev = &pdev->dev;
1413 	u32 config_reg;
1414 	int ret;
1415 
1416 	/* This configuration is only needed for BlueField 1. */
1417 	if (!mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1))
1418 		return 0;
1419 
1420 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1421 	if (!gpio_res)
1422 		return -EPERM;
1423 
1424 	/*
1425 	 * The GPIO region in TYU space is shared among I2C busses.
1426 	 * This function MUST be serialized to avoid racing when
1427 	 * claiming the memory region and/or setting up the GPIO.
1428 	 */
1429 
1430 	mutex_lock(gpio_res->lock);
1431 
1432 	ret = mlxbf_i2c_get_gpio(pdev, priv);
1433 	if (ret < 0) {
1434 		dev_err(dev, "Failed to get gpio resource");
1435 		mutex_unlock(gpio_res->lock);
1436 		return ret;
1437 	}
1438 
1439 	/*
1440 	 * TYU - Configuration for GPIO pins. Those pins must be asserted in
1441 	 * MLXBF_I2C_GPIO_0_FUNC_EN_0, i.e. GPIO 0 is controlled by HW, and must
1442 	 * be reset in MLXBF_I2C_GPIO_0_FORCE_OE_EN, i.e. GPIO_OE will be driven
1443 	 * instead of HW_OE.
1444 	 * For now, we do not reset the GPIO state when the driver is removed.
1445 	 * First, it is not necessary to disable the bus since we are using
1446 	 * the same busses. Then, some busses might be shared among Linux and
1447 	 * platform firmware; disabling the bus might compromise the system
1448 	 * functionality.
1449 	 */
1450 	config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0);
1451 	config_reg = MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(priv->bus,
1452 							 config_reg);
1453 	writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0);
1454 
1455 	config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN);
1456 	config_reg = MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(priv->bus,
1457 							config_reg);
1458 	writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN);
1459 
1460 	mutex_unlock(gpio_res->lock);
1461 
1462 	return 0;
1463 }
1464 
mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource * corepll_res)1465 static u64 mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource *corepll_res)
1466 {
1467 	u64 core_frequency;
1468 	u8 core_od, core_r;
1469 	u32 corepll_val;
1470 	u16 core_f;
1471 
1472 	corepll_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1);
1473 
1474 	/* Get Core PLL configuration bits. */
1475 	core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_TYU_MASK, corepll_val);
1476 	core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK, corepll_val);
1477 	core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_TYU_MASK, corepll_val);
1478 
1479 	/*
1480 	 * Compute PLL output frequency as follow:
1481 	 *
1482 	 *                                       CORE_F + 1
1483 	 * PLL_OUT_FREQ = PLL_IN_FREQ * ----------------------------
1484 	 *                              (CORE_R + 1) * (CORE_OD + 1)
1485 	 *
1486 	 * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency
1487 	 * and PadFrequency, respectively.
1488 	 */
1489 	core_frequency = MLXBF_I2C_PLL_IN_FREQ * (++core_f);
1490 	core_frequency /= (++core_r) * (++core_od);
1491 
1492 	return core_frequency;
1493 }
1494 
mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource * corepll_res)1495 static u64 mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource *corepll_res)
1496 {
1497 	u32 corepll_reg1_val, corepll_reg2_val;
1498 	u64 corepll_frequency;
1499 	u8 core_od, core_r;
1500 	u32 core_f;
1501 
1502 	corepll_reg1_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1);
1503 	corepll_reg2_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG2);
1504 
1505 	/* Get Core PLL configuration bits */
1506 	core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_YU_MASK, corepll_reg1_val);
1507 	core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_YU_MASK, corepll_reg1_val);
1508 	core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_YU_MASK, corepll_reg2_val);
1509 
1510 	/*
1511 	 * Compute PLL output frequency as follow:
1512 	 *
1513 	 *                                     CORE_F / 16384
1514 	 * PLL_OUT_FREQ = PLL_IN_FREQ * ----------------------------
1515 	 *                              (CORE_R + 1) * (CORE_OD + 1)
1516 	 *
1517 	 * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency
1518 	 * and PadFrequency, respectively.
1519 	 */
1520 	corepll_frequency = (MLXBF_I2C_PLL_IN_FREQ * core_f) / MLNXBF_I2C_COREPLL_CONST;
1521 	corepll_frequency /= (++core_r) * (++core_od);
1522 
1523 	return corepll_frequency;
1524 }
1525 
mlxbf_i2c_calculate_corepll_freq(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1526 static int mlxbf_i2c_calculate_corepll_freq(struct platform_device *pdev,
1527 					    struct mlxbf_i2c_priv *priv)
1528 {
1529 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1530 	struct mlxbf_i2c_resource *corepll_res;
1531 	struct device *dev = &pdev->dev;
1532 	u64 *freq = &priv->frequency;
1533 	int ret;
1534 
1535 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1536 						    MLXBF_I2C_COREPLL_RES);
1537 	if (!corepll_res)
1538 		return -EPERM;
1539 
1540 	/*
1541 	 * First, check whether the TYU core Clock frequency is set.
1542 	 * The TYU core frequency is the same for all I2C busses; when
1543 	 * the first device gets probed the frequency is determined and
1544 	 * stored into a globally visible variable. So, first of all,
1545 	 * check whether the frequency is already set. Here, we assume
1546 	 * that the frequency is expected to be greater than 0.
1547 	 */
1548 	mutex_lock(corepll_res->lock);
1549 	if (!mlxbf_i2c_corepll_frequency) {
1550 		if (!chip->calculate_freq) {
1551 			mutex_unlock(corepll_res->lock);
1552 			return -EPERM;
1553 		}
1554 
1555 		ret = mlxbf_i2c_get_corepll(pdev, priv);
1556 		if (ret < 0) {
1557 			dev_err(dev, "Failed to get corePLL resource");
1558 			mutex_unlock(corepll_res->lock);
1559 			return ret;
1560 		}
1561 
1562 		mlxbf_i2c_corepll_frequency = chip->calculate_freq(corepll_res);
1563 	}
1564 	mutex_unlock(corepll_res->lock);
1565 
1566 	*freq = mlxbf_i2c_corepll_frequency;
1567 
1568 	return 0;
1569 }
1570 
mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv * priv,struct i2c_client * slave)1571 static int mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv *priv,
1572 			      struct i2c_client *slave)
1573 {
1574 	u8 reg, reg_cnt, byte, addr_tmp;
1575 	u32 slave_reg, slave_reg_tmp;
1576 
1577 	if (!priv)
1578 		return -EPERM;
1579 
1580 	reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2;
1581 
1582 	/*
1583 	 * Read the slave registers. There are 4 * 32-bit slave registers.
1584 	 * Each slave register can hold up to 4 * 8-bit slave configuration:
1585 	 * 1) A 7-bit address
1586 	 * 2) And a status bit (1 if enabled, 0 if not).
1587 	 * Look for the next available slave register slot.
1588 	 */
1589 	for (reg = 0; reg < reg_cnt; reg++) {
1590 		slave_reg = readl(priv->slv->io +
1591 				MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4);
1592 		/*
1593 		 * Each register holds 4 slave addresses. So, we have to keep
1594 		 * the byte order consistent with the value read in order to
1595 		 * update the register correctly, if needed.
1596 		 */
1597 		slave_reg_tmp = slave_reg;
1598 		for (byte = 0; byte < 4; byte++) {
1599 			addr_tmp = slave_reg_tmp & GENMASK(7, 0);
1600 
1601 			/*
1602 			 * If an enable bit is not set in the
1603 			 * MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG register, then the
1604 			 * slave address slot associated with that bit is
1605 			 * free. So set the enable bit and write the
1606 			 * slave address bits.
1607 			 */
1608 			if (!(addr_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT)) {
1609 				slave_reg &= ~(MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK << (byte * 8));
1610 				slave_reg |= (slave->addr << (byte * 8));
1611 				slave_reg |= MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT << (byte * 8);
1612 				writel(slave_reg, priv->slv->io +
1613 					MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG +
1614 					(reg * 0x4));
1615 
1616 				/*
1617 				 * Set the slave at the corresponding index.
1618 				 */
1619 				priv->slave[(reg * 4) + byte] = slave;
1620 
1621 				return 0;
1622 			}
1623 
1624 			/* Parse next byte. */
1625 			slave_reg_tmp >>= 8;
1626 		}
1627 	}
1628 
1629 	return -EBUSY;
1630 }
1631 
mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv * priv,u8 addr)1632 static int mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv *priv, u8 addr)
1633 {
1634 	u8 addr_tmp, reg, reg_cnt, byte;
1635 	u32 slave_reg, slave_reg_tmp;
1636 
1637 	reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2;
1638 
1639 	/*
1640 	 * Read the slave registers. There are 4 * 32-bit slave registers.
1641 	 * Each slave register can hold up to 4 * 8-bit slave configuration:
1642 	 * 1) A 7-bit address
1643 	 * 2) And a status bit (1 if enabled, 0 if not).
1644 	 * Check if addr is present in the registers.
1645 	 */
1646 	for (reg = 0; reg < reg_cnt; reg++) {
1647 		slave_reg = readl(priv->slv->io +
1648 				MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4);
1649 
1650 		/* Check whether the address slots are empty. */
1651 		if (!slave_reg)
1652 			continue;
1653 
1654 		/*
1655 		 * Check if addr matches any of the 4 slave addresses
1656 		 * in the register.
1657 		 */
1658 		slave_reg_tmp = slave_reg;
1659 		for (byte = 0; byte < 4; byte++) {
1660 			addr_tmp = slave_reg_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK;
1661 			/*
1662 			 * Parse slave address bytes and check whether the
1663 			 * slave address already exists.
1664 			 */
1665 			if (addr_tmp == addr) {
1666 				/* Clear the slave address slot. */
1667 				slave_reg &= ~(GENMASK(7, 0) << (byte * 8));
1668 				writel(slave_reg, priv->slv->io +
1669 					MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG +
1670 					(reg * 0x4));
1671 				/* Free slave at the corresponding index */
1672 				priv->slave[(reg * 4) + byte] = NULL;
1673 
1674 				return 0;
1675 			}
1676 
1677 			/* Parse next byte. */
1678 			slave_reg_tmp >>= 8;
1679 		}
1680 	}
1681 
1682 	return -ENXIO;
1683 }
1684 
mlxbf_i2c_init_coalesce(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1685 static int mlxbf_i2c_init_coalesce(struct platform_device *pdev,
1686 				   struct mlxbf_i2c_priv *priv)
1687 {
1688 	struct mlxbf_i2c_resource *coalesce_res;
1689 	struct resource *params;
1690 	resource_size_t size;
1691 	int ret = 0;
1692 
1693 	/*
1694 	 * Unlike BlueField-1 platform, the coalesce registers is a dedicated
1695 	 * resource in the next generations of BlueField.
1696 	 */
1697 	if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) {
1698 		coalesce_res = mlxbf_i2c_get_shared_resource(priv,
1699 						MLXBF_I2C_COALESCE_RES);
1700 		if (!coalesce_res)
1701 			return -EPERM;
1702 
1703 		/*
1704 		 * The Cause Coalesce group in TYU space is shared among
1705 		 * I2C busses. This function MUST be serialized to avoid
1706 		 * racing when claiming the memory region.
1707 		 */
1708 		lockdep_assert_held(mlxbf_i2c_gpio_res->lock);
1709 
1710 		/* Check whether the memory map exist. */
1711 		if (coalesce_res->io) {
1712 			priv->coalesce = coalesce_res;
1713 			return 0;
1714 		}
1715 
1716 		params = coalesce_res->params;
1717 		size = resource_size(params);
1718 
1719 		if (!request_mem_region(params->start, size, params->name))
1720 			return -EFAULT;
1721 
1722 		coalesce_res->io = ioremap(params->start, size);
1723 		if (!coalesce_res->io) {
1724 			release_mem_region(params->start, size);
1725 			return -ENOMEM;
1726 		}
1727 
1728 		priv->coalesce = coalesce_res;
1729 
1730 	} else {
1731 		ret = mlxbf_i2c_init_resource(pdev, &priv->coalesce,
1732 					      MLXBF_I2C_COALESCE_RES);
1733 	}
1734 
1735 	return ret;
1736 }
1737 
mlxbf_i2c_release_coalesce(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1738 static int mlxbf_i2c_release_coalesce(struct platform_device *pdev,
1739 				      struct mlxbf_i2c_priv *priv)
1740 {
1741 	struct mlxbf_i2c_resource *coalesce_res;
1742 	struct device *dev = &pdev->dev;
1743 	struct resource *params;
1744 	resource_size_t size;
1745 
1746 	coalesce_res = priv->coalesce;
1747 
1748 	if (coalesce_res->io) {
1749 		params = coalesce_res->params;
1750 		size = resource_size(params);
1751 		if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) {
1752 			mutex_lock(coalesce_res->lock);
1753 			iounmap(coalesce_res->io);
1754 			release_mem_region(params->start, size);
1755 			mutex_unlock(coalesce_res->lock);
1756 		} else {
1757 			devm_release_mem_region(dev, params->start, size);
1758 		}
1759 	}
1760 
1761 	return 0;
1762 }
1763 
mlxbf_i2c_init_slave(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1764 static int mlxbf_i2c_init_slave(struct platform_device *pdev,
1765 				struct mlxbf_i2c_priv *priv)
1766 {
1767 	struct device *dev = &pdev->dev;
1768 	u32 int_reg;
1769 	int ret;
1770 
1771 	/* Reset FSM. */
1772 	writel(0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_FSM);
1773 
1774 	/*
1775 	 * Enable slave cause interrupt bits. Drive
1776 	 * MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE and
1777 	 * MLXBF_I2C_CAUSE_WRITE_SUCCESS, these are enabled when an external
1778 	 * masters issue a Read and Write, respectively. But, clear all
1779 	 * interrupts first.
1780 	 */
1781 	writel(~0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
1782 	int_reg = MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE;
1783 	int_reg |= MLXBF_I2C_CAUSE_WRITE_SUCCESS;
1784 	writel(int_reg, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_EVTEN0);
1785 
1786 	/* Finally, set the 'ready' bit to start handling transactions. */
1787 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1788 
1789 	/* Initialize the cause coalesce resource. */
1790 	ret = mlxbf_i2c_init_coalesce(pdev, priv);
1791 	if (ret < 0) {
1792 		dev_err(dev, "failed to initialize cause coalesce\n");
1793 		return ret;
1794 	}
1795 
1796 	return 0;
1797 }
1798 
mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv * priv,bool * read,bool * write)1799 static bool mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv *priv, bool *read,
1800 				   bool *write)
1801 {
1802 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1803 	u32 coalesce0_reg, cause_reg;
1804 	u8 slave_shift, is_set;
1805 
1806 	*write = false;
1807 	*read = false;
1808 
1809 	slave_shift = chip->type != MLXBF_I2C_CHIP_TYPE_1 ?
1810 				MLXBF_I2C_CAUSE_YU_SLAVE_BIT :
1811 				priv->bus + MLXBF_I2C_CAUSE_TYU_SLAVE_BIT;
1812 
1813 	coalesce0_reg = readl(priv->coalesce->io + MLXBF_I2C_CAUSE_COALESCE_0);
1814 	is_set = coalesce0_reg & (1 << slave_shift);
1815 
1816 	if (!is_set)
1817 		return false;
1818 
1819 	/* Check the source of the interrupt, i.e. whether a Read or Write. */
1820 	cause_reg = readl(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER);
1821 	if (cause_reg & MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE)
1822 		*read = true;
1823 	else if (cause_reg & MLXBF_I2C_CAUSE_WRITE_SUCCESS)
1824 		*write = true;
1825 
1826 	/* Clear cause bits. */
1827 	writel(~0x0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
1828 
1829 	return true;
1830 }
1831 
mlxbf_i2c_slave_wait_for_idle(struct mlxbf_i2c_priv * priv,u32 timeout)1832 static bool mlxbf_i2c_slave_wait_for_idle(struct mlxbf_i2c_priv *priv,
1833 					    u32 timeout)
1834 {
1835 	u32 mask = MLXBF_I2C_CAUSE_S_GW_BUSY_FALL;
1836 	u32 addr = MLXBF_I2C_CAUSE_ARBITER;
1837 
1838 	if (mlxbf_i2c_poll(priv->slv_cause->io, addr, mask, false, timeout))
1839 		return true;
1840 
1841 	return false;
1842 }
1843 
mlxbf_i2c_get_slave_from_addr(struct mlxbf_i2c_priv * priv,u8 addr)1844 static struct i2c_client *mlxbf_i2c_get_slave_from_addr(
1845 			struct mlxbf_i2c_priv *priv, u8 addr)
1846 {
1847 	int i;
1848 
1849 	for (i = 0; i < MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT; i++) {
1850 		if (!priv->slave[i])
1851 			continue;
1852 
1853 		if (priv->slave[i]->addr == addr)
1854 			return priv->slave[i];
1855 	}
1856 
1857 	return NULL;
1858 }
1859 
1860 /*
1861  * Send byte to 'external' smbus master. This function is executed when
1862  * an external smbus master wants to read data from the BlueField.
1863  */
mlxbf_i2c_irq_send(struct mlxbf_i2c_priv * priv,u8 recv_bytes)1864 static int mlxbf_i2c_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
1865 {
1866 	u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 };
1867 	u8 write_size, pec_en, addr, value, byte_cnt;
1868 	struct i2c_client *slave;
1869 	u32 control32, data32;
1870 	int ret = 0;
1871 
1872 	/*
1873 	 * Read the first byte received from the external master to
1874 	 * determine the slave address. This byte is located in the
1875 	 * first data descriptor register of the slave GW.
1876 	 */
1877 	data32 = ioread32be(priv->slv->io +
1878 				MLXBF_I2C_SLAVE_DATA_DESC_ADDR);
1879 	addr = (data32 & GENMASK(7, 0)) >> 1;
1880 
1881 	/*
1882 	 * Check if the slave address received in the data descriptor register
1883 	 * matches any of the slave addresses registered. If there is a match,
1884 	 * set the slave.
1885 	 */
1886 	slave = mlxbf_i2c_get_slave_from_addr(priv, addr);
1887 	if (!slave) {
1888 		ret = -ENXIO;
1889 		goto clear_csr;
1890 	}
1891 
1892 	/*
1893 	 * An I2C read can consist of a WRITE bit transaction followed by
1894 	 * a READ bit transaction. Indeed, slave devices often expect
1895 	 * the slave address to be followed by the internal address.
1896 	 * So, write the internal address byte first, and then, send the
1897 	 * requested data to the master.
1898 	 */
1899 	if (recv_bytes > 1) {
1900 		i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
1901 		value = (data32 >> 8) & GENMASK(7, 0);
1902 		ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
1903 				      &value);
1904 		i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1905 
1906 		if (ret < 0)
1907 			goto clear_csr;
1908 	}
1909 
1910 	/*
1911 	 * Send data to the master. Currently, the driver supports
1912 	 * READ_BYTE, READ_WORD and BLOCK READ protocols. The
1913 	 * hardware can send up to 128 bytes per transfer which is
1914 	 * the total size of the data registers.
1915 	 */
1916 	i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
1917 
1918 	for (byte_cnt = 0; byte_cnt < MLXBF_I2C_SLAVE_DATA_DESC_SIZE; byte_cnt++) {
1919 		data_desc[byte_cnt] = value;
1920 		i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
1921 	}
1922 
1923 	/* Send a stop condition to the backend. */
1924 	i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1925 
1926 	/* Set the number of bytes to write to master. */
1927 	write_size = (byte_cnt - 1) & 0x7f;
1928 
1929 	/* Write data to Slave GW data descriptor. */
1930 	mlxbf_i2c_smbus_write_data(priv, data_desc, byte_cnt,
1931 				   MLXBF_I2C_SLAVE_DATA_DESC_ADDR, false);
1932 
1933 	pec_en = 0; /* Disable PEC since it is not supported. */
1934 
1935 	/* Prepare control word. */
1936 	control32 = MLXBF_I2C_SLAVE_ENABLE;
1937 	control32 |= rol32(write_size, MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT);
1938 	control32 |= rol32(pec_en, MLXBF_I2C_SLAVE_SEND_PEC_SHIFT);
1939 
1940 	writel(control32, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_GW);
1941 
1942 	/*
1943 	 * Wait until the transfer is completed; the driver will wait
1944 	 * until the GW is idle, a cause will rise on fall of GW busy.
1945 	 */
1946 	mlxbf_i2c_slave_wait_for_idle(priv, MLXBF_I2C_SMBUS_TIMEOUT);
1947 
1948 clear_csr:
1949 	/* Release the Slave GW. */
1950 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
1951 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_PEC);
1952 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1953 
1954 	return ret;
1955 }
1956 
1957 /*
1958  * Receive bytes from 'external' smbus master. This function is executed when
1959  * an external smbus master wants to write data to the BlueField.
1960  */
mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv * priv,u8 recv_bytes)1961 static int mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
1962 {
1963 	u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 };
1964 	struct i2c_client *slave;
1965 	u8 value, byte, addr;
1966 	int ret = 0;
1967 
1968 	/* Read data from Slave GW data descriptor. */
1969 	mlxbf_i2c_smbus_read_data(priv, data_desc, recv_bytes,
1970 				  MLXBF_I2C_SLAVE_DATA_DESC_ADDR, false);
1971 	addr = data_desc[0] >> 1;
1972 
1973 	/*
1974 	 * Check if the slave address received in the data descriptor register
1975 	 * matches any of the slave addresses registered.
1976 	 */
1977 	slave = mlxbf_i2c_get_slave_from_addr(priv, addr);
1978 	if (!slave) {
1979 		ret = -EINVAL;
1980 		goto clear_csr;
1981 	}
1982 
1983 	/*
1984 	 * Notify the slave backend that an smbus master wants to write data
1985 	 * to the BlueField.
1986 	 */
1987 	i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
1988 
1989 	/* Send the received data to the slave backend. */
1990 	for (byte = 1; byte < recv_bytes; byte++) {
1991 		value = data_desc[byte];
1992 		ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
1993 				      &value);
1994 		if (ret < 0)
1995 			break;
1996 	}
1997 
1998 	/*
1999 	 * Send a stop event to the slave backend, to signal
2000 	 * the end of the write transactions.
2001 	 */
2002 	i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
2003 
2004 clear_csr:
2005 	/* Release the Slave GW. */
2006 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
2007 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_PEC);
2008 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
2009 
2010 	return ret;
2011 }
2012 
mlxbf_i2c_irq(int irq,void * ptr)2013 static irqreturn_t mlxbf_i2c_irq(int irq, void *ptr)
2014 {
2015 	struct mlxbf_i2c_priv *priv = ptr;
2016 	bool read, write, irq_is_set;
2017 	u32 rw_bytes_reg;
2018 	u8 recv_bytes;
2019 
2020 	/*
2021 	 * Read TYU interrupt register and determine the source of the
2022 	 * interrupt. Based on the source of the interrupt one of the
2023 	 * following actions are performed:
2024 	 *  - Receive data and send response to master.
2025 	 *  - Send data and release slave GW.
2026 	 *
2027 	 * Handle read/write transaction only. CRmaster and Iarp requests
2028 	 * are ignored for now.
2029 	 */
2030 	irq_is_set = mlxbf_i2c_has_coalesce(priv, &read, &write);
2031 	if (!irq_is_set || (!read && !write)) {
2032 		/* Nothing to do here, interrupt was not from this device. */
2033 		return IRQ_NONE;
2034 	}
2035 
2036 	/*
2037 	 * The MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES includes the number of
2038 	 * bytes from/to master. These are defined by 8-bits each. If the lower
2039 	 * 8 bits are set, then the master expect to read N bytes from the
2040 	 * slave, if the higher 8 bits are sent then the slave expect N bytes
2041 	 * from the master.
2042 	 */
2043 	rw_bytes_reg = readl(priv->slv->io +
2044 				MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
2045 	recv_bytes = (rw_bytes_reg >> 8) & GENMASK(7, 0);
2046 
2047 	/*
2048 	 * For now, the slave supports 128 bytes transfer. Discard remaining
2049 	 * data bytes if the master wrote more than
2050 	 * MLXBF_I2C_SLAVE_DATA_DESC_SIZE, i.e, the actual size of the slave
2051 	 * data descriptor.
2052 	 *
2053 	 * Note that we will never expect to transfer more than 128 bytes; as
2054 	 * specified in the SMBus standard, block transactions cannot exceed
2055 	 * 32 bytes.
2056 	 */
2057 	recv_bytes = recv_bytes > MLXBF_I2C_SLAVE_DATA_DESC_SIZE ?
2058 		MLXBF_I2C_SLAVE_DATA_DESC_SIZE : recv_bytes;
2059 
2060 	if (read)
2061 		mlxbf_i2c_irq_send(priv, recv_bytes);
2062 	else
2063 		mlxbf_i2c_irq_recv(priv, recv_bytes);
2064 
2065 	return IRQ_HANDLED;
2066 }
2067 
2068 /* Return negative errno on error. */
mlxbf_i2c_smbus_xfer(struct i2c_adapter * adap,u16 addr,unsigned short flags,char read_write,u8 command,int size,union i2c_smbus_data * data)2069 static s32 mlxbf_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
2070 				unsigned short flags, char read_write,
2071 				u8 command, int size,
2072 				union i2c_smbus_data *data)
2073 {
2074 	struct mlxbf_i2c_smbus_request request = { 0 };
2075 	struct mlxbf_i2c_priv *priv;
2076 	bool read, pec;
2077 	u8 byte_cnt;
2078 
2079 	request.slave = addr;
2080 
2081 	read = (read_write == I2C_SMBUS_READ);
2082 	pec = flags & I2C_FUNC_SMBUS_PEC;
2083 
2084 	switch (size) {
2085 	case I2C_SMBUS_QUICK:
2086 		mlxbf_i2c_smbus_quick_command(&request, read);
2087 		dev_dbg(&adap->dev, "smbus quick, slave 0x%02x\n", addr);
2088 		break;
2089 
2090 	case I2C_SMBUS_BYTE:
2091 		mlxbf_i2c_smbus_byte_func(&request,
2092 					  read ? &data->byte : &command, read,
2093 					  pec);
2094 		dev_dbg(&adap->dev, "smbus %s byte, slave 0x%02x.\n",
2095 			read ? "read" : "write", addr);
2096 		break;
2097 
2098 	case I2C_SMBUS_BYTE_DATA:
2099 		mlxbf_i2c_smbus_data_byte_func(&request, &command, &data->byte,
2100 					       read, pec);
2101 		dev_dbg(&adap->dev, "smbus %s byte data at 0x%02x, slave 0x%02x.\n",
2102 			read ? "read" : "write", command, addr);
2103 		break;
2104 
2105 	case I2C_SMBUS_WORD_DATA:
2106 		mlxbf_i2c_smbus_data_word_func(&request, &command,
2107 					       (u8 *)&data->word, read, pec);
2108 		dev_dbg(&adap->dev, "smbus %s word data at 0x%02x, slave 0x%02x.\n",
2109 			read ? "read" : "write", command, addr);
2110 		break;
2111 
2112 	case I2C_SMBUS_I2C_BLOCK_DATA:
2113 		byte_cnt = data->block[0];
2114 		mlxbf_i2c_smbus_i2c_block_func(&request, &command, data->block,
2115 					       &byte_cnt, read, pec);
2116 		dev_dbg(&adap->dev, "i2c %s block data, %d bytes at 0x%02x, slave 0x%02x.\n",
2117 			read ? "read" : "write", byte_cnt, command, addr);
2118 		break;
2119 
2120 	case I2C_SMBUS_BLOCK_DATA:
2121 		byte_cnt = read ? I2C_SMBUS_BLOCK_MAX : data->block[0];
2122 		mlxbf_i2c_smbus_block_func(&request, &command, data->block,
2123 					   &byte_cnt, read, pec);
2124 		dev_dbg(&adap->dev, "smbus %s block data, %d bytes at 0x%02x, slave 0x%02x.\n",
2125 			read ? "read" : "write", byte_cnt, command, addr);
2126 		break;
2127 
2128 	case I2C_FUNC_SMBUS_PROC_CALL:
2129 		mlxbf_i2c_smbus_process_call_func(&request, &command,
2130 						  (u8 *)&data->word, pec);
2131 		dev_dbg(&adap->dev, "process call, wr/rd at 0x%02x, slave 0x%02x.\n",
2132 			command, addr);
2133 		break;
2134 
2135 	case I2C_FUNC_SMBUS_BLOCK_PROC_CALL:
2136 		byte_cnt = data->block[0];
2137 		mlxbf_i2c_smbus_blk_process_call_func(&request, &command,
2138 						      data->block, &byte_cnt,
2139 						      pec);
2140 		dev_dbg(&adap->dev, "block process call, wr/rd %d bytes, slave 0x%02x.\n",
2141 			byte_cnt, addr);
2142 		break;
2143 
2144 	default:
2145 		dev_dbg(&adap->dev, "Unsupported I2C/SMBus command %d\n",
2146 			size);
2147 		return -EOPNOTSUPP;
2148 	}
2149 
2150 	priv = i2c_get_adapdata(adap);
2151 
2152 	return mlxbf_i2c_smbus_start_transaction(priv, &request);
2153 }
2154 
mlxbf_i2c_reg_slave(struct i2c_client * slave)2155 static int mlxbf_i2c_reg_slave(struct i2c_client *slave)
2156 {
2157 	struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
2158 	struct device *dev = &slave->dev;
2159 	int ret;
2160 
2161 	/*
2162 	 * Do not support ten bit chip address and do not use Packet Error
2163 	 * Checking (PEC).
2164 	 */
2165 	if (slave->flags & (I2C_CLIENT_TEN | I2C_CLIENT_PEC)) {
2166 		dev_err(dev, "SMBus PEC and 10 bit address not supported\n");
2167 		return -EAFNOSUPPORT;
2168 	}
2169 
2170 	ret = mlxbf_i2c_slave_enable(priv, slave);
2171 	if (ret)
2172 		dev_err(dev, "Surpassed max number of registered slaves allowed\n");
2173 
2174 	return 0;
2175 }
2176 
mlxbf_i2c_unreg_slave(struct i2c_client * slave)2177 static int mlxbf_i2c_unreg_slave(struct i2c_client *slave)
2178 {
2179 	struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
2180 	struct device *dev = &slave->dev;
2181 	int ret;
2182 
2183 	/*
2184 	 * Unregister slave by:
2185 	 * 1) Disabling the slave address in hardware
2186 	 * 2) Freeing priv->slave at the corresponding index
2187 	 */
2188 	ret = mlxbf_i2c_slave_disable(priv, slave->addr);
2189 	if (ret)
2190 		dev_err(dev, "Unable to find slave 0x%x\n", slave->addr);
2191 
2192 	return ret;
2193 }
2194 
mlxbf_i2c_functionality(struct i2c_adapter * adap)2195 static u32 mlxbf_i2c_functionality(struct i2c_adapter *adap)
2196 {
2197 	return MLXBF_I2C_FUNC_ALL;
2198 }
2199 
2200 static struct mlxbf_i2c_chip_info mlxbf_i2c_chip[] = {
2201 	[MLXBF_I2C_CHIP_TYPE_1] = {
2202 		.type = MLXBF_I2C_CHIP_TYPE_1,
2203 		.shared_res = {
2204 			[0] = &mlxbf_i2c_coalesce_res[MLXBF_I2C_CHIP_TYPE_1],
2205 			[1] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_1],
2206 			[2] = &mlxbf_i2c_gpio_res[MLXBF_I2C_CHIP_TYPE_1]
2207 		},
2208 		.calculate_freq = mlxbf_i2c_calculate_freq_from_tyu,
2209 		.smbus_master_rs_bytes_off = MLXBF_I2C_YU_SMBUS_RS_BYTES,
2210 		.smbus_master_fsm_off = MLXBF_I2C_YU_SMBUS_MASTER_FSM
2211 	},
2212 	[MLXBF_I2C_CHIP_TYPE_2] = {
2213 		.type = MLXBF_I2C_CHIP_TYPE_2,
2214 		.shared_res = {
2215 			[0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_2]
2216 		},
2217 		.calculate_freq = mlxbf_i2c_calculate_freq_from_yu,
2218 		.smbus_master_rs_bytes_off = MLXBF_I2C_YU_SMBUS_RS_BYTES,
2219 		.smbus_master_fsm_off = MLXBF_I2C_YU_SMBUS_MASTER_FSM
2220 	},
2221 	[MLXBF_I2C_CHIP_TYPE_3] = {
2222 		.type = MLXBF_I2C_CHIP_TYPE_3,
2223 		.shared_res = {
2224 			[0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_3]
2225 		},
2226 		.calculate_freq = mlxbf_i2c_calculate_freq_from_yu,
2227 		.smbus_master_rs_bytes_off = MLXBF_I2C_RSH_YU_SMBUS_RS_BYTES,
2228 		.smbus_master_fsm_off = MLXBF_I2C_RSH_YU_SMBUS_MASTER_FSM
2229 	}
2230 };
2231 
2232 static const struct i2c_algorithm mlxbf_i2c_algo = {
2233 	.smbus_xfer = mlxbf_i2c_smbus_xfer,
2234 	.functionality = mlxbf_i2c_functionality,
2235 	.reg_slave = mlxbf_i2c_reg_slave,
2236 	.unreg_slave = mlxbf_i2c_unreg_slave,
2237 };
2238 
2239 static struct i2c_adapter_quirks mlxbf_i2c_quirks = {
2240 	.max_read_len = MLXBF_I2C_MASTER_DATA_R_LENGTH,
2241 	.max_write_len = MLXBF_I2C_MASTER_DATA_W_LENGTH,
2242 };
2243 
2244 static const struct acpi_device_id mlxbf_i2c_acpi_ids[] = {
2245 	{ "MLNXBF03", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_1] },
2246 	{ "MLNXBF23", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_2] },
2247 	{ "MLNXBF31", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_3] },
2248 	{},
2249 };
2250 
2251 MODULE_DEVICE_TABLE(acpi, mlxbf_i2c_acpi_ids);
2252 
mlxbf_i2c_acpi_probe(struct device * dev,struct mlxbf_i2c_priv * priv)2253 static int mlxbf_i2c_acpi_probe(struct device *dev, struct mlxbf_i2c_priv *priv)
2254 {
2255 	const struct acpi_device_id *aid;
2256 	u64 bus_id;
2257 	int ret;
2258 
2259 	if (acpi_disabled)
2260 		return -ENOENT;
2261 
2262 	aid = acpi_match_device(mlxbf_i2c_acpi_ids, dev);
2263 	if (!aid)
2264 		return -ENODEV;
2265 
2266 	priv->chip = (struct mlxbf_i2c_chip_info *)aid->driver_data;
2267 
2268 	ret = acpi_dev_uid_to_integer(ACPI_COMPANION(dev), &bus_id);
2269 	if (ret) {
2270 		dev_err(dev, "Cannot retrieve UID\n");
2271 		return ret;
2272 	}
2273 
2274 	priv->bus = bus_id;
2275 
2276 	return 0;
2277 }
2278 
mlxbf_i2c_probe(struct platform_device * pdev)2279 static int mlxbf_i2c_probe(struct platform_device *pdev)
2280 {
2281 	struct device *dev = &pdev->dev;
2282 	struct mlxbf_i2c_priv *priv;
2283 	struct i2c_adapter *adap;
2284 	u32 resource_version;
2285 	int irq, ret;
2286 
2287 	priv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_priv), GFP_KERNEL);
2288 	if (!priv)
2289 		return -ENOMEM;
2290 
2291 	ret = mlxbf_i2c_acpi_probe(dev, priv);
2292 	if (ret < 0)
2293 		return ret;
2294 
2295 	/* This property allows the driver to stay backward compatible with older
2296 	 * ACPI tables.
2297 	 * Starting BlueField-3 SoC, the "smbus" resource was broken down into 3
2298 	 * separate resources "timer", "master" and "slave".
2299 	 */
2300 	if (device_property_read_u32(dev, "resource_version", &resource_version))
2301 		resource_version = 0;
2302 
2303 	priv->resource_version = resource_version;
2304 
2305 	if (priv->chip->type < MLXBF_I2C_CHIP_TYPE_3 && resource_version == 0) {
2306 		priv->timer = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2307 		if (!priv->timer)
2308 			return -ENOMEM;
2309 
2310 		priv->mst = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2311 		if (!priv->mst)
2312 			return -ENOMEM;
2313 
2314 		priv->slv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2315 		if (!priv->slv)
2316 			return -ENOMEM;
2317 
2318 		ret = mlxbf_i2c_init_resource(pdev, &priv->smbus,
2319 					      MLXBF_I2C_SMBUS_RES);
2320 		if (ret < 0)
2321 			return dev_err_probe(dev, ret, "Cannot fetch smbus resource info");
2322 
2323 		priv->timer->io = priv->smbus->io;
2324 		priv->mst->io = priv->smbus->io + MLXBF_I2C_MST_ADDR_OFFSET;
2325 		priv->slv->io = priv->smbus->io + MLXBF_I2C_SLV_ADDR_OFFSET;
2326 	} else {
2327 		ret = mlxbf_i2c_init_resource(pdev, &priv->timer,
2328 					      MLXBF_I2C_SMBUS_TIMER_RES);
2329 		if (ret < 0)
2330 			return dev_err_probe(dev, ret, "Cannot fetch timer resource info");
2331 
2332 		ret = mlxbf_i2c_init_resource(pdev, &priv->mst,
2333 					      MLXBF_I2C_SMBUS_MST_RES);
2334 		if (ret < 0)
2335 			return dev_err_probe(dev, ret, "Cannot fetch master resource info");
2336 
2337 		ret = mlxbf_i2c_init_resource(pdev, &priv->slv,
2338 					      MLXBF_I2C_SMBUS_SLV_RES);
2339 		if (ret < 0)
2340 			return dev_err_probe(dev, ret, "Cannot fetch slave resource info");
2341 	}
2342 
2343 	ret = mlxbf_i2c_init_resource(pdev, &priv->mst_cause,
2344 				      MLXBF_I2C_MST_CAUSE_RES);
2345 	if (ret < 0)
2346 		return dev_err_probe(dev, ret, "Cannot fetch cause master resource info");
2347 
2348 	ret = mlxbf_i2c_init_resource(pdev, &priv->slv_cause,
2349 				      MLXBF_I2C_SLV_CAUSE_RES);
2350 	if (ret < 0)
2351 		return dev_err_probe(dev, ret, "Cannot fetch cause slave resource info");
2352 
2353 	adap = &priv->adap;
2354 	adap->owner = THIS_MODULE;
2355 	adap->class = I2C_CLASS_HWMON;
2356 	adap->algo = &mlxbf_i2c_algo;
2357 	adap->quirks = &mlxbf_i2c_quirks;
2358 	adap->dev.parent = dev;
2359 	adap->dev.of_node = dev->of_node;
2360 	adap->nr = priv->bus;
2361 
2362 	snprintf(adap->name, sizeof(adap->name), "i2c%d", adap->nr);
2363 	i2c_set_adapdata(adap, priv);
2364 
2365 	/* Read Core PLL frequency. */
2366 	ret = mlxbf_i2c_calculate_corepll_freq(pdev, priv);
2367 	if (ret < 0) {
2368 		dev_err(dev, "cannot get core clock frequency\n");
2369 		/* Set to default value. */
2370 		priv->frequency = MLXBF_I2C_COREPLL_FREQ;
2371 	}
2372 
2373 	/*
2374 	 * Initialize master.
2375 	 * Note that a physical bus might be shared among Linux and firmware
2376 	 * (e.g., ATF). Thus, the bus should be initialized and ready and
2377 	 * bus initialization would be unnecessary. This requires additional
2378 	 * knowledge about physical busses. But, since an extra initialization
2379 	 * does not really hurt, then keep the code as is.
2380 	 */
2381 	ret = mlxbf_i2c_init_master(pdev, priv);
2382 	if (ret < 0)
2383 		return dev_err_probe(dev, ret, "failed to initialize smbus master %d",
2384 				     priv->bus);
2385 
2386 	mlxbf_i2c_init_timings(pdev, priv);
2387 
2388 	mlxbf_i2c_init_slave(pdev, priv);
2389 
2390 	irq = platform_get_irq(pdev, 0);
2391 	if (irq < 0)
2392 		return irq;
2393 	ret = devm_request_irq(dev, irq, mlxbf_i2c_irq,
2394 			       IRQF_SHARED | IRQF_PROBE_SHARED,
2395 			       dev_name(dev), priv);
2396 	if (ret < 0)
2397 		return dev_err_probe(dev, ret, "Cannot get irq %d\n", irq);
2398 
2399 	priv->irq = irq;
2400 
2401 	platform_set_drvdata(pdev, priv);
2402 
2403 	ret = i2c_add_numbered_adapter(adap);
2404 	if (ret < 0)
2405 		return ret;
2406 
2407 	mutex_lock(&mlxbf_i2c_bus_lock);
2408 	mlxbf_i2c_bus_count++;
2409 	mutex_unlock(&mlxbf_i2c_bus_lock);
2410 
2411 	return 0;
2412 }
2413 
mlxbf_i2c_remove(struct platform_device * pdev)2414 static void mlxbf_i2c_remove(struct platform_device *pdev)
2415 {
2416 	struct mlxbf_i2c_priv *priv = platform_get_drvdata(pdev);
2417 	struct device *dev = &pdev->dev;
2418 	struct resource *params;
2419 
2420 	if (priv->chip->type < MLXBF_I2C_CHIP_TYPE_3 && priv->resource_version == 0) {
2421 		params = priv->smbus->params;
2422 		devm_release_mem_region(dev, params->start, resource_size(params));
2423 	} else {
2424 		params = priv->timer->params;
2425 		devm_release_mem_region(dev, params->start, resource_size(params));
2426 
2427 		params = priv->mst->params;
2428 		devm_release_mem_region(dev, params->start, resource_size(params));
2429 
2430 		params = priv->slv->params;
2431 		devm_release_mem_region(dev, params->start, resource_size(params));
2432 	}
2433 
2434 	params = priv->mst_cause->params;
2435 	devm_release_mem_region(dev, params->start, resource_size(params));
2436 
2437 	params = priv->slv_cause->params;
2438 	devm_release_mem_region(dev, params->start, resource_size(params));
2439 
2440 	/*
2441 	 * Release shared resources. This should be done when releasing
2442 	 * the I2C controller.
2443 	 */
2444 	mutex_lock(&mlxbf_i2c_bus_lock);
2445 	if (--mlxbf_i2c_bus_count == 0) {
2446 		mlxbf_i2c_release_coalesce(pdev, priv);
2447 		mlxbf_i2c_release_corepll(pdev, priv);
2448 		mlxbf_i2c_release_gpio(pdev, priv);
2449 	}
2450 	mutex_unlock(&mlxbf_i2c_bus_lock);
2451 
2452 	devm_free_irq(dev, priv->irq, priv);
2453 
2454 	i2c_del_adapter(&priv->adap);
2455 }
2456 
2457 static struct platform_driver mlxbf_i2c_driver = {
2458 	.probe = mlxbf_i2c_probe,
2459 	.remove_new = mlxbf_i2c_remove,
2460 	.driver = {
2461 		.name = "i2c-mlxbf",
2462 		.acpi_match_table = ACPI_PTR(mlxbf_i2c_acpi_ids),
2463 	},
2464 };
2465 
mlxbf_i2c_init(void)2466 static int __init mlxbf_i2c_init(void)
2467 {
2468 	mutex_init(&mlxbf_i2c_coalesce_lock);
2469 	mutex_init(&mlxbf_i2c_corepll_lock);
2470 	mutex_init(&mlxbf_i2c_gpio_lock);
2471 
2472 	mutex_init(&mlxbf_i2c_bus_lock);
2473 
2474 	return platform_driver_register(&mlxbf_i2c_driver);
2475 }
2476 module_init(mlxbf_i2c_init);
2477 
mlxbf_i2c_exit(void)2478 static void __exit mlxbf_i2c_exit(void)
2479 {
2480 	platform_driver_unregister(&mlxbf_i2c_driver);
2481 
2482 	mutex_destroy(&mlxbf_i2c_bus_lock);
2483 
2484 	mutex_destroy(&mlxbf_i2c_gpio_lock);
2485 	mutex_destroy(&mlxbf_i2c_corepll_lock);
2486 	mutex_destroy(&mlxbf_i2c_coalesce_lock);
2487 }
2488 module_exit(mlxbf_i2c_exit);
2489 
2490 MODULE_DESCRIPTION("Mellanox BlueField I2C bus driver");
2491 MODULE_AUTHOR("Khalil Blaiech <kblaiech@nvidia.com>");
2492 MODULE_AUTHOR("Asmaa Mnebhi <asmaa@nvidia.com>");
2493 MODULE_LICENSE("GPL v2");
2494