xref: /linux/drivers/i2c/busses/i2c-mlxbf.c (revision 883e3c9f40814377a239ca0becbcc77deab5ffe5)
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/iopoll.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/mutex.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/string.h>
22 #include <linux/string_choices.h>
23 
24 /* Defines what functionality is present. */
25 #define MLXBF_I2C_FUNC_SMBUS_BLOCK \
26 	(I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL)
27 
28 #define MLXBF_I2C_FUNC_SMBUS_DEFAULT \
29 	(I2C_FUNC_SMBUS_BYTE      | I2C_FUNC_SMBUS_BYTE_DATA | \
30 	 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_I2C_BLOCK | \
31 	 I2C_FUNC_SMBUS_PROC_CALL)
32 
33 #define MLXBF_I2C_FUNC_ALL \
34 	(MLXBF_I2C_FUNC_SMBUS_DEFAULT | MLXBF_I2C_FUNC_SMBUS_BLOCK | \
35 	 I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SLAVE)
36 
37 /* Shared resources info in BlueField platforms. */
38 
39 #define MLXBF_I2C_COALESCE_TYU_ADDR    0x02801300
40 #define MLXBF_I2C_COALESCE_TYU_SIZE    0x010
41 
42 #define MLXBF_I2C_GPIO_TYU_ADDR        0x02802000
43 #define MLXBF_I2C_GPIO_TYU_SIZE        0x100
44 
45 #define MLXBF_I2C_COREPLL_TYU_ADDR     0x02800358
46 #define MLXBF_I2C_COREPLL_TYU_SIZE     0x008
47 
48 #define MLXBF_I2C_COREPLL_YU_ADDR      0x02800c30
49 #define MLXBF_I2C_COREPLL_YU_SIZE      0x00c
50 
51 #define MLXBF_I2C_COREPLL_RSH_YU_ADDR  0x13409824
52 #define MLXBF_I2C_COREPLL_RSH_YU_SIZE  0x00c
53 
54 #define MLXBF_I2C_SHARED_RES_MAX       3
55 
56 /*
57  * Note that the following SMBus, CAUSE, GPIO and PLL register addresses
58  * refer to their respective offsets relative to the corresponding
59  * memory-mapped region whose addresses are specified in either the DT or
60  * the ACPI tables or above.
61  */
62 
63 /*
64  * SMBus Master core clock frequency. Timing configurations are
65  * strongly dependent on the core clock frequency of the SMBus
66  * Master. Default value is set to 400MHz.
67  */
68 #define MLXBF_I2C_TYU_PLL_OUT_FREQ  (400 * 1000 * 1000)
69 /* Reference clock for Bluefield - 156 MHz. */
70 #define MLXBF_I2C_PLL_IN_FREQ       156250000ULL
71 
72 /* Constant used to determine the PLL frequency. */
73 #define MLNXBF_I2C_COREPLL_CONST    16384ULL
74 
75 #define MLXBF_I2C_FREQUENCY_1GHZ  1000000000ULL
76 
77 /* PLL registers. */
78 #define MLXBF_I2C_CORE_PLL_REG1         0x4
79 #define MLXBF_I2C_CORE_PLL_REG2         0x8
80 
81 /* OR cause register. */
82 #define MLXBF_I2C_CAUSE_OR_EVTEN0    0x14
83 #define MLXBF_I2C_CAUSE_OR_CLEAR     0x18
84 
85 /* Arbiter Cause Register. */
86 #define MLXBF_I2C_CAUSE_ARBITER      0x1c
87 
88 /*
89  * Cause Status flags. Note that those bits might be considered
90  * as interrupt enabled bits.
91  */
92 
93 /* Transaction ended with STOP. */
94 #define MLXBF_I2C_CAUSE_TRANSACTION_ENDED  BIT(0)
95 /* Master arbitration lost. */
96 #define MLXBF_I2C_CAUSE_M_ARBITRATION_LOST BIT(1)
97 /* Unexpected start detected. */
98 #define MLXBF_I2C_CAUSE_UNEXPECTED_START   BIT(2)
99 /* Unexpected stop detected. */
100 #define MLXBF_I2C_CAUSE_UNEXPECTED_STOP    BIT(3)
101 /* Wait for transfer continuation. */
102 #define MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA   BIT(4)
103 /* Failed to generate STOP. */
104 #define MLXBF_I2C_CAUSE_PUT_STOP_FAILED    BIT(5)
105 /* Failed to generate START. */
106 #define MLXBF_I2C_CAUSE_PUT_START_FAILED   BIT(6)
107 /* Clock toggle completed. */
108 #define MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE    BIT(7)
109 /* Transfer timeout occurred. */
110 #define MLXBF_I2C_CAUSE_M_FW_TIMEOUT       BIT(8)
111 /* Master busy bit reset. */
112 #define MLXBF_I2C_CAUSE_M_GW_BUSY_FALL     BIT(9)
113 
114 #define MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK     GENMASK(9, 0)
115 
116 #define MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR \
117 	(MLXBF_I2C_CAUSE_M_ARBITRATION_LOST | \
118 	 MLXBF_I2C_CAUSE_UNEXPECTED_START | \
119 	 MLXBF_I2C_CAUSE_UNEXPECTED_STOP | \
120 	 MLXBF_I2C_CAUSE_PUT_STOP_FAILED | \
121 	 MLXBF_I2C_CAUSE_PUT_START_FAILED | \
122 	 MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE | \
123 	 MLXBF_I2C_CAUSE_M_FW_TIMEOUT)
124 
125 /*
126  * Slave cause status flags. Note that those bits might be considered
127  * as interrupt enabled bits.
128  */
129 
130 /* Write transaction received successfully. */
131 #define MLXBF_I2C_CAUSE_WRITE_SUCCESS         BIT(0)
132 /* Read transaction received, waiting for response. */
133 #define MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE BIT(13)
134 /* Slave busy bit reset. */
135 #define MLXBF_I2C_CAUSE_S_GW_BUSY_FALL        BIT(18)
136 
137 /* Cause coalesce registers. */
138 #define MLXBF_I2C_CAUSE_COALESCE_0        0x00
139 
140 #define MLXBF_I2C_CAUSE_TYU_SLAVE_BIT   3
141 #define MLXBF_I2C_CAUSE_YU_SLAVE_BIT    1
142 
143 /* Functional enable register. */
144 #define MLXBF_I2C_GPIO_0_FUNC_EN_0    0x28
145 /* Force OE enable register. */
146 #define MLXBF_I2C_GPIO_0_FORCE_OE_EN  0x30
147 /*
148  * Note that Smbus GWs are on GPIOs 30:25. Two pins are used to control
149  * SDA/SCL lines:
150  *
151  *  SMBUS GW0 -> bits[26:25]
152  *  SMBUS GW1 -> bits[28:27]
153  *  SMBUS GW2 -> bits[30:29]
154  */
155 #define MLXBF_I2C_GPIO_SMBUS_GW_PINS(num) (25 + ((num) << 1))
156 
157 /* Note that gw_id can be 0,1 or 2. */
158 #define MLXBF_I2C_GPIO_SMBUS_GW_MASK(num) \
159 	(0xffffffff & (~(0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num))))
160 
161 #define MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(num, val) \
162 	((val) & MLXBF_I2C_GPIO_SMBUS_GW_MASK(num))
163 
164 #define MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(num, val) \
165 	((val) | (0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num)))
166 
167 /*
168  * Defines SMBus operating frequency and core clock frequency.
169  * According to ADB files, default values are compliant to 100KHz SMBus
170  * @ 400MHz core clock. The driver should be able to calculate core
171  * frequency based on PLL parameters.
172  */
173 #define MLXBF_I2C_COREPLL_FREQ          MLXBF_I2C_TYU_PLL_OUT_FREQ
174 
175 /* Core PLL TYU configuration. */
176 #define MLXBF_I2C_COREPLL_CORE_F_TYU_MASK   GENMASK(15, 3)
177 #define MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK  GENMASK(19, 16)
178 #define MLXBF_I2C_COREPLL_CORE_R_TYU_MASK   GENMASK(25, 20)
179 
180 /* Core PLL YU configuration. */
181 #define MLXBF_I2C_COREPLL_CORE_F_YU_MASK    GENMASK(25, 0)
182 #define MLXBF_I2C_COREPLL_CORE_OD_YU_MASK   GENMASK(3, 0)
183 #define MLXBF_I2C_COREPLL_CORE_R_YU_MASK    GENMASK(31, 26)
184 
185 /* SMBus timing parameters. */
186 #define MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH    0x00
187 #define MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE     0x04
188 #define MLXBF_I2C_SMBUS_TIMER_THOLD               0x08
189 #define MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP   0x0c
190 #define MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA         0x10
191 #define MLXBF_I2C_SMBUS_THIGH_MAX_TBUF            0x14
192 #define MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT           0x18
193 
194 #define MLXBF_I2C_SHIFT_0   0
195 #define MLXBF_I2C_SHIFT_8   8
196 #define MLXBF_I2C_SHIFT_16  16
197 #define MLXBF_I2C_SHIFT_24  24
198 
199 #define MLXBF_I2C_MASK_8    GENMASK(7, 0)
200 #define MLXBF_I2C_MASK_16   GENMASK(15, 0)
201 #define MLXBF_I2C_MASK_32   GENMASK(31, 0)
202 
203 #define MLXBF_I2C_MST_ADDR_OFFSET         0x200
204 
205 /* SMBus Master GW. */
206 #define MLXBF_I2C_SMBUS_MASTER_GW         0x0
207 /* Number of bytes received and sent. */
208 #define MLXBF_I2C_YU_SMBUS_RS_BYTES       0x100
209 #define MLXBF_I2C_RSH_YU_SMBUS_RS_BYTES   0x10c
210 /* Packet error check (PEC) value. */
211 #define MLXBF_I2C_SMBUS_MASTER_PEC        0x104
212 /* Status bits (ACK/NACK/FW Timeout). */
213 #define MLXBF_I2C_SMBUS_MASTER_STATUS     0x108
214 /* SMbus Master Finite State Machine. */
215 #define MLXBF_I2C_YU_SMBUS_MASTER_FSM     0x110
216 #define MLXBF_I2C_RSH_YU_SMBUS_MASTER_FSM 0x100
217 
218 /* SMBus master GW control bits offset in MLXBF_I2C_SMBUS_MASTER_GW[31:3]. */
219 #define MLXBF_I2C_MASTER_LOCK_BIT         BIT(31) /* Lock bit. */
220 #define MLXBF_I2C_MASTER_BUSY_BIT         BIT(30) /* Busy bit. */
221 #define MLXBF_I2C_MASTER_START_BIT        BIT(29) /* Control start. */
222 #define MLXBF_I2C_MASTER_CTL_WRITE_BIT    BIT(28) /* Control write phase. */
223 #define MLXBF_I2C_MASTER_CTL_READ_BIT     BIT(19) /* Control read phase. */
224 #define MLXBF_I2C_MASTER_STOP_BIT         BIT(3)  /* Control stop. */
225 
226 #define MLXBF_I2C_MASTER_ENABLE \
227 	(MLXBF_I2C_MASTER_LOCK_BIT | MLXBF_I2C_MASTER_BUSY_BIT | \
228 	 MLXBF_I2C_MASTER_START_BIT)
229 
230 #define MLXBF_I2C_MASTER_ENABLE_WRITE \
231 	(MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_WRITE_BIT)
232 
233 #define MLXBF_I2C_MASTER_ENABLE_READ \
234 	(MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_READ_BIT)
235 
236 #define MLXBF_I2C_MASTER_WRITE_SHIFT      21 /* Control write bytes */
237 #define MLXBF_I2C_MASTER_SEND_PEC_SHIFT   20 /* Send PEC byte when set to 1 */
238 #define MLXBF_I2C_MASTER_PARSE_EXP_SHIFT  11 /* Control parse expected bytes */
239 #define MLXBF_I2C_MASTER_SLV_ADDR_SHIFT   12 /* Slave address */
240 #define MLXBF_I2C_MASTER_READ_SHIFT       4  /* Control read bytes */
241 
242 /* SMBus master GW Data descriptor. */
243 #define MLXBF_I2C_MASTER_DATA_DESC_ADDR   0x80
244 #define MLXBF_I2C_MASTER_DATA_DESC_SIZE   0x80 /* Size in bytes. */
245 
246 /* Maximum bytes to read/write per SMBus transaction. */
247 #define MLXBF_I2C_MASTER_DATA_R_LENGTH  MLXBF_I2C_MASTER_DATA_DESC_SIZE
248 #define MLXBF_I2C_MASTER_DATA_W_LENGTH (MLXBF_I2C_MASTER_DATA_DESC_SIZE - 1)
249 
250 /* All bytes were transmitted. */
251 #define MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE      BIT(0)
252 /* NACK received. */
253 #define MLXBF_I2C_SMBUS_STATUS_NACK_RCV           BIT(1)
254 /* Slave's byte count >128 bytes. */
255 #define MLXBF_I2C_SMBUS_STATUS_READ_ERR           BIT(2)
256 /* Timeout occurred. */
257 #define MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT         BIT(3)
258 
259 #define MLXBF_I2C_SMBUS_MASTER_STATUS_MASK        GENMASK(3, 0)
260 
261 #define MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR \
262 	(MLXBF_I2C_SMBUS_STATUS_NACK_RCV | \
263 	 MLXBF_I2C_SMBUS_STATUS_READ_ERR | \
264 	 MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT)
265 
266 #define MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK      BIT(31)
267 #define MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK  BIT(15)
268 
269 #define MLXBF_I2C_SLV_ADDR_OFFSET             0x400
270 
271 /* SMBus slave GW. */
272 #define MLXBF_I2C_SMBUS_SLAVE_GW              0x0
273 /* Number of bytes received and sent from/to master. */
274 #define MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES 0x100
275 /* Packet error check (PEC) value. */
276 #define MLXBF_I2C_SMBUS_SLAVE_PEC             0x104
277 /* SMBus slave Finite State Machine (FSM). */
278 #define MLXBF_I2C_SMBUS_SLAVE_FSM             0x110
279 /*
280  * Should be set when all raised causes handled, and cleared by HW on
281  * every new cause.
282  */
283 #define MLXBF_I2C_SMBUS_SLAVE_READY           0x12c
284 
285 /* SMBus slave GW control bits offset in MLXBF_I2C_SMBUS_SLAVE_GW[31:19]. */
286 #define MLXBF_I2C_SLAVE_BUSY_BIT         BIT(30) /* Busy bit. */
287 #define MLXBF_I2C_SLAVE_WRITE_BIT        BIT(29) /* Control write enable. */
288 
289 #define MLXBF_I2C_SLAVE_ENABLE \
290 	(MLXBF_I2C_SLAVE_BUSY_BIT | MLXBF_I2C_SLAVE_WRITE_BIT)
291 
292 #define MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT 22 /* Number of bytes to write. */
293 #define MLXBF_I2C_SLAVE_SEND_PEC_SHIFT    21 /* Send PEC byte shift. */
294 
295 /* SMBus slave GW Data descriptor. */
296 #define MLXBF_I2C_SLAVE_DATA_DESC_ADDR   0x80
297 #define MLXBF_I2C_SLAVE_DATA_DESC_SIZE   0x80 /* Size in bytes. */
298 
299 /* SMbus slave configuration registers. */
300 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG        0x114
301 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT        16
302 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT     BIT(7)
303 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK       GENMASK(6, 0)
304 
305 /*
306  * Timeout is given in microsends. Note also that timeout handling is not
307  * exact.
308  */
309 #define MLXBF_I2C_SMBUS_TIMEOUT   (300 * 1000) /* 300ms */
310 #define MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT (300 * 1000) /* 300ms */
311 
312 /* Polling frequency in microseconds. */
313 #define MLXBF_I2C_POLL_FREQ_IN_USEC        200
314 
315 #define MLXBF_I2C_SMBUS_OP_CNT_1   1
316 #define MLXBF_I2C_SMBUS_OP_CNT_2   2
317 #define MLXBF_I2C_SMBUS_OP_CNT_3   3
318 #define MLXBF_I2C_SMBUS_MAX_OP_CNT MLXBF_I2C_SMBUS_OP_CNT_3
319 
320 /* Helper macro to define an I2C resource parameters. */
321 #define MLXBF_I2C_RES_PARAMS(addr, size, str) \
322 	{ \
323 		.start = (addr), \
324 		.end = (addr) + (size) - 1, \
325 		.name = (str) \
326 	}
327 
328 enum {
329 	MLXBF_I2C_TIMING_100KHZ = 100000,
330 	MLXBF_I2C_TIMING_400KHZ = 400000,
331 	MLXBF_I2C_TIMING_1000KHZ = 1000000,
332 };
333 
334 enum {
335 	MLXBF_I2C_F_READ = BIT(0),
336 	MLXBF_I2C_F_WRITE = BIT(1),
337 	MLXBF_I2C_F_NORESTART = BIT(3),
338 	MLXBF_I2C_F_SMBUS_OPERATION = BIT(4),
339 	MLXBF_I2C_F_SMBUS_BLOCK = BIT(5),
340 	MLXBF_I2C_F_SMBUS_PEC = BIT(6),
341 	MLXBF_I2C_F_SMBUS_PROCESS_CALL = BIT(7),
342 	MLXBF_I2C_F_WRITE_WITHOUT_STOP = BIT(8),
343 };
344 
345 /* Mellanox BlueField chip type. */
346 enum mlxbf_i2c_chip_type {
347 	MLXBF_I2C_CHIP_TYPE_1, /* Mellanox BlueField-1 chip. */
348 	MLXBF_I2C_CHIP_TYPE_2, /* Mellanox BlueField-2 chip. */
349 	MLXBF_I2C_CHIP_TYPE_3 /* Mellanox BlueField-3 chip. */
350 };
351 
352 /* List of chip resources that are being accessed by the driver. */
353 enum {
354 	MLXBF_I2C_SMBUS_RES,
355 	MLXBF_I2C_MST_CAUSE_RES,
356 	MLXBF_I2C_SLV_CAUSE_RES,
357 	MLXBF_I2C_COALESCE_RES,
358 	MLXBF_I2C_SMBUS_TIMER_RES,
359 	MLXBF_I2C_SMBUS_MST_RES,
360 	MLXBF_I2C_SMBUS_SLV_RES,
361 	MLXBF_I2C_COREPLL_RES,
362 	MLXBF_I2C_GPIO_RES,
363 	MLXBF_I2C_END_RES
364 };
365 
366 /* Encapsulates timing parameters. */
367 struct mlxbf_i2c_timings {
368 	u16 scl_high;		/* Clock high period. */
369 	u16 scl_low;		/* Clock low period. */
370 	u8 sda_rise;		/* Data rise time. */
371 	u8 sda_fall;		/* Data fall time. */
372 	u8 scl_rise;		/* Clock rise time. */
373 	u8 scl_fall;		/* Clock fall time. */
374 	u16 hold_start;		/* Hold time after (REPEATED) START. */
375 	u16 hold_data;		/* Data hold time. */
376 	u16 setup_start;	/* REPEATED START condition setup time. */
377 	u16 setup_stop;		/* STOP condition setup time. */
378 	u16 setup_data;		/* Data setup time. */
379 	u16 pad;		/* Padding. */
380 	u16 buf;		/* Bus free time between STOP and START. */
381 	u16 thigh_max;		/* Thigh max. */
382 	u32 timeout;		/* Detect clock low timeout. */
383 };
384 
385 struct mlxbf_i2c_smbus_operation {
386 	u32 flags;
387 	u32 length; /* Buffer length in bytes. */
388 	u8 *buffer;
389 };
390 
391 struct mlxbf_i2c_smbus_request {
392 	u8 slave;
393 	u8 operation_cnt;
394 	struct mlxbf_i2c_smbus_operation operation[MLXBF_I2C_SMBUS_MAX_OP_CNT];
395 };
396 
397 struct mlxbf_i2c_resource {
398 	void __iomem *io;
399 	struct resource *params;
400 	struct mutex *lock; /* Mutex to protect mlxbf_i2c_resource. */
401 	u8 type;
402 };
403 
404 struct mlxbf_i2c_chip_info {
405 	enum mlxbf_i2c_chip_type type;
406 	/* Chip shared resources that are being used by the I2C controller. */
407 	struct mlxbf_i2c_resource *shared_res[MLXBF_I2C_SHARED_RES_MAX];
408 
409 	/* Callback to calculate the core PLL frequency. */
410 	u64 (*calculate_freq)(struct mlxbf_i2c_resource *corepll_res);
411 
412 	/* Registers' address offset */
413 	u32 smbus_master_rs_bytes_off;
414 	u32 smbus_master_fsm_off;
415 };
416 
417 struct mlxbf_i2c_priv {
418 	const struct mlxbf_i2c_chip_info *chip;
419 	struct i2c_adapter adap;
420 	struct mlxbf_i2c_resource *smbus;
421 	struct mlxbf_i2c_resource *timer;
422 	struct mlxbf_i2c_resource *mst;
423 	struct mlxbf_i2c_resource *slv;
424 	struct mlxbf_i2c_resource *mst_cause;
425 	struct mlxbf_i2c_resource *slv_cause;
426 	struct mlxbf_i2c_resource *coalesce;
427 	u64 frequency; /* Core frequency in Hz. */
428 	int bus; /* Physical bus identifier. */
429 	int irq;
430 	struct i2c_client *slave[MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT];
431 	u32 resource_version;
432 };
433 
434 /* Core PLL frequency. */
435 static u64 mlxbf_i2c_corepll_frequency;
436 
437 static struct resource mlxbf_i2c_coalesce_tyu_params =
438 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COALESCE_TYU_ADDR,
439 				     MLXBF_I2C_COALESCE_TYU_SIZE,
440 				     "COALESCE_MEM");
441 static struct resource mlxbf_i2c_corepll_tyu_params =
442 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_TYU_ADDR,
443 				     MLXBF_I2C_COREPLL_TYU_SIZE,
444 				     "COREPLL_MEM");
445 static struct resource mlxbf_i2c_corepll_yu_params =
446 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_YU_ADDR,
447 				     MLXBF_I2C_COREPLL_YU_SIZE,
448 				     "COREPLL_MEM");
449 static struct resource mlxbf_i2c_corepll_rsh_yu_params =
450 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_RSH_YU_ADDR,
451 				     MLXBF_I2C_COREPLL_RSH_YU_SIZE,
452 				     "COREPLL_MEM");
453 static struct resource mlxbf_i2c_gpio_tyu_params =
454 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_GPIO_TYU_ADDR,
455 				     MLXBF_I2C_GPIO_TYU_SIZE,
456 				     "GPIO_MEM");
457 
458 static struct mutex mlxbf_i2c_coalesce_lock;
459 static struct mutex mlxbf_i2c_corepll_lock;
460 static struct mutex mlxbf_i2c_gpio_lock;
461 
462 static struct mlxbf_i2c_resource mlxbf_i2c_coalesce_res[] = {
463 	[MLXBF_I2C_CHIP_TYPE_1] = {
464 		.params = &mlxbf_i2c_coalesce_tyu_params,
465 		.lock = &mlxbf_i2c_coalesce_lock,
466 		.type = MLXBF_I2C_COALESCE_RES
467 	},
468 	{}
469 };
470 
471 static struct mlxbf_i2c_resource mlxbf_i2c_corepll_res[] = {
472 	[MLXBF_I2C_CHIP_TYPE_1] = {
473 		.params = &mlxbf_i2c_corepll_tyu_params,
474 		.lock = &mlxbf_i2c_corepll_lock,
475 		.type = MLXBF_I2C_COREPLL_RES
476 	},
477 	[MLXBF_I2C_CHIP_TYPE_2] = {
478 		.params = &mlxbf_i2c_corepll_yu_params,
479 		.lock = &mlxbf_i2c_corepll_lock,
480 		.type = MLXBF_I2C_COREPLL_RES,
481 	},
482 	[MLXBF_I2C_CHIP_TYPE_3] = {
483 		.params = &mlxbf_i2c_corepll_rsh_yu_params,
484 		.lock = &mlxbf_i2c_corepll_lock,
485 		.type = MLXBF_I2C_COREPLL_RES,
486 	}
487 };
488 
489 static struct mlxbf_i2c_resource mlxbf_i2c_gpio_res[] = {
490 	[MLXBF_I2C_CHIP_TYPE_1] = {
491 		.params = &mlxbf_i2c_gpio_tyu_params,
492 		.lock = &mlxbf_i2c_gpio_lock,
493 		.type = MLXBF_I2C_GPIO_RES
494 	},
495 	{}
496 };
497 
498 static u8 mlxbf_i2c_bus_count;
499 
500 static struct mutex mlxbf_i2c_bus_lock;
501 
mlxbf_i2c_smbus_transaction_success(u32 master_status,u32 cause_status)502 static bool mlxbf_i2c_smbus_transaction_success(u32 master_status,
503 						u32 cause_status)
504 {
505 	/*
506 	 * When transaction ended with STOP, all bytes were transmitted,
507 	 * and no NACK received, then the transaction ended successfully.
508 	 * On the other hand, when the GW is configured with the stop bit
509 	 * de-asserted then the SMBus expects the following GW configuration
510 	 * for transfer continuation.
511 	 */
512 	if ((cause_status & MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA) ||
513 	    ((cause_status & MLXBF_I2C_CAUSE_TRANSACTION_ENDED) &&
514 	     (master_status & MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE) &&
515 	     !(master_status & MLXBF_I2C_SMBUS_STATUS_NACK_RCV)))
516 		return true;
517 
518 	return false;
519 }
520 
521 /*
522  * Poll SMBus master status and return transaction status,
523  * i.e. whether succeeded or failed. I2C and SMBus fault codes
524  * are returned as negative numbers from most calls, with zero
525  * or some positive number indicating a non-fault return.
526  */
mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv * priv)527 static int mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv *priv)
528 {
529 	u32 master_status_bits;
530 	u32 cause_status_bits;
531 	u32 bits;
532 
533 	/*
534 	 * GW busy bit is raised by the driver and cleared by the HW
535 	 * when the transaction is completed. The busy bit is a good
536 	 * indicator of transaction status. So poll the busy bit, and
537 	 * then read the cause and master status bits to determine if
538 	 * errors occurred during the transaction.
539 	 */
540 	readl_poll_timeout_atomic(priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW,
541 				  bits, !(bits & MLXBF_I2C_MASTER_BUSY_BIT),
542 				  MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
543 
544 	/* Read cause status bits. */
545 	cause_status_bits = readl(priv->mst_cause->io +
546 					MLXBF_I2C_CAUSE_ARBITER);
547 	cause_status_bits &= MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK;
548 
549 	/*
550 	 * Parse both Cause and Master GW bits, then return transaction status.
551 	 */
552 
553 	master_status_bits = readl(priv->mst->io +
554 					MLXBF_I2C_SMBUS_MASTER_STATUS);
555 	master_status_bits &= MLXBF_I2C_SMBUS_MASTER_STATUS_MASK;
556 
557 	if (mlxbf_i2c_smbus_transaction_success(master_status_bits,
558 						cause_status_bits))
559 		return 0;
560 
561 	/*
562 	 * In case of timeout on GW busy, the ISR will clear busy bit but
563 	 * transaction ended bits cause will not be set so the transaction
564 	 * fails. Then, we must check Master GW status bits.
565 	 */
566 	if ((master_status_bits & MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR) &&
567 	    (cause_status_bits & (MLXBF_I2C_CAUSE_TRANSACTION_ENDED |
568 				  MLXBF_I2C_CAUSE_M_GW_BUSY_FALL)))
569 		return -EIO;
570 
571 	if (cause_status_bits & MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR)
572 		return -EAGAIN;
573 
574 	return -ETIMEDOUT;
575 }
576 
mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv * priv,const u8 * data,u8 length,u32 addr,bool is_master)577 static void mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv *priv,
578 				       const u8 *data, u8 length, u32 addr,
579 				       bool is_master)
580 {
581 	u8 offset, aligned_length;
582 	u32 data32;
583 
584 	aligned_length = round_up(length, 4);
585 
586 	/*
587 	 * Copy data bytes from 4-byte aligned source buffer.
588 	 * Data copied to the Master GW Data Descriptor MUST be shifted
589 	 * left so the data starts at the MSB of the descriptor registers
590 	 * as required by the underlying hardware. Enable byte swapping
591 	 * when writing data bytes to the 32 * 32-bit HW Data registers
592 	 * a.k.a Master GW Data Descriptor.
593 	 */
594 	for (offset = 0; offset < aligned_length; offset += sizeof(u32)) {
595 		data32 = *((u32 *)(data + offset));
596 		if (is_master)
597 			iowrite32be(data32, priv->mst->io + addr + offset);
598 		else
599 			iowrite32be(data32, priv->slv->io + addr + offset);
600 	}
601 }
602 
mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv * priv,u8 * data,u8 length,u32 addr,bool is_master)603 static void mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv *priv,
604 				      u8 *data, u8 length, u32 addr,
605 				      bool is_master)
606 {
607 	u32 data32, mask;
608 	u8 byte, offset;
609 
610 	mask = sizeof(u32) - 1;
611 
612 	/*
613 	 * Data bytes in the Master GW Data Descriptor are shifted left
614 	 * so the data starts at the MSB of the descriptor registers as
615 	 * set by the underlying hardware. Enable byte swapping while
616 	 * reading data bytes from the 32 * 32-bit HW Data registers
617 	 * a.k.a Master GW Data Descriptor.
618 	 */
619 
620 	for (offset = 0; offset < (length & ~mask); offset += sizeof(u32)) {
621 		if (is_master)
622 			data32 = ioread32be(priv->mst->io + addr + offset);
623 		else
624 			data32 = ioread32be(priv->slv->io + addr + offset);
625 		*((u32 *)(data + offset)) = data32;
626 	}
627 
628 	if (!(length & mask))
629 		return;
630 
631 	if (is_master)
632 		data32 = ioread32be(priv->mst->io + addr + offset);
633 	else
634 		data32 = ioread32be(priv->slv->io + addr + offset);
635 
636 	for (byte = 0; byte < (length & mask); byte++) {
637 		data[offset + byte] = data32 & GENMASK(7, 0);
638 		data32 = ror32(data32, MLXBF_I2C_SHIFT_8);
639 	}
640 }
641 
mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv * priv,u8 slave,u8 len,u8 block_en,u8 pec_en,bool read,bool stop)642 static int mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv *priv, u8 slave,
643 				  u8 len, u8 block_en, u8 pec_en, bool read,
644 				  bool stop)
645 {
646 	u32 command = 0;
647 
648 	/* Set Master GW control word. */
649 	if (stop)
650 		command |= MLXBF_I2C_MASTER_STOP_BIT;
651 	if (read) {
652 		command |= MLXBF_I2C_MASTER_ENABLE_READ;
653 		command |= rol32(len, MLXBF_I2C_MASTER_READ_SHIFT);
654 	} else {
655 		command |= MLXBF_I2C_MASTER_ENABLE_WRITE;
656 		command |= rol32(len, MLXBF_I2C_MASTER_WRITE_SHIFT);
657 	}
658 	command |= rol32(slave, MLXBF_I2C_MASTER_SLV_ADDR_SHIFT);
659 	command |= rol32(block_en, MLXBF_I2C_MASTER_PARSE_EXP_SHIFT);
660 	command |= rol32(pec_en, MLXBF_I2C_MASTER_SEND_PEC_SHIFT);
661 
662 	/* Clear status bits. */
663 	writel(0x0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_STATUS);
664 	/* Set the cause data. */
665 	writel(~0x0, priv->mst_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
666 	/* Zero PEC byte. */
667 	writel(0x0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_PEC);
668 	/* Zero byte count. */
669 	writel(0x0, priv->mst->io + priv->chip->smbus_master_rs_bytes_off);
670 
671 	/* GW activation. */
672 	writel(command, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
673 
674 	/*
675 	 * Poll master status and check status bits. An ACK is sent when
676 	 * completing writing data to the bus (Master 'byte_count_done' bit
677 	 * is set to 1).
678 	 */
679 	return mlxbf_i2c_smbus_check_status(priv);
680 }
681 
682 static int
mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv * priv,struct mlxbf_i2c_smbus_request * request)683 mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
684 				  struct mlxbf_i2c_smbus_request *request)
685 {
686 	u8 data_desc[MLXBF_I2C_MASTER_DATA_DESC_SIZE] = { 0 };
687 	u8 op_idx, data_idx, data_len, write_len, read_len;
688 	struct mlxbf_i2c_smbus_operation *operation;
689 	u8 read_en, write_en, block_en, pec_en;
690 	bool stop_after_write = true;
691 	u8 slave, addr;
692 	u8 *read_buf;
693 	u32 flags;
694 	u32 bits;
695 	int ret;
696 
697 	if (request->operation_cnt > MLXBF_I2C_SMBUS_MAX_OP_CNT)
698 		return -EINVAL;
699 
700 	read_buf = NULL;
701 	data_idx = 0;
702 	read_en = 0;
703 	write_en = 0;
704 	write_len = 0;
705 	read_len = 0;
706 	block_en = 0;
707 	pec_en = 0;
708 	slave = request->slave & GENMASK(6, 0);
709 	addr = slave << 1;
710 
711 	/*
712 	 * Try to acquire the smbus gw lock before any reads of the GW register since
713 	 * a read sets the lock.
714 	 */
715 	ret = readl_poll_timeout_atomic(priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW,
716 					bits, !(bits & MLXBF_I2C_MASTER_LOCK_BIT),
717 					MLXBF_I2C_POLL_FREQ_IN_USEC,
718 					MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT);
719 	if (WARN_ON(ret))
720 		return -EBUSY;
721 
722 	/*
723 	 * SW must make sure that the SMBus Master GW is idle before starting
724 	 * a transaction. Accordingly, this call polls the Master FSM stop bit;
725 	 * it returns -ETIMEDOUT when the bit is asserted, 0 if not.
726 	 */
727 	ret = readl_poll_timeout_atomic(priv->mst->io + priv->chip->smbus_master_fsm_off,
728 					bits, !(bits & MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK),
729 					MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
730 	if (WARN_ON(ret)) {
731 		ret = -EBUSY;
732 		goto out_unlock;
733 	}
734 
735 	/* Set first byte. */
736 	data_desc[data_idx++] = addr;
737 
738 	for (op_idx = 0; op_idx < request->operation_cnt; op_idx++) {
739 		operation = &request->operation[op_idx];
740 		flags = operation->flags;
741 
742 		/*
743 		 * Note that read and write operations might be handled by a
744 		 * single command. If the MLXBF_I2C_F_SMBUS_OPERATION is set
745 		 * then write command byte and set the optional SMBus specific
746 		 * bits such as block_en and pec_en. These bits MUST be
747 		 * submitted by the first operation only.
748 		 */
749 		if (op_idx == 0 && flags & MLXBF_I2C_F_SMBUS_OPERATION) {
750 			block_en = flags & MLXBF_I2C_F_SMBUS_BLOCK;
751 			pec_en = flags & MLXBF_I2C_F_SMBUS_PEC;
752 		}
753 
754 		if (flags & MLXBF_I2C_F_WRITE) {
755 			write_en = 1;
756 			write_len += operation->length;
757 			if (data_idx + operation->length >
758 					MLXBF_I2C_MASTER_DATA_DESC_SIZE) {
759 				ret = -ENOBUFS;
760 				goto out_unlock;
761 			}
762 			memcpy(data_desc + data_idx,
763 			       operation->buffer, operation->length);
764 			data_idx += operation->length;
765 
766 			/*
767 			 * The stop condition can be skipped when writing on the bus
768 			 * to implement a repeated start condition on the next read
769 			 * as required for several SMBus and I2C operations.
770 			 */
771 			if (flags & MLXBF_I2C_F_WRITE_WITHOUT_STOP)
772 				stop_after_write = false;
773 		}
774 
775 		/*
776 		 * We assume that read operations are performed only once per
777 		 * SMBus transaction. *TBD* protect this statement so it won't
778 		 * be executed twice? or return an error if we try to read more
779 		 * than once?
780 		 */
781 		if (flags & MLXBF_I2C_F_READ) {
782 			read_en = 1;
783 			/* Subtract 1 as required by HW. */
784 			read_len = operation->length - 1;
785 			read_buf = operation->buffer;
786 		}
787 	}
788 
789 	/* Set Master GW data descriptor. */
790 	data_len = write_len + 1; /* Add one byte of the slave address. */
791 	/*
792 	 * Note that data_len cannot be 0. Indeed, the slave address byte
793 	 * must be written to the data registers.
794 	 */
795 	mlxbf_i2c_smbus_write_data(priv, (const u8 *)data_desc, data_len,
796 				   MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
797 
798 	if (write_en) {
799 		ret = mlxbf_i2c_smbus_enable(priv, slave, write_len, block_en,
800 					 pec_en, 0, stop_after_write);
801 		if (ret)
802 			goto out_unlock;
803 	}
804 
805 	if (read_en) {
806 		/* Write slave address to Master GW data descriptor. */
807 		mlxbf_i2c_smbus_write_data(priv, (const u8 *)&addr, 1,
808 					   MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
809 		ret = mlxbf_i2c_smbus_enable(priv, slave, read_len, block_en,
810 					 pec_en, 1, true);
811 		if (!ret) {
812 			/* Get Master GW data descriptor. */
813 			mlxbf_i2c_smbus_read_data(priv, data_desc, read_len + 1,
814 					     MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
815 
816 			/* Get data from Master GW data descriptor. */
817 			memcpy(read_buf, data_desc, read_len + 1);
818 		}
819 
820 		/*
821 		 * After a read operation the SMBus FSM ps (present state)
822 		 * needs to be 'manually' reset. This should be removed in
823 		 * next tag integration.
824 		 */
825 		writel(MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK,
826 			priv->mst->io + priv->chip->smbus_master_fsm_off);
827 	}
828 
829 out_unlock:
830 	/* Clear the gw to clear the lock */
831 	writel(0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
832 
833 	return ret;
834 }
835 
836 /* I2C SMBus protocols. */
837 
838 static void
mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request * request,u8 read)839 mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request *request,
840 			      u8 read)
841 {
842 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1;
843 
844 	request->operation[0].length = 0;
845 	request->operation[0].flags = MLXBF_I2C_F_WRITE;
846 	request->operation[0].flags |= read ? MLXBF_I2C_F_READ : 0;
847 }
848 
mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request * request,u8 * data,bool read,bool pec_check)849 static void mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request *request,
850 				      u8 *data, bool read, bool pec_check)
851 {
852 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1;
853 
854 	request->operation[0].length = 1;
855 	request->operation[0].length += pec_check;
856 
857 	request->operation[0].flags = MLXBF_I2C_F_SMBUS_OPERATION;
858 	request->operation[0].flags |= read ?
859 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
860 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
861 
862 	request->operation[0].buffer = data;
863 }
864 
865 static void
mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool read,bool pec_check)866 mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request *request,
867 			       u8 *command, u8 *data, bool read, bool pec_check)
868 {
869 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
870 
871 	request->operation[0].length = 1;
872 	request->operation[0].flags =
873 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
874 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
875 	request->operation[0].buffer = command;
876 
877 	request->operation[1].length = 1;
878 	request->operation[1].length += pec_check;
879 	request->operation[1].flags = read ?
880 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
881 	request->operation[1].buffer = data;
882 }
883 
884 static void
mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool read,bool pec_check)885 mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request *request,
886 			       u8 *command, u8 *data, bool read, bool pec_check)
887 {
888 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
889 
890 	request->operation[0].length = 1;
891 	request->operation[0].flags =
892 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
893 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
894 	request->operation[0].buffer = command;
895 
896 	request->operation[1].length = 2;
897 	request->operation[1].length += pec_check;
898 	request->operation[1].flags = read ?
899 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
900 	request->operation[1].buffer = data;
901 }
902 
903 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)904 mlxbf_i2c_smbus_i2c_block_func(struct mlxbf_i2c_smbus_request *request,
905 			       u8 *command, u8 *data, u8 *data_len, bool read,
906 			       bool pec_check)
907 {
908 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
909 
910 	request->operation[0].length = 1;
911 	request->operation[0].flags =
912 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
913 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
914 	request->operation[0].buffer = command;
915 
916 	if (read)
917 		request->operation[0].flags |= MLXBF_I2C_F_WRITE_WITHOUT_STOP;
918 
919 	/*
920 	 * As specified in the standard, the max number of bytes to read/write
921 	 * per block operation is 32 bytes. In Golan code, the controller can
922 	 * read up to 128 bytes and write up to 127 bytes.
923 	 */
924 	request->operation[1].length =
925 	    (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
926 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
927 	request->operation[1].flags = read ?
928 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
929 	/*
930 	 * Skip the first data byte, which corresponds to the number of bytes
931 	 * to read/write.
932 	 */
933 	request->operation[1].buffer = data + 1;
934 
935 	*data_len = request->operation[1].length;
936 
937 	/* Set the number of byte to read. This will be used by userspace. */
938 	if (read)
939 		data[0] = *data_len;
940 }
941 
mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,u8 * data_len,bool read,bool pec_check)942 static void mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request *request,
943 				       u8 *command, u8 *data, u8 *data_len,
944 				       bool read, bool pec_check)
945 {
946 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
947 
948 	request->operation[0].length = 1;
949 	request->operation[0].flags =
950 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
951 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
952 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
953 	request->operation[0].buffer = command;
954 
955 	request->operation[1].length =
956 	    (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
957 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
958 	request->operation[1].flags = read ?
959 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
960 	request->operation[1].buffer = data + 1;
961 
962 	*data_len = request->operation[1].length;
963 
964 	/* Set the number of bytes to read. This will be used by userspace. */
965 	if (read)
966 		data[0] = *data_len;
967 }
968 
969 static void
mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool pec_check)970 mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request *request,
971 				  u8 *command, u8 *data, bool pec_check)
972 {
973 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3;
974 
975 	request->operation[0].length = 1;
976 	request->operation[0].flags =
977 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
978 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
979 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
980 	request->operation[0].buffer = command;
981 
982 	request->operation[1].length = 2;
983 	request->operation[1].flags = MLXBF_I2C_F_WRITE;
984 	request->operation[1].buffer = data;
985 
986 	request->operation[2].length = 3;
987 	request->operation[2].flags = MLXBF_I2C_F_READ;
988 	request->operation[2].buffer = data;
989 }
990 
991 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)992 mlxbf_i2c_smbus_blk_process_call_func(struct mlxbf_i2c_smbus_request *request,
993 				      u8 *command, u8 *data, u8 *data_len,
994 				      bool pec_check)
995 {
996 	u32 length;
997 
998 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3;
999 
1000 	request->operation[0].length = 1;
1001 	request->operation[0].flags =
1002 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
1003 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
1004 	request->operation[0].flags |= (pec_check) ? MLXBF_I2C_F_SMBUS_PEC : 0;
1005 	request->operation[0].buffer = command;
1006 
1007 	length = (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
1008 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
1009 
1010 	request->operation[1].length = length - pec_check;
1011 	request->operation[1].flags = MLXBF_I2C_F_WRITE;
1012 	request->operation[1].buffer = data;
1013 
1014 	request->operation[2].length = length;
1015 	request->operation[2].flags = MLXBF_I2C_F_READ;
1016 	request->operation[2].buffer = data;
1017 
1018 	*data_len = length; /* including PEC byte. */
1019 }
1020 
1021 /* Initialization functions. */
1022 
mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv * priv,u8 type)1023 static bool mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv *priv, u8 type)
1024 {
1025 	return priv->chip->type == type;
1026 }
1027 
1028 static struct mlxbf_i2c_resource *
mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv * priv,u8 type)1029 mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv *priv, u8 type)
1030 {
1031 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1032 	struct mlxbf_i2c_resource *res;
1033 	u8 res_idx = 0;
1034 
1035 	for (res_idx = 0; res_idx < MLXBF_I2C_SHARED_RES_MAX; res_idx++) {
1036 		res = chip->shared_res[res_idx];
1037 		if (res && res->type == type)
1038 			return res;
1039 	}
1040 
1041 	return NULL;
1042 }
1043 
mlxbf_i2c_init_resource(struct platform_device * pdev,struct mlxbf_i2c_resource ** res,u8 type)1044 static int mlxbf_i2c_init_resource(struct platform_device *pdev,
1045 				   struct mlxbf_i2c_resource **res,
1046 				   u8 type)
1047 {
1048 	struct mlxbf_i2c_resource *tmp_res;
1049 	struct device *dev = &pdev->dev;
1050 
1051 	if (!res || *res || type >= MLXBF_I2C_END_RES)
1052 		return -EINVAL;
1053 
1054 	tmp_res = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource),
1055 			       GFP_KERNEL);
1056 	if (!tmp_res)
1057 		return -ENOMEM;
1058 
1059 	tmp_res->io = devm_platform_get_and_ioremap_resource(pdev, type, &tmp_res->params);
1060 	if (IS_ERR(tmp_res->io)) {
1061 		devm_kfree(dev, tmp_res);
1062 		return PTR_ERR(tmp_res->io);
1063 	}
1064 
1065 	tmp_res->type = type;
1066 
1067 	*res = tmp_res;
1068 
1069 	return 0;
1070 }
1071 
mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv * priv,u64 nanoseconds,bool minimum)1072 static u32 mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv *priv, u64 nanoseconds,
1073 			       bool minimum)
1074 {
1075 	u64 frequency;
1076 	u32 ticks;
1077 
1078 	/*
1079 	 * Compute ticks as follow:
1080 	 *
1081 	 *           Ticks
1082 	 * Time = --------- x 10^9    =>    Ticks = Time x Frequency x 10^-9
1083 	 *         Frequency
1084 	 */
1085 	frequency = priv->frequency;
1086 	ticks = div_u64(nanoseconds * frequency, MLXBF_I2C_FREQUENCY_1GHZ);
1087 	/*
1088 	 * The number of ticks is rounded down and if minimum is equal to 1
1089 	 * then add one tick.
1090 	 */
1091 	if (minimum)
1092 		ticks++;
1093 
1094 	return ticks;
1095 }
1096 
mlxbf_i2c_set_timer(struct mlxbf_i2c_priv * priv,u64 nsec,bool opt,u32 mask,u8 shift)1097 static u32 mlxbf_i2c_set_timer(struct mlxbf_i2c_priv *priv, u64 nsec, bool opt,
1098 			       u32 mask, u8 shift)
1099 {
1100 	u32 val = (mlxbf_i2c_get_ticks(priv, nsec, opt) & mask) << shift;
1101 
1102 	return val;
1103 }
1104 
mlxbf_i2c_set_timings(struct mlxbf_i2c_priv * priv,const struct mlxbf_i2c_timings * timings)1105 static void mlxbf_i2c_set_timings(struct mlxbf_i2c_priv *priv,
1106 				  const struct mlxbf_i2c_timings *timings)
1107 {
1108 	u32 timer;
1109 
1110 	timer = mlxbf_i2c_set_timer(priv, timings->scl_high,
1111 				    false, MLXBF_I2C_MASK_16,
1112 				    MLXBF_I2C_SHIFT_0);
1113 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_low,
1114 				     false, MLXBF_I2C_MASK_16,
1115 				     MLXBF_I2C_SHIFT_16);
1116 	writel(timer, priv->timer->io +
1117 		MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH);
1118 
1119 	timer = mlxbf_i2c_set_timer(priv, timings->sda_rise, false,
1120 				    MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_0);
1121 	timer |= mlxbf_i2c_set_timer(priv, timings->sda_fall, false,
1122 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_8);
1123 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_rise, false,
1124 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_16);
1125 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_fall, false,
1126 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_24);
1127 	writel(timer, priv->timer->io +
1128 		MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE);
1129 
1130 	timer = mlxbf_i2c_set_timer(priv, timings->hold_start, true,
1131 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1132 	timer |= mlxbf_i2c_set_timer(priv, timings->hold_data, true,
1133 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1134 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_TIMER_THOLD);
1135 
1136 	timer = mlxbf_i2c_set_timer(priv, timings->setup_start, true,
1137 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1138 	timer |= mlxbf_i2c_set_timer(priv, timings->setup_stop, true,
1139 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1140 	writel(timer, priv->timer->io +
1141 		MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP);
1142 
1143 	timer = mlxbf_i2c_set_timer(priv, timings->setup_data, true,
1144 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1145 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA);
1146 
1147 	timer = mlxbf_i2c_set_timer(priv, timings->buf, false,
1148 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1149 	timer |= mlxbf_i2c_set_timer(priv, timings->thigh_max, false,
1150 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1151 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_THIGH_MAX_TBUF);
1152 
1153 	timer = mlxbf_i2c_set_timer(priv, timings->timeout, false,
1154 				    MLXBF_I2C_MASK_32, MLXBF_I2C_SHIFT_0);
1155 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT);
1156 }
1157 
1158 enum mlxbf_i2c_timings_config {
1159 	MLXBF_I2C_TIMING_CONFIG_100KHZ,
1160 	MLXBF_I2C_TIMING_CONFIG_400KHZ,
1161 	MLXBF_I2C_TIMING_CONFIG_1000KHZ,
1162 };
1163 
1164 /* Timing values are in nanoseconds */
1165 static const struct mlxbf_i2c_timings mlxbf_i2c_timings[] = {
1166 	[MLXBF_I2C_TIMING_CONFIG_100KHZ] = {
1167 		.scl_high = 4810,
1168 		.scl_low = 5000,
1169 		.hold_start = 4000,
1170 		.setup_start = 4800,
1171 		.setup_stop = 4000,
1172 		.setup_data = 250,
1173 		.sda_rise = 50,
1174 		.sda_fall = 50,
1175 		.scl_rise = 50,
1176 		.scl_fall = 50,
1177 		.hold_data = 300,
1178 		.buf = 20000,
1179 		.thigh_max = 50000,
1180 		.timeout = 35000000
1181 	},
1182 	[MLXBF_I2C_TIMING_CONFIG_400KHZ] = {
1183 		.scl_high = 1011,
1184 		.scl_low = 1300,
1185 		.hold_start = 600,
1186 		.setup_start = 700,
1187 		.setup_stop = 600,
1188 		.setup_data = 100,
1189 		.sda_rise = 50,
1190 		.sda_fall = 50,
1191 		.scl_rise = 50,
1192 		.scl_fall = 50,
1193 		.hold_data = 300,
1194 		.buf = 20000,
1195 		.thigh_max = 50000,
1196 		.timeout = 35000000
1197 	},
1198 	[MLXBF_I2C_TIMING_CONFIG_1000KHZ] = {
1199 		.scl_high = 383,
1200 		.scl_low = 460,
1201 		.hold_start = 600,
1202 		.setup_start = 260,
1203 		.setup_stop = 260,
1204 		.setup_data = 50,
1205 		.sda_rise = 50,
1206 		.sda_fall = 50,
1207 		.scl_rise = 50,
1208 		.scl_fall = 50,
1209 		.hold_data = 300,
1210 		.buf = 500,
1211 		.thigh_max = 50000,
1212 		.timeout = 35000000
1213 	}
1214 };
1215 
mlxbf_i2c_init_timings(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1216 static int mlxbf_i2c_init_timings(struct platform_device *pdev,
1217 				  struct mlxbf_i2c_priv *priv)
1218 {
1219 	enum mlxbf_i2c_timings_config config_idx;
1220 	struct device *dev = &pdev->dev;
1221 	u32 config_khz;
1222 
1223 	int ret;
1224 
1225 	ret = device_property_read_u32(dev, "clock-frequency", &config_khz);
1226 	if (ret < 0)
1227 		config_khz = I2C_MAX_STANDARD_MODE_FREQ;
1228 
1229 	switch (config_khz) {
1230 	default:
1231 		/* Default settings is 100 KHz. */
1232 		pr_warn("Illegal value %d: defaulting to 100 KHz\n",
1233 			config_khz);
1234 		fallthrough;
1235 	case I2C_MAX_STANDARD_MODE_FREQ:
1236 		config_idx = MLXBF_I2C_TIMING_CONFIG_100KHZ;
1237 		break;
1238 
1239 	case I2C_MAX_FAST_MODE_FREQ:
1240 		config_idx = MLXBF_I2C_TIMING_CONFIG_400KHZ;
1241 		break;
1242 
1243 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
1244 		config_idx = MLXBF_I2C_TIMING_CONFIG_1000KHZ;
1245 		break;
1246 	}
1247 
1248 	mlxbf_i2c_set_timings(priv, &mlxbf_i2c_timings[config_idx]);
1249 
1250 	return 0;
1251 }
1252 
mlxbf_i2c_get_gpio(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1253 static int mlxbf_i2c_get_gpio(struct platform_device *pdev,
1254 			      struct mlxbf_i2c_priv *priv)
1255 {
1256 	struct mlxbf_i2c_resource *gpio_res;
1257 	struct device *dev = &pdev->dev;
1258 	struct resource	*params;
1259 	resource_size_t size;
1260 
1261 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1262 	if (!gpio_res)
1263 		return -EPERM;
1264 
1265 	/*
1266 	 * The GPIO region in TYU space is shared among I2C busses.
1267 	 * This function MUST be serialized to avoid racing when
1268 	 * claiming the memory region and/or setting up the GPIO.
1269 	 */
1270 	lockdep_assert_held(gpio_res->lock);
1271 
1272 	/* Check whether the memory map exist. */
1273 	if (gpio_res->io)
1274 		return 0;
1275 
1276 	params = gpio_res->params;
1277 	size = resource_size(params);
1278 
1279 	if (!devm_request_mem_region(dev, params->start, size, params->name))
1280 		return -EFAULT;
1281 
1282 	gpio_res->io = devm_ioremap(dev, params->start, size);
1283 	if (!gpio_res->io) {
1284 		devm_release_mem_region(dev, params->start, size);
1285 		return -ENOMEM;
1286 	}
1287 
1288 	return 0;
1289 }
1290 
mlxbf_i2c_release_gpio(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1291 static int mlxbf_i2c_release_gpio(struct platform_device *pdev,
1292 				  struct mlxbf_i2c_priv *priv)
1293 {
1294 	struct mlxbf_i2c_resource *gpio_res;
1295 	struct device *dev = &pdev->dev;
1296 	struct resource	*params;
1297 
1298 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1299 	if (!gpio_res)
1300 		return 0;
1301 
1302 	mutex_lock(gpio_res->lock);
1303 
1304 	if (gpio_res->io) {
1305 		/* Release the GPIO resource. */
1306 		params = gpio_res->params;
1307 		devm_iounmap(dev, gpio_res->io);
1308 		devm_release_mem_region(dev, params->start,
1309 					resource_size(params));
1310 	}
1311 
1312 	mutex_unlock(gpio_res->lock);
1313 
1314 	return 0;
1315 }
1316 
mlxbf_i2c_get_corepll(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1317 static int mlxbf_i2c_get_corepll(struct platform_device *pdev,
1318 				 struct mlxbf_i2c_priv *priv)
1319 {
1320 	struct mlxbf_i2c_resource *corepll_res;
1321 	struct device *dev = &pdev->dev;
1322 	struct resource *params;
1323 	resource_size_t size;
1324 
1325 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1326 						    MLXBF_I2C_COREPLL_RES);
1327 	if (!corepll_res)
1328 		return -EPERM;
1329 
1330 	/*
1331 	 * The COREPLL region in TYU space is shared among I2C busses.
1332 	 * This function MUST be serialized to avoid racing when
1333 	 * claiming the memory region.
1334 	 */
1335 	lockdep_assert_held(corepll_res->lock);
1336 
1337 	/* Check whether the memory map exist. */
1338 	if (corepll_res->io)
1339 		return 0;
1340 
1341 	params = corepll_res->params;
1342 	size = resource_size(params);
1343 
1344 	if (!devm_request_mem_region(dev, params->start, size, params->name))
1345 		return -EFAULT;
1346 
1347 	corepll_res->io = devm_ioremap(dev, params->start, size);
1348 	if (!corepll_res->io) {
1349 		devm_release_mem_region(dev, params->start, size);
1350 		return -ENOMEM;
1351 	}
1352 
1353 	return 0;
1354 }
1355 
mlxbf_i2c_release_corepll(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1356 static int mlxbf_i2c_release_corepll(struct platform_device *pdev,
1357 				     struct mlxbf_i2c_priv *priv)
1358 {
1359 	struct mlxbf_i2c_resource *corepll_res;
1360 	struct device *dev = &pdev->dev;
1361 	struct resource *params;
1362 
1363 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1364 						    MLXBF_I2C_COREPLL_RES);
1365 
1366 	mutex_lock(corepll_res->lock);
1367 
1368 	if (corepll_res->io) {
1369 		/* Release the CorePLL resource. */
1370 		params = corepll_res->params;
1371 		devm_iounmap(dev, corepll_res->io);
1372 		devm_release_mem_region(dev, params->start,
1373 					resource_size(params));
1374 	}
1375 
1376 	mutex_unlock(corepll_res->lock);
1377 
1378 	return 0;
1379 }
1380 
mlxbf_i2c_init_master(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1381 static int mlxbf_i2c_init_master(struct platform_device *pdev,
1382 				 struct mlxbf_i2c_priv *priv)
1383 {
1384 	struct mlxbf_i2c_resource *gpio_res;
1385 	struct device *dev = &pdev->dev;
1386 	u32 config_reg;
1387 	int ret;
1388 
1389 	/* This configuration is only needed for BlueField 1. */
1390 	if (!mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1))
1391 		return 0;
1392 
1393 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1394 	if (!gpio_res)
1395 		return -EPERM;
1396 
1397 	/*
1398 	 * The GPIO region in TYU space is shared among I2C busses.
1399 	 * This function MUST be serialized to avoid racing when
1400 	 * claiming the memory region and/or setting up the GPIO.
1401 	 */
1402 
1403 	mutex_lock(gpio_res->lock);
1404 
1405 	ret = mlxbf_i2c_get_gpio(pdev, priv);
1406 	if (ret < 0) {
1407 		dev_err(dev, "Failed to get gpio resource");
1408 		mutex_unlock(gpio_res->lock);
1409 		return ret;
1410 	}
1411 
1412 	/*
1413 	 * TYU - Configuration for GPIO pins. Those pins must be asserted in
1414 	 * MLXBF_I2C_GPIO_0_FUNC_EN_0, i.e. GPIO 0 is controlled by HW, and must
1415 	 * be reset in MLXBF_I2C_GPIO_0_FORCE_OE_EN, i.e. GPIO_OE will be driven
1416 	 * instead of HW_OE.
1417 	 * For now, we do not reset the GPIO state when the driver is removed.
1418 	 * First, it is not necessary to disable the bus since we are using
1419 	 * the same busses. Then, some busses might be shared among Linux and
1420 	 * platform firmware; disabling the bus might compromise the system
1421 	 * functionality.
1422 	 */
1423 	config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0);
1424 	config_reg = MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(priv->bus,
1425 							 config_reg);
1426 	writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0);
1427 
1428 	config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN);
1429 	config_reg = MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(priv->bus,
1430 							config_reg);
1431 	writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN);
1432 
1433 	mutex_unlock(gpio_res->lock);
1434 
1435 	return 0;
1436 }
1437 
mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource * corepll_res)1438 static u64 mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource *corepll_res)
1439 {
1440 	u64 core_frequency;
1441 	u8 core_od, core_r;
1442 	u32 corepll_val;
1443 	u16 core_f;
1444 
1445 	corepll_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1);
1446 
1447 	/* Get Core PLL configuration bits. */
1448 	core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_TYU_MASK, corepll_val);
1449 	core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK, corepll_val);
1450 	core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_TYU_MASK, corepll_val);
1451 
1452 	/*
1453 	 * Compute PLL output frequency as follow:
1454 	 *
1455 	 *                                       CORE_F + 1
1456 	 * PLL_OUT_FREQ = PLL_IN_FREQ * ----------------------------
1457 	 *                              (CORE_R + 1) * (CORE_OD + 1)
1458 	 *
1459 	 * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency
1460 	 * and PadFrequency, respectively.
1461 	 */
1462 	core_frequency = MLXBF_I2C_PLL_IN_FREQ * (++core_f);
1463 
1464 	return div_u64(core_frequency, (++core_r) * (++core_od));
1465 }
1466 
mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource * corepll_res)1467 static u64 mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource *corepll_res)
1468 {
1469 	u32 corepll_reg1_val, corepll_reg2_val;
1470 	u64 corepll_frequency;
1471 	u8 core_od, core_r;
1472 	u32 core_f;
1473 
1474 	corepll_reg1_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1);
1475 	corepll_reg2_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG2);
1476 
1477 	/* Get Core PLL configuration bits */
1478 	core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_YU_MASK, corepll_reg1_val);
1479 	core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_YU_MASK, corepll_reg1_val);
1480 	core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_YU_MASK, corepll_reg2_val);
1481 
1482 	/*
1483 	 * Compute PLL output frequency as follow:
1484 	 *
1485 	 *                                     CORE_F / 16384
1486 	 * PLL_OUT_FREQ = PLL_IN_FREQ * ----------------------------
1487 	 *                              (CORE_R + 1) * (CORE_OD + 1)
1488 	 *
1489 	 * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency
1490 	 * and PadFrequency, respectively.
1491 	 */
1492 	corepll_frequency = (MLXBF_I2C_PLL_IN_FREQ * core_f) / MLNXBF_I2C_COREPLL_CONST;
1493 
1494 	return div_u64(corepll_frequency, (++core_r) * (++core_od));
1495 }
1496 
mlxbf_i2c_calculate_corepll_freq(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1497 static int mlxbf_i2c_calculate_corepll_freq(struct platform_device *pdev,
1498 					    struct mlxbf_i2c_priv *priv)
1499 {
1500 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1501 	struct mlxbf_i2c_resource *corepll_res;
1502 	struct device *dev = &pdev->dev;
1503 	u64 *freq = &priv->frequency;
1504 	int ret;
1505 
1506 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1507 						    MLXBF_I2C_COREPLL_RES);
1508 	if (!corepll_res)
1509 		return -EPERM;
1510 
1511 	/*
1512 	 * First, check whether the TYU core Clock frequency is set.
1513 	 * The TYU core frequency is the same for all I2C busses; when
1514 	 * the first device gets probed the frequency is determined and
1515 	 * stored into a globally visible variable. So, first of all,
1516 	 * check whether the frequency is already set. Here, we assume
1517 	 * that the frequency is expected to be greater than 0.
1518 	 */
1519 	mutex_lock(corepll_res->lock);
1520 	if (!mlxbf_i2c_corepll_frequency) {
1521 		if (!chip->calculate_freq) {
1522 			mutex_unlock(corepll_res->lock);
1523 			return -EPERM;
1524 		}
1525 
1526 		ret = mlxbf_i2c_get_corepll(pdev, priv);
1527 		if (ret < 0) {
1528 			dev_err(dev, "Failed to get corePLL resource");
1529 			mutex_unlock(corepll_res->lock);
1530 			return ret;
1531 		}
1532 
1533 		mlxbf_i2c_corepll_frequency = chip->calculate_freq(corepll_res);
1534 	}
1535 	mutex_unlock(corepll_res->lock);
1536 
1537 	*freq = mlxbf_i2c_corepll_frequency;
1538 
1539 	return 0;
1540 }
1541 
mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv * priv,struct i2c_client * slave)1542 static int mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv *priv,
1543 			      struct i2c_client *slave)
1544 {
1545 	u8 reg, reg_cnt, byte, addr_tmp;
1546 	u32 slave_reg, slave_reg_tmp;
1547 
1548 	if (!priv)
1549 		return -EPERM;
1550 
1551 	reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2;
1552 
1553 	/*
1554 	 * Read the slave registers. There are 4 * 32-bit slave registers.
1555 	 * Each slave register can hold up to 4 * 8-bit slave configuration:
1556 	 * 1) A 7-bit address
1557 	 * 2) And a status bit (1 if enabled, 0 if not).
1558 	 * Look for the next available slave register slot.
1559 	 */
1560 	for (reg = 0; reg < reg_cnt; reg++) {
1561 		slave_reg = readl(priv->slv->io +
1562 				MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4);
1563 		/*
1564 		 * Each register holds 4 slave addresses. So, we have to keep
1565 		 * the byte order consistent with the value read in order to
1566 		 * update the register correctly, if needed.
1567 		 */
1568 		slave_reg_tmp = slave_reg;
1569 		for (byte = 0; byte < 4; byte++) {
1570 			addr_tmp = slave_reg_tmp & GENMASK(7, 0);
1571 
1572 			/*
1573 			 * If an enable bit is not set in the
1574 			 * MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG register, then the
1575 			 * slave address slot associated with that bit is
1576 			 * free. So set the enable bit and write the
1577 			 * slave address bits.
1578 			 */
1579 			if (!(addr_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT)) {
1580 				slave_reg &= ~(MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK << (byte * 8));
1581 				slave_reg |= (slave->addr << (byte * 8));
1582 				slave_reg |= MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT << (byte * 8);
1583 				writel(slave_reg, priv->slv->io +
1584 					MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG +
1585 					(reg * 0x4));
1586 
1587 				/*
1588 				 * Set the slave at the corresponding index.
1589 				 */
1590 				priv->slave[(reg * 4) + byte] = slave;
1591 
1592 				return 0;
1593 			}
1594 
1595 			/* Parse next byte. */
1596 			slave_reg_tmp >>= 8;
1597 		}
1598 	}
1599 
1600 	return -EBUSY;
1601 }
1602 
mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv * priv,u8 addr)1603 static int mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv *priv, u8 addr)
1604 {
1605 	u8 addr_tmp, reg, reg_cnt, byte;
1606 	u32 slave_reg, slave_reg_tmp;
1607 
1608 	reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2;
1609 
1610 	/*
1611 	 * Read the slave registers. There are 4 * 32-bit slave registers.
1612 	 * Each slave register can hold up to 4 * 8-bit slave configuration:
1613 	 * 1) A 7-bit address
1614 	 * 2) And a status bit (1 if enabled, 0 if not).
1615 	 * Check if addr is present in the registers.
1616 	 */
1617 	for (reg = 0; reg < reg_cnt; reg++) {
1618 		slave_reg = readl(priv->slv->io +
1619 				MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4);
1620 
1621 		/* Check whether the address slots are empty. */
1622 		if (!slave_reg)
1623 			continue;
1624 
1625 		/*
1626 		 * Check if addr matches any of the 4 slave addresses
1627 		 * in the register.
1628 		 */
1629 		slave_reg_tmp = slave_reg;
1630 		for (byte = 0; byte < 4; byte++) {
1631 			addr_tmp = slave_reg_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK;
1632 			/*
1633 			 * Parse slave address bytes and check whether the
1634 			 * slave address already exists.
1635 			 */
1636 			if (addr_tmp == addr) {
1637 				/* Clear the slave address slot. */
1638 				slave_reg &= ~(GENMASK(7, 0) << (byte * 8));
1639 				writel(slave_reg, priv->slv->io +
1640 					MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG +
1641 					(reg * 0x4));
1642 				/* Free slave at the corresponding index */
1643 				priv->slave[(reg * 4) + byte] = NULL;
1644 
1645 				return 0;
1646 			}
1647 
1648 			/* Parse next byte. */
1649 			slave_reg_tmp >>= 8;
1650 		}
1651 	}
1652 
1653 	return -ENXIO;
1654 }
1655 
mlxbf_i2c_init_coalesce(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1656 static int mlxbf_i2c_init_coalesce(struct platform_device *pdev,
1657 				   struct mlxbf_i2c_priv *priv)
1658 {
1659 	struct mlxbf_i2c_resource *coalesce_res;
1660 	struct resource *params;
1661 	resource_size_t size;
1662 	int ret = 0;
1663 
1664 	/*
1665 	 * Unlike BlueField-1 platform, the coalesce registers is a dedicated
1666 	 * resource in the next generations of BlueField.
1667 	 */
1668 	if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) {
1669 		coalesce_res = mlxbf_i2c_get_shared_resource(priv,
1670 						MLXBF_I2C_COALESCE_RES);
1671 		if (!coalesce_res)
1672 			return -EPERM;
1673 
1674 		/*
1675 		 * The Cause Coalesce group in TYU space is shared among
1676 		 * I2C busses. This function MUST be serialized to avoid
1677 		 * racing when claiming the memory region.
1678 		 */
1679 		lockdep_assert_held(mlxbf_i2c_gpio_res->lock);
1680 
1681 		/* Check whether the memory map exist. */
1682 		if (coalesce_res->io) {
1683 			priv->coalesce = coalesce_res;
1684 			return 0;
1685 		}
1686 
1687 		params = coalesce_res->params;
1688 		size = resource_size(params);
1689 
1690 		if (!request_mem_region(params->start, size, params->name))
1691 			return -EFAULT;
1692 
1693 		coalesce_res->io = ioremap(params->start, size);
1694 		if (!coalesce_res->io) {
1695 			release_mem_region(params->start, size);
1696 			return -ENOMEM;
1697 		}
1698 
1699 		priv->coalesce = coalesce_res;
1700 
1701 	} else {
1702 		ret = mlxbf_i2c_init_resource(pdev, &priv->coalesce,
1703 					      MLXBF_I2C_COALESCE_RES);
1704 	}
1705 
1706 	return ret;
1707 }
1708 
mlxbf_i2c_release_coalesce(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1709 static int mlxbf_i2c_release_coalesce(struct platform_device *pdev,
1710 				      struct mlxbf_i2c_priv *priv)
1711 {
1712 	struct mlxbf_i2c_resource *coalesce_res;
1713 	struct device *dev = &pdev->dev;
1714 	struct resource *params;
1715 	resource_size_t size;
1716 
1717 	coalesce_res = priv->coalesce;
1718 
1719 	if (coalesce_res->io) {
1720 		params = coalesce_res->params;
1721 		size = resource_size(params);
1722 		if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) {
1723 			mutex_lock(coalesce_res->lock);
1724 			iounmap(coalesce_res->io);
1725 			release_mem_region(params->start, size);
1726 			mutex_unlock(coalesce_res->lock);
1727 		} else {
1728 			devm_release_mem_region(dev, params->start, size);
1729 		}
1730 	}
1731 
1732 	return 0;
1733 }
1734 
mlxbf_i2c_init_slave(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1735 static int mlxbf_i2c_init_slave(struct platform_device *pdev,
1736 				struct mlxbf_i2c_priv *priv)
1737 {
1738 	struct device *dev = &pdev->dev;
1739 	u32 int_reg;
1740 	int ret;
1741 
1742 	/* Reset FSM. */
1743 	writel(0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_FSM);
1744 
1745 	/*
1746 	 * Enable slave cause interrupt bits. Drive
1747 	 * MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE and
1748 	 * MLXBF_I2C_CAUSE_WRITE_SUCCESS, these are enabled when an external
1749 	 * masters issue a Read and Write, respectively. But, clear all
1750 	 * interrupts first.
1751 	 */
1752 	writel(~0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
1753 	int_reg = MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE;
1754 	int_reg |= MLXBF_I2C_CAUSE_WRITE_SUCCESS;
1755 	writel(int_reg, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_EVTEN0);
1756 
1757 	/* Finally, set the 'ready' bit to start handling transactions. */
1758 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1759 
1760 	/* Initialize the cause coalesce resource. */
1761 	ret = mlxbf_i2c_init_coalesce(pdev, priv);
1762 	if (ret < 0) {
1763 		dev_err(dev, "failed to initialize cause coalesce\n");
1764 		return ret;
1765 	}
1766 
1767 	return 0;
1768 }
1769 
mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv * priv,bool * read,bool * write)1770 static bool mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv *priv, bool *read,
1771 				   bool *write)
1772 {
1773 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1774 	u32 coalesce0_reg, cause_reg;
1775 	u8 slave_shift, is_set;
1776 
1777 	*write = false;
1778 	*read = false;
1779 
1780 	slave_shift = chip->type != MLXBF_I2C_CHIP_TYPE_1 ?
1781 				MLXBF_I2C_CAUSE_YU_SLAVE_BIT :
1782 				priv->bus + MLXBF_I2C_CAUSE_TYU_SLAVE_BIT;
1783 
1784 	coalesce0_reg = readl(priv->coalesce->io + MLXBF_I2C_CAUSE_COALESCE_0);
1785 	is_set = coalesce0_reg & (1 << slave_shift);
1786 
1787 	if (!is_set)
1788 		return false;
1789 
1790 	/* Check the source of the interrupt, i.e. whether a Read or Write. */
1791 	cause_reg = readl(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER);
1792 	if (cause_reg & MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE)
1793 		*read = true;
1794 	else if (cause_reg & MLXBF_I2C_CAUSE_WRITE_SUCCESS)
1795 		*write = true;
1796 
1797 	/* Clear cause bits. */
1798 	writel(~0x0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
1799 
1800 	return true;
1801 }
1802 
mlxbf_i2c_get_slave_from_addr(struct mlxbf_i2c_priv * priv,u8 addr)1803 static struct i2c_client *mlxbf_i2c_get_slave_from_addr(
1804 			struct mlxbf_i2c_priv *priv, u8 addr)
1805 {
1806 	int i;
1807 
1808 	for (i = 0; i < MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT; i++) {
1809 		if (!priv->slave[i])
1810 			continue;
1811 
1812 		if (priv->slave[i]->addr == addr)
1813 			return priv->slave[i];
1814 	}
1815 
1816 	return NULL;
1817 }
1818 
1819 /*
1820  * Send byte to 'external' smbus master. This function is executed when
1821  * an external smbus master wants to read data from the BlueField.
1822  */
mlxbf_i2c_irq_send(struct mlxbf_i2c_priv * priv,u8 recv_bytes)1823 static int mlxbf_i2c_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
1824 {
1825 	u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 };
1826 	u8 write_size, pec_en, addr, value, byte_cnt;
1827 	struct i2c_client *slave;
1828 	u32 control32, data32;
1829 	int ret = 0;
1830 
1831 	/*
1832 	 * Read the first byte received from the external master to
1833 	 * determine the slave address. This byte is located in the
1834 	 * first data descriptor register of the slave GW.
1835 	 */
1836 	data32 = ioread32be(priv->slv->io +
1837 				MLXBF_I2C_SLAVE_DATA_DESC_ADDR);
1838 	addr = (data32 & GENMASK(7, 0)) >> 1;
1839 
1840 	/*
1841 	 * Check if the slave address received in the data descriptor register
1842 	 * matches any of the slave addresses registered. If there is a match,
1843 	 * set the slave.
1844 	 */
1845 	slave = mlxbf_i2c_get_slave_from_addr(priv, addr);
1846 	if (!slave) {
1847 		ret = -ENXIO;
1848 		goto clear_csr;
1849 	}
1850 
1851 	/*
1852 	 * An I2C read can consist of a WRITE bit transaction followed by
1853 	 * a READ bit transaction. Indeed, slave devices often expect
1854 	 * the slave address to be followed by the internal address.
1855 	 * So, write the internal address byte first, and then, send the
1856 	 * requested data to the master.
1857 	 */
1858 	if (recv_bytes > 1) {
1859 		i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
1860 		value = (data32 >> 8) & GENMASK(7, 0);
1861 		ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
1862 				      &value);
1863 		i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1864 
1865 		if (ret < 0)
1866 			goto clear_csr;
1867 	}
1868 
1869 	/*
1870 	 * Send data to the master. Currently, the driver supports
1871 	 * READ_BYTE, READ_WORD and BLOCK READ protocols. The
1872 	 * hardware can send up to 128 bytes per transfer which is
1873 	 * the total size of the data registers.
1874 	 */
1875 	i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
1876 
1877 	for (byte_cnt = 0; byte_cnt < MLXBF_I2C_SLAVE_DATA_DESC_SIZE; byte_cnt++) {
1878 		data_desc[byte_cnt] = value;
1879 		i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
1880 	}
1881 
1882 	/* Send a stop condition to the backend. */
1883 	i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1884 
1885 	/* Set the number of bytes to write to master. */
1886 	write_size = (byte_cnt - 1) & 0x7f;
1887 
1888 	/* Write data to Slave GW data descriptor. */
1889 	mlxbf_i2c_smbus_write_data(priv, data_desc, byte_cnt,
1890 				   MLXBF_I2C_SLAVE_DATA_DESC_ADDR, false);
1891 
1892 	pec_en = 0; /* Disable PEC since it is not supported. */
1893 
1894 	/* Prepare control word. */
1895 	control32 = MLXBF_I2C_SLAVE_ENABLE;
1896 	control32 |= rol32(write_size, MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT);
1897 	control32 |= rol32(pec_en, MLXBF_I2C_SLAVE_SEND_PEC_SHIFT);
1898 
1899 	writel(control32, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_GW);
1900 
1901 	/*
1902 	 * Wait until the transfer is completed; the driver will wait
1903 	 * until the GW is idle, a cause will rise on fall of GW busy.
1904 	 */
1905 	readl_poll_timeout_atomic(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER,
1906 				  data32, data32 & MLXBF_I2C_CAUSE_S_GW_BUSY_FALL,
1907 				  MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
1908 
1909 clear_csr:
1910 	/* Release the Slave GW. */
1911 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
1912 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_PEC);
1913 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1914 
1915 	return ret;
1916 }
1917 
1918 /*
1919  * Receive bytes from 'external' smbus master. This function is executed when
1920  * an external smbus master wants to write data to the BlueField.
1921  */
mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv * priv,u8 recv_bytes)1922 static int mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
1923 {
1924 	u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 };
1925 	struct i2c_client *slave;
1926 	u8 value, byte, addr;
1927 	int ret = 0;
1928 
1929 	/* Read data from Slave GW data descriptor. */
1930 	mlxbf_i2c_smbus_read_data(priv, data_desc, recv_bytes,
1931 				  MLXBF_I2C_SLAVE_DATA_DESC_ADDR, false);
1932 	addr = data_desc[0] >> 1;
1933 
1934 	/*
1935 	 * Check if the slave address received in the data descriptor register
1936 	 * matches any of the slave addresses registered.
1937 	 */
1938 	slave = mlxbf_i2c_get_slave_from_addr(priv, addr);
1939 	if (!slave) {
1940 		ret = -EINVAL;
1941 		goto clear_csr;
1942 	}
1943 
1944 	/*
1945 	 * Notify the slave backend that an smbus master wants to write data
1946 	 * to the BlueField.
1947 	 */
1948 	i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
1949 
1950 	/* Send the received data to the slave backend. */
1951 	for (byte = 1; byte < recv_bytes; byte++) {
1952 		value = data_desc[byte];
1953 		ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
1954 				      &value);
1955 		if (ret < 0)
1956 			break;
1957 	}
1958 
1959 	/*
1960 	 * Send a stop event to the slave backend, to signal
1961 	 * the end of the write transactions.
1962 	 */
1963 	i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1964 
1965 clear_csr:
1966 	/* Release the Slave GW. */
1967 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
1968 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_PEC);
1969 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1970 
1971 	return ret;
1972 }
1973 
mlxbf_i2c_irq(int irq,void * ptr)1974 static irqreturn_t mlxbf_i2c_irq(int irq, void *ptr)
1975 {
1976 	struct mlxbf_i2c_priv *priv = ptr;
1977 	bool read, write, irq_is_set;
1978 	u32 rw_bytes_reg;
1979 	u8 recv_bytes;
1980 
1981 	/*
1982 	 * Read TYU interrupt register and determine the source of the
1983 	 * interrupt. Based on the source of the interrupt one of the
1984 	 * following actions are performed:
1985 	 *  - Receive data and send response to master.
1986 	 *  - Send data and release slave GW.
1987 	 *
1988 	 * Handle read/write transaction only. CRmaster and Iarp requests
1989 	 * are ignored for now.
1990 	 */
1991 	irq_is_set = mlxbf_i2c_has_coalesce(priv, &read, &write);
1992 	if (!irq_is_set || (!read && !write)) {
1993 		/* Nothing to do here, interrupt was not from this device. */
1994 		return IRQ_NONE;
1995 	}
1996 
1997 	/*
1998 	 * The MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES includes the number of
1999 	 * bytes from/to master. These are defined by 8-bits each. If the lower
2000 	 * 8 bits are set, then the master expect to read N bytes from the
2001 	 * slave, if the higher 8 bits are sent then the slave expect N bytes
2002 	 * from the master.
2003 	 */
2004 	rw_bytes_reg = readl(priv->slv->io +
2005 				MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
2006 	recv_bytes = (rw_bytes_reg >> 8) & GENMASK(7, 0);
2007 
2008 	/*
2009 	 * For now, the slave supports 128 bytes transfer. Discard remaining
2010 	 * data bytes if the master wrote more than
2011 	 * MLXBF_I2C_SLAVE_DATA_DESC_SIZE, i.e, the actual size of the slave
2012 	 * data descriptor.
2013 	 *
2014 	 * Note that we will never expect to transfer more than 128 bytes; as
2015 	 * specified in the SMBus standard, block transactions cannot exceed
2016 	 * 32 bytes.
2017 	 */
2018 	recv_bytes = recv_bytes > MLXBF_I2C_SLAVE_DATA_DESC_SIZE ?
2019 		MLXBF_I2C_SLAVE_DATA_DESC_SIZE : recv_bytes;
2020 
2021 	if (read)
2022 		mlxbf_i2c_irq_send(priv, recv_bytes);
2023 	else
2024 		mlxbf_i2c_irq_recv(priv, recv_bytes);
2025 
2026 	return IRQ_HANDLED;
2027 }
2028 
2029 /* 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)2030 static s32 mlxbf_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
2031 				unsigned short flags, char read_write,
2032 				u8 command, int size,
2033 				union i2c_smbus_data *data)
2034 {
2035 	struct mlxbf_i2c_smbus_request request = { 0 };
2036 	struct mlxbf_i2c_priv *priv;
2037 	bool read, pec;
2038 	u8 byte_cnt;
2039 
2040 	request.slave = addr;
2041 
2042 	read = (read_write == I2C_SMBUS_READ);
2043 	pec = flags & I2C_FUNC_SMBUS_PEC;
2044 
2045 	switch (size) {
2046 	case I2C_SMBUS_QUICK:
2047 		mlxbf_i2c_smbus_quick_command(&request, read);
2048 		dev_dbg(&adap->dev, "smbus quick, slave 0x%02x\n", addr);
2049 		break;
2050 
2051 	case I2C_SMBUS_BYTE:
2052 		mlxbf_i2c_smbus_byte_func(&request,
2053 					  read ? &data->byte : &command, read,
2054 					  pec);
2055 		dev_dbg(&adap->dev, "smbus %s byte, slave 0x%02x.\n",
2056 			str_read_write(read), addr);
2057 		break;
2058 
2059 	case I2C_SMBUS_BYTE_DATA:
2060 		mlxbf_i2c_smbus_data_byte_func(&request, &command, &data->byte,
2061 					       read, pec);
2062 		dev_dbg(&adap->dev, "smbus %s byte data at 0x%02x, slave 0x%02x.\n",
2063 			str_read_write(read), command, addr);
2064 		break;
2065 
2066 	case I2C_SMBUS_WORD_DATA:
2067 		mlxbf_i2c_smbus_data_word_func(&request, &command,
2068 					       (u8 *)&data->word, read, pec);
2069 		dev_dbg(&adap->dev, "smbus %s word data at 0x%02x, slave 0x%02x.\n",
2070 			str_read_write(read), command, addr);
2071 		break;
2072 
2073 	case I2C_SMBUS_I2C_BLOCK_DATA:
2074 		byte_cnt = data->block[0];
2075 		mlxbf_i2c_smbus_i2c_block_func(&request, &command, data->block,
2076 					       &byte_cnt, read, pec);
2077 		dev_dbg(&adap->dev, "i2c %s block data, %d bytes at 0x%02x, slave 0x%02x.\n",
2078 			str_read_write(read), byte_cnt, command, addr);
2079 		break;
2080 
2081 	case I2C_SMBUS_BLOCK_DATA:
2082 		byte_cnt = read ? I2C_SMBUS_BLOCK_MAX : data->block[0];
2083 		mlxbf_i2c_smbus_block_func(&request, &command, data->block,
2084 					   &byte_cnt, read, pec);
2085 		dev_dbg(&adap->dev, "smbus %s block data, %d bytes at 0x%02x, slave 0x%02x.\n",
2086 			str_read_write(read), byte_cnt, command, addr);
2087 		break;
2088 
2089 	case I2C_FUNC_SMBUS_PROC_CALL:
2090 		mlxbf_i2c_smbus_process_call_func(&request, &command,
2091 						  (u8 *)&data->word, pec);
2092 		dev_dbg(&adap->dev, "process call, wr/rd at 0x%02x, slave 0x%02x.\n",
2093 			command, addr);
2094 		break;
2095 
2096 	case I2C_FUNC_SMBUS_BLOCK_PROC_CALL:
2097 		byte_cnt = data->block[0];
2098 		mlxbf_i2c_smbus_blk_process_call_func(&request, &command,
2099 						      data->block, &byte_cnt,
2100 						      pec);
2101 		dev_dbg(&adap->dev, "block process call, wr/rd %d bytes, slave 0x%02x.\n",
2102 			byte_cnt, addr);
2103 		break;
2104 
2105 	default:
2106 		dev_dbg(&adap->dev, "Unsupported I2C/SMBus command %d\n",
2107 			size);
2108 		return -EOPNOTSUPP;
2109 	}
2110 
2111 	priv = i2c_get_adapdata(adap);
2112 
2113 	return mlxbf_i2c_smbus_start_transaction(priv, &request);
2114 }
2115 
mlxbf_i2c_reg_slave(struct i2c_client * slave)2116 static int mlxbf_i2c_reg_slave(struct i2c_client *slave)
2117 {
2118 	struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
2119 	struct device *dev = &slave->dev;
2120 	int ret;
2121 
2122 	/*
2123 	 * Do not support ten bit chip address and do not use Packet Error
2124 	 * Checking (PEC).
2125 	 */
2126 	if (slave->flags & (I2C_CLIENT_TEN | I2C_CLIENT_PEC)) {
2127 		dev_err(dev, "SMBus PEC and 10 bit address not supported\n");
2128 		return -EAFNOSUPPORT;
2129 	}
2130 
2131 	ret = mlxbf_i2c_slave_enable(priv, slave);
2132 	if (ret)
2133 		dev_err(dev, "Surpassed max number of registered slaves allowed\n");
2134 
2135 	return 0;
2136 }
2137 
mlxbf_i2c_unreg_slave(struct i2c_client * slave)2138 static int mlxbf_i2c_unreg_slave(struct i2c_client *slave)
2139 {
2140 	struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
2141 	struct device *dev = &slave->dev;
2142 	int ret;
2143 
2144 	/*
2145 	 * Unregister slave by:
2146 	 * 1) Disabling the slave address in hardware
2147 	 * 2) Freeing priv->slave at the corresponding index
2148 	 */
2149 	ret = mlxbf_i2c_slave_disable(priv, slave->addr);
2150 	if (ret)
2151 		dev_err(dev, "Unable to find slave 0x%x\n", slave->addr);
2152 
2153 	return ret;
2154 }
2155 
mlxbf_i2c_functionality(struct i2c_adapter * adap)2156 static u32 mlxbf_i2c_functionality(struct i2c_adapter *adap)
2157 {
2158 	return MLXBF_I2C_FUNC_ALL;
2159 }
2160 
2161 static struct mlxbf_i2c_chip_info mlxbf_i2c_chip[] = {
2162 	[MLXBF_I2C_CHIP_TYPE_1] = {
2163 		.type = MLXBF_I2C_CHIP_TYPE_1,
2164 		.shared_res = {
2165 			[0] = &mlxbf_i2c_coalesce_res[MLXBF_I2C_CHIP_TYPE_1],
2166 			[1] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_1],
2167 			[2] = &mlxbf_i2c_gpio_res[MLXBF_I2C_CHIP_TYPE_1]
2168 		},
2169 		.calculate_freq = mlxbf_i2c_calculate_freq_from_tyu,
2170 		.smbus_master_rs_bytes_off = MLXBF_I2C_YU_SMBUS_RS_BYTES,
2171 		.smbus_master_fsm_off = MLXBF_I2C_YU_SMBUS_MASTER_FSM
2172 	},
2173 	[MLXBF_I2C_CHIP_TYPE_2] = {
2174 		.type = MLXBF_I2C_CHIP_TYPE_2,
2175 		.shared_res = {
2176 			[0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_2]
2177 		},
2178 		.calculate_freq = mlxbf_i2c_calculate_freq_from_yu,
2179 		.smbus_master_rs_bytes_off = MLXBF_I2C_YU_SMBUS_RS_BYTES,
2180 		.smbus_master_fsm_off = MLXBF_I2C_YU_SMBUS_MASTER_FSM
2181 	},
2182 	[MLXBF_I2C_CHIP_TYPE_3] = {
2183 		.type = MLXBF_I2C_CHIP_TYPE_3,
2184 		.shared_res = {
2185 			[0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_3]
2186 		},
2187 		.calculate_freq = mlxbf_i2c_calculate_freq_from_yu,
2188 		.smbus_master_rs_bytes_off = MLXBF_I2C_RSH_YU_SMBUS_RS_BYTES,
2189 		.smbus_master_fsm_off = MLXBF_I2C_RSH_YU_SMBUS_MASTER_FSM
2190 	}
2191 };
2192 
2193 static const struct i2c_algorithm mlxbf_i2c_algo = {
2194 	.smbus_xfer = mlxbf_i2c_smbus_xfer,
2195 	.functionality = mlxbf_i2c_functionality,
2196 	.reg_slave = mlxbf_i2c_reg_slave,
2197 	.unreg_slave = mlxbf_i2c_unreg_slave,
2198 };
2199 
2200 static struct i2c_adapter_quirks mlxbf_i2c_quirks = {
2201 	.max_read_len = MLXBF_I2C_MASTER_DATA_R_LENGTH,
2202 	.max_write_len = MLXBF_I2C_MASTER_DATA_W_LENGTH,
2203 };
2204 
2205 static const struct acpi_device_id mlxbf_i2c_acpi_ids[] = {
2206 	{ "MLNXBF03", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_1] },
2207 	{ "MLNXBF23", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_2] },
2208 	{ "MLNXBF31", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_3] },
2209 	{},
2210 };
2211 
2212 MODULE_DEVICE_TABLE(acpi, mlxbf_i2c_acpi_ids);
2213 
mlxbf_i2c_acpi_probe(struct device * dev,struct mlxbf_i2c_priv * priv)2214 static int mlxbf_i2c_acpi_probe(struct device *dev, struct mlxbf_i2c_priv *priv)
2215 {
2216 	const struct acpi_device_id *aid;
2217 	u64 bus_id;
2218 	int ret;
2219 
2220 	if (acpi_disabled)
2221 		return -ENOENT;
2222 
2223 	aid = acpi_match_device(mlxbf_i2c_acpi_ids, dev);
2224 	if (!aid)
2225 		return -ENODEV;
2226 
2227 	priv->chip = (struct mlxbf_i2c_chip_info *)aid->driver_data;
2228 
2229 	ret = acpi_dev_uid_to_integer(ACPI_COMPANION(dev), &bus_id);
2230 	if (ret) {
2231 		dev_err(dev, "Cannot retrieve UID\n");
2232 		return ret;
2233 	}
2234 
2235 	priv->bus = bus_id;
2236 
2237 	return 0;
2238 }
2239 
mlxbf_i2c_probe(struct platform_device * pdev)2240 static int mlxbf_i2c_probe(struct platform_device *pdev)
2241 {
2242 	struct device *dev = &pdev->dev;
2243 	struct mlxbf_i2c_priv *priv;
2244 	struct i2c_adapter *adap;
2245 	u32 resource_version;
2246 	int irq, ret;
2247 
2248 	priv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_priv), GFP_KERNEL);
2249 	if (!priv)
2250 		return -ENOMEM;
2251 
2252 	ret = mlxbf_i2c_acpi_probe(dev, priv);
2253 	if (ret < 0)
2254 		return ret;
2255 
2256 	/* This property allows the driver to stay backward compatible with older
2257 	 * ACPI tables.
2258 	 * Starting BlueField-3 SoC, the "smbus" resource was broken down into 3
2259 	 * separate resources "timer", "master" and "slave".
2260 	 */
2261 	if (device_property_read_u32(dev, "resource_version", &resource_version))
2262 		resource_version = 0;
2263 
2264 	priv->resource_version = resource_version;
2265 
2266 	if (priv->chip->type < MLXBF_I2C_CHIP_TYPE_3 && resource_version == 0) {
2267 		priv->timer = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2268 		if (!priv->timer)
2269 			return -ENOMEM;
2270 
2271 		priv->mst = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2272 		if (!priv->mst)
2273 			return -ENOMEM;
2274 
2275 		priv->slv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2276 		if (!priv->slv)
2277 			return -ENOMEM;
2278 
2279 		ret = mlxbf_i2c_init_resource(pdev, &priv->smbus,
2280 					      MLXBF_I2C_SMBUS_RES);
2281 		if (ret < 0)
2282 			return dev_err_probe(dev, ret, "Cannot fetch smbus resource info");
2283 
2284 		priv->timer->io = priv->smbus->io;
2285 		priv->mst->io = priv->smbus->io + MLXBF_I2C_MST_ADDR_OFFSET;
2286 		priv->slv->io = priv->smbus->io + MLXBF_I2C_SLV_ADDR_OFFSET;
2287 	} else {
2288 		ret = mlxbf_i2c_init_resource(pdev, &priv->timer,
2289 					      MLXBF_I2C_SMBUS_TIMER_RES);
2290 		if (ret < 0)
2291 			return dev_err_probe(dev, ret, "Cannot fetch timer resource info");
2292 
2293 		ret = mlxbf_i2c_init_resource(pdev, &priv->mst,
2294 					      MLXBF_I2C_SMBUS_MST_RES);
2295 		if (ret < 0)
2296 			return dev_err_probe(dev, ret, "Cannot fetch master resource info");
2297 
2298 		ret = mlxbf_i2c_init_resource(pdev, &priv->slv,
2299 					      MLXBF_I2C_SMBUS_SLV_RES);
2300 		if (ret < 0)
2301 			return dev_err_probe(dev, ret, "Cannot fetch slave resource info");
2302 	}
2303 
2304 	ret = mlxbf_i2c_init_resource(pdev, &priv->mst_cause,
2305 				      MLXBF_I2C_MST_CAUSE_RES);
2306 	if (ret < 0)
2307 		return dev_err_probe(dev, ret, "Cannot fetch cause master resource info");
2308 
2309 	ret = mlxbf_i2c_init_resource(pdev, &priv->slv_cause,
2310 				      MLXBF_I2C_SLV_CAUSE_RES);
2311 	if (ret < 0)
2312 		return dev_err_probe(dev, ret, "Cannot fetch cause slave resource info");
2313 
2314 	adap = &priv->adap;
2315 	adap->owner = THIS_MODULE;
2316 	adap->class = I2C_CLASS_HWMON;
2317 	adap->algo = &mlxbf_i2c_algo;
2318 	adap->quirks = &mlxbf_i2c_quirks;
2319 	adap->dev.parent = dev;
2320 	adap->dev.of_node = dev->of_node;
2321 	adap->nr = priv->bus;
2322 
2323 	snprintf(adap->name, sizeof(adap->name), "i2c%d", adap->nr);
2324 	i2c_set_adapdata(adap, priv);
2325 
2326 	/* Read Core PLL frequency. */
2327 	ret = mlxbf_i2c_calculate_corepll_freq(pdev, priv);
2328 	if (ret < 0) {
2329 		dev_err(dev, "cannot get core clock frequency\n");
2330 		/* Set to default value. */
2331 		priv->frequency = MLXBF_I2C_COREPLL_FREQ;
2332 	}
2333 
2334 	/*
2335 	 * Initialize master.
2336 	 * Note that a physical bus might be shared among Linux and firmware
2337 	 * (e.g., ATF). Thus, the bus should be initialized and ready and
2338 	 * bus initialization would be unnecessary. This requires additional
2339 	 * knowledge about physical busses. But, since an extra initialization
2340 	 * does not really hurt, then keep the code as is.
2341 	 */
2342 	ret = mlxbf_i2c_init_master(pdev, priv);
2343 	if (ret < 0)
2344 		return dev_err_probe(dev, ret, "failed to initialize smbus master %d",
2345 				     priv->bus);
2346 
2347 	mlxbf_i2c_init_timings(pdev, priv);
2348 
2349 	mlxbf_i2c_init_slave(pdev, priv);
2350 
2351 	irq = platform_get_irq(pdev, 0);
2352 	if (irq < 0)
2353 		return irq;
2354 	ret = devm_request_irq(dev, irq, mlxbf_i2c_irq,
2355 			       IRQF_SHARED | IRQF_PROBE_SHARED,
2356 			       dev_name(dev), priv);
2357 	if (ret < 0)
2358 		return dev_err_probe(dev, ret, "Cannot get irq %d\n", irq);
2359 
2360 	priv->irq = irq;
2361 
2362 	platform_set_drvdata(pdev, priv);
2363 
2364 	ret = i2c_add_numbered_adapter(adap);
2365 	if (ret < 0)
2366 		return ret;
2367 
2368 	mutex_lock(&mlxbf_i2c_bus_lock);
2369 	mlxbf_i2c_bus_count++;
2370 	mutex_unlock(&mlxbf_i2c_bus_lock);
2371 
2372 	return 0;
2373 }
2374 
mlxbf_i2c_remove(struct platform_device * pdev)2375 static void mlxbf_i2c_remove(struct platform_device *pdev)
2376 {
2377 	struct mlxbf_i2c_priv *priv = platform_get_drvdata(pdev);
2378 	struct device *dev = &pdev->dev;
2379 	struct resource *params;
2380 
2381 	if (priv->chip->type < MLXBF_I2C_CHIP_TYPE_3 && priv->resource_version == 0) {
2382 		params = priv->smbus->params;
2383 		devm_release_mem_region(dev, params->start, resource_size(params));
2384 	} else {
2385 		params = priv->timer->params;
2386 		devm_release_mem_region(dev, params->start, resource_size(params));
2387 
2388 		params = priv->mst->params;
2389 		devm_release_mem_region(dev, params->start, resource_size(params));
2390 
2391 		params = priv->slv->params;
2392 		devm_release_mem_region(dev, params->start, resource_size(params));
2393 	}
2394 
2395 	params = priv->mst_cause->params;
2396 	devm_release_mem_region(dev, params->start, resource_size(params));
2397 
2398 	params = priv->slv_cause->params;
2399 	devm_release_mem_region(dev, params->start, resource_size(params));
2400 
2401 	/*
2402 	 * Release shared resources. This should be done when releasing
2403 	 * the I2C controller.
2404 	 */
2405 	mutex_lock(&mlxbf_i2c_bus_lock);
2406 	if (--mlxbf_i2c_bus_count == 0) {
2407 		mlxbf_i2c_release_coalesce(pdev, priv);
2408 		mlxbf_i2c_release_corepll(pdev, priv);
2409 		mlxbf_i2c_release_gpio(pdev, priv);
2410 	}
2411 	mutex_unlock(&mlxbf_i2c_bus_lock);
2412 
2413 	devm_free_irq(dev, priv->irq, priv);
2414 
2415 	i2c_del_adapter(&priv->adap);
2416 }
2417 
2418 static struct platform_driver mlxbf_i2c_driver = {
2419 	.probe = mlxbf_i2c_probe,
2420 	.remove = mlxbf_i2c_remove,
2421 	.driver = {
2422 		.name = "i2c-mlxbf",
2423 		.acpi_match_table = ACPI_PTR(mlxbf_i2c_acpi_ids),
2424 	},
2425 };
2426 
mlxbf_i2c_init(void)2427 static int __init mlxbf_i2c_init(void)
2428 {
2429 	mutex_init(&mlxbf_i2c_coalesce_lock);
2430 	mutex_init(&mlxbf_i2c_corepll_lock);
2431 	mutex_init(&mlxbf_i2c_gpio_lock);
2432 
2433 	mutex_init(&mlxbf_i2c_bus_lock);
2434 
2435 	return platform_driver_register(&mlxbf_i2c_driver);
2436 }
2437 module_init(mlxbf_i2c_init);
2438 
mlxbf_i2c_exit(void)2439 static void __exit mlxbf_i2c_exit(void)
2440 {
2441 	platform_driver_unregister(&mlxbf_i2c_driver);
2442 
2443 	mutex_destroy(&mlxbf_i2c_bus_lock);
2444 
2445 	mutex_destroy(&mlxbf_i2c_gpio_lock);
2446 	mutex_destroy(&mlxbf_i2c_corepll_lock);
2447 	mutex_destroy(&mlxbf_i2c_coalesce_lock);
2448 }
2449 module_exit(mlxbf_i2c_exit);
2450 
2451 MODULE_DESCRIPTION("Mellanox BlueField I2C bus driver");
2452 MODULE_AUTHOR("Khalil Blaiech <kblaiech@nvidia.com>");
2453 MODULE_AUTHOR("Asmaa Mnebhi <asmaa@nvidia.com>");
2454 MODULE_LICENSE("GPL v2");
2455