xref: /linux/drivers/i2c/busses/i2c-mlxbf.c (revision 47096fc3d064a07c0842f748b99ebf01be120f2b)
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 #include <linux/units.h>
24 
25 /* Defines what functionality is present. */
26 #define MLXBF_I2C_FUNC_SMBUS_BLOCK \
27 	(I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_BLOCK_PROC_CALL)
28 
29 #define MLXBF_I2C_FUNC_SMBUS_DEFAULT \
30 	(I2C_FUNC_SMBUS_BYTE      | I2C_FUNC_SMBUS_BYTE_DATA | \
31 	 I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_I2C_BLOCK | \
32 	 I2C_FUNC_SMBUS_PROC_CALL)
33 
34 #define MLXBF_I2C_FUNC_ALL \
35 	(MLXBF_I2C_FUNC_SMBUS_DEFAULT | MLXBF_I2C_FUNC_SMBUS_BLOCK | \
36 	 I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SLAVE)
37 
38 /* Shared resources info in BlueField platforms. */
39 
40 #define MLXBF_I2C_COALESCE_TYU_ADDR    0x02801300
41 #define MLXBF_I2C_COALESCE_TYU_SIZE    0x010
42 
43 #define MLXBF_I2C_GPIO_TYU_ADDR        0x02802000
44 #define MLXBF_I2C_GPIO_TYU_SIZE        0x100
45 
46 #define MLXBF_I2C_COREPLL_TYU_ADDR     0x02800358
47 #define MLXBF_I2C_COREPLL_TYU_SIZE     0x008
48 
49 #define MLXBF_I2C_COREPLL_YU_ADDR      0x02800c30
50 #define MLXBF_I2C_COREPLL_YU_SIZE      0x00c
51 
52 #define MLXBF_I2C_COREPLL_RSH_YU_ADDR  0x13409824
53 #define MLXBF_I2C_COREPLL_RSH_YU_SIZE  0x00c
54 
55 #define MLXBF_I2C_SHARED_RES_MAX       3
56 
57 /*
58  * Note that the following SMBus, CAUSE, GPIO and PLL register addresses
59  * refer to their respective offsets relative to the corresponding
60  * memory-mapped region whose addresses are specified in either the DT or
61  * the ACPI tables or above.
62  */
63 
64 /*
65  * SMBus Master core clock frequency. Timing configurations are
66  * strongly dependent on the core clock frequency of the SMBus
67  * Master. Default value is set to 400MHz.
68  */
69 #define MLXBF_I2C_TYU_PLL_OUT_FREQ  (400 * HZ_PER_MHZ)
70 /* Reference clock for Bluefield - 156 MHz. */
71 #define MLXBF_I2C_PLL_IN_FREQ       156250000ULL
72 
73 /* Constant used to determine the PLL frequency. */
74 #define MLNXBF_I2C_COREPLL_CONST    16384ULL
75 
76 /* PLL registers. */
77 #define MLXBF_I2C_CORE_PLL_REG1         0x4
78 #define MLXBF_I2C_CORE_PLL_REG2         0x8
79 
80 /* OR cause register. */
81 #define MLXBF_I2C_CAUSE_OR_EVTEN0    0x14
82 #define MLXBF_I2C_CAUSE_OR_CLEAR     0x18
83 
84 /* Arbiter Cause Register. */
85 #define MLXBF_I2C_CAUSE_ARBITER      0x1c
86 
87 /*
88  * Cause Status flags. Note that those bits might be considered
89  * as interrupt enabled bits.
90  */
91 
92 /* Transaction ended with STOP. */
93 #define MLXBF_I2C_CAUSE_TRANSACTION_ENDED  BIT(0)
94 /* Master arbitration lost. */
95 #define MLXBF_I2C_CAUSE_M_ARBITRATION_LOST BIT(1)
96 /* Unexpected start detected. */
97 #define MLXBF_I2C_CAUSE_UNEXPECTED_START   BIT(2)
98 /* Unexpected stop detected. */
99 #define MLXBF_I2C_CAUSE_UNEXPECTED_STOP    BIT(3)
100 /* Wait for transfer continuation. */
101 #define MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA   BIT(4)
102 /* Failed to generate STOP. */
103 #define MLXBF_I2C_CAUSE_PUT_STOP_FAILED    BIT(5)
104 /* Failed to generate START. */
105 #define MLXBF_I2C_CAUSE_PUT_START_FAILED   BIT(6)
106 /* Clock toggle completed. */
107 #define MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE    BIT(7)
108 /* Transfer timeout occurred. */
109 #define MLXBF_I2C_CAUSE_M_FW_TIMEOUT       BIT(8)
110 /* Master busy bit reset. */
111 #define MLXBF_I2C_CAUSE_M_GW_BUSY_FALL     BIT(9)
112 
113 #define MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK     GENMASK(9, 0)
114 
115 #define MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR \
116 	(MLXBF_I2C_CAUSE_M_ARBITRATION_LOST | \
117 	 MLXBF_I2C_CAUSE_UNEXPECTED_START | \
118 	 MLXBF_I2C_CAUSE_UNEXPECTED_STOP | \
119 	 MLXBF_I2C_CAUSE_PUT_STOP_FAILED | \
120 	 MLXBF_I2C_CAUSE_PUT_START_FAILED | \
121 	 MLXBF_I2C_CAUSE_CLK_TOGGLE_DONE | \
122 	 MLXBF_I2C_CAUSE_M_FW_TIMEOUT)
123 
124 /*
125  * Slave cause status flags. Note that those bits might be considered
126  * as interrupt enabled bits.
127  */
128 
129 /* Write transaction received successfully. */
130 #define MLXBF_I2C_CAUSE_WRITE_SUCCESS         BIT(0)
131 /* Read transaction received, waiting for response. */
132 #define MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE BIT(13)
133 /* Slave busy bit reset. */
134 #define MLXBF_I2C_CAUSE_S_GW_BUSY_FALL        BIT(18)
135 
136 /* Cause coalesce registers. */
137 #define MLXBF_I2C_CAUSE_COALESCE_0        0x00
138 
139 #define MLXBF_I2C_CAUSE_TYU_SLAVE_BIT   3
140 #define MLXBF_I2C_CAUSE_YU_SLAVE_BIT    1
141 
142 /* Functional enable register. */
143 #define MLXBF_I2C_GPIO_0_FUNC_EN_0    0x28
144 /* Force OE enable register. */
145 #define MLXBF_I2C_GPIO_0_FORCE_OE_EN  0x30
146 /*
147  * Note that Smbus GWs are on GPIOs 30:25. Two pins are used to control
148  * SDA/SCL lines:
149  *
150  *  SMBUS GW0 -> bits[26:25]
151  *  SMBUS GW1 -> bits[28:27]
152  *  SMBUS GW2 -> bits[30:29]
153  */
154 #define MLXBF_I2C_GPIO_SMBUS_GW_PINS(num) (25 + ((num) << 1))
155 
156 /* Note that gw_id can be 0,1 or 2. */
157 #define MLXBF_I2C_GPIO_SMBUS_GW_MASK(num) \
158 	(0xffffffff & (~(0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num))))
159 
160 #define MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(num, val) \
161 	((val) & MLXBF_I2C_GPIO_SMBUS_GW_MASK(num))
162 
163 #define MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(num, val) \
164 	((val) | (0x3 << MLXBF_I2C_GPIO_SMBUS_GW_PINS(num)))
165 
166 /*
167  * Defines SMBus operating frequency and core clock frequency.
168  * According to ADB files, default values are compliant to 100KHz SMBus
169  * @ 400MHz core clock. The driver should be able to calculate core
170  * frequency based on PLL parameters.
171  */
172 #define MLXBF_I2C_COREPLL_FREQ          MLXBF_I2C_TYU_PLL_OUT_FREQ
173 
174 /* Core PLL TYU configuration. */
175 #define MLXBF_I2C_COREPLL_CORE_F_TYU_MASK   GENMASK(15, 3)
176 #define MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK  GENMASK(19, 16)
177 #define MLXBF_I2C_COREPLL_CORE_R_TYU_MASK   GENMASK(25, 20)
178 
179 /* Core PLL YU configuration. */
180 #define MLXBF_I2C_COREPLL_CORE_F_YU_MASK    GENMASK(25, 0)
181 #define MLXBF_I2C_COREPLL_CORE_OD_YU_MASK   GENMASK(3, 0)
182 #define MLXBF_I2C_COREPLL_CORE_R_YU_MASK    GENMASK(31, 26)
183 
184 /* SMBus timing parameters. */
185 #define MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH    0x00
186 #define MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE     0x04
187 #define MLXBF_I2C_SMBUS_TIMER_THOLD               0x08
188 #define MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP   0x0c
189 #define MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA         0x10
190 #define MLXBF_I2C_SMBUS_THIGH_MAX_TBUF            0x14
191 #define MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT           0x18
192 
193 #define MLXBF_I2C_SHIFT_0   0
194 #define MLXBF_I2C_SHIFT_8   8
195 #define MLXBF_I2C_SHIFT_16  16
196 #define MLXBF_I2C_SHIFT_24  24
197 
198 #define MLXBF_I2C_MASK_8    GENMASK(7, 0)
199 #define MLXBF_I2C_MASK_16   GENMASK(15, 0)
200 #define MLXBF_I2C_MASK_32   GENMASK(31, 0)
201 
202 #define MLXBF_I2C_MST_ADDR_OFFSET         0x200
203 
204 /* SMBus Master GW. */
205 #define MLXBF_I2C_SMBUS_MASTER_GW         0x0
206 /* Number of bytes received and sent. */
207 #define MLXBF_I2C_YU_SMBUS_RS_BYTES       0x100
208 #define MLXBF_I2C_RSH_YU_SMBUS_RS_BYTES   0x10c
209 /* Packet error check (PEC) value. */
210 #define MLXBF_I2C_SMBUS_MASTER_PEC        0x104
211 /* Status bits (ACK/NACK/FW Timeout). */
212 #define MLXBF_I2C_SMBUS_MASTER_STATUS     0x108
213 /* SMbus Master Finite State Machine. */
214 #define MLXBF_I2C_YU_SMBUS_MASTER_FSM     0x110
215 #define MLXBF_I2C_RSH_YU_SMBUS_MASTER_FSM 0x100
216 
217 /* SMBus master GW control bits offset in MLXBF_I2C_SMBUS_MASTER_GW[31:3]. */
218 #define MLXBF_I2C_MASTER_LOCK_BIT         BIT(31) /* Lock bit. */
219 #define MLXBF_I2C_MASTER_BUSY_BIT         BIT(30) /* Busy bit. */
220 #define MLXBF_I2C_MASTER_START_BIT        BIT(29) /* Control start. */
221 #define MLXBF_I2C_MASTER_CTL_WRITE_BIT    BIT(28) /* Control write phase. */
222 #define MLXBF_I2C_MASTER_CTL_READ_BIT     BIT(19) /* Control read phase. */
223 #define MLXBF_I2C_MASTER_STOP_BIT         BIT(3)  /* Control stop. */
224 
225 #define MLXBF_I2C_MASTER_ENABLE \
226 	(MLXBF_I2C_MASTER_LOCK_BIT | MLXBF_I2C_MASTER_BUSY_BIT | \
227 	 MLXBF_I2C_MASTER_START_BIT)
228 
229 #define MLXBF_I2C_MASTER_ENABLE_WRITE \
230 	(MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_WRITE_BIT)
231 
232 #define MLXBF_I2C_MASTER_ENABLE_READ \
233 	(MLXBF_I2C_MASTER_ENABLE | MLXBF_I2C_MASTER_CTL_READ_BIT)
234 
235 #define MLXBF_I2C_MASTER_WRITE_SHIFT      21 /* Control write bytes */
236 #define MLXBF_I2C_MASTER_SEND_PEC_SHIFT   20 /* Send PEC byte when set to 1 */
237 #define MLXBF_I2C_MASTER_PARSE_EXP_SHIFT  11 /* Control parse expected bytes */
238 #define MLXBF_I2C_MASTER_SLV_ADDR_SHIFT   12 /* Slave address */
239 #define MLXBF_I2C_MASTER_READ_SHIFT       4  /* Control read bytes */
240 
241 /* SMBus master GW Data descriptor. */
242 #define MLXBF_I2C_MASTER_DATA_DESC_ADDR   0x80
243 #define MLXBF_I2C_MASTER_DATA_DESC_SIZE   0x80 /* Size in bytes. */
244 
245 /* Maximum bytes to read/write per SMBus transaction. */
246 #define MLXBF_I2C_MASTER_DATA_R_LENGTH  MLXBF_I2C_MASTER_DATA_DESC_SIZE
247 #define MLXBF_I2C_MASTER_DATA_W_LENGTH (MLXBF_I2C_MASTER_DATA_DESC_SIZE - 1)
248 
249 /* All bytes were transmitted. */
250 #define MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE      BIT(0)
251 /* NACK received. */
252 #define MLXBF_I2C_SMBUS_STATUS_NACK_RCV           BIT(1)
253 /* Slave's byte count >128 bytes. */
254 #define MLXBF_I2C_SMBUS_STATUS_READ_ERR           BIT(2)
255 /* Timeout occurred. */
256 #define MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT         BIT(3)
257 
258 #define MLXBF_I2C_SMBUS_MASTER_STATUS_MASK        GENMASK(3, 0)
259 
260 #define MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR \
261 	(MLXBF_I2C_SMBUS_STATUS_NACK_RCV | \
262 	 MLXBF_I2C_SMBUS_STATUS_READ_ERR | \
263 	 MLXBF_I2C_SMBUS_STATUS_FW_TIMEOUT)
264 
265 #define MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK      BIT(31)
266 #define MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK  BIT(15)
267 
268 #define MLXBF_I2C_SLV_ADDR_OFFSET             0x400
269 
270 /* SMBus slave GW. */
271 #define MLXBF_I2C_SMBUS_SLAVE_GW              0x0
272 /* Number of bytes received and sent from/to master. */
273 #define MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES 0x100
274 /* Packet error check (PEC) value. */
275 #define MLXBF_I2C_SMBUS_SLAVE_PEC             0x104
276 /* SMBus slave Finite State Machine (FSM). */
277 #define MLXBF_I2C_SMBUS_SLAVE_FSM             0x110
278 /*
279  * Should be set when all raised causes handled, and cleared by HW on
280  * every new cause.
281  */
282 #define MLXBF_I2C_SMBUS_SLAVE_READY           0x12c
283 
284 /* SMBus slave GW control bits offset in MLXBF_I2C_SMBUS_SLAVE_GW[31:19]. */
285 #define MLXBF_I2C_SLAVE_BUSY_BIT         BIT(30) /* Busy bit. */
286 #define MLXBF_I2C_SLAVE_WRITE_BIT        BIT(29) /* Control write enable. */
287 
288 #define MLXBF_I2C_SLAVE_ENABLE \
289 	(MLXBF_I2C_SLAVE_BUSY_BIT | MLXBF_I2C_SLAVE_WRITE_BIT)
290 
291 #define MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT 22 /* Number of bytes to write. */
292 #define MLXBF_I2C_SLAVE_SEND_PEC_SHIFT    21 /* Send PEC byte shift. */
293 
294 /* SMBus slave GW Data descriptor. */
295 #define MLXBF_I2C_SLAVE_DATA_DESC_ADDR   0x80
296 #define MLXBF_I2C_SLAVE_DATA_DESC_SIZE   0x80 /* Size in bytes. */
297 
298 /* SMbus slave configuration registers. */
299 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG        0x114
300 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT        16
301 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT     BIT(7)
302 #define MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK       GENMASK(6, 0)
303 
304 /*
305  * Timeout is given in microsends. Note also that timeout handling is not
306  * exact.
307  */
308 #define MLXBF_I2C_SMBUS_TIMEOUT   (300 * 1000) /* 300ms */
309 #define MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT (300 * 1000) /* 300ms */
310 
311 /* Polling frequency in microseconds. */
312 #define MLXBF_I2C_POLL_FREQ_IN_USEC        200
313 
314 #define MLXBF_I2C_SMBUS_OP_CNT_1   1
315 #define MLXBF_I2C_SMBUS_OP_CNT_2   2
316 #define MLXBF_I2C_SMBUS_OP_CNT_3   3
317 #define MLXBF_I2C_SMBUS_MAX_OP_CNT MLXBF_I2C_SMBUS_OP_CNT_3
318 
319 /* Helper macro to define an I2C resource parameters. */
320 #define MLXBF_I2C_RES_PARAMS(addr, size, str) \
321 	{ \
322 		.start = (addr), \
323 		.end = (addr) + (size) - 1, \
324 		.name = (str) \
325 	}
326 
327 enum {
328 	MLXBF_I2C_F_READ = BIT(0),
329 	MLXBF_I2C_F_WRITE = BIT(1),
330 	MLXBF_I2C_F_NORESTART = BIT(3),
331 	MLXBF_I2C_F_SMBUS_OPERATION = BIT(4),
332 	MLXBF_I2C_F_SMBUS_BLOCK = BIT(5),
333 	MLXBF_I2C_F_SMBUS_PEC = BIT(6),
334 	MLXBF_I2C_F_SMBUS_PROCESS_CALL = BIT(7),
335 	MLXBF_I2C_F_WRITE_WITHOUT_STOP = BIT(8),
336 };
337 
338 /* Mellanox BlueField chip type. */
339 enum mlxbf_i2c_chip_type {
340 	MLXBF_I2C_CHIP_TYPE_1, /* Mellanox BlueField-1 chip. */
341 	MLXBF_I2C_CHIP_TYPE_2, /* Mellanox BlueField-2 chip. */
342 	MLXBF_I2C_CHIP_TYPE_3 /* Mellanox BlueField-3 chip. */
343 };
344 
345 /* List of chip resources that are being accessed by the driver. */
346 enum {
347 	MLXBF_I2C_SMBUS_RES,
348 	MLXBF_I2C_MST_CAUSE_RES,
349 	MLXBF_I2C_SLV_CAUSE_RES,
350 	MLXBF_I2C_COALESCE_RES,
351 	MLXBF_I2C_SMBUS_TIMER_RES,
352 	MLXBF_I2C_SMBUS_MST_RES,
353 	MLXBF_I2C_SMBUS_SLV_RES,
354 	MLXBF_I2C_COREPLL_RES,
355 	MLXBF_I2C_GPIO_RES,
356 	MLXBF_I2C_END_RES
357 };
358 
359 /* Encapsulates timing parameters. */
360 struct mlxbf_i2c_timings {
361 	u16 scl_high;		/* Clock high period. */
362 	u16 scl_low;		/* Clock low period. */
363 	u8 sda_rise;		/* Data rise time. */
364 	u8 sda_fall;		/* Data fall time. */
365 	u8 scl_rise;		/* Clock rise time. */
366 	u8 scl_fall;		/* Clock fall time. */
367 	u16 hold_start;		/* Hold time after (REPEATED) START. */
368 	u16 hold_data;		/* Data hold time. */
369 	u16 setup_start;	/* REPEATED START condition setup time. */
370 	u16 setup_stop;		/* STOP condition setup time. */
371 	u16 setup_data;		/* Data setup time. */
372 	u16 pad;		/* Padding. */
373 	u16 buf;		/* Bus free time between STOP and START. */
374 	u16 thigh_max;		/* Thigh max. */
375 	u32 timeout;		/* Detect clock low timeout. */
376 };
377 
378 struct mlxbf_i2c_smbus_operation {
379 	u32 flags;
380 	u32 length; /* Buffer length in bytes. */
381 	u8 *buffer;
382 };
383 
384 struct mlxbf_i2c_smbus_request {
385 	u8 slave;
386 	u8 operation_cnt;
387 	struct mlxbf_i2c_smbus_operation operation[MLXBF_I2C_SMBUS_MAX_OP_CNT];
388 };
389 
390 struct mlxbf_i2c_resource {
391 	void __iomem *io;
392 	struct resource *params;
393 	struct mutex *lock; /* Mutex to protect mlxbf_i2c_resource. */
394 	u8 type;
395 };
396 
397 struct mlxbf_i2c_chip_info {
398 	enum mlxbf_i2c_chip_type type;
399 	/* Chip shared resources that are being used by the I2C controller. */
400 	struct mlxbf_i2c_resource *shared_res[MLXBF_I2C_SHARED_RES_MAX];
401 
402 	/* Callback to calculate the core PLL frequency. */
403 	u64 (*calculate_freq)(struct mlxbf_i2c_resource *corepll_res);
404 
405 	/* Registers' address offset */
406 	u32 smbus_master_rs_bytes_off;
407 	u32 smbus_master_fsm_off;
408 };
409 
410 struct mlxbf_i2c_priv {
411 	const struct mlxbf_i2c_chip_info *chip;
412 	struct i2c_adapter adap;
413 	struct mlxbf_i2c_resource *smbus;
414 	struct mlxbf_i2c_resource *timer;
415 	struct mlxbf_i2c_resource *mst;
416 	struct mlxbf_i2c_resource *slv;
417 	struct mlxbf_i2c_resource *mst_cause;
418 	struct mlxbf_i2c_resource *slv_cause;
419 	struct mlxbf_i2c_resource *coalesce;
420 	u64 frequency; /* Core frequency in Hz. */
421 	int bus; /* Physical bus identifier. */
422 	int irq;
423 	struct i2c_client *slave[MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT];
424 	u32 resource_version;
425 };
426 
427 /* Core PLL frequency. */
428 static u64 mlxbf_i2c_corepll_frequency;
429 
430 static struct resource mlxbf_i2c_coalesce_tyu_params =
431 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COALESCE_TYU_ADDR,
432 				     MLXBF_I2C_COALESCE_TYU_SIZE,
433 				     "COALESCE_MEM");
434 static struct resource mlxbf_i2c_corepll_tyu_params =
435 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_TYU_ADDR,
436 				     MLXBF_I2C_COREPLL_TYU_SIZE,
437 				     "COREPLL_MEM");
438 static struct resource mlxbf_i2c_corepll_yu_params =
439 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_YU_ADDR,
440 				     MLXBF_I2C_COREPLL_YU_SIZE,
441 				     "COREPLL_MEM");
442 static struct resource mlxbf_i2c_corepll_rsh_yu_params =
443 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_COREPLL_RSH_YU_ADDR,
444 				     MLXBF_I2C_COREPLL_RSH_YU_SIZE,
445 				     "COREPLL_MEM");
446 static struct resource mlxbf_i2c_gpio_tyu_params =
447 		MLXBF_I2C_RES_PARAMS(MLXBF_I2C_GPIO_TYU_ADDR,
448 				     MLXBF_I2C_GPIO_TYU_SIZE,
449 				     "GPIO_MEM");
450 
451 static struct mutex mlxbf_i2c_coalesce_lock;
452 static struct mutex mlxbf_i2c_corepll_lock;
453 static struct mutex mlxbf_i2c_gpio_lock;
454 
455 static struct mlxbf_i2c_resource mlxbf_i2c_coalesce_res[] = {
456 	[MLXBF_I2C_CHIP_TYPE_1] = {
457 		.params = &mlxbf_i2c_coalesce_tyu_params,
458 		.lock = &mlxbf_i2c_coalesce_lock,
459 		.type = MLXBF_I2C_COALESCE_RES
460 	},
461 	{}
462 };
463 
464 static struct mlxbf_i2c_resource mlxbf_i2c_corepll_res[] = {
465 	[MLXBF_I2C_CHIP_TYPE_1] = {
466 		.params = &mlxbf_i2c_corepll_tyu_params,
467 		.lock = &mlxbf_i2c_corepll_lock,
468 		.type = MLXBF_I2C_COREPLL_RES
469 	},
470 	[MLXBF_I2C_CHIP_TYPE_2] = {
471 		.params = &mlxbf_i2c_corepll_yu_params,
472 		.lock = &mlxbf_i2c_corepll_lock,
473 		.type = MLXBF_I2C_COREPLL_RES,
474 	},
475 	[MLXBF_I2C_CHIP_TYPE_3] = {
476 		.params = &mlxbf_i2c_corepll_rsh_yu_params,
477 		.lock = &mlxbf_i2c_corepll_lock,
478 		.type = MLXBF_I2C_COREPLL_RES,
479 	}
480 };
481 
482 static struct mlxbf_i2c_resource mlxbf_i2c_gpio_res[] = {
483 	[MLXBF_I2C_CHIP_TYPE_1] = {
484 		.params = &mlxbf_i2c_gpio_tyu_params,
485 		.lock = &mlxbf_i2c_gpio_lock,
486 		.type = MLXBF_I2C_GPIO_RES
487 	},
488 	{}
489 };
490 
491 static u8 mlxbf_i2c_bus_count;
492 
493 static struct mutex mlxbf_i2c_bus_lock;
494 
mlxbf_i2c_smbus_transaction_success(u32 master_status,u32 cause_status)495 static bool mlxbf_i2c_smbus_transaction_success(u32 master_status,
496 						u32 cause_status)
497 {
498 	/*
499 	 * When transaction ended with STOP, all bytes were transmitted,
500 	 * and no NACK received, then the transaction ended successfully.
501 	 * On the other hand, when the GW is configured with the stop bit
502 	 * de-asserted then the SMBus expects the following GW configuration
503 	 * for transfer continuation.
504 	 */
505 	if ((cause_status & MLXBF_I2C_CAUSE_WAIT_FOR_FW_DATA) ||
506 	    ((cause_status & MLXBF_I2C_CAUSE_TRANSACTION_ENDED) &&
507 	     (master_status & MLXBF_I2C_SMBUS_STATUS_BYTE_CNT_DONE) &&
508 	     !(master_status & MLXBF_I2C_SMBUS_STATUS_NACK_RCV)))
509 		return true;
510 
511 	return false;
512 }
513 
514 /*
515  * Poll SMBus master status and return transaction status,
516  * i.e. whether succeeded or failed. I2C and SMBus fault codes
517  * are returned as negative numbers from most calls, with zero
518  * or some positive number indicating a non-fault return.
519  */
mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv * priv)520 static int mlxbf_i2c_smbus_check_status(struct mlxbf_i2c_priv *priv)
521 {
522 	u32 master_status_bits;
523 	u32 cause_status_bits;
524 	u32 bits;
525 
526 	/*
527 	 * GW busy bit is raised by the driver and cleared by the HW
528 	 * when the transaction is completed. The busy bit is a good
529 	 * indicator of transaction status. So poll the busy bit, and
530 	 * then read the cause and master status bits to determine if
531 	 * errors occurred during the transaction.
532 	 */
533 	readl_poll_timeout_atomic(priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW,
534 				  bits, !(bits & MLXBF_I2C_MASTER_BUSY_BIT),
535 				  MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
536 
537 	/* Read cause status bits. */
538 	cause_status_bits = readl(priv->mst_cause->io +
539 					MLXBF_I2C_CAUSE_ARBITER);
540 	cause_status_bits &= MLXBF_I2C_CAUSE_MASTER_ARBITER_BITS_MASK;
541 
542 	/*
543 	 * Parse both Cause and Master GW bits, then return transaction status.
544 	 */
545 
546 	master_status_bits = readl(priv->mst->io +
547 					MLXBF_I2C_SMBUS_MASTER_STATUS);
548 	master_status_bits &= MLXBF_I2C_SMBUS_MASTER_STATUS_MASK;
549 
550 	if (mlxbf_i2c_smbus_transaction_success(master_status_bits,
551 						cause_status_bits))
552 		return 0;
553 
554 	/*
555 	 * In case of timeout on GW busy, the ISR will clear busy bit but
556 	 * transaction ended bits cause will not be set so the transaction
557 	 * fails. Then, we must check Master GW status bits.
558 	 */
559 	if ((master_status_bits & MLXBF_I2C_SMBUS_MASTER_STATUS_ERROR) &&
560 	    (cause_status_bits & (MLXBF_I2C_CAUSE_TRANSACTION_ENDED |
561 				  MLXBF_I2C_CAUSE_M_GW_BUSY_FALL)))
562 		return -EIO;
563 
564 	if (cause_status_bits & MLXBF_I2C_CAUSE_MASTER_STATUS_ERROR)
565 		return -EAGAIN;
566 
567 	return -ETIMEDOUT;
568 }
569 
mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv * priv,const u8 * data,u8 length,u32 addr,bool is_master)570 static void mlxbf_i2c_smbus_write_data(struct mlxbf_i2c_priv *priv,
571 				       const u8 *data, u8 length, u32 addr,
572 				       bool is_master)
573 {
574 	u8 offset, aligned_length;
575 	u32 data32;
576 
577 	aligned_length = round_up(length, 4);
578 
579 	/*
580 	 * Copy data bytes from 4-byte aligned source buffer.
581 	 * Data copied to the Master GW Data Descriptor MUST be shifted
582 	 * left so the data starts at the MSB of the descriptor registers
583 	 * as required by the underlying hardware. Enable byte swapping
584 	 * when writing data bytes to the 32 * 32-bit HW Data registers
585 	 * a.k.a Master GW Data Descriptor.
586 	 */
587 	for (offset = 0; offset < aligned_length; offset += sizeof(u32)) {
588 		data32 = *((u32 *)(data + offset));
589 		if (is_master)
590 			iowrite32be(data32, priv->mst->io + addr + offset);
591 		else
592 			iowrite32be(data32, priv->slv->io + addr + offset);
593 	}
594 }
595 
mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv * priv,u8 * data,u8 length,u32 addr,bool is_master)596 static void mlxbf_i2c_smbus_read_data(struct mlxbf_i2c_priv *priv,
597 				      u8 *data, u8 length, u32 addr,
598 				      bool is_master)
599 {
600 	u32 data32, mask;
601 	u8 byte, offset;
602 
603 	mask = sizeof(u32) - 1;
604 
605 	/*
606 	 * Data bytes in the Master GW Data Descriptor are shifted left
607 	 * so the data starts at the MSB of the descriptor registers as
608 	 * set by the underlying hardware. Enable byte swapping while
609 	 * reading data bytes from the 32 * 32-bit HW Data registers
610 	 * a.k.a Master GW Data Descriptor.
611 	 */
612 
613 	for (offset = 0; offset < (length & ~mask); offset += sizeof(u32)) {
614 		if (is_master)
615 			data32 = ioread32be(priv->mst->io + addr + offset);
616 		else
617 			data32 = ioread32be(priv->slv->io + addr + offset);
618 		*((u32 *)(data + offset)) = data32;
619 	}
620 
621 	if (!(length & mask))
622 		return;
623 
624 	if (is_master)
625 		data32 = ioread32be(priv->mst->io + addr + offset);
626 	else
627 		data32 = ioread32be(priv->slv->io + addr + offset);
628 
629 	for (byte = 0; byte < (length & mask); byte++) {
630 		data[offset + byte] = data32 & GENMASK(7, 0);
631 		data32 = ror32(data32, MLXBF_I2C_SHIFT_8);
632 	}
633 }
634 
mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv * priv,u8 slave,u8 len,u8 block_en,u8 pec_en,bool read,bool stop)635 static int mlxbf_i2c_smbus_enable(struct mlxbf_i2c_priv *priv, u8 slave,
636 				  u8 len, u8 block_en, u8 pec_en, bool read,
637 				  bool stop)
638 {
639 	u32 command = 0;
640 
641 	/* Set Master GW control word. */
642 	if (stop)
643 		command |= MLXBF_I2C_MASTER_STOP_BIT;
644 	if (read) {
645 		command |= MLXBF_I2C_MASTER_ENABLE_READ;
646 		command |= rol32(len, MLXBF_I2C_MASTER_READ_SHIFT);
647 	} else {
648 		command |= MLXBF_I2C_MASTER_ENABLE_WRITE;
649 		command |= rol32(len, MLXBF_I2C_MASTER_WRITE_SHIFT);
650 	}
651 	command |= rol32(slave, MLXBF_I2C_MASTER_SLV_ADDR_SHIFT);
652 	command |= rol32(block_en, MLXBF_I2C_MASTER_PARSE_EXP_SHIFT);
653 	command |= rol32(pec_en, MLXBF_I2C_MASTER_SEND_PEC_SHIFT);
654 
655 	/* Clear status bits. */
656 	writel(0x0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_STATUS);
657 	/* Set the cause data. */
658 	writel(~0x0, priv->mst_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
659 	/* Zero PEC byte. */
660 	writel(0x0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_PEC);
661 	/* Zero byte count. */
662 	writel(0x0, priv->mst->io + priv->chip->smbus_master_rs_bytes_off);
663 
664 	/* GW activation. */
665 	writel(command, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
666 
667 	/*
668 	 * Poll master status and check status bits. An ACK is sent when
669 	 * completing writing data to the bus (Master 'byte_count_done' bit
670 	 * is set to 1).
671 	 */
672 	return mlxbf_i2c_smbus_check_status(priv);
673 }
674 
675 static int
mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv * priv,struct mlxbf_i2c_smbus_request * request)676 mlxbf_i2c_smbus_start_transaction(struct mlxbf_i2c_priv *priv,
677 				  struct mlxbf_i2c_smbus_request *request)
678 {
679 	u8 data_desc[MLXBF_I2C_MASTER_DATA_DESC_SIZE] = { 0 };
680 	u8 op_idx, data_idx, data_len, write_len, read_len;
681 	struct mlxbf_i2c_smbus_operation *operation;
682 	u8 read_en, write_en, block_en, pec_en;
683 	bool stop_after_write = true;
684 	u8 slave, addr;
685 	u8 *read_buf;
686 	u32 flags;
687 	u32 bits;
688 	int ret;
689 
690 	if (request->operation_cnt > MLXBF_I2C_SMBUS_MAX_OP_CNT)
691 		return -EINVAL;
692 
693 	read_buf = NULL;
694 	data_idx = 0;
695 	read_en = 0;
696 	write_en = 0;
697 	write_len = 0;
698 	read_len = 0;
699 	block_en = 0;
700 	pec_en = 0;
701 	slave = request->slave & GENMASK(6, 0);
702 	addr = slave << 1;
703 
704 	/*
705 	 * Try to acquire the smbus gw lock before any reads of the GW register since
706 	 * a read sets the lock.
707 	 */
708 	ret = readl_poll_timeout_atomic(priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW,
709 					bits, !(bits & MLXBF_I2C_MASTER_LOCK_BIT),
710 					MLXBF_I2C_POLL_FREQ_IN_USEC,
711 					MLXBF_I2C_SMBUS_LOCK_POLL_TIMEOUT);
712 	if (WARN_ON(ret))
713 		return -EBUSY;
714 
715 	/*
716 	 * SW must make sure that the SMBus Master GW is idle before starting
717 	 * a transaction. Accordingly, this call polls the Master FSM stop bit;
718 	 * it returns -ETIMEDOUT when the bit is asserted, 0 if not.
719 	 */
720 	ret = readl_poll_timeout_atomic(priv->mst->io + priv->chip->smbus_master_fsm_off,
721 					bits, !(bits & MLXBF_I2C_SMBUS_MASTER_FSM_STOP_MASK),
722 					MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
723 	if (WARN_ON(ret)) {
724 		ret = -EBUSY;
725 		goto out_unlock;
726 	}
727 
728 	/* Set first byte. */
729 	data_desc[data_idx++] = addr;
730 
731 	for (op_idx = 0; op_idx < request->operation_cnt; op_idx++) {
732 		operation = &request->operation[op_idx];
733 		flags = operation->flags;
734 
735 		/*
736 		 * Note that read and write operations might be handled by a
737 		 * single command. If the MLXBF_I2C_F_SMBUS_OPERATION is set
738 		 * then write command byte and set the optional SMBus specific
739 		 * bits such as block_en and pec_en. These bits MUST be
740 		 * submitted by the first operation only.
741 		 */
742 		if (op_idx == 0 && flags & MLXBF_I2C_F_SMBUS_OPERATION) {
743 			block_en = flags & MLXBF_I2C_F_SMBUS_BLOCK;
744 			pec_en = flags & MLXBF_I2C_F_SMBUS_PEC;
745 		}
746 
747 		if (flags & MLXBF_I2C_F_WRITE) {
748 			write_en = 1;
749 			write_len += operation->length;
750 			if (data_idx + operation->length >
751 					MLXBF_I2C_MASTER_DATA_DESC_SIZE) {
752 				ret = -ENOBUFS;
753 				goto out_unlock;
754 			}
755 			memcpy(data_desc + data_idx,
756 			       operation->buffer, operation->length);
757 			data_idx += operation->length;
758 
759 			/*
760 			 * The stop condition can be skipped when writing on the bus
761 			 * to implement a repeated start condition on the next read
762 			 * as required for several SMBus and I2C operations.
763 			 */
764 			if (flags & MLXBF_I2C_F_WRITE_WITHOUT_STOP)
765 				stop_after_write = false;
766 		}
767 
768 		/*
769 		 * We assume that read operations are performed only once per
770 		 * SMBus transaction. *TBD* protect this statement so it won't
771 		 * be executed twice? or return an error if we try to read more
772 		 * than once?
773 		 */
774 		if (flags & MLXBF_I2C_F_READ) {
775 			read_en = 1;
776 			/* Subtract 1 as required by HW. */
777 			read_len = operation->length - 1;
778 			read_buf = operation->buffer;
779 		}
780 	}
781 
782 	/* Set Master GW data descriptor. */
783 	data_len = write_len + 1; /* Add one byte of the slave address. */
784 	/*
785 	 * Note that data_len cannot be 0. Indeed, the slave address byte
786 	 * must be written to the data registers.
787 	 */
788 	mlxbf_i2c_smbus_write_data(priv, (const u8 *)data_desc, data_len,
789 				   MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
790 
791 	if (write_en) {
792 		ret = mlxbf_i2c_smbus_enable(priv, slave, write_len, block_en,
793 					 pec_en, 0, stop_after_write);
794 		if (ret)
795 			goto out_unlock;
796 	}
797 
798 	if (read_en) {
799 		/* Write slave address to Master GW data descriptor. */
800 		mlxbf_i2c_smbus_write_data(priv, (const u8 *)&addr, 1,
801 					   MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
802 		ret = mlxbf_i2c_smbus_enable(priv, slave, read_len, block_en,
803 					 pec_en, 1, true);
804 		if (!ret) {
805 			/* Get Master GW data descriptor. */
806 			mlxbf_i2c_smbus_read_data(priv, data_desc, read_len + 1,
807 					     MLXBF_I2C_MASTER_DATA_DESC_ADDR, true);
808 
809 			/* Get data from Master GW data descriptor. */
810 			memcpy(read_buf, data_desc, read_len + 1);
811 		}
812 
813 		/*
814 		 * After a read operation the SMBus FSM ps (present state)
815 		 * needs to be 'manually' reset. This should be removed in
816 		 * next tag integration.
817 		 */
818 		writel(MLXBF_I2C_SMBUS_MASTER_FSM_PS_STATE_MASK,
819 			priv->mst->io + priv->chip->smbus_master_fsm_off);
820 	}
821 
822 out_unlock:
823 	/* Clear the gw to clear the lock */
824 	writel(0, priv->mst->io + MLXBF_I2C_SMBUS_MASTER_GW);
825 
826 	return ret;
827 }
828 
829 /* I2C SMBus protocols. */
830 
831 static void
mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request * request,u8 read)832 mlxbf_i2c_smbus_quick_command(struct mlxbf_i2c_smbus_request *request,
833 			      u8 read)
834 {
835 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1;
836 
837 	request->operation[0].length = 0;
838 	request->operation[0].flags = MLXBF_I2C_F_WRITE;
839 	request->operation[0].flags |= read ? MLXBF_I2C_F_READ : 0;
840 }
841 
mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request * request,u8 * data,bool read,bool pec_check)842 static void mlxbf_i2c_smbus_byte_func(struct mlxbf_i2c_smbus_request *request,
843 				      u8 *data, bool read, bool pec_check)
844 {
845 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_1;
846 
847 	request->operation[0].length = 1;
848 	request->operation[0].length += pec_check;
849 
850 	request->operation[0].flags = MLXBF_I2C_F_SMBUS_OPERATION;
851 	request->operation[0].flags |= read ?
852 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
853 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
854 
855 	request->operation[0].buffer = data;
856 }
857 
858 static void
mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool read,bool pec_check)859 mlxbf_i2c_smbus_data_byte_func(struct mlxbf_i2c_smbus_request *request,
860 			       u8 *command, u8 *data, bool read, bool pec_check)
861 {
862 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
863 
864 	request->operation[0].length = 1;
865 	request->operation[0].flags =
866 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
867 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
868 	request->operation[0].buffer = command;
869 
870 	request->operation[1].length = 1;
871 	request->operation[1].length += pec_check;
872 	request->operation[1].flags = read ?
873 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
874 	request->operation[1].buffer = data;
875 }
876 
877 static void
mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool read,bool pec_check)878 mlxbf_i2c_smbus_data_word_func(struct mlxbf_i2c_smbus_request *request,
879 			       u8 *command, u8 *data, bool read, bool pec_check)
880 {
881 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
882 
883 	request->operation[0].length = 1;
884 	request->operation[0].flags =
885 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
886 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
887 	request->operation[0].buffer = command;
888 
889 	request->operation[1].length = 2;
890 	request->operation[1].length += pec_check;
891 	request->operation[1].flags = read ?
892 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
893 	request->operation[1].buffer = data;
894 }
895 
896 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)897 mlxbf_i2c_smbus_i2c_block_func(struct mlxbf_i2c_smbus_request *request,
898 			       u8 *command, u8 *data, u8 *data_len, bool read,
899 			       bool pec_check)
900 {
901 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
902 
903 	request->operation[0].length = 1;
904 	request->operation[0].flags =
905 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
906 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
907 	request->operation[0].buffer = command;
908 
909 	if (read)
910 		request->operation[0].flags |= MLXBF_I2C_F_WRITE_WITHOUT_STOP;
911 
912 	/*
913 	 * As specified in the standard, the max number of bytes to read/write
914 	 * per block operation is 32 bytes. In Golan code, the controller can
915 	 * read up to 128 bytes and write up to 127 bytes.
916 	 */
917 	request->operation[1].length =
918 	    (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
919 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
920 	request->operation[1].flags = read ?
921 				MLXBF_I2C_F_READ : MLXBF_I2C_F_WRITE;
922 	/*
923 	 * Skip the first data byte, which corresponds to the number of bytes
924 	 * to read/write.
925 	 */
926 	request->operation[1].buffer = data + 1;
927 
928 	*data_len = request->operation[1].length;
929 
930 	/* Set the number of byte to read. This will be used by userspace. */
931 	if (read)
932 		data[0] = *data_len;
933 }
934 
mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,u8 * data_len,bool read,bool pec_check)935 static void mlxbf_i2c_smbus_block_func(struct mlxbf_i2c_smbus_request *request,
936 				       u8 *command, u8 *data, u8 *data_len,
937 				       bool read, bool pec_check)
938 {
939 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_2;
940 
941 	request->operation[0].length = 1;
942 	request->operation[0].flags =
943 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
944 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
945 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
946 	request->operation[0].buffer = command;
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 	request->operation[1].buffer = data + 1;
954 
955 	*data_len = request->operation[1].length;
956 
957 	/* Set the number of bytes to read. This will be used by userspace. */
958 	if (read)
959 		data[0] = *data_len;
960 }
961 
962 static void
mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request * request,u8 * command,u8 * data,bool pec_check)963 mlxbf_i2c_smbus_process_call_func(struct mlxbf_i2c_smbus_request *request,
964 				  u8 *command, u8 *data, bool pec_check)
965 {
966 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3;
967 
968 	request->operation[0].length = 1;
969 	request->operation[0].flags =
970 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
971 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
972 	request->operation[0].flags |= pec_check ? MLXBF_I2C_F_SMBUS_PEC : 0;
973 	request->operation[0].buffer = command;
974 
975 	request->operation[1].length = 2;
976 	request->operation[1].flags = MLXBF_I2C_F_WRITE;
977 	request->operation[1].buffer = data;
978 
979 	request->operation[2].length = 3;
980 	request->operation[2].flags = MLXBF_I2C_F_READ;
981 	request->operation[2].buffer = data;
982 }
983 
984 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)985 mlxbf_i2c_smbus_blk_process_call_func(struct mlxbf_i2c_smbus_request *request,
986 				      u8 *command, u8 *data, u8 *data_len,
987 				      bool pec_check)
988 {
989 	u32 length;
990 
991 	request->operation_cnt = MLXBF_I2C_SMBUS_OP_CNT_3;
992 
993 	request->operation[0].length = 1;
994 	request->operation[0].flags =
995 			MLXBF_I2C_F_SMBUS_OPERATION | MLXBF_I2C_F_WRITE;
996 	request->operation[0].flags |= MLXBF_I2C_F_SMBUS_BLOCK;
997 	request->operation[0].flags |= (pec_check) ? MLXBF_I2C_F_SMBUS_PEC : 0;
998 	request->operation[0].buffer = command;
999 
1000 	length = (*data_len + pec_check > I2C_SMBUS_BLOCK_MAX) ?
1001 	    I2C_SMBUS_BLOCK_MAX : *data_len + pec_check;
1002 
1003 	request->operation[1].length = length - pec_check;
1004 	request->operation[1].flags = MLXBF_I2C_F_WRITE;
1005 	request->operation[1].buffer = data;
1006 
1007 	request->operation[2].length = length;
1008 	request->operation[2].flags = MLXBF_I2C_F_READ;
1009 	request->operation[2].buffer = data;
1010 
1011 	*data_len = length; /* including PEC byte. */
1012 }
1013 
1014 /* Initialization functions. */
1015 
mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv * priv,u8 type)1016 static bool mlxbf_i2c_has_chip_type(struct mlxbf_i2c_priv *priv, u8 type)
1017 {
1018 	return priv->chip->type == type;
1019 }
1020 
1021 static struct mlxbf_i2c_resource *
mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv * priv,u8 type)1022 mlxbf_i2c_get_shared_resource(struct mlxbf_i2c_priv *priv, u8 type)
1023 {
1024 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1025 	struct mlxbf_i2c_resource *res;
1026 	u8 res_idx = 0;
1027 
1028 	for (res_idx = 0; res_idx < MLXBF_I2C_SHARED_RES_MAX; res_idx++) {
1029 		res = chip->shared_res[res_idx];
1030 		if (res && res->type == type)
1031 			return res;
1032 	}
1033 
1034 	return NULL;
1035 }
1036 
mlxbf_i2c_init_resource(struct platform_device * pdev,struct mlxbf_i2c_resource ** res,u8 type)1037 static int mlxbf_i2c_init_resource(struct platform_device *pdev,
1038 				   struct mlxbf_i2c_resource **res,
1039 				   u8 type)
1040 {
1041 	struct mlxbf_i2c_resource *tmp_res;
1042 	struct device *dev = &pdev->dev;
1043 
1044 	if (!res || *res || type >= MLXBF_I2C_END_RES)
1045 		return -EINVAL;
1046 
1047 	tmp_res = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource),
1048 			       GFP_KERNEL);
1049 	if (!tmp_res)
1050 		return -ENOMEM;
1051 
1052 	tmp_res->io = devm_platform_get_and_ioremap_resource(pdev, type, &tmp_res->params);
1053 	if (IS_ERR(tmp_res->io)) {
1054 		int ret = PTR_ERR(tmp_res->io);
1055 
1056 		devm_kfree(dev, tmp_res);
1057 		return ret;
1058 	}
1059 
1060 	tmp_res->type = type;
1061 
1062 	*res = tmp_res;
1063 
1064 	return 0;
1065 }
1066 
mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv * priv,u64 nanoseconds,bool minimum)1067 static u32 mlxbf_i2c_get_ticks(struct mlxbf_i2c_priv *priv, u64 nanoseconds,
1068 			       bool minimum)
1069 {
1070 	u64 frequency;
1071 	u32 ticks;
1072 
1073 	/*
1074 	 * Compute ticks as follow:
1075 	 *
1076 	 *           Ticks
1077 	 * Time = --------- x 10^9    =>    Ticks = Time x Frequency x 10^-9
1078 	 *         Frequency
1079 	 */
1080 	frequency = priv->frequency;
1081 	ticks = div_u64(nanoseconds * frequency, HZ_PER_GHZ);
1082 	/*
1083 	 * The number of ticks is rounded down and if minimum is equal to 1
1084 	 * then add one tick.
1085 	 */
1086 	if (minimum)
1087 		ticks++;
1088 
1089 	return ticks;
1090 }
1091 
mlxbf_i2c_set_timer(struct mlxbf_i2c_priv * priv,u64 nsec,bool opt,u32 mask,u8 shift)1092 static u32 mlxbf_i2c_set_timer(struct mlxbf_i2c_priv *priv, u64 nsec, bool opt,
1093 			       u32 mask, u8 shift)
1094 {
1095 	u32 val = (mlxbf_i2c_get_ticks(priv, nsec, opt) & mask) << shift;
1096 
1097 	return val;
1098 }
1099 
mlxbf_i2c_set_timings(struct mlxbf_i2c_priv * priv,const struct mlxbf_i2c_timings * timings)1100 static void mlxbf_i2c_set_timings(struct mlxbf_i2c_priv *priv,
1101 				  const struct mlxbf_i2c_timings *timings)
1102 {
1103 	u32 timer;
1104 
1105 	timer = mlxbf_i2c_set_timer(priv, timings->scl_high,
1106 				    false, MLXBF_I2C_MASK_16,
1107 				    MLXBF_I2C_SHIFT_0);
1108 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_low,
1109 				     false, MLXBF_I2C_MASK_16,
1110 				     MLXBF_I2C_SHIFT_16);
1111 	writel(timer, priv->timer->io +
1112 		MLXBF_I2C_SMBUS_TIMER_SCL_LOW_SCL_HIGH);
1113 
1114 	timer = mlxbf_i2c_set_timer(priv, timings->sda_rise, false,
1115 				    MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_0);
1116 	timer |= mlxbf_i2c_set_timer(priv, timings->sda_fall, false,
1117 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_8);
1118 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_rise, false,
1119 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_16);
1120 	timer |= mlxbf_i2c_set_timer(priv, timings->scl_fall, false,
1121 				     MLXBF_I2C_MASK_8, MLXBF_I2C_SHIFT_24);
1122 	writel(timer, priv->timer->io +
1123 		MLXBF_I2C_SMBUS_TIMER_FALL_RISE_SPIKE);
1124 
1125 	timer = mlxbf_i2c_set_timer(priv, timings->hold_start, true,
1126 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1127 	timer |= mlxbf_i2c_set_timer(priv, timings->hold_data, true,
1128 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1129 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_TIMER_THOLD);
1130 
1131 	timer = mlxbf_i2c_set_timer(priv, timings->setup_start, true,
1132 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1133 	timer |= mlxbf_i2c_set_timer(priv, timings->setup_stop, true,
1134 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1135 	writel(timer, priv->timer->io +
1136 		MLXBF_I2C_SMBUS_TIMER_TSETUP_START_STOP);
1137 
1138 	timer = mlxbf_i2c_set_timer(priv, timings->setup_data, true,
1139 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1140 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_TIMER_TSETUP_DATA);
1141 
1142 	timer = mlxbf_i2c_set_timer(priv, timings->buf, false,
1143 				    MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_0);
1144 	timer |= mlxbf_i2c_set_timer(priv, timings->thigh_max, false,
1145 				     MLXBF_I2C_MASK_16, MLXBF_I2C_SHIFT_16);
1146 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_THIGH_MAX_TBUF);
1147 
1148 	timer = mlxbf_i2c_set_timer(priv, timings->timeout, false,
1149 				    MLXBF_I2C_MASK_32, MLXBF_I2C_SHIFT_0);
1150 	writel(timer, priv->timer->io + MLXBF_I2C_SMBUS_SCL_LOW_TIMEOUT);
1151 }
1152 
1153 enum mlxbf_i2c_timings_config {
1154 	MLXBF_I2C_TIMING_CONFIG_100KHZ,
1155 	MLXBF_I2C_TIMING_CONFIG_400KHZ,
1156 	MLXBF_I2C_TIMING_CONFIG_1000KHZ,
1157 };
1158 
1159 /* Timing values are in nanoseconds */
1160 static const struct mlxbf_i2c_timings mlxbf_i2c_timings[] = {
1161 	[MLXBF_I2C_TIMING_CONFIG_100KHZ] = {
1162 		.scl_high = 4810,
1163 		.scl_low = 5000,
1164 		.hold_start = 4000,
1165 		.setup_start = 4800,
1166 		.setup_stop = 4000,
1167 		.setup_data = 250,
1168 		.sda_rise = 50,
1169 		.sda_fall = 50,
1170 		.scl_rise = 50,
1171 		.scl_fall = 50,
1172 		.hold_data = 300,
1173 		.buf = 20000,
1174 		.thigh_max = 50000,
1175 		.timeout = 35000000
1176 	},
1177 	[MLXBF_I2C_TIMING_CONFIG_400KHZ] = {
1178 		.scl_high = 1011,
1179 		.scl_low = 1300,
1180 		.hold_start = 600,
1181 		.setup_start = 700,
1182 		.setup_stop = 600,
1183 		.setup_data = 100,
1184 		.sda_rise = 50,
1185 		.sda_fall = 50,
1186 		.scl_rise = 50,
1187 		.scl_fall = 50,
1188 		.hold_data = 300,
1189 		.buf = 20000,
1190 		.thigh_max = 50000,
1191 		.timeout = 35000000
1192 	},
1193 	[MLXBF_I2C_TIMING_CONFIG_1000KHZ] = {
1194 		.scl_high = 383,
1195 		.scl_low = 460,
1196 		.hold_start = 600,
1197 		.setup_start = 260,
1198 		.setup_stop = 260,
1199 		.setup_data = 50,
1200 		.sda_rise = 50,
1201 		.sda_fall = 50,
1202 		.scl_rise = 50,
1203 		.scl_fall = 50,
1204 		.hold_data = 300,
1205 		.buf = 500,
1206 		.thigh_max = 50000,
1207 		.timeout = 35000000
1208 	}
1209 };
1210 
mlxbf_i2c_init_timings(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1211 static int mlxbf_i2c_init_timings(struct platform_device *pdev,
1212 				  struct mlxbf_i2c_priv *priv)
1213 {
1214 	enum mlxbf_i2c_timings_config config_idx;
1215 	struct device *dev = &pdev->dev;
1216 	u32 config_khz;
1217 
1218 	int ret;
1219 
1220 	ret = device_property_read_u32(dev, "clock-frequency", &config_khz);
1221 	if (ret < 0)
1222 		config_khz = I2C_MAX_STANDARD_MODE_FREQ;
1223 
1224 	switch (config_khz) {
1225 	default:
1226 		/* Default settings is 100 KHz. */
1227 		pr_warn("Illegal value %d: defaulting to 100 KHz\n",
1228 			config_khz);
1229 		fallthrough;
1230 	case I2C_MAX_STANDARD_MODE_FREQ:
1231 		config_idx = MLXBF_I2C_TIMING_CONFIG_100KHZ;
1232 		break;
1233 
1234 	case I2C_MAX_FAST_MODE_FREQ:
1235 		config_idx = MLXBF_I2C_TIMING_CONFIG_400KHZ;
1236 		break;
1237 
1238 	case I2C_MAX_FAST_MODE_PLUS_FREQ:
1239 		config_idx = MLXBF_I2C_TIMING_CONFIG_1000KHZ;
1240 		break;
1241 	}
1242 
1243 	mlxbf_i2c_set_timings(priv, &mlxbf_i2c_timings[config_idx]);
1244 
1245 	return 0;
1246 }
1247 
mlxbf_i2c_get_gpio(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1248 static int mlxbf_i2c_get_gpio(struct platform_device *pdev,
1249 			      struct mlxbf_i2c_priv *priv)
1250 {
1251 	struct mlxbf_i2c_resource *gpio_res;
1252 	struct device *dev = &pdev->dev;
1253 	struct resource	*params;
1254 	resource_size_t size;
1255 
1256 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1257 	if (!gpio_res)
1258 		return -EPERM;
1259 
1260 	/*
1261 	 * The GPIO region in TYU space is shared among I2C busses.
1262 	 * This function MUST be serialized to avoid racing when
1263 	 * claiming the memory region and/or setting up the GPIO.
1264 	 */
1265 	lockdep_assert_held(gpio_res->lock);
1266 
1267 	/* Check whether the memory map exist. */
1268 	if (gpio_res->io)
1269 		return 0;
1270 
1271 	params = gpio_res->params;
1272 	size = resource_size(params);
1273 
1274 	if (!devm_request_mem_region(dev, params->start, size, params->name))
1275 		return -EFAULT;
1276 
1277 	gpio_res->io = devm_ioremap(dev, params->start, size);
1278 	if (!gpio_res->io) {
1279 		devm_release_mem_region(dev, params->start, size);
1280 		return -ENOMEM;
1281 	}
1282 
1283 	return 0;
1284 }
1285 
mlxbf_i2c_release_gpio(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1286 static int mlxbf_i2c_release_gpio(struct platform_device *pdev,
1287 				  struct mlxbf_i2c_priv *priv)
1288 {
1289 	struct mlxbf_i2c_resource *gpio_res;
1290 	struct device *dev = &pdev->dev;
1291 	struct resource	*params;
1292 
1293 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1294 	if (!gpio_res)
1295 		return 0;
1296 
1297 	mutex_lock(gpio_res->lock);
1298 
1299 	if (gpio_res->io) {
1300 		/* Release the GPIO resource. */
1301 		params = gpio_res->params;
1302 		devm_iounmap(dev, gpio_res->io);
1303 		devm_release_mem_region(dev, params->start,
1304 					resource_size(params));
1305 	}
1306 
1307 	mutex_unlock(gpio_res->lock);
1308 
1309 	return 0;
1310 }
1311 
mlxbf_i2c_get_corepll(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1312 static int mlxbf_i2c_get_corepll(struct platform_device *pdev,
1313 				 struct mlxbf_i2c_priv *priv)
1314 {
1315 	struct mlxbf_i2c_resource *corepll_res;
1316 	struct device *dev = &pdev->dev;
1317 	struct resource *params;
1318 	resource_size_t size;
1319 
1320 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1321 						    MLXBF_I2C_COREPLL_RES);
1322 	if (!corepll_res)
1323 		return -EPERM;
1324 
1325 	/*
1326 	 * The COREPLL region in TYU space is shared among I2C busses.
1327 	 * This function MUST be serialized to avoid racing when
1328 	 * claiming the memory region.
1329 	 */
1330 	lockdep_assert_held(corepll_res->lock);
1331 
1332 	/* Check whether the memory map exist. */
1333 	if (corepll_res->io)
1334 		return 0;
1335 
1336 	params = corepll_res->params;
1337 	size = resource_size(params);
1338 
1339 	if (!devm_request_mem_region(dev, params->start, size, params->name))
1340 		return -EFAULT;
1341 
1342 	corepll_res->io = devm_ioremap(dev, params->start, size);
1343 	if (!corepll_res->io) {
1344 		devm_release_mem_region(dev, params->start, size);
1345 		return -ENOMEM;
1346 	}
1347 
1348 	return 0;
1349 }
1350 
mlxbf_i2c_release_corepll(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1351 static int mlxbf_i2c_release_corepll(struct platform_device *pdev,
1352 				     struct mlxbf_i2c_priv *priv)
1353 {
1354 	struct mlxbf_i2c_resource *corepll_res;
1355 	struct device *dev = &pdev->dev;
1356 	struct resource *params;
1357 
1358 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1359 						    MLXBF_I2C_COREPLL_RES);
1360 
1361 	mutex_lock(corepll_res->lock);
1362 
1363 	if (corepll_res->io) {
1364 		/* Release the CorePLL resource. */
1365 		params = corepll_res->params;
1366 		devm_iounmap(dev, corepll_res->io);
1367 		devm_release_mem_region(dev, params->start,
1368 					resource_size(params));
1369 	}
1370 
1371 	mutex_unlock(corepll_res->lock);
1372 
1373 	return 0;
1374 }
1375 
mlxbf_i2c_init_master(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1376 static int mlxbf_i2c_init_master(struct platform_device *pdev,
1377 				 struct mlxbf_i2c_priv *priv)
1378 {
1379 	struct mlxbf_i2c_resource *gpio_res;
1380 	struct device *dev = &pdev->dev;
1381 	u32 config_reg;
1382 	int ret;
1383 
1384 	/* This configuration is only needed for BlueField 1. */
1385 	if (!mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1))
1386 		return 0;
1387 
1388 	gpio_res = mlxbf_i2c_get_shared_resource(priv, MLXBF_I2C_GPIO_RES);
1389 	if (!gpio_res)
1390 		return -EPERM;
1391 
1392 	/*
1393 	 * The GPIO region in TYU space is shared among I2C busses.
1394 	 * This function MUST be serialized to avoid racing when
1395 	 * claiming the memory region and/or setting up the GPIO.
1396 	 */
1397 
1398 	mutex_lock(gpio_res->lock);
1399 
1400 	ret = mlxbf_i2c_get_gpio(pdev, priv);
1401 	if (ret < 0) {
1402 		dev_err(dev, "Failed to get gpio resource");
1403 		mutex_unlock(gpio_res->lock);
1404 		return ret;
1405 	}
1406 
1407 	/*
1408 	 * TYU - Configuration for GPIO pins. Those pins must be asserted in
1409 	 * MLXBF_I2C_GPIO_0_FUNC_EN_0, i.e. GPIO 0 is controlled by HW, and must
1410 	 * be reset in MLXBF_I2C_GPIO_0_FORCE_OE_EN, i.e. GPIO_OE will be driven
1411 	 * instead of HW_OE.
1412 	 * For now, we do not reset the GPIO state when the driver is removed.
1413 	 * First, it is not necessary to disable the bus since we are using
1414 	 * the same busses. Then, some busses might be shared among Linux and
1415 	 * platform firmware; disabling the bus might compromise the system
1416 	 * functionality.
1417 	 */
1418 	config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0);
1419 	config_reg = MLXBF_I2C_GPIO_SMBUS_GW_ASSERT_PINS(priv->bus,
1420 							 config_reg);
1421 	writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FUNC_EN_0);
1422 
1423 	config_reg = readl(gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN);
1424 	config_reg = MLXBF_I2C_GPIO_SMBUS_GW_RESET_PINS(priv->bus,
1425 							config_reg);
1426 	writel(config_reg, gpio_res->io + MLXBF_I2C_GPIO_0_FORCE_OE_EN);
1427 
1428 	mutex_unlock(gpio_res->lock);
1429 
1430 	return 0;
1431 }
1432 
mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource * corepll_res)1433 static u64 mlxbf_i2c_calculate_freq_from_tyu(struct mlxbf_i2c_resource *corepll_res)
1434 {
1435 	u64 core_frequency;
1436 	u8 core_od, core_r;
1437 	u32 corepll_val;
1438 	u16 core_f;
1439 
1440 	corepll_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1);
1441 
1442 	/* Get Core PLL configuration bits. */
1443 	core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_TYU_MASK, corepll_val);
1444 	core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_TYU_MASK, corepll_val);
1445 	core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_TYU_MASK, corepll_val);
1446 
1447 	/*
1448 	 * Compute PLL output frequency as follow:
1449 	 *
1450 	 *                                       CORE_F + 1
1451 	 * PLL_OUT_FREQ = PLL_IN_FREQ * ----------------------------
1452 	 *                              (CORE_R + 1) * (CORE_OD + 1)
1453 	 *
1454 	 * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency
1455 	 * and PadFrequency, respectively.
1456 	 */
1457 	core_frequency = MLXBF_I2C_PLL_IN_FREQ * (++core_f);
1458 
1459 	return div_u64(core_frequency, (++core_r) * (++core_od));
1460 }
1461 
mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource * corepll_res)1462 static u64 mlxbf_i2c_calculate_freq_from_yu(struct mlxbf_i2c_resource *corepll_res)
1463 {
1464 	u32 corepll_reg1_val, corepll_reg2_val;
1465 	u64 corepll_frequency;
1466 	u8 core_od, core_r;
1467 	u32 core_f;
1468 
1469 	corepll_reg1_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG1);
1470 	corepll_reg2_val = readl(corepll_res->io + MLXBF_I2C_CORE_PLL_REG2);
1471 
1472 	/* Get Core PLL configuration bits */
1473 	core_f = FIELD_GET(MLXBF_I2C_COREPLL_CORE_F_YU_MASK, corepll_reg1_val);
1474 	core_r = FIELD_GET(MLXBF_I2C_COREPLL_CORE_R_YU_MASK, corepll_reg1_val);
1475 	core_od = FIELD_GET(MLXBF_I2C_COREPLL_CORE_OD_YU_MASK, corepll_reg2_val);
1476 
1477 	/*
1478 	 * Compute PLL output frequency as follow:
1479 	 *
1480 	 *                                     CORE_F / 16384
1481 	 * PLL_OUT_FREQ = PLL_IN_FREQ * ----------------------------
1482 	 *                              (CORE_R + 1) * (CORE_OD + 1)
1483 	 *
1484 	 * Where PLL_OUT_FREQ and PLL_IN_FREQ refer to CoreFrequency
1485 	 * and PadFrequency, respectively.
1486 	 */
1487 	corepll_frequency = (MLXBF_I2C_PLL_IN_FREQ * core_f) / MLNXBF_I2C_COREPLL_CONST;
1488 
1489 	return div_u64(corepll_frequency, (++core_r) * (++core_od));
1490 }
1491 
mlxbf_i2c_calculate_corepll_freq(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1492 static int mlxbf_i2c_calculate_corepll_freq(struct platform_device *pdev,
1493 					    struct mlxbf_i2c_priv *priv)
1494 {
1495 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1496 	struct mlxbf_i2c_resource *corepll_res;
1497 	struct device *dev = &pdev->dev;
1498 	u64 *freq = &priv->frequency;
1499 	int ret;
1500 
1501 	corepll_res = mlxbf_i2c_get_shared_resource(priv,
1502 						    MLXBF_I2C_COREPLL_RES);
1503 	if (!corepll_res)
1504 		return -EPERM;
1505 
1506 	/*
1507 	 * First, check whether the TYU core Clock frequency is set.
1508 	 * The TYU core frequency is the same for all I2C busses; when
1509 	 * the first device gets probed the frequency is determined and
1510 	 * stored into a globally visible variable. So, first of all,
1511 	 * check whether the frequency is already set. Here, we assume
1512 	 * that the frequency is expected to be greater than 0.
1513 	 */
1514 	mutex_lock(corepll_res->lock);
1515 	if (!mlxbf_i2c_corepll_frequency) {
1516 		if (!chip->calculate_freq) {
1517 			mutex_unlock(corepll_res->lock);
1518 			return -EPERM;
1519 		}
1520 
1521 		ret = mlxbf_i2c_get_corepll(pdev, priv);
1522 		if (ret < 0) {
1523 			dev_err(dev, "Failed to get corePLL resource");
1524 			mutex_unlock(corepll_res->lock);
1525 			return ret;
1526 		}
1527 
1528 		mlxbf_i2c_corepll_frequency = chip->calculate_freq(corepll_res);
1529 	}
1530 	mutex_unlock(corepll_res->lock);
1531 
1532 	*freq = mlxbf_i2c_corepll_frequency;
1533 
1534 	return 0;
1535 }
1536 
mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv * priv,struct i2c_client * slave)1537 static int mlxbf_i2c_slave_enable(struct mlxbf_i2c_priv *priv,
1538 			      struct i2c_client *slave)
1539 {
1540 	u8 reg, reg_cnt, byte, addr_tmp;
1541 	u32 slave_reg, slave_reg_tmp;
1542 
1543 	if (!priv)
1544 		return -EPERM;
1545 
1546 	reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2;
1547 
1548 	/*
1549 	 * Read the slave registers. There are 4 * 32-bit slave registers.
1550 	 * Each slave register can hold up to 4 * 8-bit slave configuration:
1551 	 * 1) A 7-bit address
1552 	 * 2) And a status bit (1 if enabled, 0 if not).
1553 	 * Look for the next available slave register slot.
1554 	 */
1555 	for (reg = 0; reg < reg_cnt; reg++) {
1556 		slave_reg = readl(priv->slv->io +
1557 				MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4);
1558 		/*
1559 		 * Each register holds 4 slave addresses. So, we have to keep
1560 		 * the byte order consistent with the value read in order to
1561 		 * update the register correctly, if needed.
1562 		 */
1563 		slave_reg_tmp = slave_reg;
1564 		for (byte = 0; byte < 4; byte++) {
1565 			addr_tmp = slave_reg_tmp & GENMASK(7, 0);
1566 
1567 			/*
1568 			 * If an enable bit is not set in the
1569 			 * MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG register, then the
1570 			 * slave address slot associated with that bit is
1571 			 * free. So set the enable bit and write the
1572 			 * slave address bits.
1573 			 */
1574 			if (!(addr_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT)) {
1575 				slave_reg &= ~(MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK << (byte * 8));
1576 				slave_reg |= (slave->addr << (byte * 8));
1577 				slave_reg |= MLXBF_I2C_SMBUS_SLAVE_ADDR_EN_BIT << (byte * 8);
1578 				writel(slave_reg, priv->slv->io +
1579 					MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG +
1580 					(reg * 0x4));
1581 
1582 				/*
1583 				 * Set the slave at the corresponding index.
1584 				 */
1585 				priv->slave[(reg * 4) + byte] = slave;
1586 
1587 				return 0;
1588 			}
1589 
1590 			/* Parse next byte. */
1591 			slave_reg_tmp >>= 8;
1592 		}
1593 	}
1594 
1595 	return -EBUSY;
1596 }
1597 
mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv * priv,u8 addr)1598 static int mlxbf_i2c_slave_disable(struct mlxbf_i2c_priv *priv, u8 addr)
1599 {
1600 	u8 addr_tmp, reg, reg_cnt, byte;
1601 	u32 slave_reg, slave_reg_tmp;
1602 
1603 	reg_cnt = MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT >> 2;
1604 
1605 	/*
1606 	 * Read the slave registers. There are 4 * 32-bit slave registers.
1607 	 * Each slave register can hold up to 4 * 8-bit slave configuration:
1608 	 * 1) A 7-bit address
1609 	 * 2) And a status bit (1 if enabled, 0 if not).
1610 	 * Check if addr is present in the registers.
1611 	 */
1612 	for (reg = 0; reg < reg_cnt; reg++) {
1613 		slave_reg = readl(priv->slv->io +
1614 				MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG + reg * 0x4);
1615 
1616 		/* Check whether the address slots are empty. */
1617 		if (!slave_reg)
1618 			continue;
1619 
1620 		/*
1621 		 * Check if addr matches any of the 4 slave addresses
1622 		 * in the register.
1623 		 */
1624 		slave_reg_tmp = slave_reg;
1625 		for (byte = 0; byte < 4; byte++) {
1626 			addr_tmp = slave_reg_tmp & MLXBF_I2C_SMBUS_SLAVE_ADDR_MASK;
1627 			/*
1628 			 * Parse slave address bytes and check whether the
1629 			 * slave address already exists.
1630 			 */
1631 			if (addr_tmp == addr) {
1632 				/* Clear the slave address slot. */
1633 				slave_reg &= ~(GENMASK(7, 0) << (byte * 8));
1634 				writel(slave_reg, priv->slv->io +
1635 					MLXBF_I2C_SMBUS_SLAVE_ADDR_CFG +
1636 					(reg * 0x4));
1637 				/* Free slave at the corresponding index */
1638 				priv->slave[(reg * 4) + byte] = NULL;
1639 
1640 				return 0;
1641 			}
1642 
1643 			/* Parse next byte. */
1644 			slave_reg_tmp >>= 8;
1645 		}
1646 	}
1647 
1648 	return -ENXIO;
1649 }
1650 
mlxbf_i2c_init_coalesce(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1651 static int mlxbf_i2c_init_coalesce(struct platform_device *pdev,
1652 				   struct mlxbf_i2c_priv *priv)
1653 {
1654 	struct mlxbf_i2c_resource *coalesce_res;
1655 	struct resource *params;
1656 	resource_size_t size;
1657 	int ret = 0;
1658 
1659 	/*
1660 	 * Unlike BlueField-1 platform, the coalesce registers is a dedicated
1661 	 * resource in the next generations of BlueField.
1662 	 */
1663 	if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) {
1664 		coalesce_res = mlxbf_i2c_get_shared_resource(priv,
1665 						MLXBF_I2C_COALESCE_RES);
1666 		if (!coalesce_res)
1667 			return -EPERM;
1668 
1669 		/*
1670 		 * The Cause Coalesce group in TYU space is shared among
1671 		 * I2C busses. This function MUST be serialized to avoid
1672 		 * racing when claiming the memory region.
1673 		 */
1674 		lockdep_assert_held(mlxbf_i2c_gpio_res->lock);
1675 
1676 		/* Check whether the memory map exist. */
1677 		if (coalesce_res->io) {
1678 			priv->coalesce = coalesce_res;
1679 			return 0;
1680 		}
1681 
1682 		params = coalesce_res->params;
1683 		size = resource_size(params);
1684 
1685 		if (!request_mem_region(params->start, size, params->name))
1686 			return -EFAULT;
1687 
1688 		coalesce_res->io = ioremap(params->start, size);
1689 		if (!coalesce_res->io) {
1690 			release_mem_region(params->start, size);
1691 			return -ENOMEM;
1692 		}
1693 
1694 		priv->coalesce = coalesce_res;
1695 
1696 	} else {
1697 		ret = mlxbf_i2c_init_resource(pdev, &priv->coalesce,
1698 					      MLXBF_I2C_COALESCE_RES);
1699 	}
1700 
1701 	return ret;
1702 }
1703 
mlxbf_i2c_release_coalesce(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1704 static int mlxbf_i2c_release_coalesce(struct platform_device *pdev,
1705 				      struct mlxbf_i2c_priv *priv)
1706 {
1707 	struct mlxbf_i2c_resource *coalesce_res;
1708 	struct device *dev = &pdev->dev;
1709 	struct resource *params;
1710 	resource_size_t size;
1711 
1712 	coalesce_res = priv->coalesce;
1713 
1714 	if (coalesce_res->io) {
1715 		params = coalesce_res->params;
1716 		size = resource_size(params);
1717 		if (mlxbf_i2c_has_chip_type(priv, MLXBF_I2C_CHIP_TYPE_1)) {
1718 			mutex_lock(coalesce_res->lock);
1719 			iounmap(coalesce_res->io);
1720 			release_mem_region(params->start, size);
1721 			mutex_unlock(coalesce_res->lock);
1722 		} else {
1723 			devm_release_mem_region(dev, params->start, size);
1724 		}
1725 	}
1726 
1727 	return 0;
1728 }
1729 
mlxbf_i2c_init_slave(struct platform_device * pdev,struct mlxbf_i2c_priv * priv)1730 static int mlxbf_i2c_init_slave(struct platform_device *pdev,
1731 				struct mlxbf_i2c_priv *priv)
1732 {
1733 	struct device *dev = &pdev->dev;
1734 	u32 int_reg;
1735 	int ret;
1736 
1737 	/* Reset FSM. */
1738 	writel(0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_FSM);
1739 
1740 	/*
1741 	 * Enable slave cause interrupt bits. Drive
1742 	 * MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE and
1743 	 * MLXBF_I2C_CAUSE_WRITE_SUCCESS, these are enabled when an external
1744 	 * masters issue a Read and Write, respectively. But, clear all
1745 	 * interrupts first.
1746 	 */
1747 	writel(~0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
1748 	int_reg = MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE;
1749 	int_reg |= MLXBF_I2C_CAUSE_WRITE_SUCCESS;
1750 	writel(int_reg, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_EVTEN0);
1751 
1752 	/* Finally, set the 'ready' bit to start handling transactions. */
1753 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1754 
1755 	/* Initialize the cause coalesce resource. */
1756 	ret = mlxbf_i2c_init_coalesce(pdev, priv);
1757 	if (ret < 0) {
1758 		dev_err(dev, "failed to initialize cause coalesce\n");
1759 		return ret;
1760 	}
1761 
1762 	return 0;
1763 }
1764 
mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv * priv,bool * read,bool * write)1765 static bool mlxbf_i2c_has_coalesce(struct mlxbf_i2c_priv *priv, bool *read,
1766 				   bool *write)
1767 {
1768 	const struct mlxbf_i2c_chip_info *chip = priv->chip;
1769 	u32 coalesce0_reg, cause_reg;
1770 	u8 slave_shift, is_set;
1771 
1772 	*write = false;
1773 	*read = false;
1774 
1775 	slave_shift = chip->type != MLXBF_I2C_CHIP_TYPE_1 ?
1776 				MLXBF_I2C_CAUSE_YU_SLAVE_BIT :
1777 				priv->bus + MLXBF_I2C_CAUSE_TYU_SLAVE_BIT;
1778 
1779 	coalesce0_reg = readl(priv->coalesce->io + MLXBF_I2C_CAUSE_COALESCE_0);
1780 	is_set = coalesce0_reg & (1 << slave_shift);
1781 
1782 	if (!is_set)
1783 		return false;
1784 
1785 	/* Check the source of the interrupt, i.e. whether a Read or Write. */
1786 	cause_reg = readl(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER);
1787 	if (cause_reg & MLXBF_I2C_CAUSE_READ_WAIT_FW_RESPONSE)
1788 		*read = true;
1789 	else if (cause_reg & MLXBF_I2C_CAUSE_WRITE_SUCCESS)
1790 		*write = true;
1791 
1792 	/* Clear cause bits. */
1793 	writel(~0x0, priv->slv_cause->io + MLXBF_I2C_CAUSE_OR_CLEAR);
1794 
1795 	return true;
1796 }
1797 
mlxbf_i2c_get_slave_from_addr(struct mlxbf_i2c_priv * priv,u8 addr)1798 static struct i2c_client *mlxbf_i2c_get_slave_from_addr(
1799 			struct mlxbf_i2c_priv *priv, u8 addr)
1800 {
1801 	int i;
1802 
1803 	for (i = 0; i < MLXBF_I2C_SMBUS_SLAVE_ADDR_CNT; i++) {
1804 		if (!priv->slave[i])
1805 			continue;
1806 
1807 		if (priv->slave[i]->addr == addr)
1808 			return priv->slave[i];
1809 	}
1810 
1811 	return NULL;
1812 }
1813 
1814 /*
1815  * Send byte to 'external' smbus master. This function is executed when
1816  * an external smbus master wants to read data from the BlueField.
1817  */
mlxbf_i2c_irq_send(struct mlxbf_i2c_priv * priv,u8 recv_bytes)1818 static int mlxbf_i2c_irq_send(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
1819 {
1820 	u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 };
1821 	u8 write_size, pec_en, addr, value, byte_cnt;
1822 	struct i2c_client *slave;
1823 	u32 control32, data32;
1824 	int ret = 0;
1825 
1826 	/*
1827 	 * Read the first byte received from the external master to
1828 	 * determine the slave address. This byte is located in the
1829 	 * first data descriptor register of the slave GW.
1830 	 */
1831 	data32 = ioread32be(priv->slv->io +
1832 				MLXBF_I2C_SLAVE_DATA_DESC_ADDR);
1833 	addr = (data32 & GENMASK(7, 0)) >> 1;
1834 
1835 	/*
1836 	 * Check if the slave address received in the data descriptor register
1837 	 * matches any of the slave addresses registered. If there is a match,
1838 	 * set the slave.
1839 	 */
1840 	slave = mlxbf_i2c_get_slave_from_addr(priv, addr);
1841 	if (!slave) {
1842 		ret = -ENXIO;
1843 		goto clear_csr;
1844 	}
1845 
1846 	/*
1847 	 * An I2C read can consist of a WRITE bit transaction followed by
1848 	 * a READ bit transaction. Indeed, slave devices often expect
1849 	 * the slave address to be followed by the internal address.
1850 	 * So, write the internal address byte first, and then, send the
1851 	 * requested data to the master.
1852 	 */
1853 	if (recv_bytes > 1) {
1854 		i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
1855 		value = (data32 >> 8) & GENMASK(7, 0);
1856 		ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
1857 				      &value);
1858 		i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1859 
1860 		if (ret < 0)
1861 			goto clear_csr;
1862 	}
1863 
1864 	/*
1865 	 * Send data to the master. Currently, the driver supports
1866 	 * READ_BYTE, READ_WORD and BLOCK READ protocols. The
1867 	 * hardware can send up to 128 bytes per transfer which is
1868 	 * the total size of the data registers.
1869 	 */
1870 	i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
1871 
1872 	for (byte_cnt = 0; byte_cnt < MLXBF_I2C_SLAVE_DATA_DESC_SIZE; byte_cnt++) {
1873 		data_desc[byte_cnt] = value;
1874 		i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
1875 	}
1876 
1877 	/* Send a stop condition to the backend. */
1878 	i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1879 
1880 	/* Set the number of bytes to write to master. */
1881 	write_size = (byte_cnt - 1) & 0x7f;
1882 
1883 	/* Write data to Slave GW data descriptor. */
1884 	mlxbf_i2c_smbus_write_data(priv, data_desc, byte_cnt,
1885 				   MLXBF_I2C_SLAVE_DATA_DESC_ADDR, false);
1886 
1887 	pec_en = 0; /* Disable PEC since it is not supported. */
1888 
1889 	/* Prepare control word. */
1890 	control32 = MLXBF_I2C_SLAVE_ENABLE;
1891 	control32 |= rol32(write_size, MLXBF_I2C_SLAVE_WRITE_BYTES_SHIFT);
1892 	control32 |= rol32(pec_en, MLXBF_I2C_SLAVE_SEND_PEC_SHIFT);
1893 
1894 	writel(control32, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_GW);
1895 
1896 	/*
1897 	 * Wait until the transfer is completed; the driver will wait
1898 	 * until the GW is idle, a cause will rise on fall of GW busy.
1899 	 */
1900 	readl_poll_timeout_atomic(priv->slv_cause->io + MLXBF_I2C_CAUSE_ARBITER,
1901 				  data32, data32 & MLXBF_I2C_CAUSE_S_GW_BUSY_FALL,
1902 				  MLXBF_I2C_POLL_FREQ_IN_USEC, MLXBF_I2C_SMBUS_TIMEOUT);
1903 
1904 clear_csr:
1905 	/* Release the Slave GW. */
1906 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
1907 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_PEC);
1908 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1909 
1910 	return ret;
1911 }
1912 
1913 /*
1914  * Receive bytes from 'external' smbus master. This function is executed when
1915  * an external smbus master wants to write data to the BlueField.
1916  */
mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv * priv,u8 recv_bytes)1917 static int mlxbf_i2c_irq_recv(struct mlxbf_i2c_priv *priv, u8 recv_bytes)
1918 {
1919 	u8 data_desc[MLXBF_I2C_SLAVE_DATA_DESC_SIZE] = { 0 };
1920 	struct i2c_client *slave;
1921 	u8 value, byte, addr;
1922 	int ret = 0;
1923 
1924 	/* Read data from Slave GW data descriptor. */
1925 	mlxbf_i2c_smbus_read_data(priv, data_desc, recv_bytes,
1926 				  MLXBF_I2C_SLAVE_DATA_DESC_ADDR, false);
1927 	addr = data_desc[0] >> 1;
1928 
1929 	/*
1930 	 * Check if the slave address received in the data descriptor register
1931 	 * matches any of the slave addresses registered.
1932 	 */
1933 	slave = mlxbf_i2c_get_slave_from_addr(priv, addr);
1934 	if (!slave) {
1935 		ret = -EINVAL;
1936 		goto clear_csr;
1937 	}
1938 
1939 	/*
1940 	 * Notify the slave backend that an smbus master wants to write data
1941 	 * to the BlueField.
1942 	 */
1943 	i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
1944 
1945 	/* Send the received data to the slave backend. */
1946 	for (byte = 1; byte < recv_bytes; byte++) {
1947 		value = data_desc[byte];
1948 		ret = i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED,
1949 				      &value);
1950 		if (ret < 0)
1951 			break;
1952 	}
1953 
1954 	/*
1955 	 * Send a stop event to the slave backend, to signal
1956 	 * the end of the write transactions.
1957 	 */
1958 	i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
1959 
1960 clear_csr:
1961 	/* Release the Slave GW. */
1962 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
1963 	writel(0x0, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_PEC);
1964 	writel(0x1, priv->slv->io + MLXBF_I2C_SMBUS_SLAVE_READY);
1965 
1966 	return ret;
1967 }
1968 
mlxbf_i2c_irq(int irq,void * ptr)1969 static irqreturn_t mlxbf_i2c_irq(int irq, void *ptr)
1970 {
1971 	struct mlxbf_i2c_priv *priv = ptr;
1972 	bool read, write, irq_is_set;
1973 	u32 rw_bytes_reg;
1974 	u8 recv_bytes;
1975 
1976 	/*
1977 	 * Read TYU interrupt register and determine the source of the
1978 	 * interrupt. Based on the source of the interrupt one of the
1979 	 * following actions are performed:
1980 	 *  - Receive data and send response to master.
1981 	 *  - Send data and release slave GW.
1982 	 *
1983 	 * Handle read/write transaction only. CRmaster and Iarp requests
1984 	 * are ignored for now.
1985 	 */
1986 	irq_is_set = mlxbf_i2c_has_coalesce(priv, &read, &write);
1987 	if (!irq_is_set || (!read && !write)) {
1988 		/* Nothing to do here, interrupt was not from this device. */
1989 		return IRQ_NONE;
1990 	}
1991 
1992 	/*
1993 	 * The MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES includes the number of
1994 	 * bytes from/to master. These are defined by 8-bits each. If the lower
1995 	 * 8 bits are set, then the master expect to read N bytes from the
1996 	 * slave, if the higher 8 bits are sent then the slave expect N bytes
1997 	 * from the master.
1998 	 */
1999 	rw_bytes_reg = readl(priv->slv->io +
2000 				MLXBF_I2C_SMBUS_SLAVE_RS_MASTER_BYTES);
2001 	recv_bytes = (rw_bytes_reg >> 8) & GENMASK(7, 0);
2002 
2003 	/*
2004 	 * For now, the slave supports 128 bytes transfer. Discard remaining
2005 	 * data bytes if the master wrote more than
2006 	 * MLXBF_I2C_SLAVE_DATA_DESC_SIZE, i.e, the actual size of the slave
2007 	 * data descriptor.
2008 	 *
2009 	 * Note that we will never expect to transfer more than 128 bytes; as
2010 	 * specified in the SMBus standard, block transactions cannot exceed
2011 	 * 32 bytes.
2012 	 */
2013 	recv_bytes = recv_bytes > MLXBF_I2C_SLAVE_DATA_DESC_SIZE ?
2014 		MLXBF_I2C_SLAVE_DATA_DESC_SIZE : recv_bytes;
2015 
2016 	if (read)
2017 		mlxbf_i2c_irq_send(priv, recv_bytes);
2018 	else
2019 		mlxbf_i2c_irq_recv(priv, recv_bytes);
2020 
2021 	return IRQ_HANDLED;
2022 }
2023 
2024 /* 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)2025 static s32 mlxbf_i2c_smbus_xfer(struct i2c_adapter *adap, u16 addr,
2026 				unsigned short flags, char read_write,
2027 				u8 command, int size,
2028 				union i2c_smbus_data *data)
2029 {
2030 	struct mlxbf_i2c_smbus_request request = { 0 };
2031 	struct mlxbf_i2c_priv *priv;
2032 	bool read, pec;
2033 	u8 byte_cnt;
2034 
2035 	request.slave = addr;
2036 
2037 	read = (read_write == I2C_SMBUS_READ);
2038 	pec = flags & I2C_FUNC_SMBUS_PEC;
2039 
2040 	switch (size) {
2041 	case I2C_SMBUS_QUICK:
2042 		mlxbf_i2c_smbus_quick_command(&request, read);
2043 		dev_dbg(&adap->dev, "smbus quick, slave 0x%02x\n", addr);
2044 		break;
2045 
2046 	case I2C_SMBUS_BYTE:
2047 		mlxbf_i2c_smbus_byte_func(&request,
2048 					  read ? &data->byte : &command, read,
2049 					  pec);
2050 		dev_dbg(&adap->dev, "smbus %s byte, slave 0x%02x.\n",
2051 			str_read_write(read), addr);
2052 		break;
2053 
2054 	case I2C_SMBUS_BYTE_DATA:
2055 		mlxbf_i2c_smbus_data_byte_func(&request, &command, &data->byte,
2056 					       read, pec);
2057 		dev_dbg(&adap->dev, "smbus %s byte data at 0x%02x, slave 0x%02x.\n",
2058 			str_read_write(read), command, addr);
2059 		break;
2060 
2061 	case I2C_SMBUS_WORD_DATA:
2062 		mlxbf_i2c_smbus_data_word_func(&request, &command,
2063 					       (u8 *)&data->word, read, pec);
2064 		dev_dbg(&adap->dev, "smbus %s word data at 0x%02x, slave 0x%02x.\n",
2065 			str_read_write(read), command, addr);
2066 		break;
2067 
2068 	case I2C_SMBUS_I2C_BLOCK_DATA:
2069 		byte_cnt = data->block[0];
2070 		mlxbf_i2c_smbus_i2c_block_func(&request, &command, data->block,
2071 					       &byte_cnt, read, pec);
2072 		dev_dbg(&adap->dev, "i2c %s block data, %d bytes at 0x%02x, slave 0x%02x.\n",
2073 			str_read_write(read), byte_cnt, command, addr);
2074 		break;
2075 
2076 	case I2C_SMBUS_BLOCK_DATA:
2077 		byte_cnt = read ? I2C_SMBUS_BLOCK_MAX : data->block[0];
2078 		mlxbf_i2c_smbus_block_func(&request, &command, data->block,
2079 					   &byte_cnt, read, pec);
2080 		dev_dbg(&adap->dev, "smbus %s block data, %d bytes at 0x%02x, slave 0x%02x.\n",
2081 			str_read_write(read), byte_cnt, command, addr);
2082 		break;
2083 
2084 	case I2C_FUNC_SMBUS_PROC_CALL:
2085 		mlxbf_i2c_smbus_process_call_func(&request, &command,
2086 						  (u8 *)&data->word, pec);
2087 		dev_dbg(&adap->dev, "process call, wr/rd at 0x%02x, slave 0x%02x.\n",
2088 			command, addr);
2089 		break;
2090 
2091 	case I2C_FUNC_SMBUS_BLOCK_PROC_CALL:
2092 		byte_cnt = data->block[0];
2093 		mlxbf_i2c_smbus_blk_process_call_func(&request, &command,
2094 						      data->block, &byte_cnt,
2095 						      pec);
2096 		dev_dbg(&adap->dev, "block process call, wr/rd %d bytes, slave 0x%02x.\n",
2097 			byte_cnt, addr);
2098 		break;
2099 
2100 	default:
2101 		dev_dbg(&adap->dev, "Unsupported I2C/SMBus command %d\n",
2102 			size);
2103 		return -EOPNOTSUPP;
2104 	}
2105 
2106 	priv = i2c_get_adapdata(adap);
2107 
2108 	return mlxbf_i2c_smbus_start_transaction(priv, &request);
2109 }
2110 
mlxbf_i2c_reg_slave(struct i2c_client * slave)2111 static int mlxbf_i2c_reg_slave(struct i2c_client *slave)
2112 {
2113 	struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
2114 	struct device *dev = &slave->dev;
2115 	int ret;
2116 
2117 	/*
2118 	 * Do not support ten bit chip address and do not use Packet Error
2119 	 * Checking (PEC).
2120 	 */
2121 	if (slave->flags & (I2C_CLIENT_TEN | I2C_CLIENT_PEC)) {
2122 		dev_err(dev, "SMBus PEC and 10 bit address not supported\n");
2123 		return -EAFNOSUPPORT;
2124 	}
2125 
2126 	ret = mlxbf_i2c_slave_enable(priv, slave);
2127 	if (ret)
2128 		dev_err(dev, "Surpassed max number of registered slaves allowed\n");
2129 
2130 	return 0;
2131 }
2132 
mlxbf_i2c_unreg_slave(struct i2c_client * slave)2133 static int mlxbf_i2c_unreg_slave(struct i2c_client *slave)
2134 {
2135 	struct mlxbf_i2c_priv *priv = i2c_get_adapdata(slave->adapter);
2136 	struct device *dev = &slave->dev;
2137 	int ret;
2138 
2139 	/*
2140 	 * Unregister slave by:
2141 	 * 1) Disabling the slave address in hardware
2142 	 * 2) Freeing priv->slave at the corresponding index
2143 	 */
2144 	ret = mlxbf_i2c_slave_disable(priv, slave->addr);
2145 	if (ret)
2146 		dev_err(dev, "Unable to find slave 0x%x\n", slave->addr);
2147 
2148 	return ret;
2149 }
2150 
mlxbf_i2c_functionality(struct i2c_adapter * adap)2151 static u32 mlxbf_i2c_functionality(struct i2c_adapter *adap)
2152 {
2153 	return MLXBF_I2C_FUNC_ALL;
2154 }
2155 
2156 static struct mlxbf_i2c_chip_info mlxbf_i2c_chip[] = {
2157 	[MLXBF_I2C_CHIP_TYPE_1] = {
2158 		.type = MLXBF_I2C_CHIP_TYPE_1,
2159 		.shared_res = {
2160 			[0] = &mlxbf_i2c_coalesce_res[MLXBF_I2C_CHIP_TYPE_1],
2161 			[1] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_1],
2162 			[2] = &mlxbf_i2c_gpio_res[MLXBF_I2C_CHIP_TYPE_1]
2163 		},
2164 		.calculate_freq = mlxbf_i2c_calculate_freq_from_tyu,
2165 		.smbus_master_rs_bytes_off = MLXBF_I2C_YU_SMBUS_RS_BYTES,
2166 		.smbus_master_fsm_off = MLXBF_I2C_YU_SMBUS_MASTER_FSM
2167 	},
2168 	[MLXBF_I2C_CHIP_TYPE_2] = {
2169 		.type = MLXBF_I2C_CHIP_TYPE_2,
2170 		.shared_res = {
2171 			[0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_2]
2172 		},
2173 		.calculate_freq = mlxbf_i2c_calculate_freq_from_yu,
2174 		.smbus_master_rs_bytes_off = MLXBF_I2C_YU_SMBUS_RS_BYTES,
2175 		.smbus_master_fsm_off = MLXBF_I2C_YU_SMBUS_MASTER_FSM
2176 	},
2177 	[MLXBF_I2C_CHIP_TYPE_3] = {
2178 		.type = MLXBF_I2C_CHIP_TYPE_3,
2179 		.shared_res = {
2180 			[0] = &mlxbf_i2c_corepll_res[MLXBF_I2C_CHIP_TYPE_3]
2181 		},
2182 		.calculate_freq = mlxbf_i2c_calculate_freq_from_yu,
2183 		.smbus_master_rs_bytes_off = MLXBF_I2C_RSH_YU_SMBUS_RS_BYTES,
2184 		.smbus_master_fsm_off = MLXBF_I2C_RSH_YU_SMBUS_MASTER_FSM
2185 	}
2186 };
2187 
2188 static const struct i2c_algorithm mlxbf_i2c_algo = {
2189 	.smbus_xfer = mlxbf_i2c_smbus_xfer,
2190 	.functionality = mlxbf_i2c_functionality,
2191 	.reg_slave = mlxbf_i2c_reg_slave,
2192 	.unreg_slave = mlxbf_i2c_unreg_slave,
2193 };
2194 
2195 static struct i2c_adapter_quirks mlxbf_i2c_quirks = {
2196 	.max_read_len = MLXBF_I2C_MASTER_DATA_R_LENGTH,
2197 	.max_write_len = MLXBF_I2C_MASTER_DATA_W_LENGTH,
2198 };
2199 
2200 static const struct acpi_device_id mlxbf_i2c_acpi_ids[] = {
2201 	{ "MLNXBF03", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_1] },
2202 	{ "MLNXBF23", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_2] },
2203 	{ "MLNXBF31", (kernel_ulong_t)&mlxbf_i2c_chip[MLXBF_I2C_CHIP_TYPE_3] },
2204 	{},
2205 };
2206 
2207 MODULE_DEVICE_TABLE(acpi, mlxbf_i2c_acpi_ids);
2208 
mlxbf_i2c_acpi_probe(struct device * dev,struct mlxbf_i2c_priv * priv)2209 static int mlxbf_i2c_acpi_probe(struct device *dev, struct mlxbf_i2c_priv *priv)
2210 {
2211 	const struct acpi_device_id *aid;
2212 	u64 bus_id;
2213 	int ret;
2214 
2215 	if (acpi_disabled)
2216 		return -ENOENT;
2217 
2218 	aid = acpi_match_device(mlxbf_i2c_acpi_ids, dev);
2219 	if (!aid)
2220 		return -ENODEV;
2221 
2222 	priv->chip = (struct mlxbf_i2c_chip_info *)aid->driver_data;
2223 
2224 	ret = acpi_dev_uid_to_integer(ACPI_COMPANION(dev), &bus_id);
2225 	if (ret) {
2226 		dev_err(dev, "Cannot retrieve UID\n");
2227 		return ret;
2228 	}
2229 
2230 	priv->bus = bus_id;
2231 
2232 	return 0;
2233 }
2234 
mlxbf_i2c_probe(struct platform_device * pdev)2235 static int mlxbf_i2c_probe(struct platform_device *pdev)
2236 {
2237 	struct device *dev = &pdev->dev;
2238 	struct mlxbf_i2c_priv *priv;
2239 	struct i2c_adapter *adap;
2240 	u32 resource_version;
2241 	int irq, ret;
2242 
2243 	priv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_priv), GFP_KERNEL);
2244 	if (!priv)
2245 		return -ENOMEM;
2246 
2247 	ret = mlxbf_i2c_acpi_probe(dev, priv);
2248 	if (ret < 0)
2249 		return ret;
2250 
2251 	/* This property allows the driver to stay backward compatible with older
2252 	 * ACPI tables.
2253 	 * Starting BlueField-3 SoC, the "smbus" resource was broken down into 3
2254 	 * separate resources "timer", "master" and "slave".
2255 	 */
2256 	if (device_property_read_u32(dev, "resource_version", &resource_version))
2257 		resource_version = 0;
2258 
2259 	priv->resource_version = resource_version;
2260 
2261 	if (priv->chip->type < MLXBF_I2C_CHIP_TYPE_3 && resource_version == 0) {
2262 		priv->timer = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2263 		if (!priv->timer)
2264 			return -ENOMEM;
2265 
2266 		priv->mst = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2267 		if (!priv->mst)
2268 			return -ENOMEM;
2269 
2270 		priv->slv = devm_kzalloc(dev, sizeof(struct mlxbf_i2c_resource), GFP_KERNEL);
2271 		if (!priv->slv)
2272 			return -ENOMEM;
2273 
2274 		ret = mlxbf_i2c_init_resource(pdev, &priv->smbus,
2275 					      MLXBF_I2C_SMBUS_RES);
2276 		if (ret < 0)
2277 			return dev_err_probe(dev, ret, "Cannot fetch smbus resource info");
2278 
2279 		priv->timer->io = priv->smbus->io;
2280 		priv->mst->io = priv->smbus->io + MLXBF_I2C_MST_ADDR_OFFSET;
2281 		priv->slv->io = priv->smbus->io + MLXBF_I2C_SLV_ADDR_OFFSET;
2282 	} else {
2283 		ret = mlxbf_i2c_init_resource(pdev, &priv->timer,
2284 					      MLXBF_I2C_SMBUS_TIMER_RES);
2285 		if (ret < 0)
2286 			return dev_err_probe(dev, ret, "Cannot fetch timer resource info");
2287 
2288 		ret = mlxbf_i2c_init_resource(pdev, &priv->mst,
2289 					      MLXBF_I2C_SMBUS_MST_RES);
2290 		if (ret < 0)
2291 			return dev_err_probe(dev, ret, "Cannot fetch master resource info");
2292 
2293 		ret = mlxbf_i2c_init_resource(pdev, &priv->slv,
2294 					      MLXBF_I2C_SMBUS_SLV_RES);
2295 		if (ret < 0)
2296 			return dev_err_probe(dev, ret, "Cannot fetch slave resource info");
2297 	}
2298 
2299 	ret = mlxbf_i2c_init_resource(pdev, &priv->mst_cause,
2300 				      MLXBF_I2C_MST_CAUSE_RES);
2301 	if (ret < 0)
2302 		return dev_err_probe(dev, ret, "Cannot fetch cause master resource info");
2303 
2304 	ret = mlxbf_i2c_init_resource(pdev, &priv->slv_cause,
2305 				      MLXBF_I2C_SLV_CAUSE_RES);
2306 	if (ret < 0)
2307 		return dev_err_probe(dev, ret, "Cannot fetch cause slave resource info");
2308 
2309 	adap = &priv->adap;
2310 	adap->owner = THIS_MODULE;
2311 	adap->class = I2C_CLASS_HWMON;
2312 	adap->algo = &mlxbf_i2c_algo;
2313 	adap->quirks = &mlxbf_i2c_quirks;
2314 	adap->dev.parent = dev;
2315 	adap->dev.of_node = dev->of_node;
2316 	adap->nr = priv->bus;
2317 
2318 	snprintf(adap->name, sizeof(adap->name), "i2c%d", adap->nr);
2319 	i2c_set_adapdata(adap, priv);
2320 
2321 	/* Read Core PLL frequency. */
2322 	ret = mlxbf_i2c_calculate_corepll_freq(pdev, priv);
2323 	if (ret < 0) {
2324 		dev_err(dev, "cannot get core clock frequency\n");
2325 		/* Set to default value. */
2326 		priv->frequency = MLXBF_I2C_COREPLL_FREQ;
2327 	}
2328 
2329 	/*
2330 	 * Initialize master.
2331 	 * Note that a physical bus might be shared among Linux and firmware
2332 	 * (e.g., ATF). Thus, the bus should be initialized and ready and
2333 	 * bus initialization would be unnecessary. This requires additional
2334 	 * knowledge about physical busses. But, since an extra initialization
2335 	 * does not really hurt, then keep the code as is.
2336 	 */
2337 	ret = mlxbf_i2c_init_master(pdev, priv);
2338 	if (ret < 0)
2339 		return dev_err_probe(dev, ret, "failed to initialize smbus master %d",
2340 				     priv->bus);
2341 
2342 	mlxbf_i2c_init_timings(pdev, priv);
2343 
2344 	mlxbf_i2c_init_slave(pdev, priv);
2345 
2346 	irq = platform_get_irq(pdev, 0);
2347 	if (irq < 0)
2348 		return irq;
2349 	ret = devm_request_irq(dev, irq, mlxbf_i2c_irq,
2350 			       IRQF_SHARED | IRQF_PROBE_SHARED,
2351 			       dev_name(dev), priv);
2352 	if (ret < 0)
2353 		return ret;
2354 
2355 	priv->irq = irq;
2356 
2357 	platform_set_drvdata(pdev, priv);
2358 
2359 	ret = i2c_add_numbered_adapter(adap);
2360 	if (ret < 0)
2361 		return ret;
2362 
2363 	mutex_lock(&mlxbf_i2c_bus_lock);
2364 	mlxbf_i2c_bus_count++;
2365 	mutex_unlock(&mlxbf_i2c_bus_lock);
2366 
2367 	return 0;
2368 }
2369 
mlxbf_i2c_remove(struct platform_device * pdev)2370 static void mlxbf_i2c_remove(struct platform_device *pdev)
2371 {
2372 	struct mlxbf_i2c_priv *priv = platform_get_drvdata(pdev);
2373 	struct device *dev = &pdev->dev;
2374 	struct resource *params;
2375 
2376 	if (priv->chip->type < MLXBF_I2C_CHIP_TYPE_3 && priv->resource_version == 0) {
2377 		params = priv->smbus->params;
2378 		devm_release_mem_region(dev, params->start, resource_size(params));
2379 	} else {
2380 		params = priv->timer->params;
2381 		devm_release_mem_region(dev, params->start, resource_size(params));
2382 
2383 		params = priv->mst->params;
2384 		devm_release_mem_region(dev, params->start, resource_size(params));
2385 
2386 		params = priv->slv->params;
2387 		devm_release_mem_region(dev, params->start, resource_size(params));
2388 	}
2389 
2390 	params = priv->mst_cause->params;
2391 	devm_release_mem_region(dev, params->start, resource_size(params));
2392 
2393 	params = priv->slv_cause->params;
2394 	devm_release_mem_region(dev, params->start, resource_size(params));
2395 
2396 	/*
2397 	 * Release shared resources. This should be done when releasing
2398 	 * the I2C controller.
2399 	 */
2400 	mutex_lock(&mlxbf_i2c_bus_lock);
2401 	if (--mlxbf_i2c_bus_count == 0) {
2402 		mlxbf_i2c_release_coalesce(pdev, priv);
2403 		mlxbf_i2c_release_corepll(pdev, priv);
2404 		mlxbf_i2c_release_gpio(pdev, priv);
2405 	}
2406 	mutex_unlock(&mlxbf_i2c_bus_lock);
2407 
2408 	devm_free_irq(dev, priv->irq, priv);
2409 
2410 	i2c_del_adapter(&priv->adap);
2411 }
2412 
2413 static struct platform_driver mlxbf_i2c_driver = {
2414 	.probe = mlxbf_i2c_probe,
2415 	.remove = mlxbf_i2c_remove,
2416 	.driver = {
2417 		.name = "i2c-mlxbf",
2418 		.acpi_match_table = ACPI_PTR(mlxbf_i2c_acpi_ids),
2419 	},
2420 };
2421 
mlxbf_i2c_init(void)2422 static int __init mlxbf_i2c_init(void)
2423 {
2424 	mutex_init(&mlxbf_i2c_coalesce_lock);
2425 	mutex_init(&mlxbf_i2c_corepll_lock);
2426 	mutex_init(&mlxbf_i2c_gpio_lock);
2427 
2428 	mutex_init(&mlxbf_i2c_bus_lock);
2429 
2430 	return platform_driver_register(&mlxbf_i2c_driver);
2431 }
2432 module_init(mlxbf_i2c_init);
2433 
mlxbf_i2c_exit(void)2434 static void __exit mlxbf_i2c_exit(void)
2435 {
2436 	platform_driver_unregister(&mlxbf_i2c_driver);
2437 
2438 	mutex_destroy(&mlxbf_i2c_bus_lock);
2439 
2440 	mutex_destroy(&mlxbf_i2c_gpio_lock);
2441 	mutex_destroy(&mlxbf_i2c_corepll_lock);
2442 	mutex_destroy(&mlxbf_i2c_coalesce_lock);
2443 }
2444 module_exit(mlxbf_i2c_exit);
2445 
2446 MODULE_DESCRIPTION("Mellanox BlueField I2C bus driver");
2447 MODULE_AUTHOR("Khalil Blaiech <kblaiech@nvidia.com>");
2448 MODULE_AUTHOR("Asmaa Mnebhi <asmaa@nvidia.com>");
2449 MODULE_LICENSE("GPL v2");
2450