1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /* Copyright (c) 2016-2018 Mellanox Technologies. All rights reserved */
3 
4 #include <linux/err.h>
5 #include <linux/i2c.h>
6 #include <linux/init.h>
7 #include <linux/jiffies.h>
8 #include <linux/kernel.h>
9 #include <linux/mutex.h>
10 #include <linux/module.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/platform_data/mlxreg.h>
13 #include <linux/slab.h>
14 
15 #include "cmd.h"
16 #include "core.h"
17 #include "i2c.h"
18 #include "resources.h"
19 
20 #define MLXSW_I2C_CIR2_BASE		0x72000
21 #define MLXSW_I2C_CIR_STATUS_OFF	0x18
22 #define MLXSW_I2C_CIR2_OFF_STATUS	(MLXSW_I2C_CIR2_BASE + \
23 					 MLXSW_I2C_CIR_STATUS_OFF)
24 #define MLXSW_I2C_OPMOD_SHIFT		12
25 #define MLXSW_I2C_EVENT_BIT_SHIFT	22
26 #define MLXSW_I2C_GO_BIT_SHIFT		23
27 #define MLXSW_I2C_CIR_CTRL_STATUS_SHIFT	24
28 #define MLXSW_I2C_EVENT_BIT		BIT(MLXSW_I2C_EVENT_BIT_SHIFT)
29 #define MLXSW_I2C_GO_BIT		BIT(MLXSW_I2C_GO_BIT_SHIFT)
30 #define MLXSW_I2C_GO_OPMODE		BIT(MLXSW_I2C_OPMOD_SHIFT)
31 #define MLXSW_I2C_SET_IMM_CMD		(MLXSW_I2C_GO_OPMODE | \
32 					 MLXSW_CMD_OPCODE_QUERY_FW)
33 #define MLXSW_I2C_PUSH_IMM_CMD		(MLXSW_I2C_GO_BIT | \
34 					 MLXSW_I2C_SET_IMM_CMD)
35 #define MLXSW_I2C_SET_CMD		(MLXSW_CMD_OPCODE_ACCESS_REG)
36 #define MLXSW_I2C_PUSH_CMD		(MLXSW_I2C_GO_BIT | MLXSW_I2C_SET_CMD)
37 #define MLXSW_I2C_TLV_HDR_SIZE		0x10
38 #define MLXSW_I2C_ADDR_WIDTH		4
39 #define MLXSW_I2C_PUSH_CMD_SIZE		(MLXSW_I2C_ADDR_WIDTH + 4)
40 #define MLXSW_I2C_SET_EVENT_CMD		(MLXSW_I2C_EVENT_BIT)
41 #define MLXSW_I2C_PUSH_EVENT_CMD	(MLXSW_I2C_GO_BIT | \
42 					 MLXSW_I2C_SET_EVENT_CMD)
43 #define MLXSW_I2C_READ_SEMA_SIZE	4
44 #define MLXSW_I2C_PREP_SIZE		(MLXSW_I2C_ADDR_WIDTH + 28)
45 #define MLXSW_I2C_MBOX_SIZE		20
46 #define MLXSW_I2C_MBOX_OUT_PARAM_OFF	12
47 #define MLXSW_I2C_MBOX_OFFSET_BITS	20
48 #define MLXSW_I2C_MBOX_SIZE_BITS	12
49 #define MLXSW_I2C_ADDR_BUF_SIZE		4
50 #define MLXSW_I2C_BLK_DEF		32
51 #define MLXSW_I2C_RETRY			5
52 #define MLXSW_I2C_TIMEOUT_MSECS		5000
53 #define MLXSW_I2C_MAX_DATA_SIZE		256
54 
55 /* Driver can be initialized by kernel platform driver or from the user
56  * space. In the first case IRQ line number is passed through the platform
57  * data, otherwise default IRQ line is to be used. Default IRQ is relevant
58  * only for specific I2C slave address, allowing 3.4 MHz I2C path to the chip
59  * (special hardware feature for I2C acceleration).
60  */
61 #define MLXSW_I2C_DEFAULT_IRQ		17
62 #define MLXSW_FAST_I2C_SLAVE		0x37
63 
64 /**
65  * struct mlxsw_i2c - device private data:
66  * @cmd: command attributes;
67  * @cmd.mb_size_in: input mailbox size;
68  * @cmd.mb_off_in: input mailbox offset in register space;
69  * @cmd.mb_size_out: output mailbox size;
70  * @cmd.mb_off_out: output mailbox offset in register space;
71  * @cmd.lock: command execution lock;
72  * @dev: I2C device;
73  * @core: switch core pointer;
74  * @bus_info: bus info block;
75  * @block_size: maximum block size allowed to pass to under layer;
76  * @pdata: device platform data;
77  * @irq_work: interrupts work item;
78  * @irq: IRQ line number;
79  */
80 struct mlxsw_i2c {
81 	struct {
82 		u32 mb_size_in;
83 		u32 mb_off_in;
84 		u32 mb_size_out;
85 		u32 mb_off_out;
86 		struct mutex lock;
87 	} cmd;
88 	struct device *dev;
89 	struct mlxsw_core *core;
90 	struct mlxsw_bus_info bus_info;
91 	u16 block_size;
92 	struct mlxreg_core_hotplug_platform_data *pdata;
93 	struct work_struct irq_work;
94 	int irq;
95 };
96 
97 #define MLXSW_I2C_READ_MSG(_client, _addr_buf, _buf, _len) {	\
98 	{ .addr = (_client)->addr,				\
99 	  .buf = (_addr_buf),					\
100 	  .len = MLXSW_I2C_ADDR_BUF_SIZE,			\
101 	  .flags = 0 },						\
102 	{ .addr = (_client)->addr,				\
103 	  .buf = (_buf),					\
104 	  .len = (_len),					\
105 	  .flags = I2C_M_RD } }
106 
107 #define MLXSW_I2C_WRITE_MSG(_client, _buf, _len)		\
108 	{ .addr = (_client)->addr,				\
109 	  .buf = (u8 *)(_buf),					\
110 	  .len = (_len),					\
111 	  .flags = 0 }
112 
113 /* Routine converts in and out mail boxes offset and size. */
114 static inline void
115 mlxsw_i2c_convert_mbox(struct mlxsw_i2c *mlxsw_i2c, u8 *buf)
116 {
117 	u32 tmp;
118 
119 	/* Local in/out mailboxes: 20 bits for offset, 12 for size */
120 	tmp = be32_to_cpup((__be32 *) buf);
121 	mlxsw_i2c->cmd.mb_off_in = tmp &
122 				   GENMASK(MLXSW_I2C_MBOX_OFFSET_BITS - 1, 0);
123 	mlxsw_i2c->cmd.mb_size_in = (tmp & GENMASK(31,
124 					MLXSW_I2C_MBOX_OFFSET_BITS)) >>
125 					MLXSW_I2C_MBOX_OFFSET_BITS;
126 
127 	tmp = be32_to_cpup((__be32 *) (buf + MLXSW_I2C_ADDR_WIDTH));
128 	mlxsw_i2c->cmd.mb_off_out = tmp &
129 				    GENMASK(MLXSW_I2C_MBOX_OFFSET_BITS - 1, 0);
130 	mlxsw_i2c->cmd.mb_size_out = (tmp & GENMASK(31,
131 					MLXSW_I2C_MBOX_OFFSET_BITS)) >>
132 					MLXSW_I2C_MBOX_OFFSET_BITS;
133 }
134 
135 /* Routine obtains register size from mail box buffer. */
136 static inline int mlxsw_i2c_get_reg_size(u8 *in_mbox)
137 {
138 	u16  tmp = be16_to_cpup((__be16 *) (in_mbox + MLXSW_I2C_TLV_HDR_SIZE));
139 
140 	return (tmp & 0x7ff) * 4 + MLXSW_I2C_TLV_HDR_SIZE;
141 }
142 
143 /* Routine sets I2C device internal offset in the transaction buffer. */
144 static inline void mlxsw_i2c_set_slave_addr(u8 *buf, u32 off)
145 {
146 	__be32 *val = (__be32 *) buf;
147 
148 	*val = htonl(off);
149 }
150 
151 /* Routine waits until go bit is cleared. */
152 static int mlxsw_i2c_wait_go_bit(struct i2c_client *client,
153 				 struct mlxsw_i2c *mlxsw_i2c, u8 *p_status)
154 {
155 	u8 addr_buf[MLXSW_I2C_ADDR_BUF_SIZE];
156 	u8 buf[MLXSW_I2C_READ_SEMA_SIZE];
157 	int len = MLXSW_I2C_READ_SEMA_SIZE;
158 	struct i2c_msg read_sema[] =
159 		MLXSW_I2C_READ_MSG(client, addr_buf, buf, len);
160 	bool wait_done = false;
161 	unsigned long end;
162 	int i = 0, err;
163 
164 	mlxsw_i2c_set_slave_addr(addr_buf, MLXSW_I2C_CIR2_OFF_STATUS);
165 
166 	end = jiffies + msecs_to_jiffies(MLXSW_I2C_TIMEOUT_MSECS);
167 	do {
168 		u32 ctrl;
169 
170 		err = i2c_transfer(client->adapter, read_sema,
171 				   ARRAY_SIZE(read_sema));
172 
173 		ctrl = be32_to_cpu(*(__be32 *) buf);
174 		if (err == ARRAY_SIZE(read_sema)) {
175 			if (!(ctrl & MLXSW_I2C_GO_BIT)) {
176 				wait_done = true;
177 				*p_status = ctrl >>
178 					    MLXSW_I2C_CIR_CTRL_STATUS_SHIFT;
179 				break;
180 			}
181 		}
182 		cond_resched();
183 	} while ((time_before(jiffies, end)) || (i++ < MLXSW_I2C_RETRY));
184 
185 	if (wait_done) {
186 		if (*p_status)
187 			err = -EIO;
188 	} else {
189 		return -ETIMEDOUT;
190 	}
191 
192 	return err > 0 ? 0 : err;
193 }
194 
195 /* Routine posts a command to ASIC through mail box. */
196 static int mlxsw_i2c_write_cmd(struct i2c_client *client,
197 			       struct mlxsw_i2c *mlxsw_i2c,
198 			       int immediate)
199 {
200 	__be32 push_cmd_buf[MLXSW_I2C_PUSH_CMD_SIZE / 4] = {
201 		0, cpu_to_be32(MLXSW_I2C_PUSH_IMM_CMD)
202 	};
203 	__be32 prep_cmd_buf[MLXSW_I2C_PREP_SIZE / 4] = {
204 		0, 0, 0, 0, 0, 0,
205 		cpu_to_be32(client->adapter->nr & 0xffff),
206 		cpu_to_be32(MLXSW_I2C_SET_IMM_CMD)
207 	};
208 	struct i2c_msg push_cmd =
209 		MLXSW_I2C_WRITE_MSG(client, push_cmd_buf,
210 				    MLXSW_I2C_PUSH_CMD_SIZE);
211 	struct i2c_msg prep_cmd =
212 		MLXSW_I2C_WRITE_MSG(client, prep_cmd_buf, MLXSW_I2C_PREP_SIZE);
213 	int err;
214 
215 	if (!immediate) {
216 		push_cmd_buf[1] = cpu_to_be32(MLXSW_I2C_PUSH_CMD);
217 		prep_cmd_buf[7] = cpu_to_be32(MLXSW_I2C_SET_CMD);
218 	}
219 	mlxsw_i2c_set_slave_addr((u8 *)prep_cmd_buf,
220 				 MLXSW_I2C_CIR2_BASE);
221 	mlxsw_i2c_set_slave_addr((u8 *)push_cmd_buf,
222 				 MLXSW_I2C_CIR2_OFF_STATUS);
223 
224 	/* Prepare Command Interface Register for transaction */
225 	err = i2c_transfer(client->adapter, &prep_cmd, 1);
226 	if (err < 0)
227 		return err;
228 	else if (err != 1)
229 		return -EIO;
230 
231 	/* Write out Command Interface Register GO bit to push transaction */
232 	err = i2c_transfer(client->adapter, &push_cmd, 1);
233 	if (err < 0)
234 		return err;
235 	else if (err != 1)
236 		return -EIO;
237 
238 	return 0;
239 }
240 
241 /* Routine posts initialization command to ASIC through mail box. */
242 static int
243 mlxsw_i2c_write_init_cmd(struct i2c_client *client,
244 			 struct mlxsw_i2c *mlxsw_i2c, u16 opcode, u32 in_mod)
245 {
246 	__be32 push_cmd_buf[MLXSW_I2C_PUSH_CMD_SIZE / 4] = {
247 		0, cpu_to_be32(MLXSW_I2C_PUSH_EVENT_CMD)
248 	};
249 	__be32 prep_cmd_buf[MLXSW_I2C_PREP_SIZE / 4] = {
250 		0, 0, 0, 0, 0, 0,
251 		cpu_to_be32(client->adapter->nr & 0xffff),
252 		cpu_to_be32(MLXSW_I2C_SET_EVENT_CMD)
253 	};
254 	struct i2c_msg push_cmd =
255 		MLXSW_I2C_WRITE_MSG(client, push_cmd_buf,
256 				    MLXSW_I2C_PUSH_CMD_SIZE);
257 	struct i2c_msg prep_cmd =
258 		MLXSW_I2C_WRITE_MSG(client, prep_cmd_buf, MLXSW_I2C_PREP_SIZE);
259 	u8 status;
260 	int err;
261 
262 	push_cmd_buf[1] = cpu_to_be32(MLXSW_I2C_PUSH_EVENT_CMD | opcode);
263 	prep_cmd_buf[3] = cpu_to_be32(in_mod);
264 	prep_cmd_buf[7] = cpu_to_be32(MLXSW_I2C_GO_BIT | opcode);
265 	mlxsw_i2c_set_slave_addr((u8 *)prep_cmd_buf,
266 				 MLXSW_I2C_CIR2_BASE);
267 	mlxsw_i2c_set_slave_addr((u8 *)push_cmd_buf,
268 				 MLXSW_I2C_CIR2_OFF_STATUS);
269 
270 	/* Prepare Command Interface Register for transaction */
271 	err = i2c_transfer(client->adapter, &prep_cmd, 1);
272 	if (err < 0)
273 		return err;
274 	else if (err != 1)
275 		return -EIO;
276 
277 	/* Write out Command Interface Register GO bit to push transaction */
278 	err = i2c_transfer(client->adapter, &push_cmd, 1);
279 	if (err < 0)
280 		return err;
281 	else if (err != 1)
282 		return -EIO;
283 
284 	/* Wait until go bit is cleared. */
285 	err = mlxsw_i2c_wait_go_bit(client, mlxsw_i2c, &status);
286 	if (err) {
287 		dev_err(&client->dev, "HW semaphore is not released");
288 		return err;
289 	}
290 
291 	/* Validate transaction completion status. */
292 	if (status) {
293 		dev_err(&client->dev, "Bad transaction completion status %x\n",
294 			status);
295 		return -EIO;
296 	}
297 
298 	return 0;
299 }
300 
301 /* Routine obtains mail box offsets from ASIC register space. */
302 static int mlxsw_i2c_get_mbox(struct i2c_client *client,
303 			      struct mlxsw_i2c *mlxsw_i2c)
304 {
305 	u8 addr_buf[MLXSW_I2C_ADDR_BUF_SIZE];
306 	u8 buf[MLXSW_I2C_MBOX_SIZE];
307 	struct i2c_msg mbox_cmd[] =
308 		MLXSW_I2C_READ_MSG(client, addr_buf, buf, MLXSW_I2C_MBOX_SIZE);
309 	int err;
310 
311 	/* Read mail boxes offsets. */
312 	mlxsw_i2c_set_slave_addr(addr_buf, MLXSW_I2C_CIR2_BASE);
313 	err = i2c_transfer(client->adapter, mbox_cmd, 2);
314 	if (err != 2) {
315 		dev_err(&client->dev, "Could not obtain mail boxes\n");
316 		if (!err)
317 			return -EIO;
318 		else
319 			return err;
320 	}
321 
322 	/* Convert mail boxes. */
323 	mlxsw_i2c_convert_mbox(mlxsw_i2c, &buf[MLXSW_I2C_MBOX_OUT_PARAM_OFF]);
324 
325 	return err;
326 }
327 
328 /* Routine sends I2C write transaction to ASIC device. */
329 static int
330 mlxsw_i2c_write(struct device *dev, size_t in_mbox_size, u8 *in_mbox, int num,
331 		u8 *p_status)
332 {
333 	struct i2c_client *client = to_i2c_client(dev);
334 	struct mlxsw_i2c *mlxsw_i2c = i2c_get_clientdata(client);
335 	unsigned long timeout = msecs_to_jiffies(MLXSW_I2C_TIMEOUT_MSECS);
336 	int off = mlxsw_i2c->cmd.mb_off_in, chunk_size, i, j;
337 	unsigned long end;
338 	u8 *tran_buf;
339 	struct i2c_msg write_tran =
340 		MLXSW_I2C_WRITE_MSG(client, NULL, MLXSW_I2C_PUSH_CMD_SIZE);
341 	int err;
342 
343 	tran_buf = kmalloc(mlxsw_i2c->block_size + MLXSW_I2C_ADDR_BUF_SIZE,
344 			   GFP_KERNEL);
345 	if (!tran_buf)
346 		return -ENOMEM;
347 
348 	write_tran.buf = tran_buf;
349 	for (i = 0; i < num; i++) {
350 		chunk_size = (in_mbox_size > mlxsw_i2c->block_size) ?
351 			     mlxsw_i2c->block_size : in_mbox_size;
352 		write_tran.len = MLXSW_I2C_ADDR_WIDTH + chunk_size;
353 		mlxsw_i2c_set_slave_addr(tran_buf, off);
354 		memcpy(&tran_buf[MLXSW_I2C_ADDR_BUF_SIZE], in_mbox +
355 		       mlxsw_i2c->block_size * i, chunk_size);
356 
357 		j = 0;
358 		end = jiffies + timeout;
359 		do {
360 			err = i2c_transfer(client->adapter, &write_tran, 1);
361 			if (err == 1)
362 				break;
363 
364 			cond_resched();
365 		} while ((time_before(jiffies, end)) ||
366 			 (j++ < MLXSW_I2C_RETRY));
367 
368 		if (err != 1) {
369 			if (!err) {
370 				err = -EIO;
371 				goto mlxsw_i2c_write_exit;
372 			}
373 		}
374 
375 		off += chunk_size;
376 		in_mbox_size -= chunk_size;
377 	}
378 
379 	/* Prepare and write out Command Interface Register for transaction. */
380 	err = mlxsw_i2c_write_cmd(client, mlxsw_i2c, 0);
381 	if (err) {
382 		dev_err(&client->dev, "Could not start transaction");
383 		err = -EIO;
384 		goto mlxsw_i2c_write_exit;
385 	}
386 
387 	/* Wait until go bit is cleared. */
388 	err = mlxsw_i2c_wait_go_bit(client, mlxsw_i2c, p_status);
389 	if (err) {
390 		dev_err(&client->dev, "HW semaphore is not released");
391 		goto mlxsw_i2c_write_exit;
392 	}
393 
394 	/* Validate transaction completion status. */
395 	if (*p_status) {
396 		dev_err(&client->dev, "Bad transaction completion status %x\n",
397 			*p_status);
398 		err = -EIO;
399 	}
400 
401 mlxsw_i2c_write_exit:
402 	kfree(tran_buf);
403 	return err;
404 }
405 
406 /* Routine executes I2C command. */
407 static int
408 mlxsw_i2c_cmd(struct device *dev, u16 opcode, u32 in_mod, size_t in_mbox_size,
409 	      u8 *in_mbox, size_t out_mbox_size, u8 *out_mbox, u8 *status)
410 {
411 	struct i2c_client *client = to_i2c_client(dev);
412 	struct mlxsw_i2c *mlxsw_i2c = i2c_get_clientdata(client);
413 	unsigned long timeout = msecs_to_jiffies(MLXSW_I2C_TIMEOUT_MSECS);
414 	u8 tran_buf[MLXSW_I2C_ADDR_BUF_SIZE];
415 	int num, chunk_size, reg_size, i, j;
416 	int off = mlxsw_i2c->cmd.mb_off_out;
417 	unsigned long end;
418 	struct i2c_msg read_tran[] =
419 		MLXSW_I2C_READ_MSG(client, tran_buf, NULL, 0);
420 	int err;
421 
422 	WARN_ON(in_mbox_size % sizeof(u32) || out_mbox_size % sizeof(u32));
423 
424 	if (in_mbox) {
425 		reg_size = mlxsw_i2c_get_reg_size(in_mbox);
426 		num = reg_size / mlxsw_i2c->block_size;
427 		if (reg_size % mlxsw_i2c->block_size)
428 			num++;
429 
430 		if (mutex_lock_interruptible(&mlxsw_i2c->cmd.lock) < 0) {
431 			dev_err(&client->dev, "Could not acquire lock");
432 			return -EINVAL;
433 		}
434 
435 		err = mlxsw_i2c_write(dev, reg_size, in_mbox, num, status);
436 		if (err)
437 			goto cmd_fail;
438 
439 		/* No out mailbox is case of write transaction. */
440 		if (!out_mbox) {
441 			mutex_unlock(&mlxsw_i2c->cmd.lock);
442 			return 0;
443 		}
444 	} else {
445 		/* No input mailbox is case of initialization query command. */
446 		reg_size = MLXSW_I2C_MAX_DATA_SIZE;
447 		num = reg_size / mlxsw_i2c->block_size;
448 
449 		if (mutex_lock_interruptible(&mlxsw_i2c->cmd.lock) < 0) {
450 			dev_err(&client->dev, "Could not acquire lock");
451 			return -EINVAL;
452 		}
453 
454 		err = mlxsw_i2c_write_init_cmd(client, mlxsw_i2c, opcode,
455 					       in_mod);
456 		if (err)
457 			goto cmd_fail;
458 	}
459 
460 	/* Send read transaction to get output mailbox content. */
461 	read_tran[1].buf = out_mbox;
462 	for (i = 0; i < num; i++) {
463 		chunk_size = (reg_size > mlxsw_i2c->block_size) ?
464 			     mlxsw_i2c->block_size : reg_size;
465 		read_tran[1].len = chunk_size;
466 		mlxsw_i2c_set_slave_addr(tran_buf, off);
467 
468 		j = 0;
469 		end = jiffies + timeout;
470 		do {
471 			err = i2c_transfer(client->adapter, read_tran,
472 					   ARRAY_SIZE(read_tran));
473 			if (err == ARRAY_SIZE(read_tran))
474 				break;
475 
476 			cond_resched();
477 		} while ((time_before(jiffies, end)) ||
478 			 (j++ < MLXSW_I2C_RETRY));
479 
480 		if (err != ARRAY_SIZE(read_tran)) {
481 			if (!err)
482 				err = -EIO;
483 
484 			goto cmd_fail;
485 		}
486 
487 		off += chunk_size;
488 		reg_size -= chunk_size;
489 		read_tran[1].buf += chunk_size;
490 	}
491 
492 	mutex_unlock(&mlxsw_i2c->cmd.lock);
493 
494 	return 0;
495 
496 cmd_fail:
497 	mutex_unlock(&mlxsw_i2c->cmd.lock);
498 	return err;
499 }
500 
501 static int mlxsw_i2c_cmd_exec(void *bus_priv, u16 opcode, u8 opcode_mod,
502 			      u32 in_mod, bool out_mbox_direct,
503 			      char *in_mbox, size_t in_mbox_size,
504 			      char *out_mbox, size_t out_mbox_size,
505 			      u8 *status)
506 {
507 	struct mlxsw_i2c *mlxsw_i2c = bus_priv;
508 
509 	return mlxsw_i2c_cmd(mlxsw_i2c->dev, opcode, in_mod, in_mbox_size,
510 			     in_mbox, out_mbox_size, out_mbox, status);
511 }
512 
513 static bool mlxsw_i2c_skb_transmit_busy(void *bus_priv,
514 					const struct mlxsw_tx_info *tx_info)
515 {
516 	return false;
517 }
518 
519 static int mlxsw_i2c_skb_transmit(void *bus_priv, struct sk_buff *skb,
520 				  const struct mlxsw_tx_info *tx_info)
521 {
522 	return 0;
523 }
524 
525 static int
526 mlxsw_i2c_init(void *bus_priv, struct mlxsw_core *mlxsw_core,
527 	       const struct mlxsw_config_profile *profile,
528 	       struct mlxsw_res *res)
529 {
530 	struct mlxsw_i2c *mlxsw_i2c = bus_priv;
531 	char *mbox;
532 	int err;
533 
534 	mlxsw_i2c->core = mlxsw_core;
535 
536 	mbox = mlxsw_cmd_mbox_alloc();
537 	if (!mbox)
538 		return -ENOMEM;
539 
540 	err = mlxsw_cmd_query_fw(mlxsw_core, mbox);
541 	if (err)
542 		goto mbox_put;
543 
544 	mlxsw_i2c->bus_info.fw_rev.major =
545 		mlxsw_cmd_mbox_query_fw_fw_rev_major_get(mbox);
546 	mlxsw_i2c->bus_info.fw_rev.minor =
547 		mlxsw_cmd_mbox_query_fw_fw_rev_minor_get(mbox);
548 	mlxsw_i2c->bus_info.fw_rev.subminor =
549 		mlxsw_cmd_mbox_query_fw_fw_rev_subminor_get(mbox);
550 
551 	err = mlxsw_core_resources_query(mlxsw_core, mbox, res);
552 
553 mbox_put:
554 	mlxsw_cmd_mbox_free(mbox);
555 	return err;
556 }
557 
558 static void mlxsw_i2c_fini(void *bus_priv)
559 {
560 	struct mlxsw_i2c *mlxsw_i2c = bus_priv;
561 
562 	mlxsw_i2c->core = NULL;
563 }
564 
565 static void mlxsw_i2c_work_handler(struct work_struct *work)
566 {
567 	struct mlxsw_i2c *mlxsw_i2c;
568 
569 	mlxsw_i2c = container_of(work, struct mlxsw_i2c, irq_work);
570 	mlxsw_core_irq_event_handlers_call(mlxsw_i2c->core);
571 }
572 
573 static irqreturn_t mlxsw_i2c_irq_handler(int irq, void *dev)
574 {
575 	struct mlxsw_i2c *mlxsw_i2c = dev;
576 
577 	mlxsw_core_schedule_work(&mlxsw_i2c->irq_work);
578 
579 	/* Interrupt handler shares IRQ line with 'main' interrupt handler.
580 	 * Return here IRQ_NONE, while main handler will return IRQ_HANDLED.
581 	 */
582 	return IRQ_NONE;
583 }
584 
585 static int mlxsw_i2c_irq_init(struct mlxsw_i2c *mlxsw_i2c, u8 addr)
586 {
587 	int err;
588 
589 	/* Initialize interrupt handler if system hotplug driver is reachable,
590 	 * otherwise interrupt line is not enabled and interrupts will not be
591 	 * raised to CPU. Also request_irq() call will be not valid.
592 	 */
593 	if (!IS_REACHABLE(CONFIG_MLXREG_HOTPLUG))
594 		return 0;
595 
596 	/* Set default interrupt line. */
597 	if (mlxsw_i2c->pdata && mlxsw_i2c->pdata->irq)
598 		mlxsw_i2c->irq = mlxsw_i2c->pdata->irq;
599 	else if (addr == MLXSW_FAST_I2C_SLAVE)
600 		mlxsw_i2c->irq = MLXSW_I2C_DEFAULT_IRQ;
601 
602 	if (!mlxsw_i2c->irq)
603 		return 0;
604 
605 	INIT_WORK(&mlxsw_i2c->irq_work, mlxsw_i2c_work_handler);
606 	err = request_irq(mlxsw_i2c->irq, mlxsw_i2c_irq_handler,
607 			  IRQF_TRIGGER_FALLING | IRQF_SHARED, "mlxsw-i2c",
608 			  mlxsw_i2c);
609 	if (err) {
610 		dev_err(mlxsw_i2c->bus_info.dev, "Failed to request irq: %d\n",
611 			err);
612 		return err;
613 	}
614 
615 	return 0;
616 }
617 
618 static void mlxsw_i2c_irq_fini(struct mlxsw_i2c *mlxsw_i2c)
619 {
620 	if (!IS_REACHABLE(CONFIG_MLXREG_HOTPLUG) || !mlxsw_i2c->irq)
621 		return;
622 	cancel_work_sync(&mlxsw_i2c->irq_work);
623 	free_irq(mlxsw_i2c->irq, mlxsw_i2c);
624 }
625 
626 static const struct mlxsw_bus mlxsw_i2c_bus = {
627 	.kind			= "i2c",
628 	.init			= mlxsw_i2c_init,
629 	.fini			= mlxsw_i2c_fini,
630 	.skb_transmit_busy	= mlxsw_i2c_skb_transmit_busy,
631 	.skb_transmit		= mlxsw_i2c_skb_transmit,
632 	.cmd_exec		= mlxsw_i2c_cmd_exec,
633 };
634 
635 static int mlxsw_i2c_probe(struct i2c_client *client)
636 {
637 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
638 	const struct i2c_adapter_quirks *quirks = client->adapter->quirks;
639 	struct mlxsw_i2c *mlxsw_i2c;
640 	u8 status;
641 	int err;
642 
643 	mlxsw_i2c = devm_kzalloc(&client->dev, sizeof(*mlxsw_i2c), GFP_KERNEL);
644 	if (!mlxsw_i2c)
645 		return -ENOMEM;
646 
647 	if (quirks) {
648 		if ((quirks->max_read_len &&
649 		     quirks->max_read_len < MLXSW_I2C_BLK_DEF) ||
650 		    (quirks->max_write_len &&
651 		     quirks->max_write_len < MLXSW_I2C_BLK_DEF)) {
652 			dev_err(&client->dev, "Insufficient transaction buffer length\n");
653 			return -EOPNOTSUPP;
654 		}
655 
656 		mlxsw_i2c->block_size = max_t(u16, MLXSW_I2C_BLK_DEF,
657 					      min_t(u16, quirks->max_read_len,
658 						    quirks->max_write_len));
659 	} else {
660 		mlxsw_i2c->block_size = MLXSW_I2C_BLK_DEF;
661 	}
662 
663 	i2c_set_clientdata(client, mlxsw_i2c);
664 	mutex_init(&mlxsw_i2c->cmd.lock);
665 
666 	/* In order to use mailboxes through the i2c, special area is reserved
667 	 * on the i2c address space that can be used for input and output
668 	 * mailboxes. Such mailboxes are called local mailboxes. When using a
669 	 * local mailbox, software should specify 0 as the Input/Output
670 	 * parameters. The location of the Local Mailbox addresses on the i2c
671 	 * space can be retrieved through the QUERY_FW command.
672 	 * For this purpose QUERY_FW is to be issued with opcode modifier equal
673 	 * 0x01. For such command the output parameter is an immediate value.
674 	 * Here QUERY_FW command is invoked for ASIC probing and for getting
675 	 * local mailboxes addresses from immedate output parameters.
676 	 */
677 
678 	/* Prepare and write out Command Interface Register for transaction */
679 	err = mlxsw_i2c_write_cmd(client, mlxsw_i2c, 1);
680 	if (err) {
681 		dev_err(&client->dev, "Could not start transaction");
682 		goto errout;
683 	}
684 
685 	/* Wait until go bit is cleared. */
686 	err = mlxsw_i2c_wait_go_bit(client, mlxsw_i2c, &status);
687 	if (err) {
688 		dev_err(&client->dev, "HW semaphore is not released");
689 		goto errout;
690 	}
691 
692 	/* Validate transaction completion status. */
693 	if (status) {
694 		dev_err(&client->dev, "Bad transaction completion status %x\n",
695 			status);
696 		err = -EIO;
697 		goto errout;
698 	}
699 
700 	/* Get mailbox offsets. */
701 	err = mlxsw_i2c_get_mbox(client, mlxsw_i2c);
702 	if (err < 0) {
703 		dev_err(&client->dev, "Fail to get mailboxes\n");
704 		goto errout;
705 	}
706 
707 	dev_info(&client->dev, "%s mb size=%x off=0x%08x out mb size=%x off=0x%08x\n",
708 		 id->name, mlxsw_i2c->cmd.mb_size_in,
709 		 mlxsw_i2c->cmd.mb_off_in, mlxsw_i2c->cmd.mb_size_out,
710 		 mlxsw_i2c->cmd.mb_off_out);
711 
712 	/* Register device bus. */
713 	mlxsw_i2c->bus_info.device_kind = id->name;
714 	mlxsw_i2c->bus_info.device_name = client->name;
715 	mlxsw_i2c->bus_info.dev = &client->dev;
716 	mlxsw_i2c->bus_info.low_frequency = true;
717 	mlxsw_i2c->dev = &client->dev;
718 	mlxsw_i2c->pdata = client->dev.platform_data;
719 
720 	err = mlxsw_i2c_irq_init(mlxsw_i2c, client->addr);
721 	if (err)
722 		goto errout;
723 
724 	err = mlxsw_core_bus_device_register(&mlxsw_i2c->bus_info,
725 					     &mlxsw_i2c_bus, mlxsw_i2c, false,
726 					     NULL, NULL);
727 	if (err) {
728 		dev_err(&client->dev, "Fail to register core bus\n");
729 		goto err_bus_device_register;
730 	}
731 
732 	return 0;
733 
734 err_bus_device_register:
735 	mlxsw_i2c_irq_fini(mlxsw_i2c);
736 errout:
737 	mutex_destroy(&mlxsw_i2c->cmd.lock);
738 	i2c_set_clientdata(client, NULL);
739 
740 	return err;
741 }
742 
743 static void mlxsw_i2c_remove(struct i2c_client *client)
744 {
745 	struct mlxsw_i2c *mlxsw_i2c = i2c_get_clientdata(client);
746 
747 	mlxsw_core_bus_device_unregister(mlxsw_i2c->core, false);
748 	mlxsw_i2c_irq_fini(mlxsw_i2c);
749 	mutex_destroy(&mlxsw_i2c->cmd.lock);
750 }
751 
752 int mlxsw_i2c_driver_register(struct i2c_driver *i2c_driver)
753 {
754 	i2c_driver->probe_new = mlxsw_i2c_probe;
755 	i2c_driver->remove = mlxsw_i2c_remove;
756 	return i2c_add_driver(i2c_driver);
757 }
758 EXPORT_SYMBOL(mlxsw_i2c_driver_register);
759 
760 void mlxsw_i2c_driver_unregister(struct i2c_driver *i2c_driver)
761 {
762 	i2c_del_driver(i2c_driver);
763 }
764 EXPORT_SYMBOL(mlxsw_i2c_driver_unregister);
765 
766 MODULE_AUTHOR("Vadim Pasternak <vadimp@mellanox.com>");
767 MODULE_DESCRIPTION("Mellanox switch I2C interface driver");
768 MODULE_LICENSE("Dual BSD/GPL");
769