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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Aspeed 24XX/25XX I2C Controller.
4 *
5 * Copyright (C) 2012-2017 ASPEED Technology Inc.
6 * Copyright 2017 IBM Corporation
7 * Copyright 2017 Google, Inc.
8 */
9
10#include <linux/clk.h>
11#include <linux/completion.h>
12#include <linux/err.h>
13#include <linux/errno.h>
14#include <linux/i2c.h>
15#include <linux/init.h>
16#include <linux/interrupt.h>
17#include <linux/io.h>
18#include <linux/irq.h>
19#include <linux/irqchip/chained_irq.h>
20#include <linux/irqdomain.h>
21#include <linux/kernel.h>
22#include <linux/module.h>
23#include <linux/of_address.h>
24#include <linux/of_irq.h>
25#include <linux/of_platform.h>
26#include <linux/platform_device.h>
27#include <linux/reset.h>
28#include <linux/slab.h>
29
30/* I2C Register */
31#define ASPEED_I2C_FUN_CTRL_REG 0x00
32#define ASPEED_I2C_AC_TIMING_REG1 0x04
33#define ASPEED_I2C_AC_TIMING_REG2 0x08
34#define ASPEED_I2C_INTR_CTRL_REG 0x0c
35#define ASPEED_I2C_INTR_STS_REG 0x10
36#define ASPEED_I2C_CMD_REG 0x14
37#define ASPEED_I2C_DEV_ADDR_REG 0x18
38#define ASPEED_I2C_BYTE_BUF_REG 0x20
39
40/* Global Register Definition */
41/* 0x00 : I2C Interrupt Status Register */
42/* 0x08 : I2C Interrupt Target Assignment */
43
44/* Device Register Definition */
45/* 0x00 : I2CD Function Control Register */
46#define ASPEED_I2CD_MULTI_MASTER_DIS BIT(15)
47#define ASPEED_I2CD_SDA_DRIVE_1T_EN BIT(8)
48#define ASPEED_I2CD_M_SDA_DRIVE_1T_EN BIT(7)
49#define ASPEED_I2CD_M_HIGH_SPEED_EN BIT(6)
50#define ASPEED_I2CD_SLAVE_EN BIT(1)
51#define ASPEED_I2CD_MASTER_EN BIT(0)
52
53/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
54#define ASPEED_I2CD_TIME_TBUF_MASK GENMASK(31, 28)
55#define ASPEED_I2CD_TIME_THDSTA_MASK GENMASK(27, 24)
56#define ASPEED_I2CD_TIME_TACST_MASK GENMASK(23, 20)
57#define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT 16
58#define ASPEED_I2CD_TIME_SCL_HIGH_MASK GENMASK(19, 16)
59#define ASPEED_I2CD_TIME_SCL_LOW_SHIFT 12
60#define ASPEED_I2CD_TIME_SCL_LOW_MASK GENMASK(15, 12)
61#define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK GENMASK(3, 0)
62#define ASPEED_I2CD_TIME_SCL_REG_MAX GENMASK(3, 0)
63/* 0x08 : I2CD Clock and AC Timing Control Register #2 */
64#define ASPEED_NO_TIMEOUT_CTRL 0
65
66/* 0x0c : I2CD Interrupt Control Register &
67 * 0x10 : I2CD Interrupt Status Register
68 *
69 * These share bit definitions, so use the same values for the enable &
70 * status bits.
71 */
72#define ASPEED_I2CD_INTR_RECV_MASK 0xf000ffff
73#define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT BIT(14)
74#define ASPEED_I2CD_INTR_BUS_RECOVER_DONE BIT(13)
75#define ASPEED_I2CD_INTR_SLAVE_MATCH BIT(7)
76#define ASPEED_I2CD_INTR_SCL_TIMEOUT BIT(6)
77#define ASPEED_I2CD_INTR_ABNORMAL BIT(5)
78#define ASPEED_I2CD_INTR_NORMAL_STOP BIT(4)
79#define ASPEED_I2CD_INTR_ARBIT_LOSS BIT(3)
80#define ASPEED_I2CD_INTR_RX_DONE BIT(2)
81#define ASPEED_I2CD_INTR_TX_NAK BIT(1)
82#define ASPEED_I2CD_INTR_TX_ACK BIT(0)
83#define ASPEED_I2CD_INTR_MASTER_ERRORS \
84 (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \
85 ASPEED_I2CD_INTR_SCL_TIMEOUT | \
86 ASPEED_I2CD_INTR_ABNORMAL | \
87 ASPEED_I2CD_INTR_ARBIT_LOSS)
88#define ASPEED_I2CD_INTR_ALL \
89 (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT | \
90 ASPEED_I2CD_INTR_BUS_RECOVER_DONE | \
91 ASPEED_I2CD_INTR_SCL_TIMEOUT | \
92 ASPEED_I2CD_INTR_ABNORMAL | \
93 ASPEED_I2CD_INTR_NORMAL_STOP | \
94 ASPEED_I2CD_INTR_ARBIT_LOSS | \
95 ASPEED_I2CD_INTR_RX_DONE | \
96 ASPEED_I2CD_INTR_TX_NAK | \
97 ASPEED_I2CD_INTR_TX_ACK)
98
99/* 0x14 : I2CD Command/Status Register */
100#define ASPEED_I2CD_SCL_LINE_STS BIT(18)
101#define ASPEED_I2CD_SDA_LINE_STS BIT(17)
102#define ASPEED_I2CD_BUS_BUSY_STS BIT(16)
103#define ASPEED_I2CD_BUS_RECOVER_CMD BIT(11)
104
105/* Command Bit */
106#define ASPEED_I2CD_M_STOP_CMD BIT(5)
107#define ASPEED_I2CD_M_S_RX_CMD_LAST BIT(4)
108#define ASPEED_I2CD_M_RX_CMD BIT(3)
109#define ASPEED_I2CD_S_TX_CMD BIT(2)
110#define ASPEED_I2CD_M_TX_CMD BIT(1)
111#define ASPEED_I2CD_M_START_CMD BIT(0)
112#define ASPEED_I2CD_MASTER_CMDS_MASK \
113 (ASPEED_I2CD_M_STOP_CMD | \
114 ASPEED_I2CD_M_S_RX_CMD_LAST | \
115 ASPEED_I2CD_M_RX_CMD | \
116 ASPEED_I2CD_M_TX_CMD | \
117 ASPEED_I2CD_M_START_CMD)
118
119/* 0x18 : I2CD Slave Device Address Register */
120#define ASPEED_I2CD_DEV_ADDR_MASK GENMASK(6, 0)
121
122enum aspeed_i2c_master_state {
123 ASPEED_I2C_MASTER_INACTIVE,
124 ASPEED_I2C_MASTER_PENDING,
125 ASPEED_I2C_MASTER_START,
126 ASPEED_I2C_MASTER_TX_FIRST,
127 ASPEED_I2C_MASTER_TX,
128 ASPEED_I2C_MASTER_RX_FIRST,
129 ASPEED_I2C_MASTER_RX,
130 ASPEED_I2C_MASTER_STOP,
131};
132
133enum aspeed_i2c_slave_state {
134 ASPEED_I2C_SLAVE_INACTIVE,
135 ASPEED_I2C_SLAVE_START,
136 ASPEED_I2C_SLAVE_READ_REQUESTED,
137 ASPEED_I2C_SLAVE_READ_PROCESSED,
138 ASPEED_I2C_SLAVE_WRITE_REQUESTED,
139 ASPEED_I2C_SLAVE_WRITE_RECEIVED,
140 ASPEED_I2C_SLAVE_STOP,
141};
142
143struct aspeed_i2c_bus {
144 struct i2c_adapter adap;
145 struct device *dev;
146 void __iomem *base;
147 struct reset_control *rst;
148 /* Synchronizes I/O mem access to base. */
149 spinlock_t lock;
150 struct completion cmd_complete;
151 u32 (*get_clk_reg_val)(struct device *dev,
152 u32 divisor);
153 unsigned long parent_clk_frequency;
154 u32 bus_frequency;
155 /* Transaction state. */
156 enum aspeed_i2c_master_state master_state;
157 struct i2c_msg *msgs;
158 size_t buf_index;
159 size_t msgs_index;
160 size_t msgs_count;
161 bool send_stop;
162 int cmd_err;
163 /* Protected only by i2c_lock_bus */
164 int master_xfer_result;
165 /* Multi-master */
166 bool multi_master;
167#if IS_ENABLED(CONFIG_I2C_SLAVE)
168 struct i2c_client *slave;
169 enum aspeed_i2c_slave_state slave_state;
170#endif /* CONFIG_I2C_SLAVE */
171};
172
173static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus);
174
175static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
176{
177 unsigned long time_left, flags;
178 int ret = 0;
179 u32 command;
180
181 spin_lock_irqsave(&bus->lock, flags);
182 command = readl(bus->base + ASPEED_I2C_CMD_REG);
183
184 if (command & ASPEED_I2CD_SDA_LINE_STS) {
185 /* Bus is idle: no recovery needed. */
186 if (command & ASPEED_I2CD_SCL_LINE_STS)
187 goto out;
188 dev_dbg(bus->dev, "SCL hung (state %x), attempting recovery\n",
189 command);
190
191 reinit_completion(&bus->cmd_complete);
192 writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
193 spin_unlock_irqrestore(&bus->lock, flags);
194
195 time_left = wait_for_completion_timeout(
196 &bus->cmd_complete, bus->adap.timeout);
197
198 spin_lock_irqsave(&bus->lock, flags);
199 if (time_left == 0)
200 goto reset_out;
201 else if (bus->cmd_err)
202 goto reset_out;
203 /* Recovery failed. */
204 else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
205 ASPEED_I2CD_SCL_LINE_STS))
206 goto reset_out;
207 /* Bus error. */
208 } else {
209 dev_dbg(bus->dev, "SDA hung (state %x), attempting recovery\n",
210 command);
211
212 reinit_completion(&bus->cmd_complete);
213 /* Writes 1 to 8 SCL clock cycles until SDA is released. */
214 writel(ASPEED_I2CD_BUS_RECOVER_CMD,
215 bus->base + ASPEED_I2C_CMD_REG);
216 spin_unlock_irqrestore(&bus->lock, flags);
217
218 time_left = wait_for_completion_timeout(
219 &bus->cmd_complete, bus->adap.timeout);
220
221 spin_lock_irqsave(&bus->lock, flags);
222 if (time_left == 0)
223 goto reset_out;
224 else if (bus->cmd_err)
225 goto reset_out;
226 /* Recovery failed. */
227 else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
228 ASPEED_I2CD_SDA_LINE_STS))
229 goto reset_out;
230 }
231
232out:
233 spin_unlock_irqrestore(&bus->lock, flags);
234
235 return ret;
236
237reset_out:
238 spin_unlock_irqrestore(&bus->lock, flags);
239
240 return aspeed_i2c_reset(bus);
241}
242
243#if IS_ENABLED(CONFIG_I2C_SLAVE)
244static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
245{
246 u32 command, irq_handled = 0;
247 struct i2c_client *slave = bus->slave;
248 u8 value;
249
250 if (!slave)
251 return 0;
252
253 command = readl(bus->base + ASPEED_I2C_CMD_REG);
254
255 /* Slave was requested, restart state machine. */
256 if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
257 irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
258 bus->slave_state = ASPEED_I2C_SLAVE_START;
259 }
260
261 /* Slave is not currently active, irq was for someone else. */
262 if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
263 return irq_handled;
264
265 dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
266 irq_status, command);
267
268 /* Slave was sent something. */
269 if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {
270 value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
271 /* Handle address frame. */
272 if (bus->slave_state == ASPEED_I2C_SLAVE_START) {
273 if (value & 0x1)
274 bus->slave_state =
275 ASPEED_I2C_SLAVE_READ_REQUESTED;
276 else
277 bus->slave_state =
278 ASPEED_I2C_SLAVE_WRITE_REQUESTED;
279 }
280 irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
281 }
282
283 /* Slave was asked to stop. */
284 if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
285 irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
286 bus->slave_state = ASPEED_I2C_SLAVE_STOP;
287 }
288 if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
289 bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
290 irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
291 bus->slave_state = ASPEED_I2C_SLAVE_STOP;
292 }
293
294 switch (bus->slave_state) {
295 case ASPEED_I2C_SLAVE_READ_REQUESTED:
296 if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_ACK))
297 dev_err(bus->dev, "Unexpected ACK on read request.\n");
298 bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED;
299 i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
300 writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
301 writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
302 break;
303 case ASPEED_I2C_SLAVE_READ_PROCESSED:
304 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
305 dev_err(bus->dev,
306 "Expected ACK after processed read.\n");
307 break;
308 }
309 irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
310 i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
311 writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
312 writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
313 break;
314 case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
315 bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
316 i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
317 break;
318 case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
319 i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
320 break;
321 case ASPEED_I2C_SLAVE_STOP:
322 i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
323 bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
324 break;
325 case ASPEED_I2C_SLAVE_START:
326 /* Slave was just started. Waiting for the next event. */;
327 break;
328 default:
329 dev_err(bus->dev, "unknown slave_state: %d\n",
330 bus->slave_state);
331 bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
332 break;
333 }
334
335 return irq_handled;
336}
337#endif /* CONFIG_I2C_SLAVE */
338
339/* precondition: bus.lock has been acquired. */
340static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
341{
342 u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
343 struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
344 u8 slave_addr = i2c_8bit_addr_from_msg(msg);
345
346#if IS_ENABLED(CONFIG_I2C_SLAVE)
347 /*
348 * If it's requested in the middle of a slave session, set the master
349 * state to 'pending' then H/W will continue handling this master
350 * command when the bus comes back to the idle state.
351 */
352 if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) {
353 bus->master_state = ASPEED_I2C_MASTER_PENDING;
354 return;
355 }
356#endif /* CONFIG_I2C_SLAVE */
357
358 bus->master_state = ASPEED_I2C_MASTER_START;
359 bus->buf_index = 0;
360
361 if (msg->flags & I2C_M_RD) {
362 command |= ASPEED_I2CD_M_RX_CMD;
363 /* Need to let the hardware know to NACK after RX. */
364 if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
365 command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
366 }
367
368 writel(slave_addr, bus->base + ASPEED_I2C_BYTE_BUF_REG);
369 writel(command, bus->base + ASPEED_I2C_CMD_REG);
370}
371
372/* precondition: bus.lock has been acquired. */
373static void aspeed_i2c_do_stop(struct aspeed_i2c_bus *bus)
374{
375 bus->master_state = ASPEED_I2C_MASTER_STOP;
376 writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
377}
378
379/* precondition: bus.lock has been acquired. */
380static void aspeed_i2c_next_msg_or_stop(struct aspeed_i2c_bus *bus)
381{
382 if (bus->msgs_index + 1 < bus->msgs_count) {
383 bus->msgs_index++;
384 aspeed_i2c_do_start(bus);
385 } else {
386 aspeed_i2c_do_stop(bus);
387 }
388}
389
390static int aspeed_i2c_is_irq_error(u32 irq_status)
391{
392 if (irq_status & ASPEED_I2CD_INTR_ARBIT_LOSS)
393 return -EAGAIN;
394 if (irq_status & (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |
395 ASPEED_I2CD_INTR_SCL_TIMEOUT))
396 return -EBUSY;
397 if (irq_status & (ASPEED_I2CD_INTR_ABNORMAL))
398 return -EPROTO;
399
400 return 0;
401}
402
403static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
404{
405 u32 irq_handled = 0, command = 0;
406 struct i2c_msg *msg;
407 u8 recv_byte;
408 int ret;
409
410 if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
411 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
412 irq_handled |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
413 goto out_complete;
414 }
415
416 /*
417 * We encountered an interrupt that reports an error: the hardware
418 * should clear the command queue effectively taking us back to the
419 * INACTIVE state.
420 */
421 ret = aspeed_i2c_is_irq_error(irq_status);
422 if (ret) {
423 dev_dbg(bus->dev, "received error interrupt: 0x%08x\n",
424 irq_status);
425 irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
426 if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
427 bus->cmd_err = ret;
428 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
429 goto out_complete;
430 }
431 }
432
433 /* Master is not currently active, irq was for someone else. */
434 if (bus->master_state == ASPEED_I2C_MASTER_INACTIVE ||
435 bus->master_state == ASPEED_I2C_MASTER_PENDING)
436 goto out_no_complete;
437
438 /* We are in an invalid state; reset bus to a known state. */
439 if (!bus->msgs) {
440 dev_err(bus->dev, "bus in unknown state. irq_status: 0x%x\n",
441 irq_status);
442 bus->cmd_err = -EIO;
443 if (bus->master_state != ASPEED_I2C_MASTER_STOP &&
444 bus->master_state != ASPEED_I2C_MASTER_INACTIVE)
445 aspeed_i2c_do_stop(bus);
446 goto out_no_complete;
447 }
448 msg = &bus->msgs[bus->msgs_index];
449
450 /*
451 * START is a special case because we still have to handle a subsequent
452 * TX or RX immediately after we handle it, so we handle it here and
453 * then update the state and handle the new state below.
454 */
455 if (bus->master_state == ASPEED_I2C_MASTER_START) {
456#if IS_ENABLED(CONFIG_I2C_SLAVE)
457 /*
458 * If a peer master starts a xfer immediately after it queues a
459 * master command, clear the queued master command and change
460 * its state to 'pending'. To simplify handling of pending
461 * cases, it uses S/W solution instead of H/W command queue
462 * handling.
463 */
464 if (unlikely(irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH)) {
465 writel(readl(bus->base + ASPEED_I2C_CMD_REG) &
466 ~ASPEED_I2CD_MASTER_CMDS_MASK,
467 bus->base + ASPEED_I2C_CMD_REG);
468 bus->master_state = ASPEED_I2C_MASTER_PENDING;
469 dev_dbg(bus->dev,
470 "master goes pending due to a slave start\n");
471 goto out_no_complete;
472 }
473#endif /* CONFIG_I2C_SLAVE */
474 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
475 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_NAK))) {
476 bus->cmd_err = -ENXIO;
477 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
478 goto out_complete;
479 }
480 pr_devel("no slave present at %02x\n", msg->addr);
481 irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
482 bus->cmd_err = -ENXIO;
483 aspeed_i2c_do_stop(bus);
484 goto out_no_complete;
485 }
486 irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
487 if (msg->len == 0) { /* SMBUS_QUICK */
488 aspeed_i2c_do_stop(bus);
489 goto out_no_complete;
490 }
491 if (msg->flags & I2C_M_RD)
492 bus->master_state = ASPEED_I2C_MASTER_RX_FIRST;
493 else
494 bus->master_state = ASPEED_I2C_MASTER_TX_FIRST;
495 }
496
497 switch (bus->master_state) {
498 case ASPEED_I2C_MASTER_TX:
499 if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
500 dev_dbg(bus->dev, "slave NACKed TX\n");
501 irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
502 goto error_and_stop;
503 } else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
504 dev_err(bus->dev, "slave failed to ACK TX\n");
505 goto error_and_stop;
506 }
507 irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
508 fallthrough;
509 case ASPEED_I2C_MASTER_TX_FIRST:
510 if (bus->buf_index < msg->len) {
511 bus->master_state = ASPEED_I2C_MASTER_TX;
512 writel(msg->buf[bus->buf_index++],
513 bus->base + ASPEED_I2C_BYTE_BUF_REG);
514 writel(ASPEED_I2CD_M_TX_CMD,
515 bus->base + ASPEED_I2C_CMD_REG);
516 } else {
517 aspeed_i2c_next_msg_or_stop(bus);
518 }
519 goto out_no_complete;
520 case ASPEED_I2C_MASTER_RX_FIRST:
521 /* RX may not have completed yet (only address cycle) */
522 if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE))
523 goto out_no_complete;
524 fallthrough;
525 case ASPEED_I2C_MASTER_RX:
526 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
527 dev_err(bus->dev, "master failed to RX\n");
528 goto error_and_stop;
529 }
530 irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
531
532 recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
533 msg->buf[bus->buf_index++] = recv_byte;
534
535 if (msg->flags & I2C_M_RECV_LEN) {
536 if (unlikely(recv_byte > I2C_SMBUS_BLOCK_MAX)) {
537 bus->cmd_err = -EPROTO;
538 aspeed_i2c_do_stop(bus);
539 goto out_no_complete;
540 }
541 msg->len = recv_byte +
542 ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
543 msg->flags &= ~I2C_M_RECV_LEN;
544 }
545
546 if (bus->buf_index < msg->len) {
547 bus->master_state = ASPEED_I2C_MASTER_RX;
548 command = ASPEED_I2CD_M_RX_CMD;
549 if (bus->buf_index + 1 == msg->len)
550 command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
551 writel(command, bus->base + ASPEED_I2C_CMD_REG);
552 } else {
553 aspeed_i2c_next_msg_or_stop(bus);
554 }
555 goto out_no_complete;
556 case ASPEED_I2C_MASTER_STOP:
557 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP))) {
558 dev_err(bus->dev,
559 "master failed to STOP. irq_status:0x%x\n",
560 irq_status);
561 bus->cmd_err = -EIO;
562 /* Do not STOP as we have already tried. */
563 } else {
564 irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
565 }
566
567 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
568 goto out_complete;
569 case ASPEED_I2C_MASTER_INACTIVE:
570 dev_err(bus->dev,
571 "master received interrupt 0x%08x, but is inactive\n",
572 irq_status);
573 bus->cmd_err = -EIO;
574 /* Do not STOP as we should be inactive. */
575 goto out_complete;
576 default:
577 WARN(1, "unknown master state\n");
578 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
579 bus->cmd_err = -EINVAL;
580 goto out_complete;
581 }
582error_and_stop:
583 bus->cmd_err = -EIO;
584 aspeed_i2c_do_stop(bus);
585 goto out_no_complete;
586out_complete:
587 bus->msgs = NULL;
588 if (bus->cmd_err)
589 bus->master_xfer_result = bus->cmd_err;
590 else
591 bus->master_xfer_result = bus->msgs_index + 1;
592 complete(&bus->cmd_complete);
593out_no_complete:
594 return irq_handled;
595}
596
597static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
598{
599 struct aspeed_i2c_bus *bus = dev_id;
600 u32 irq_received, irq_remaining, irq_handled;
601
602 spin_lock(&bus->lock);
603 irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
604 /* Ack all interrupts except for Rx done */
605 writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
606 bus->base + ASPEED_I2C_INTR_STS_REG);
607 readl(bus->base + ASPEED_I2C_INTR_STS_REG);
608 irq_received &= ASPEED_I2CD_INTR_RECV_MASK;
609 irq_remaining = irq_received;
610
611#if IS_ENABLED(CONFIG_I2C_SLAVE)
612 /*
613 * In most cases, interrupt bits will be set one by one, although
614 * multiple interrupt bits could be set at the same time. It's also
615 * possible that master interrupt bits could be set along with slave
616 * interrupt bits. Each case needs to be handled using corresponding
617 * handlers depending on the current state.
618 */
619 if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE &&
620 bus->master_state != ASPEED_I2C_MASTER_PENDING) {
621 irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
622 irq_remaining &= ~irq_handled;
623 if (irq_remaining)
624 irq_handled |= aspeed_i2c_slave_irq(bus, irq_remaining);
625 } else {
626 irq_handled = aspeed_i2c_slave_irq(bus, irq_remaining);
627 irq_remaining &= ~irq_handled;
628 if (irq_remaining)
629 irq_handled |= aspeed_i2c_master_irq(bus,
630 irq_remaining);
631 }
632
633 /*
634 * Start a pending master command at here if a slave operation is
635 * completed.
636 */
637 if (bus->master_state == ASPEED_I2C_MASTER_PENDING &&
638 bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
639 aspeed_i2c_do_start(bus);
640#else
641 irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
642#endif /* CONFIG_I2C_SLAVE */
643
644 irq_remaining &= ~irq_handled;
645 if (irq_remaining)
646 dev_err(bus->dev,
647 "irq handled != irq. expected 0x%08x, but was 0x%08x\n",
648 irq_received, irq_handled);
649
650 /* Ack Rx done */
651 if (irq_received & ASPEED_I2CD_INTR_RX_DONE) {
652 writel(ASPEED_I2CD_INTR_RX_DONE,
653 bus->base + ASPEED_I2C_INTR_STS_REG);
654 readl(bus->base + ASPEED_I2C_INTR_STS_REG);
655 }
656 spin_unlock(&bus->lock);
657 return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
658}
659
660static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
661 struct i2c_msg *msgs, int num)
662{
663 struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);
664 unsigned long time_left, flags;
665
666 spin_lock_irqsave(&bus->lock, flags);
667 bus->cmd_err = 0;
668
669 /* If bus is busy in a single master environment, attempt recovery. */
670 if (!bus->multi_master &&
671 (readl(bus->base + ASPEED_I2C_CMD_REG) &
672 ASPEED_I2CD_BUS_BUSY_STS)) {
673 int ret;
674
675 spin_unlock_irqrestore(&bus->lock, flags);
676 ret = aspeed_i2c_recover_bus(bus);
677 if (ret)
678 return ret;
679 spin_lock_irqsave(&bus->lock, flags);
680 }
681
682 bus->cmd_err = 0;
683 bus->msgs = msgs;
684 bus->msgs_index = 0;
685 bus->msgs_count = num;
686
687 reinit_completion(&bus->cmd_complete);
688 aspeed_i2c_do_start(bus);
689 spin_unlock_irqrestore(&bus->lock, flags);
690
691 time_left = wait_for_completion_timeout(&bus->cmd_complete,
692 bus->adap.timeout);
693
694 if (time_left == 0) {
695 /*
696 * If timed out and bus is still busy in a multi master
697 * environment, attempt recovery at here.
698 */
699 if (bus->multi_master &&
700 (readl(bus->base + ASPEED_I2C_CMD_REG) &
701 ASPEED_I2CD_BUS_BUSY_STS))
702 aspeed_i2c_recover_bus(bus);
703
704 /*
705 * If timed out and the state is still pending, drop the pending
706 * master command.
707 */
708 spin_lock_irqsave(&bus->lock, flags);
709 if (bus->master_state == ASPEED_I2C_MASTER_PENDING)
710 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
711 spin_unlock_irqrestore(&bus->lock, flags);
712
713 return -ETIMEDOUT;
714 }
715
716 return bus->master_xfer_result;
717}
718
719static u32 aspeed_i2c_functionality(struct i2c_adapter *adap)
720{
721 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
722}
723
724#if IS_ENABLED(CONFIG_I2C_SLAVE)
725/* precondition: bus.lock has been acquired. */
726static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr)
727{
728 u32 addr_reg_val, func_ctrl_reg_val;
729
730 /* Set slave addr. */
731 addr_reg_val = readl(bus->base + ASPEED_I2C_DEV_ADDR_REG);
732 addr_reg_val &= ~ASPEED_I2CD_DEV_ADDR_MASK;
733 addr_reg_val |= slave_addr & ASPEED_I2CD_DEV_ADDR_MASK;
734 writel(addr_reg_val, bus->base + ASPEED_I2C_DEV_ADDR_REG);
735
736 /* Turn on slave mode. */
737 func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
738 func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
739 writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
740}
741
742static int aspeed_i2c_reg_slave(struct i2c_client *client)
743{
744 struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
745 unsigned long flags;
746
747 spin_lock_irqsave(&bus->lock, flags);
748 if (bus->slave) {
749 spin_unlock_irqrestore(&bus->lock, flags);
750 return -EINVAL;
751 }
752
753 __aspeed_i2c_reg_slave(bus, client->addr);
754
755 bus->slave = client;
756 bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
757 spin_unlock_irqrestore(&bus->lock, flags);
758
759 return 0;
760}
761
762static int aspeed_i2c_unreg_slave(struct i2c_client *client)
763{
764 struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
765 u32 func_ctrl_reg_val;
766 unsigned long flags;
767
768 spin_lock_irqsave(&bus->lock, flags);
769 if (!bus->slave) {
770 spin_unlock_irqrestore(&bus->lock, flags);
771 return -EINVAL;
772 }
773
774 /* Turn off slave mode. */
775 func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
776 func_ctrl_reg_val &= ~ASPEED_I2CD_SLAVE_EN;
777 writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
778
779 bus->slave = NULL;
780 spin_unlock_irqrestore(&bus->lock, flags);
781
782 return 0;
783}
784#endif /* CONFIG_I2C_SLAVE */
785
786static const struct i2c_algorithm aspeed_i2c_algo = {
787 .master_xfer = aspeed_i2c_master_xfer,
788 .functionality = aspeed_i2c_functionality,
789#if IS_ENABLED(CONFIG_I2C_SLAVE)
790 .reg_slave = aspeed_i2c_reg_slave,
791 .unreg_slave = aspeed_i2c_unreg_slave,
792#endif /* CONFIG_I2C_SLAVE */
793};
794
795static u32 aspeed_i2c_get_clk_reg_val(struct device *dev,
796 u32 clk_high_low_mask,
797 u32 divisor)
798{
799 u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp;
800
801 /*
802 * SCL_high and SCL_low represent a value 1 greater than what is stored
803 * since a zero divider is meaningless. Thus, the max value each can
804 * store is every bit set + 1. Since SCL_high and SCL_low are added
805 * together (see below), the max value of both is the max value of one
806 * them times two.
807 */
808 clk_high_low_max = (clk_high_low_mask + 1) * 2;
809
810 /*
811 * The actual clock frequency of SCL is:
812 * SCL_freq = APB_freq / (base_freq * (SCL_high + SCL_low))
813 * = APB_freq / divisor
814 * where base_freq is a programmable clock divider; its value is
815 * base_freq = 1 << base_clk_divisor
816 * SCL_high is the number of base_freq clock cycles that SCL stays high
817 * and SCL_low is the number of base_freq clock cycles that SCL stays
818 * low for a period of SCL.
819 * The actual register has a minimum SCL_high and SCL_low minimum of 1;
820 * thus, they start counting at zero. So
821 * SCL_high = clk_high + 1
822 * SCL_low = clk_low + 1
823 * Thus,
824 * SCL_freq = APB_freq /
825 * ((1 << base_clk_divisor) * (clk_high + 1 + clk_low + 1))
826 * The documentation recommends clk_high >= clk_high_max / 2 and
827 * clk_low >= clk_low_max / 2 - 1 when possible; this last constraint
828 * gives us the following solution:
829 */
830 base_clk_divisor = divisor > clk_high_low_max ?
831 ilog2((divisor - 1) / clk_high_low_max) + 1 : 0;
832
833 if (base_clk_divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) {
834 base_clk_divisor = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK;
835 clk_low = clk_high_low_mask;
836 clk_high = clk_high_low_mask;
837 dev_err(dev,
838 "clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n",
839 divisor, (1 << base_clk_divisor) * clk_high_low_max);
840 } else {
841 tmp = (divisor + (1 << base_clk_divisor) - 1)
842 >> base_clk_divisor;
843 clk_low = tmp / 2;
844 clk_high = tmp - clk_low;
845
846 if (clk_high)
847 clk_high--;
848
849 if (clk_low)
850 clk_low--;
851 }
852
853
854 return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
855 & ASPEED_I2CD_TIME_SCL_HIGH_MASK)
856 | ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT)
857 & ASPEED_I2CD_TIME_SCL_LOW_MASK)
858 | (base_clk_divisor
859 & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
860}
861
862static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor)
863{
864 /*
865 * clk_high and clk_low are each 3 bits wide, so each can hold a max
866 * value of 8 giving a clk_high_low_max of 16.
867 */
868 return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor);
869}
870
871static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor)
872{
873 /*
874 * clk_high and clk_low are each 4 bits wide, so each can hold a max
875 * value of 16 giving a clk_high_low_max of 32.
876 */
877 return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor);
878}
879
880/* precondition: bus.lock has been acquired. */
881static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus)
882{
883 u32 divisor, clk_reg_val;
884
885 divisor = DIV_ROUND_UP(bus->parent_clk_frequency, bus->bus_frequency);
886 clk_reg_val = readl(bus->base + ASPEED_I2C_AC_TIMING_REG1);
887 clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK |
888 ASPEED_I2CD_TIME_THDSTA_MASK |
889 ASPEED_I2CD_TIME_TACST_MASK);
890 clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor);
891 writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1);
892 writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2);
893
894 return 0;
895}
896
897/* precondition: bus.lock has been acquired. */
898static int aspeed_i2c_init(struct aspeed_i2c_bus *bus,
899 struct platform_device *pdev)
900{
901 u32 fun_ctrl_reg = ASPEED_I2CD_MASTER_EN;
902 int ret;
903
904 /* Disable everything. */
905 writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
906
907 ret = aspeed_i2c_init_clk(bus);
908 if (ret < 0)
909 return ret;
910
911 if (of_property_read_bool(pdev->dev.of_node, "multi-master"))
912 bus->multi_master = true;
913 else
914 fun_ctrl_reg |= ASPEED_I2CD_MULTI_MASTER_DIS;
915
916 /* Enable Master Mode */
917 writel(readl(bus->base + ASPEED_I2C_FUN_CTRL_REG) | fun_ctrl_reg,
918 bus->base + ASPEED_I2C_FUN_CTRL_REG);
919
920#if IS_ENABLED(CONFIG_I2C_SLAVE)
921 /* If slave has already been registered, re-enable it. */
922 if (bus->slave)
923 __aspeed_i2c_reg_slave(bus, bus->slave->addr);
924#endif /* CONFIG_I2C_SLAVE */
925
926 /* Set interrupt generation of I2C controller */
927 writel(ASPEED_I2CD_INTR_ALL, bus->base + ASPEED_I2C_INTR_CTRL_REG);
928
929 return 0;
930}
931
932static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus)
933{
934 struct platform_device *pdev = to_platform_device(bus->dev);
935 unsigned long flags;
936 int ret;
937
938 spin_lock_irqsave(&bus->lock, flags);
939
940 /* Disable and ack all interrupts. */
941 writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
942 writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
943
944 ret = aspeed_i2c_init(bus, pdev);
945
946 spin_unlock_irqrestore(&bus->lock, flags);
947
948 return ret;
949}
950
951static const struct of_device_id aspeed_i2c_bus_of_table[] = {
952 {
953 .compatible = "aspeed,ast2400-i2c-bus",
954 .data = aspeed_i2c_24xx_get_clk_reg_val,
955 },
956 {
957 .compatible = "aspeed,ast2500-i2c-bus",
958 .data = aspeed_i2c_25xx_get_clk_reg_val,
959 },
960 {
961 .compatible = "aspeed,ast2600-i2c-bus",
962 .data = aspeed_i2c_25xx_get_clk_reg_val,
963 },
964 { },
965};
966MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table);
967
968static int aspeed_i2c_probe_bus(struct platform_device *pdev)
969{
970 const struct of_device_id *match;
971 struct aspeed_i2c_bus *bus;
972 struct clk *parent_clk;
973 struct resource *res;
974 int irq, ret;
975
976 bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
977 if (!bus)
978 return -ENOMEM;
979
980 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
981 bus->base = devm_ioremap_resource(&pdev->dev, res);
982 if (IS_ERR(bus->base))
983 return PTR_ERR(bus->base);
984
985 parent_clk = devm_clk_get(&pdev->dev, NULL);
986 if (IS_ERR(parent_clk))
987 return PTR_ERR(parent_clk);
988 bus->parent_clk_frequency = clk_get_rate(parent_clk);
989 /* We just need the clock rate, we don't actually use the clk object. */
990 devm_clk_put(&pdev->dev, parent_clk);
991
992 bus->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
993 if (IS_ERR(bus->rst)) {
994 dev_err(&pdev->dev,
995 "missing or invalid reset controller device tree entry\n");
996 return PTR_ERR(bus->rst);
997 }
998 reset_control_deassert(bus->rst);
999
1000 ret = of_property_read_u32(pdev->dev.of_node,
1001 "bus-frequency", &bus->bus_frequency);
1002 if (ret < 0) {
1003 dev_err(&pdev->dev,
1004 "Could not read bus-frequency property\n");
1005 bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ;
1006 }
1007
1008 match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node);
1009 if (!match)
1010 bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val;
1011 else
1012 bus->get_clk_reg_val = (u32 (*)(struct device *, u32))
1013 match->data;
1014
1015 /* Initialize the I2C adapter */
1016 spin_lock_init(&bus->lock);
1017 init_completion(&bus->cmd_complete);
1018 bus->adap.owner = THIS_MODULE;
1019 bus->adap.retries = 0;
1020 bus->adap.algo = &aspeed_i2c_algo;
1021 bus->adap.dev.parent = &pdev->dev;
1022 bus->adap.dev.of_node = pdev->dev.of_node;
1023 strlcpy(bus->adap.name, pdev->name, sizeof(bus->adap.name));
1024 i2c_set_adapdata(&bus->adap, bus);
1025
1026 bus->dev = &pdev->dev;
1027
1028 /* Clean up any left over interrupt state. */
1029 writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
1030 writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
1031 /*
1032 * bus.lock does not need to be held because the interrupt handler has
1033 * not been enabled yet.
1034 */
1035 ret = aspeed_i2c_init(bus, pdev);
1036 if (ret < 0)
1037 return ret;
1038
1039 irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
1040 ret = devm_request_irq(&pdev->dev, irq, aspeed_i2c_bus_irq,
1041 0, dev_name(&pdev->dev), bus);
1042 if (ret < 0)
1043 return ret;
1044
1045 ret = i2c_add_adapter(&bus->adap);
1046 if (ret < 0)
1047 return ret;
1048
1049 platform_set_drvdata(pdev, bus);
1050
1051 dev_info(bus->dev, "i2c bus %d registered, irq %d\n",
1052 bus->adap.nr, irq);
1053
1054 return 0;
1055}
1056
1057static int aspeed_i2c_remove_bus(struct platform_device *pdev)
1058{
1059 struct aspeed_i2c_bus *bus = platform_get_drvdata(pdev);
1060 unsigned long flags;
1061
1062 spin_lock_irqsave(&bus->lock, flags);
1063
1064 /* Disable everything. */
1065 writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
1066 writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
1067
1068 spin_unlock_irqrestore(&bus->lock, flags);
1069
1070 reset_control_assert(bus->rst);
1071
1072 i2c_del_adapter(&bus->adap);
1073
1074 return 0;
1075}
1076
1077static struct platform_driver aspeed_i2c_bus_driver = {
1078 .probe = aspeed_i2c_probe_bus,
1079 .remove = aspeed_i2c_remove_bus,
1080 .driver = {
1081 .name = "aspeed-i2c-bus",
1082 .of_match_table = aspeed_i2c_bus_of_table,
1083 },
1084};
1085module_platform_driver(aspeed_i2c_bus_driver);
1086
1087MODULE_AUTHOR("Brendan Higgins <brendanhiggins@google.com>");
1088MODULE_DESCRIPTION("Aspeed I2C Bus Driver");
1089MODULE_LICENSE("GPL v2");