forked from ~ljy/RK356X_SDK_RELEASE
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2024-01-31 f9004dbfff8a3fbbd7e2a88c8a4327c7f2f8e5b2 
 kernel/drivers/i2c/busses/i2c-ocores.c
....@@ -1,3 +1,4 @@
1
+// SPDX-License-Identifier: GPL-2.0
12 /*
23  * i2c-ocores.c: I2C bus driver for OpenCores I2C controller
34  * (https://opencores.org/project/i2c/overview)
....@@ -6,13 +7,10 @@
67  *
78  * Support for the GRLIB port of the controller by
89  * Andreas Larsson <andreas@gaisler.com>
9
- *
10
- * This file is licensed under the terms of the GNU General Public License
11
- * version 2.  This program is licensed "as is" without any warranty of any
12
- * kind, whether express or implied.
1310  */
1411 
1512 #include <linux/clk.h>
13
+#include <linux/delay.h>
1614 #include <linux/err.h>
1715 #include <linux/kernel.h>
1816 #include <linux/module.h>
....@@ -25,17 +23,26 @@
2523 #include <linux/slab.h>
2624 #include <linux/io.h>
2725 #include <linux/log2.h>
26
+#include <linux/spinlock.h>
27
+#include <linux/jiffies.h>
2828 
29
+/*
30
+ * 'process_lock' exists because ocores_process() and ocores_process_timeout()
31
+ * can't run in parallel.
32
+ */
2933 struct ocores_i2c {
3034 	void __iomem *base;
35
+	int iobase;
3136 	u32 reg_shift;
3237 	u32 reg_io_width;
38
+	unsigned long flags;
3339 	wait_queue_head_t wait;
3440 	struct i2c_adapter adap;
3541 	struct i2c_msg *msg;
3642 	int pos;
3743 	int nmsgs;
3844 	int state; /* see STATE_ */
45
+	spinlock_t process_lock;
3946 	struct clk *clk;
4047 	int ip_clock_khz;
4148 	int bus_clock_khz;
....@@ -76,6 +83,9 @@
7683 
7784 #define TYPE_OCORES		0
7885 #define TYPE_GRLIB		1
86
+#define TYPE_SIFIVE_REV0	2
87
+
88
+#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */
7989 
8090 static void oc_setreg_8(struct ocores_i2c *i2c, int reg, u8 value)
8191 {
....@@ -127,6 +137,16 @@
127137 	return ioread32be(i2c->base + (reg << i2c->reg_shift));
128138 }
129139 
140
+static void oc_setreg_io_8(struct ocores_i2c *i2c, int reg, u8 value)
141
+{
142
+	outb(value, i2c->iobase + reg);
143
+}
144
+
145
+static inline u8 oc_getreg_io_8(struct ocores_i2c *i2c, int reg)
146
+{
147
+	return inb(i2c->iobase + reg);
148
+}
149
+
130150 static inline void oc_setreg(struct ocores_i2c *i2c, int reg, u8 value)
131151 {
132152 	i2c->setreg(i2c, reg, value);
....@@ -137,23 +157,29 @@
137157 	return i2c->getreg(i2c, reg);
138158 }
139159 
140
-static void ocores_process(struct ocores_i2c *i2c)
160
+static void ocores_process(struct ocores_i2c *i2c, u8 stat)
141161 {
142162 	struct i2c_msg *msg = i2c->msg;
143
-	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
163
+	unsigned long flags;
164
+
165
+	/*
166
+	 * If we spin here is because we are in timeout, so we are going
167
+	 * to be in STATE_ERROR. See ocores_process_timeout()
168
+	 */
169
+	spin_lock_irqsave(&i2c->process_lock, flags);
144170 
145171 	if ((i2c->state == STATE_DONE) || (i2c->state == STATE_ERROR)) {
146172 		/* stop has been sent */
147173 		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
148174 		wake_up(&i2c->wait);
149
-		return;
175
+		goto out;
150176 	}
151177 
152178 	/* error? */
153179 	if (stat & OCI2C_STAT_ARBLOST) {
154180 		i2c->state = STATE_ERROR;
155181 		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
156
-		return;
182
+		goto out;
157183 	}
158184 
159185 	if ((i2c->state == STATE_START) || (i2c->state == STATE_WRITE)) {
....@@ -163,10 +189,11 @@
163189 		if (stat & OCI2C_STAT_NACK) {
164190 			i2c->state = STATE_ERROR;
165191 			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
166
-			return;
192
+			goto out;
167193 		}
168
-	} else
194
+	} else {
169195 		msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);
196
+	}
170197 
171198 	/* end of msg? */
172199 	if (i2c->pos == msg->len) {
....@@ -183,15 +210,15 @@
183210 				i2c->state = STATE_START;
184211 
185212 				oc_setreg(i2c, OCI2C_DATA, addr);
186
-				oc_setreg(i2c, OCI2C_CMD,  OCI2C_CMD_START);
187
-				return;
188
-			} else
189
-				i2c->state = (msg->flags & I2C_M_RD)
190
-					? STATE_READ : STATE_WRITE;
213
+				oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
214
+				goto out;
215
+			}
216
+			i2c->state = (msg->flags & I2C_M_RD)
217
+				? STATE_READ : STATE_WRITE;
191218 		} else {
192219 			i2c->state = STATE_DONE;
193220 			oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
194
-			return;
221
+			goto out;
195222 		}
196223 	}
197224 
....@@ -202,20 +229,158 @@
202229 		oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);
203230 		oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);
204231 	}
232
+
233
+out:
234
+	spin_unlock_irqrestore(&i2c->process_lock, flags);
205235 }
206236 
207237 static irqreturn_t ocores_isr(int irq, void *dev_id)
208238 {
209239 	struct ocores_i2c *i2c = dev_id;
240
+	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
210241 
211
-	ocores_process(i2c);
242
+	if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {
243
+		if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY))
244
+			return IRQ_NONE;
245
+	} else if (!(stat & OCI2C_STAT_IF)) {
246
+		return IRQ_NONE;
247
+	}
248
+	ocores_process(i2c, stat);
212249 
213250 	return IRQ_HANDLED;
214251 }
215252 
216
-static int ocores_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
253
+/**
254
+ * Process timeout event
255
+ * @i2c: ocores I2C device instance
256
+ */
257
+static void ocores_process_timeout(struct ocores_i2c *i2c)
217258 {
218
-	struct ocores_i2c *i2c = i2c_get_adapdata(adap);
259
+	unsigned long flags;
260
+
261
+	spin_lock_irqsave(&i2c->process_lock, flags);
262
+	i2c->state = STATE_ERROR;
263
+	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);
264
+	spin_unlock_irqrestore(&i2c->process_lock, flags);
265
+}
266
+
267
+/**
268
+ * Wait until something change in a given register
269
+ * @i2c: ocores I2C device instance
270
+ * @reg: register to query
271
+ * @mask: bitmask to apply on register value
272
+ * @val: expected result
273
+ * @timeout: timeout in jiffies
274
+ *
275
+ * Timeout is necessary to avoid to stay here forever when the chip
276
+ * does not answer correctly.
277
+ *
278
+ * Return: 0 on success, -ETIMEDOUT on timeout
279
+ */
280
+static int ocores_wait(struct ocores_i2c *i2c,
281
+		       int reg, u8 mask, u8 val,
282
+		       const unsigned long timeout)
283
+{
284
+	unsigned long j;
285
+
286
+	j = jiffies + timeout;
287
+	while (1) {
288
+		u8 status = oc_getreg(i2c, reg);
289
+
290
+		if ((status & mask) == val)
291
+			break;
292
+
293
+		if (time_after(jiffies, j))
294
+			return -ETIMEDOUT;
295
+	}
296
+	return 0;
297
+}
298
+
299
+/**
300
+ * Wait until is possible to process some data
301
+ * @i2c: ocores I2C device instance
302
+ *
303
+ * Used when the device is in polling mode (interrupts disabled).
304
+ *
305
+ * Return: 0 on success, -ETIMEDOUT on timeout
306
+ */
307
+static int ocores_poll_wait(struct ocores_i2c *i2c)
308
+{
309
+	u8 mask;
310
+	int err;
311
+
312
+	if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {
313
+		/* transfer is over */
314
+		mask = OCI2C_STAT_BUSY;
315
+	} else {
316
+		/* on going transfer */
317
+		mask = OCI2C_STAT_TIP;
318
+		/*
319
+		 * We wait for the data to be transferred (8bit),
320
+		 * then we start polling on the ACK/NACK bit
321
+		 */
322
+		udelay((8 * 1000) / i2c->bus_clock_khz);
323
+	}
324
+
325
+	/*
326
+	 * once we are here we expect to get the expected result immediately
327
+	 * so if after 1ms we timeout then something is broken.
328
+	 */
329
+	err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, msecs_to_jiffies(1));
330
+	if (err)
331
+		dev_warn(i2c->adap.dev.parent,
332
+			 "%s: STATUS timeout, bit 0x%x did not clear in 1ms\n",
333
+			 __func__, mask);
334
+	return err;
335
+}
336
+
337
+/**
338
+ * It handles an IRQ-less transfer
339
+ * @i2c: ocores I2C device instance
340
+ *
341
+ * Even if IRQ are disabled, the I2C OpenCore IP behavior is exactly the same
342
+ * (only that IRQ are not produced). This means that we can re-use entirely
343
+ * ocores_isr(), we just add our polling code around it.
344
+ *
345
+ * It can run in atomic context
346
+ *
347
+ * Return: 0 on success, -ETIMEDOUT on timeout
348
+ */
349
+static int ocores_process_polling(struct ocores_i2c *i2c)
350
+{
351
+	irqreturn_t ret;
352
+	int err = 0;
353
+
354
+	while (1) {
355
+		err = ocores_poll_wait(i2c);
356
+		if (err)
357
+			break; /* timeout */
358
+
359
+		ret = ocores_isr(-1, i2c);
360
+		if (ret == IRQ_NONE)
361
+			break; /* all messages have been transferred */
362
+		else {
363
+			if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)
364
+				if (i2c->state == STATE_DONE)
365
+					break;
366
+		}
367
+	}
368
+
369
+	return err;
370
+}
371
+
372
+static int ocores_xfer_core(struct ocores_i2c *i2c,
373
+			    struct i2c_msg *msgs, int num,
374
+			    bool polling)
375
+{
376
+	int ret = 0;
377
+	u8 ctrl;
378
+
379
+	ctrl = oc_getreg(i2c, OCI2C_CONTROL);
380
+	if (polling)
381
+		oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~OCI2C_CTRL_IEN);
382
+	else
383
+		oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN);
219384 
220385 	i2c->msg = msgs;
221386 	i2c->pos = 0;
....@@ -225,11 +390,32 @@
225390 	oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg));
226391 	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);
227392 
228
-	if (wait_event_timeout(i2c->wait, (i2c->state == STATE_ERROR) ||
229
-			       (i2c->state == STATE_DONE), HZ))
230
-		return (i2c->state == STATE_DONE) ? num : -EIO;
231
-	else
232
-		return -ETIMEDOUT;
393
+	if (polling) {
394
+		ret = ocores_process_polling(i2c);
395
+	} else {
396
+		if (wait_event_timeout(i2c->wait,
397
+				       (i2c->state == STATE_ERROR) ||
398
+				       (i2c->state == STATE_DONE), HZ) == 0)
399
+			ret = -ETIMEDOUT;
400
+	}
401
+	if (ret) {
402
+		ocores_process_timeout(i2c);
403
+		return ret;
404
+	}
405
+
406
+	return (i2c->state == STATE_DONE) ? num : -EIO;
407
+}
408
+
409
+static int ocores_xfer_polling(struct i2c_adapter *adap,
410
+			       struct i2c_msg *msgs, int num)
411
+{
412
+	return ocores_xfer_core(i2c_get_adapdata(adap), msgs, num, true);
413
+}
414
+
415
+static int ocores_xfer(struct i2c_adapter *adap,
416
+		       struct i2c_msg *msgs, int num)
417
+{
418
+	return ocores_xfer_core(i2c_get_adapdata(adap), msgs, num, false);
233419 }
234420 
235421 static int ocores_init(struct device *dev, struct ocores_i2c *i2c)
....@@ -239,7 +425,8 @@
239425 	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
240426 
241427 	/* make sure the device is disabled */
242
-	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
428
+	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
429
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl);
243430 
244431 	prescale = (i2c->ip_clock_khz / (5 * i2c->bus_clock_khz)) - 1;
245432 	prescale = clamp(prescale, 0, 0xffff);
....@@ -257,7 +444,7 @@
257444 
258445 	/* Init the device */
259446 	oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);
260
-	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_IEN | OCI2C_CTRL_EN);
447
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl | OCI2C_CTRL_EN);
261448 
262449 	return 0;
263450 }
....@@ -268,8 +455,9 @@
268455 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
269456 }
270457 
271
-static const struct i2c_algorithm ocores_algorithm = {
458
+static struct i2c_algorithm ocores_algorithm = {
272459 	.master_xfer = ocores_xfer,
460
+	.master_xfer_atomic = ocores_xfer_polling,
273461 	.functionality = ocores_func,
274462 };
275463 
....@@ -289,18 +477,29 @@
289477 		.compatible = "aeroflexgaisler,i2cmst",
290478 		.data = (void *)TYPE_GRLIB,
291479 	},
480
+	{
481
+		.compatible = "sifive,fu540-c000-i2c",
482
+		.data = (void *)TYPE_SIFIVE_REV0,
483
+	},
484
+	{
485
+		.compatible = "sifive,i2c0",
486
+		.data = (void *)TYPE_SIFIVE_REV0,
487
+	},
292488 	{},
293489 };
294490 MODULE_DEVICE_TABLE(of, ocores_i2c_match);
295491 
296492 #ifdef CONFIG_OF
297
-/* Read and write functions for the GRLIB port of the controller. Registers are
493
+/*
494
+ * Read and write functions for the GRLIB port of the controller. Registers are
298495  * 32-bit big endian and the PRELOW and PREHIGH registers are merged into one
299
- * register. The subsequent registers has their offset decreased accordingly. */
496
+ * register. The subsequent registers have their offsets decreased accordingly.
497
+ */
300498 static u8 oc_getreg_grlib(struct ocores_i2c *i2c, int reg)
301499 {
302500 	u32 rd;
303501 	int rreg = reg;
502
+
304503 	if (reg != OCI2C_PRELOW)
305504 		rreg--;
306505 	rd = ioread32be(i2c->base + (rreg << i2c->reg_shift));
....@@ -314,6 +513,7 @@
314513 {
315514 	u32 curr, wr;
316515 	int rreg = reg;
516
+
317517 	if (reg != OCI2C_PRELOW)
318518 		rreg--;
319519 	if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {
....@@ -402,37 +602,54 @@
402602 	return 0;
403603 }
404604 #else
405
-#define ocores_i2c_of_probe(pdev,i2c) -ENODEV
605
+#define ocores_i2c_of_probe(pdev, i2c) -ENODEV
406606 #endif
407607 
408608 static int ocores_i2c_probe(struct platform_device *pdev)
409609 {
410610 	struct ocores_i2c *i2c;
411611 	struct ocores_i2c_platform_data *pdata;
612
+	const struct of_device_id *match;
412613 	struct resource *res;
413614 	int irq;
414615 	int ret;
415616 	int i;
416617 
417
-	irq = platform_get_irq(pdev, 0);
418
-	if (irq < 0)
419
-		return irq;
420
-
421618 	i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
422619 	if (!i2c)
423620 		return -ENOMEM;
424621 
622
+	spin_lock_init(&i2c->process_lock);
623
+
425624 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
426
-	i2c->base = devm_ioremap_resource(&pdev->dev, res);
427
-	if (IS_ERR(i2c->base))
428
-		return PTR_ERR(i2c->base);
625
+	if (res) {
626
+		i2c->base = devm_ioremap_resource(&pdev->dev, res);
627
+		if (IS_ERR(i2c->base))
628
+			return PTR_ERR(i2c->base);
629
+	} else {
630
+		res = platform_get_resource(pdev, IORESOURCE_IO, 0);
631
+		if (!res)
632
+			return -EINVAL;
633
+		i2c->iobase = res->start;
634
+		if (!devm_request_region(&pdev->dev, res->start,
635
+					 resource_size(res),
636
+					 pdev->name)) {
637
+			dev_err(&pdev->dev, "Can't get I/O resource.\n");
638
+			return -EBUSY;
639
+		}
640
+		i2c->setreg = oc_setreg_io_8;
641
+		i2c->getreg = oc_getreg_io_8;
642
+	}
429643 
430644 	pdata = dev_get_platdata(&pdev->dev);
431645 	if (pdata) {
432646 		i2c->reg_shift = pdata->reg_shift;
433647 		i2c->reg_io_width = pdata->reg_io_width;
434648 		i2c->ip_clock_khz = pdata->clock_khz;
435
-		i2c->bus_clock_khz = 100;
649
+		if (pdata->bus_khz)
650
+			i2c->bus_clock_khz = pdata->bus_khz;
651
+		else
652
+			i2c->bus_clock_khz = 100;
436653 	} else {
437654 		ret = ocores_i2c_of_probe(pdev, i2c);
438655 		if (ret)
....@@ -470,17 +687,37 @@
470687 		}
471688 	}
472689 
690
+	init_waitqueue_head(&i2c->wait);
691
+
692
+	irq = platform_get_irq(pdev, 0);
693
+	if (irq == -ENXIO) {
694
+		ocores_algorithm.master_xfer = ocores_xfer_polling;
695
+
696
+		/*
697
+		 * Set in OCORES_FLAG_BROKEN_IRQ to enable workaround for
698
+		 * FU540-C000 SoC in polling mode.
699
+		 */
700
+		match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
701
+		if (match && (long)match->data == TYPE_SIFIVE_REV0)
702
+			i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
703
+	} else {
704
+		if (irq < 0)
705
+			return irq;
706
+	}
707
+
708
+	if (ocores_algorithm.master_xfer != ocores_xfer_polling) {
709
+		ret = devm_request_any_context_irq(&pdev->dev, irq,
710
+						   ocores_isr, 0,
711
+						   pdev->name, i2c);
712
+		if (ret) {
713
+			dev_err(&pdev->dev, "Cannot claim IRQ\n");
714
+			goto err_clk;
715
+		}
716
+	}
717
+
473718 	ret = ocores_init(&pdev->dev, i2c);
474719 	if (ret)
475720 		goto err_clk;
476
-
477
-	init_waitqueue_head(&i2c->wait);
478
-	ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
479
-			       pdev->name, i2c);
480
-	if (ret) {
481
-		dev_err(&pdev->dev, "Cannot claim IRQ\n");
482
-		goto err_clk;
483
-	}
484721 
485722 	/* hook up driver to tree */
486723 	platform_set_drvdata(pdev, i2c);
....@@ -497,7 +734,7 @@
497734 	/* add in known devices to the bus */
498735 	if (pdata) {
499736 		for (i = 0; i < pdata->num_devices; i++)
500
-			i2c_new_device(&i2c->adap, pdata->devices + i);
737
+			i2c_new_client_device(&i2c->adap, pdata->devices + i);
501738 	}
502739 
503740 	return 0;
....@@ -510,10 +747,11 @@
510747 static int ocores_i2c_remove(struct platform_device *pdev)
511748 {
512749 	struct ocores_i2c *i2c = platform_get_drvdata(pdev);
750
+	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
513751 
514752 	/* disable i2c logic */
515
-	oc_setreg(i2c, OCI2C_CONTROL, oc_getreg(i2c, OCI2C_CONTROL)
516
-		  & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
753
+	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
754
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl);
517755 
518756 	/* remove adapter & data */
519757 	i2c_del_adapter(&i2c->adap);
....@@ -531,7 +769,8 @@
531769 	u8 ctrl = oc_getreg(i2c, OCI2C_CONTROL);
532770 
533771 	/* make sure the device is disabled */
534
-	oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~(OCI2C_CTRL_EN|OCI2C_CTRL_IEN));
772
+	ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);
773
+	oc_setreg(i2c, OCI2C_CONTROL, ctrl);
535774 
536775 	if (!IS_ERR(i2c->clk))
537776 		clk_disable_unprepare(i2c->clk);