xref: /openbmc/linux/drivers/bus/brcmstb_gisb.c (revision 8b030a57)
1 /*
2  * Copyright (C) 2014-2017 Broadcom
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  *
8  * This program is distributed in the hope that it will be useful,
9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11  * GNU General Public License for more details.
12  */
13 
14 #include <linux/init.h>
15 #include <linux/types.h>
16 #include <linux/module.h>
17 #include <linux/platform_device.h>
18 #include <linux/interrupt.h>
19 #include <linux/sysfs.h>
20 #include <linux/io.h>
21 #include <linux/string.h>
22 #include <linux/device.h>
23 #include <linux/list.h>
24 #include <linux/of.h>
25 #include <linux/bitops.h>
26 #include <linux/pm.h>
27 #include <linux/kernel.h>
28 #include <linux/kdebug.h>
29 #include <linux/notifier.h>
30 
31 #ifdef CONFIG_MIPS
32 #include <asm/traps.h>
33 #endif
34 
35 #define  ARB_ERR_CAP_CLEAR		(1 << 0)
36 #define  ARB_ERR_CAP_STATUS_TIMEOUT	(1 << 12)
37 #define  ARB_ERR_CAP_STATUS_TEA		(1 << 11)
38 #define  ARB_ERR_CAP_STATUS_WRITE	(1 << 1)
39 #define  ARB_ERR_CAP_STATUS_VALID	(1 << 0)
40 
41 enum {
42 	ARB_TIMER,
43 	ARB_ERR_CAP_CLR,
44 	ARB_ERR_CAP_HI_ADDR,
45 	ARB_ERR_CAP_ADDR,
46 	ARB_ERR_CAP_STATUS,
47 	ARB_ERR_CAP_MASTER,
48 };
49 
50 static const int gisb_offsets_bcm7038[] = {
51 	[ARB_TIMER]		= 0x00c,
52 	[ARB_ERR_CAP_CLR]	= 0x0c4,
53 	[ARB_ERR_CAP_HI_ADDR]	= -1,
54 	[ARB_ERR_CAP_ADDR]	= 0x0c8,
55 	[ARB_ERR_CAP_STATUS]	= 0x0d0,
56 	[ARB_ERR_CAP_MASTER]	= -1,
57 };
58 
59 static const int gisb_offsets_bcm7278[] = {
60 	[ARB_TIMER]		= 0x008,
61 	[ARB_ERR_CAP_CLR]	= 0x7f8,
62 	[ARB_ERR_CAP_HI_ADDR]	= -1,
63 	[ARB_ERR_CAP_ADDR]	= 0x7e0,
64 	[ARB_ERR_CAP_STATUS]	= 0x7f0,
65 	[ARB_ERR_CAP_MASTER]	= 0x7f4,
66 };
67 
68 static const int gisb_offsets_bcm7400[] = {
69 	[ARB_TIMER]		= 0x00c,
70 	[ARB_ERR_CAP_CLR]	= 0x0c8,
71 	[ARB_ERR_CAP_HI_ADDR]	= -1,
72 	[ARB_ERR_CAP_ADDR]	= 0x0cc,
73 	[ARB_ERR_CAP_STATUS]	= 0x0d4,
74 	[ARB_ERR_CAP_MASTER]	= 0x0d8,
75 };
76 
77 static const int gisb_offsets_bcm7435[] = {
78 	[ARB_TIMER]		= 0x00c,
79 	[ARB_ERR_CAP_CLR]	= 0x168,
80 	[ARB_ERR_CAP_HI_ADDR]	= -1,
81 	[ARB_ERR_CAP_ADDR]	= 0x16c,
82 	[ARB_ERR_CAP_STATUS]	= 0x174,
83 	[ARB_ERR_CAP_MASTER]	= 0x178,
84 };
85 
86 static const int gisb_offsets_bcm7445[] = {
87 	[ARB_TIMER]		= 0x008,
88 	[ARB_ERR_CAP_CLR]	= 0x7e4,
89 	[ARB_ERR_CAP_HI_ADDR]	= 0x7e8,
90 	[ARB_ERR_CAP_ADDR]	= 0x7ec,
91 	[ARB_ERR_CAP_STATUS]	= 0x7f4,
92 	[ARB_ERR_CAP_MASTER]	= 0x7f8,
93 };
94 
95 struct brcmstb_gisb_arb_device {
96 	void __iomem	*base;
97 	const int	*gisb_offsets;
98 	bool		big_endian;
99 	struct mutex	lock;
100 	struct list_head next;
101 	u32 valid_mask;
102 	const char *master_names[sizeof(u32) * BITS_PER_BYTE];
103 	u32 saved_timeout;
104 };
105 
106 static LIST_HEAD(brcmstb_gisb_arb_device_list);
107 
108 static u32 gisb_read(struct brcmstb_gisb_arb_device *gdev, int reg)
109 {
110 	int offset = gdev->gisb_offsets[reg];
111 
112 	if (offset < 0) {
113 		/* return 1 if the hardware doesn't have ARB_ERR_CAP_MASTER */
114 		if (reg == ARB_ERR_CAP_MASTER)
115 			return 1;
116 		else
117 			return 0;
118 	}
119 
120 	if (gdev->big_endian)
121 		return ioread32be(gdev->base + offset);
122 	else
123 		return ioread32(gdev->base + offset);
124 }
125 
126 static u64 gisb_read_address(struct brcmstb_gisb_arb_device *gdev)
127 {
128 	u64 value;
129 
130 	value = gisb_read(gdev, ARB_ERR_CAP_ADDR);
131 	value |= (u64)gisb_read(gdev, ARB_ERR_CAP_HI_ADDR) << 32;
132 
133 	return value;
134 }
135 
136 static void gisb_write(struct brcmstb_gisb_arb_device *gdev, u32 val, int reg)
137 {
138 	int offset = gdev->gisb_offsets[reg];
139 
140 	if (offset == -1)
141 		return;
142 
143 	if (gdev->big_endian)
144 		iowrite32be(val, gdev->base + offset);
145 	else
146 		iowrite32(val, gdev->base + offset);
147 }
148 
149 static ssize_t gisb_arb_get_timeout(struct device *dev,
150 				    struct device_attribute *attr,
151 				    char *buf)
152 {
153 	struct brcmstb_gisb_arb_device *gdev = dev_get_drvdata(dev);
154 	u32 timeout;
155 
156 	mutex_lock(&gdev->lock);
157 	timeout = gisb_read(gdev, ARB_TIMER);
158 	mutex_unlock(&gdev->lock);
159 
160 	return sprintf(buf, "%d", timeout);
161 }
162 
163 static ssize_t gisb_arb_set_timeout(struct device *dev,
164 				    struct device_attribute *attr,
165 				    const char *buf, size_t count)
166 {
167 	struct brcmstb_gisb_arb_device *gdev = dev_get_drvdata(dev);
168 	int val, ret;
169 
170 	ret = kstrtoint(buf, 10, &val);
171 	if (ret < 0)
172 		return ret;
173 
174 	if (val == 0 || val >= 0xffffffff)
175 		return -EINVAL;
176 
177 	mutex_lock(&gdev->lock);
178 	gisb_write(gdev, val, ARB_TIMER);
179 	mutex_unlock(&gdev->lock);
180 
181 	return count;
182 }
183 
184 static const char *
185 brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
186 						u32 masters)
187 {
188 	u32 mask = gdev->valid_mask & masters;
189 
190 	if (hweight_long(mask) != 1)
191 		return NULL;
192 
193 	return gdev->master_names[ffs(mask) - 1];
194 }
195 
196 static int brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device *gdev,
197 					const char *reason)
198 {
199 	u32 cap_status;
200 	u64 arb_addr;
201 	u32 master;
202 	const char *m_name;
203 	char m_fmt[11];
204 
205 	cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
206 
207 	/* Invalid captured address, bail out */
208 	if (!(cap_status & ARB_ERR_CAP_STATUS_VALID))
209 		return 1;
210 
211 	/* Read the address and master */
212 	arb_addr = gisb_read_address(gdev);
213 	master = gisb_read(gdev, ARB_ERR_CAP_MASTER);
214 
215 	m_name = brcmstb_gisb_master_to_str(gdev, master);
216 	if (!m_name) {
217 		snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
218 		m_name = m_fmt;
219 	}
220 
221 	pr_crit("%s: %s at 0x%llx [%c %s], core: %s\n",
222 		__func__, reason, arb_addr,
223 		cap_status & ARB_ERR_CAP_STATUS_WRITE ? 'W' : 'R',
224 		cap_status & ARB_ERR_CAP_STATUS_TIMEOUT ? "timeout" : "",
225 		m_name);
226 
227 	/* clear the GISB error */
228 	gisb_write(gdev, ARB_ERR_CAP_CLEAR, ARB_ERR_CAP_CLR);
229 
230 	return 0;
231 }
232 
233 #ifdef CONFIG_MIPS
234 static int brcmstb_bus_error_handler(struct pt_regs *regs, int is_fixup)
235 {
236 	int ret = 0;
237 	struct brcmstb_gisb_arb_device *gdev;
238 	u32 cap_status;
239 
240 	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next) {
241 		cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
242 
243 		/* Invalid captured address, bail out */
244 		if (!(cap_status & ARB_ERR_CAP_STATUS_VALID)) {
245 			is_fixup = 1;
246 			goto out;
247 		}
248 
249 		ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
250 	}
251 out:
252 	return is_fixup ? MIPS_BE_FIXUP : MIPS_BE_FATAL;
253 }
254 #endif
255 
256 static irqreturn_t brcmstb_gisb_timeout_handler(int irq, void *dev_id)
257 {
258 	brcmstb_gisb_arb_decode_addr(dev_id, "timeout");
259 
260 	return IRQ_HANDLED;
261 }
262 
263 static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
264 {
265 	brcmstb_gisb_arb_decode_addr(dev_id, "target abort");
266 
267 	return IRQ_HANDLED;
268 }
269 
270 /*
271  * Dump out gisb errors on die or panic.
272  */
273 static int dump_gisb_error(struct notifier_block *self, unsigned long v,
274 			   void *p);
275 
276 static struct notifier_block gisb_die_notifier = {
277 	.notifier_call = dump_gisb_error,
278 };
279 
280 static struct notifier_block gisb_panic_notifier = {
281 	.notifier_call = dump_gisb_error,
282 };
283 
284 static int dump_gisb_error(struct notifier_block *self, unsigned long v,
285 			   void *p)
286 {
287 	struct brcmstb_gisb_arb_device *gdev;
288 	const char *reason = "panic";
289 
290 	if (self == &gisb_die_notifier)
291 		reason = "die";
292 
293 	/* iterate over each GISB arb registered handlers */
294 	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
295 		brcmstb_gisb_arb_decode_addr(gdev, reason);
296 
297 	return NOTIFY_DONE;
298 }
299 
300 static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
301 		gisb_arb_get_timeout, gisb_arb_set_timeout);
302 
303 static struct attribute *gisb_arb_sysfs_attrs[] = {
304 	&dev_attr_gisb_arb_timeout.attr,
305 	NULL,
306 };
307 
308 static struct attribute_group gisb_arb_sysfs_attr_group = {
309 	.attrs = gisb_arb_sysfs_attrs,
310 };
311 
312 static const struct of_device_id brcmstb_gisb_arb_of_match[] = {
313 	{ .compatible = "brcm,gisb-arb",         .data = gisb_offsets_bcm7445 },
314 	{ .compatible = "brcm,bcm7445-gisb-arb", .data = gisb_offsets_bcm7445 },
315 	{ .compatible = "brcm,bcm7435-gisb-arb", .data = gisb_offsets_bcm7435 },
316 	{ .compatible = "brcm,bcm7400-gisb-arb", .data = gisb_offsets_bcm7400 },
317 	{ .compatible = "brcm,bcm7278-gisb-arb", .data = gisb_offsets_bcm7278 },
318 	{ .compatible = "brcm,bcm7038-gisb-arb", .data = gisb_offsets_bcm7038 },
319 	{ },
320 };
321 
322 static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
323 {
324 	struct device_node *dn = pdev->dev.of_node;
325 	struct brcmstb_gisb_arb_device *gdev;
326 	const struct of_device_id *of_id;
327 	struct resource *r;
328 	int err, timeout_irq, tea_irq;
329 	unsigned int num_masters, j = 0;
330 	int i, first, last;
331 
332 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
333 	timeout_irq = platform_get_irq(pdev, 0);
334 	tea_irq = platform_get_irq(pdev, 1);
335 
336 	gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
337 	if (!gdev)
338 		return -ENOMEM;
339 
340 	mutex_init(&gdev->lock);
341 	INIT_LIST_HEAD(&gdev->next);
342 
343 	gdev->base = devm_ioremap_resource(&pdev->dev, r);
344 	if (IS_ERR(gdev->base))
345 		return PTR_ERR(gdev->base);
346 
347 	of_id = of_match_node(brcmstb_gisb_arb_of_match, dn);
348 	if (!of_id) {
349 		pr_err("failed to look up compatible string\n");
350 		return -EINVAL;
351 	}
352 	gdev->gisb_offsets = of_id->data;
353 	gdev->big_endian = of_device_is_big_endian(dn);
354 
355 	err = devm_request_irq(&pdev->dev, timeout_irq,
356 				brcmstb_gisb_timeout_handler, 0, pdev->name,
357 				gdev);
358 	if (err < 0)
359 		return err;
360 
361 	err = devm_request_irq(&pdev->dev, tea_irq,
362 				brcmstb_gisb_tea_handler, 0, pdev->name,
363 				gdev);
364 	if (err < 0)
365 		return err;
366 
367 	/* If we do not have a valid mask, assume all masters are enabled */
368 	if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
369 				&gdev->valid_mask))
370 		gdev->valid_mask = 0xffffffff;
371 
372 	/* Proceed with reading the litteral names if we agree on the
373 	 * number of masters
374 	 */
375 	num_masters = of_property_count_strings(dn,
376 			"brcm,gisb-arb-master-names");
377 	if (hweight_long(gdev->valid_mask) == num_masters) {
378 		first = ffs(gdev->valid_mask) - 1;
379 		last = fls(gdev->valid_mask) - 1;
380 
381 		for (i = first; i < last; i++) {
382 			if (!(gdev->valid_mask & BIT(i)))
383 				continue;
384 
385 			of_property_read_string_index(dn,
386 					"brcm,gisb-arb-master-names", j,
387 					&gdev->master_names[i]);
388 			j++;
389 		}
390 	}
391 
392 	err = sysfs_create_group(&pdev->dev.kobj, &gisb_arb_sysfs_attr_group);
393 	if (err)
394 		return err;
395 
396 	platform_set_drvdata(pdev, gdev);
397 
398 	list_add_tail(&gdev->next, &brcmstb_gisb_arb_device_list);
399 
400 #ifdef CONFIG_MIPS
401 	board_be_handler = brcmstb_bus_error_handler;
402 #endif
403 
404 	if (list_is_singular(&brcmstb_gisb_arb_device_list)) {
405 		register_die_notifier(&gisb_die_notifier);
406 		atomic_notifier_chain_register(&panic_notifier_list,
407 					       &gisb_panic_notifier);
408 	}
409 
410 	dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
411 			gdev->base, timeout_irq, tea_irq);
412 
413 	return 0;
414 }
415 
416 #ifdef CONFIG_PM_SLEEP
417 static int brcmstb_gisb_arb_suspend(struct device *dev)
418 {
419 	struct brcmstb_gisb_arb_device *gdev = dev_get_drvdata(dev);
420 
421 	gdev->saved_timeout = gisb_read(gdev, ARB_TIMER);
422 
423 	return 0;
424 }
425 
426 /* Make sure we provide the same timeout value that was configured before, and
427  * do this before the GISB timeout interrupt handler has any chance to run.
428  */
429 static int brcmstb_gisb_arb_resume_noirq(struct device *dev)
430 {
431 	struct brcmstb_gisb_arb_device *gdev = dev_get_drvdata(dev);
432 
433 	gisb_write(gdev, gdev->saved_timeout, ARB_TIMER);
434 
435 	return 0;
436 }
437 #else
438 #define brcmstb_gisb_arb_suspend       NULL
439 #define brcmstb_gisb_arb_resume_noirq  NULL
440 #endif
441 
442 static const struct dev_pm_ops brcmstb_gisb_arb_pm_ops = {
443 	.suspend	= brcmstb_gisb_arb_suspend,
444 	.resume_noirq	= brcmstb_gisb_arb_resume_noirq,
445 };
446 
447 static struct platform_driver brcmstb_gisb_arb_driver = {
448 	.driver = {
449 		.name	= "brcm-gisb-arb",
450 		.of_match_table = brcmstb_gisb_arb_of_match,
451 		.pm	= &brcmstb_gisb_arb_pm_ops,
452 	},
453 };
454 
455 static int __init brcm_gisb_driver_init(void)
456 {
457 	return platform_driver_probe(&brcmstb_gisb_arb_driver,
458 				     brcmstb_gisb_arb_probe);
459 }
460 
461 module_init(brcm_gisb_driver_init);
462