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 
gisb_read(struct brcmstb_gisb_arb_device * gdev,int reg)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 
gisb_read_address(struct brcmstb_gisb_arb_device * gdev)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 
gisb_write(struct brcmstb_gisb_arb_device * gdev,u32 val,int reg)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 
gisb_arb_get_timeout(struct device * dev,struct device_attribute * attr,char * buf)149 static ssize_t gisb_arb_get_timeout(struct device *dev,
150 				    struct device_attribute *attr,
151 				    char *buf)
152 {
153 	struct platform_device *pdev = to_platform_device(dev);
154 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
155 	u32 timeout;
156 
157 	mutex_lock(&gdev->lock);
158 	timeout = gisb_read(gdev, ARB_TIMER);
159 	mutex_unlock(&gdev->lock);
160 
161 	return sprintf(buf, "%d", timeout);
162 }
163 
gisb_arb_set_timeout(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)164 static ssize_t gisb_arb_set_timeout(struct device *dev,
165 				    struct device_attribute *attr,
166 				    const char *buf, size_t count)
167 {
168 	struct platform_device *pdev = to_platform_device(dev);
169 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
170 	int val, ret;
171 
172 	ret = kstrtoint(buf, 10, &val);
173 	if (ret < 0)
174 		return ret;
175 
176 	if (val == 0 || val >= 0xffffffff)
177 		return -EINVAL;
178 
179 	mutex_lock(&gdev->lock);
180 	gisb_write(gdev, val, ARB_TIMER);
181 	mutex_unlock(&gdev->lock);
182 
183 	return count;
184 }
185 
186 static const char *
brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device * gdev,u32 masters)187 brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
188 						u32 masters)
189 {
190 	u32 mask = gdev->valid_mask & masters;
191 
192 	if (hweight_long(mask) != 1)
193 		return NULL;
194 
195 	return gdev->master_names[ffs(mask) - 1];
196 }
197 
brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device * gdev,const char * reason)198 static int brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device *gdev,
199 					const char *reason)
200 {
201 	u32 cap_status;
202 	u64 arb_addr;
203 	u32 master;
204 	const char *m_name;
205 	char m_fmt[11];
206 
207 	cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
208 
209 	/* Invalid captured address, bail out */
210 	if (!(cap_status & ARB_ERR_CAP_STATUS_VALID))
211 		return 1;
212 
213 	/* Read the address and master */
214 	arb_addr = gisb_read_address(gdev);
215 	master = gisb_read(gdev, ARB_ERR_CAP_MASTER);
216 
217 	m_name = brcmstb_gisb_master_to_str(gdev, master);
218 	if (!m_name) {
219 		snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
220 		m_name = m_fmt;
221 	}
222 
223 	pr_crit("%s: %s at 0x%llx [%c %s], core: %s\n",
224 		__func__, reason, arb_addr,
225 		cap_status & ARB_ERR_CAP_STATUS_WRITE ? 'W' : 'R',
226 		cap_status & ARB_ERR_CAP_STATUS_TIMEOUT ? "timeout" : "",
227 		m_name);
228 
229 	/* clear the GISB error */
230 	gisb_write(gdev, ARB_ERR_CAP_CLEAR, ARB_ERR_CAP_CLR);
231 
232 	return 0;
233 }
234 
235 #ifdef CONFIG_MIPS
brcmstb_bus_error_handler(struct pt_regs * regs,int is_fixup)236 static int brcmstb_bus_error_handler(struct pt_regs *regs, int is_fixup)
237 {
238 	int ret = 0;
239 	struct brcmstb_gisb_arb_device *gdev;
240 	u32 cap_status;
241 
242 	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next) {
243 		cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
244 
245 		/* Invalid captured address, bail out */
246 		if (!(cap_status & ARB_ERR_CAP_STATUS_VALID)) {
247 			is_fixup = 1;
248 			goto out;
249 		}
250 
251 		ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
252 	}
253 out:
254 	return is_fixup ? MIPS_BE_FIXUP : MIPS_BE_FATAL;
255 }
256 #endif
257 
brcmstb_gisb_timeout_handler(int irq,void * dev_id)258 static irqreturn_t brcmstb_gisb_timeout_handler(int irq, void *dev_id)
259 {
260 	brcmstb_gisb_arb_decode_addr(dev_id, "timeout");
261 
262 	return IRQ_HANDLED;
263 }
264 
brcmstb_gisb_tea_handler(int irq,void * dev_id)265 static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
266 {
267 	brcmstb_gisb_arb_decode_addr(dev_id, "target abort");
268 
269 	return IRQ_HANDLED;
270 }
271 
272 /*
273  * Dump out gisb errors on die or panic.
274  */
275 static int dump_gisb_error(struct notifier_block *self, unsigned long v,
276 			   void *p);
277 
278 static struct notifier_block gisb_die_notifier = {
279 	.notifier_call = dump_gisb_error,
280 };
281 
282 static struct notifier_block gisb_panic_notifier = {
283 	.notifier_call = dump_gisb_error,
284 };
285 
dump_gisb_error(struct notifier_block * self,unsigned long v,void * p)286 static int dump_gisb_error(struct notifier_block *self, unsigned long v,
287 			   void *p)
288 {
289 	struct brcmstb_gisb_arb_device *gdev;
290 	const char *reason = "panic";
291 
292 	if (self == &gisb_die_notifier)
293 		reason = "die";
294 
295 	/* iterate over each GISB arb registered handlers */
296 	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
297 		brcmstb_gisb_arb_decode_addr(gdev, reason);
298 
299 	return NOTIFY_DONE;
300 }
301 
302 static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
303 		gisb_arb_get_timeout, gisb_arb_set_timeout);
304 
305 static struct attribute *gisb_arb_sysfs_attrs[] = {
306 	&dev_attr_gisb_arb_timeout.attr,
307 	NULL,
308 };
309 
310 static struct attribute_group gisb_arb_sysfs_attr_group = {
311 	.attrs = gisb_arb_sysfs_attrs,
312 };
313 
314 static const struct of_device_id brcmstb_gisb_arb_of_match[] = {
315 	{ .compatible = "brcm,gisb-arb",         .data = gisb_offsets_bcm7445 },
316 	{ .compatible = "brcm,bcm7445-gisb-arb", .data = gisb_offsets_bcm7445 },
317 	{ .compatible = "brcm,bcm7435-gisb-arb", .data = gisb_offsets_bcm7435 },
318 	{ .compatible = "brcm,bcm7400-gisb-arb", .data = gisb_offsets_bcm7400 },
319 	{ .compatible = "brcm,bcm7278-gisb-arb", .data = gisb_offsets_bcm7278 },
320 	{ .compatible = "brcm,bcm7038-gisb-arb", .data = gisb_offsets_bcm7038 },
321 	{ },
322 };
323 
brcmstb_gisb_arb_probe(struct platform_device * pdev)324 static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
325 {
326 	struct device_node *dn = pdev->dev.of_node;
327 	struct brcmstb_gisb_arb_device *gdev;
328 	const struct of_device_id *of_id;
329 	struct resource *r;
330 	int err, timeout_irq, tea_irq;
331 	unsigned int num_masters, j = 0;
332 	int i, first, last;
333 
334 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
335 	timeout_irq = platform_get_irq(pdev, 0);
336 	tea_irq = platform_get_irq(pdev, 1);
337 
338 	gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
339 	if (!gdev)
340 		return -ENOMEM;
341 
342 	mutex_init(&gdev->lock);
343 	INIT_LIST_HEAD(&gdev->next);
344 
345 	gdev->base = devm_ioremap_resource(&pdev->dev, r);
346 	if (IS_ERR(gdev->base))
347 		return PTR_ERR(gdev->base);
348 
349 	of_id = of_match_node(brcmstb_gisb_arb_of_match, dn);
350 	if (!of_id) {
351 		pr_err("failed to look up compatible string\n");
352 		return -EINVAL;
353 	}
354 	gdev->gisb_offsets = of_id->data;
355 	gdev->big_endian = of_device_is_big_endian(dn);
356 
357 	err = devm_request_irq(&pdev->dev, timeout_irq,
358 				brcmstb_gisb_timeout_handler, 0, pdev->name,
359 				gdev);
360 	if (err < 0)
361 		return err;
362 
363 	err = devm_request_irq(&pdev->dev, tea_irq,
364 				brcmstb_gisb_tea_handler, 0, pdev->name,
365 				gdev);
366 	if (err < 0)
367 		return err;
368 
369 	/* If we do not have a valid mask, assume all masters are enabled */
370 	if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
371 				&gdev->valid_mask))
372 		gdev->valid_mask = 0xffffffff;
373 
374 	/* Proceed with reading the litteral names if we agree on the
375 	 * number of masters
376 	 */
377 	num_masters = of_property_count_strings(dn,
378 			"brcm,gisb-arb-master-names");
379 	if (hweight_long(gdev->valid_mask) == num_masters) {
380 		first = ffs(gdev->valid_mask) - 1;
381 		last = fls(gdev->valid_mask) - 1;
382 
383 		for (i = first; i < last; i++) {
384 			if (!(gdev->valid_mask & BIT(i)))
385 				continue;
386 
387 			of_property_read_string_index(dn,
388 					"brcm,gisb-arb-master-names", j,
389 					&gdev->master_names[i]);
390 			j++;
391 		}
392 	}
393 
394 	err = sysfs_create_group(&pdev->dev.kobj, &gisb_arb_sysfs_attr_group);
395 	if (err)
396 		return err;
397 
398 	platform_set_drvdata(pdev, gdev);
399 
400 	list_add_tail(&gdev->next, &brcmstb_gisb_arb_device_list);
401 
402 #ifdef CONFIG_MIPS
403 	board_be_handler = brcmstb_bus_error_handler;
404 #endif
405 
406 	if (list_is_singular(&brcmstb_gisb_arb_device_list)) {
407 		register_die_notifier(&gisb_die_notifier);
408 		atomic_notifier_chain_register(&panic_notifier_list,
409 					       &gisb_panic_notifier);
410 	}
411 
412 	dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
413 			gdev->base, timeout_irq, tea_irq);
414 
415 	return 0;
416 }
417 
418 #ifdef CONFIG_PM_SLEEP
brcmstb_gisb_arb_suspend(struct device * dev)419 static int brcmstb_gisb_arb_suspend(struct device *dev)
420 {
421 	struct platform_device *pdev = to_platform_device(dev);
422 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
423 
424 	gdev->saved_timeout = gisb_read(gdev, ARB_TIMER);
425 
426 	return 0;
427 }
428 
429 /* Make sure we provide the same timeout value that was configured before, and
430  * do this before the GISB timeout interrupt handler has any chance to run.
431  */
brcmstb_gisb_arb_resume_noirq(struct device * dev)432 static int brcmstb_gisb_arb_resume_noirq(struct device *dev)
433 {
434 	struct platform_device *pdev = to_platform_device(dev);
435 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
436 
437 	gisb_write(gdev, gdev->saved_timeout, ARB_TIMER);
438 
439 	return 0;
440 }
441 #else
442 #define brcmstb_gisb_arb_suspend       NULL
443 #define brcmstb_gisb_arb_resume_noirq  NULL
444 #endif
445 
446 static const struct dev_pm_ops brcmstb_gisb_arb_pm_ops = {
447 	.suspend	= brcmstb_gisb_arb_suspend,
448 	.resume_noirq	= brcmstb_gisb_arb_resume_noirq,
449 };
450 
451 static struct platform_driver brcmstb_gisb_arb_driver = {
452 	.driver = {
453 		.name	= "brcm-gisb-arb",
454 		.of_match_table = brcmstb_gisb_arb_of_match,
455 		.pm	= &brcmstb_gisb_arb_pm_ops,
456 	},
457 };
458 
brcm_gisb_driver_init(void)459 static int __init brcm_gisb_driver_init(void)
460 {
461 	return platform_driver_probe(&brcmstb_gisb_arb_driver,
462 				     brcmstb_gisb_arb_probe);
463 }
464 
465 module_init(brcm_gisb_driver_init);
466