xref: /openbmc/linux/drivers/bus/brcmstb_gisb.c (revision 78700c0a)
1 /*
2  * Copyright (C) 2014 Broadcom Corporation
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 
28 #ifdef CONFIG_ARM
29 #include <asm/bug.h>
30 #include <asm/signal.h>
31 #endif
32 
33 #ifdef CONFIG_MIPS
34 #include <asm/traps.h>
35 #endif
36 
37 #define  ARB_ERR_CAP_CLEAR		(1 << 0)
38 #define  ARB_ERR_CAP_STATUS_TIMEOUT	(1 << 12)
39 #define  ARB_ERR_CAP_STATUS_TEA		(1 << 11)
40 #define  ARB_ERR_CAP_STATUS_BS_SHIFT	(1 << 2)
41 #define  ARB_ERR_CAP_STATUS_BS_MASK	0x3c
42 #define  ARB_ERR_CAP_STATUS_WRITE	(1 << 1)
43 #define  ARB_ERR_CAP_STATUS_VALID	(1 << 0)
44 
45 enum {
46 	ARB_TIMER,
47 	ARB_ERR_CAP_CLR,
48 	ARB_ERR_CAP_HI_ADDR,
49 	ARB_ERR_CAP_ADDR,
50 	ARB_ERR_CAP_DATA,
51 	ARB_ERR_CAP_STATUS,
52 	ARB_ERR_CAP_MASTER,
53 };
54 
55 static const int gisb_offsets_bcm7038[] = {
56 	[ARB_TIMER]		= 0x00c,
57 	[ARB_ERR_CAP_CLR]	= 0x0c4,
58 	[ARB_ERR_CAP_HI_ADDR]	= -1,
59 	[ARB_ERR_CAP_ADDR]	= 0x0c8,
60 	[ARB_ERR_CAP_DATA]	= 0x0cc,
61 	[ARB_ERR_CAP_STATUS]	= 0x0d0,
62 	[ARB_ERR_CAP_MASTER]	= -1,
63 };
64 
65 static const int gisb_offsets_bcm7400[] = {
66 	[ARB_TIMER]		= 0x00c,
67 	[ARB_ERR_CAP_CLR]	= 0x0c8,
68 	[ARB_ERR_CAP_HI_ADDR]	= -1,
69 	[ARB_ERR_CAP_ADDR]	= 0x0cc,
70 	[ARB_ERR_CAP_DATA]	= 0x0d0,
71 	[ARB_ERR_CAP_STATUS]	= 0x0d4,
72 	[ARB_ERR_CAP_MASTER]	= 0x0d8,
73 };
74 
75 static const int gisb_offsets_bcm7435[] = {
76 	[ARB_TIMER]		= 0x00c,
77 	[ARB_ERR_CAP_CLR]	= 0x168,
78 	[ARB_ERR_CAP_HI_ADDR]	= -1,
79 	[ARB_ERR_CAP_ADDR]	= 0x16c,
80 	[ARB_ERR_CAP_DATA]	= 0x170,
81 	[ARB_ERR_CAP_STATUS]	= 0x174,
82 	[ARB_ERR_CAP_MASTER]	= 0x178,
83 };
84 
85 static const int gisb_offsets_bcm7445[] = {
86 	[ARB_TIMER]		= 0x008,
87 	[ARB_ERR_CAP_CLR]	= 0x7e4,
88 	[ARB_ERR_CAP_HI_ADDR]	= 0x7e8,
89 	[ARB_ERR_CAP_ADDR]	= 0x7ec,
90 	[ARB_ERR_CAP_DATA]	= 0x7f0,
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 	/* return 1 if the hardware doesn't have ARB_ERR_CAP_MASTER */
113 	if (offset == -1)
114 		return 1;
115 
116 	if (gdev->big_endian)
117 		return ioread32be(gdev->base + offset);
118 	else
119 		return ioread32(gdev->base + offset);
120 }
121 
122 static void gisb_write(struct brcmstb_gisb_arb_device *gdev, u32 val, int reg)
123 {
124 	int offset = gdev->gisb_offsets[reg];
125 
126 	if (offset == -1)
127 		return;
128 
129 	if (gdev->big_endian)
130 		iowrite32be(val, gdev->base + reg);
131 	else
132 		iowrite32(val, gdev->base + reg);
133 }
134 
135 static ssize_t gisb_arb_get_timeout(struct device *dev,
136 				    struct device_attribute *attr,
137 				    char *buf)
138 {
139 	struct platform_device *pdev = to_platform_device(dev);
140 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
141 	u32 timeout;
142 
143 	mutex_lock(&gdev->lock);
144 	timeout = gisb_read(gdev, ARB_TIMER);
145 	mutex_unlock(&gdev->lock);
146 
147 	return sprintf(buf, "%d", timeout);
148 }
149 
150 static ssize_t gisb_arb_set_timeout(struct device *dev,
151 				    struct device_attribute *attr,
152 				    const char *buf, size_t count)
153 {
154 	struct platform_device *pdev = to_platform_device(dev);
155 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
156 	int val, ret;
157 
158 	ret = kstrtoint(buf, 10, &val);
159 	if (ret < 0)
160 		return ret;
161 
162 	if (val == 0 || val >= 0xffffffff)
163 		return -EINVAL;
164 
165 	mutex_lock(&gdev->lock);
166 	gisb_write(gdev, val, ARB_TIMER);
167 	mutex_unlock(&gdev->lock);
168 
169 	return count;
170 }
171 
172 static const char *
173 brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
174 						u32 masters)
175 {
176 	u32 mask = gdev->valid_mask & masters;
177 
178 	if (hweight_long(mask) != 1)
179 		return NULL;
180 
181 	return gdev->master_names[ffs(mask) - 1];
182 }
183 
184 static int brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device *gdev,
185 					const char *reason)
186 {
187 	u32 cap_status;
188 	unsigned long arb_addr;
189 	u32 master;
190 	const char *m_name;
191 	char m_fmt[11];
192 
193 	cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
194 
195 	/* Invalid captured address, bail out */
196 	if (!(cap_status & ARB_ERR_CAP_STATUS_VALID))
197 		return 1;
198 
199 	/* Read the address and master */
200 	arb_addr = gisb_read(gdev, ARB_ERR_CAP_ADDR) & 0xffffffff;
201 #if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))
202 	arb_addr |= (u64)gisb_read(gdev, ARB_ERR_CAP_HI_ADDR) << 32;
203 #endif
204 	master = gisb_read(gdev, ARB_ERR_CAP_MASTER);
205 
206 	m_name = brcmstb_gisb_master_to_str(gdev, master);
207 	if (!m_name) {
208 		snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
209 		m_name = m_fmt;
210 	}
211 
212 	pr_crit("%s: %s at 0x%lx [%c %s], core: %s\n",
213 		__func__, reason, arb_addr,
214 		cap_status & ARB_ERR_CAP_STATUS_WRITE ? 'W' : 'R',
215 		cap_status & ARB_ERR_CAP_STATUS_TIMEOUT ? "timeout" : "",
216 		m_name);
217 
218 	/* clear the GISB error */
219 	gisb_write(gdev, ARB_ERR_CAP_CLEAR, ARB_ERR_CAP_CLR);
220 
221 	return 0;
222 }
223 
224 #ifdef CONFIG_ARM
225 static int brcmstb_bus_error_handler(unsigned long addr, unsigned int fsr,
226 				     struct pt_regs *regs)
227 {
228 	int ret = 0;
229 	struct brcmstb_gisb_arb_device *gdev;
230 
231 	/* iterate over each GISB arb registered handlers */
232 	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
233 		ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
234 	/*
235 	 * If it was an imprecise abort, then we need to correct the
236 	 * return address to be _after_ the instruction.
237 	*/
238 	if (fsr & (1 << 10))
239 		regs->ARM_pc += 4;
240 
241 	return ret;
242 }
243 #endif
244 
245 #ifdef CONFIG_MIPS
246 static int brcmstb_bus_error_handler(struct pt_regs *regs, int is_fixup)
247 {
248 	int ret = 0;
249 	struct brcmstb_gisb_arb_device *gdev;
250 	u32 cap_status;
251 
252 	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next) {
253 		cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
254 
255 		/* Invalid captured address, bail out */
256 		if (!(cap_status & ARB_ERR_CAP_STATUS_VALID)) {
257 			is_fixup = 1;
258 			goto out;
259 		}
260 
261 		ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
262 	}
263 out:
264 	return is_fixup ? MIPS_BE_FIXUP : MIPS_BE_FATAL;
265 }
266 #endif
267 
268 static irqreturn_t brcmstb_gisb_timeout_handler(int irq, void *dev_id)
269 {
270 	brcmstb_gisb_arb_decode_addr(dev_id, "timeout");
271 
272 	return IRQ_HANDLED;
273 }
274 
275 static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
276 {
277 	brcmstb_gisb_arb_decode_addr(dev_id, "target abort");
278 
279 	return IRQ_HANDLED;
280 }
281 
282 static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
283 		gisb_arb_get_timeout, gisb_arb_set_timeout);
284 
285 static struct attribute *gisb_arb_sysfs_attrs[] = {
286 	&dev_attr_gisb_arb_timeout.attr,
287 	NULL,
288 };
289 
290 static struct attribute_group gisb_arb_sysfs_attr_group = {
291 	.attrs = gisb_arb_sysfs_attrs,
292 };
293 
294 static const struct of_device_id brcmstb_gisb_arb_of_match[] = {
295 	{ .compatible = "brcm,gisb-arb",         .data = gisb_offsets_bcm7445 },
296 	{ .compatible = "brcm,bcm7445-gisb-arb", .data = gisb_offsets_bcm7445 },
297 	{ .compatible = "brcm,bcm7435-gisb-arb", .data = gisb_offsets_bcm7435 },
298 	{ .compatible = "brcm,bcm7400-gisb-arb", .data = gisb_offsets_bcm7400 },
299 	{ .compatible = "brcm,bcm7038-gisb-arb", .data = gisb_offsets_bcm7038 },
300 	{ },
301 };
302 
303 static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
304 {
305 	struct device_node *dn = pdev->dev.of_node;
306 	struct brcmstb_gisb_arb_device *gdev;
307 	const struct of_device_id *of_id;
308 	struct resource *r;
309 	int err, timeout_irq, tea_irq;
310 	unsigned int num_masters, j = 0;
311 	int i, first, last;
312 
313 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
314 	timeout_irq = platform_get_irq(pdev, 0);
315 	tea_irq = platform_get_irq(pdev, 1);
316 
317 	gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
318 	if (!gdev)
319 		return -ENOMEM;
320 
321 	mutex_init(&gdev->lock);
322 	INIT_LIST_HEAD(&gdev->next);
323 
324 	gdev->base = devm_ioremap_resource(&pdev->dev, r);
325 	if (IS_ERR(gdev->base))
326 		return PTR_ERR(gdev->base);
327 
328 	of_id = of_match_node(brcmstb_gisb_arb_of_match, dn);
329 	if (!of_id) {
330 		pr_err("failed to look up compatible string\n");
331 		return -EINVAL;
332 	}
333 	gdev->gisb_offsets = of_id->data;
334 	gdev->big_endian = of_device_is_big_endian(dn);
335 
336 	err = devm_request_irq(&pdev->dev, timeout_irq,
337 				brcmstb_gisb_timeout_handler, 0, pdev->name,
338 				gdev);
339 	if (err < 0)
340 		return err;
341 
342 	err = devm_request_irq(&pdev->dev, tea_irq,
343 				brcmstb_gisb_tea_handler, 0, pdev->name,
344 				gdev);
345 	if (err < 0)
346 		return err;
347 
348 	/* If we do not have a valid mask, assume all masters are enabled */
349 	if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
350 				&gdev->valid_mask))
351 		gdev->valid_mask = 0xffffffff;
352 
353 	/* Proceed with reading the litteral names if we agree on the
354 	 * number of masters
355 	 */
356 	num_masters = of_property_count_strings(dn,
357 			"brcm,gisb-arb-master-names");
358 	if (hweight_long(gdev->valid_mask) == num_masters) {
359 		first = ffs(gdev->valid_mask) - 1;
360 		last = fls(gdev->valid_mask) - 1;
361 
362 		for (i = first; i < last; i++) {
363 			if (!(gdev->valid_mask & BIT(i)))
364 				continue;
365 
366 			of_property_read_string_index(dn,
367 					"brcm,gisb-arb-master-names", j,
368 					&gdev->master_names[i]);
369 			j++;
370 		}
371 	}
372 
373 	err = sysfs_create_group(&pdev->dev.kobj, &gisb_arb_sysfs_attr_group);
374 	if (err)
375 		return err;
376 
377 	platform_set_drvdata(pdev, gdev);
378 
379 	list_add_tail(&gdev->next, &brcmstb_gisb_arb_device_list);
380 
381 #ifdef CONFIG_ARM
382 	hook_fault_code(22, brcmstb_bus_error_handler, SIGBUS, 0,
383 			"imprecise external abort");
384 #endif
385 #ifdef CONFIG_MIPS
386 	board_be_handler = brcmstb_bus_error_handler;
387 #endif
388 
389 	dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
390 			gdev->base, timeout_irq, tea_irq);
391 
392 	return 0;
393 }
394 
395 #ifdef CONFIG_PM_SLEEP
396 static int brcmstb_gisb_arb_suspend(struct device *dev)
397 {
398 	struct platform_device *pdev = to_platform_device(dev);
399 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
400 
401 	gdev->saved_timeout = gisb_read(gdev, ARB_TIMER);
402 
403 	return 0;
404 }
405 
406 /* Make sure we provide the same timeout value that was configured before, and
407  * do this before the GISB timeout interrupt handler has any chance to run.
408  */
409 static int brcmstb_gisb_arb_resume_noirq(struct device *dev)
410 {
411 	struct platform_device *pdev = to_platform_device(dev);
412 	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
413 
414 	gisb_write(gdev, gdev->saved_timeout, ARB_TIMER);
415 
416 	return 0;
417 }
418 #else
419 #define brcmstb_gisb_arb_suspend       NULL
420 #define brcmstb_gisb_arb_resume_noirq  NULL
421 #endif
422 
423 static const struct dev_pm_ops brcmstb_gisb_arb_pm_ops = {
424 	.suspend	= brcmstb_gisb_arb_suspend,
425 	.resume_noirq	= brcmstb_gisb_arb_resume_noirq,
426 };
427 
428 static struct platform_driver brcmstb_gisb_arb_driver = {
429 	.driver = {
430 		.name	= "brcm-gisb-arb",
431 		.of_match_table = brcmstb_gisb_arb_of_match,
432 		.pm	= &brcmstb_gisb_arb_pm_ops,
433 	},
434 };
435 
436 static int __init brcm_gisb_driver_init(void)
437 {
438 	return platform_driver_probe(&brcmstb_gisb_arb_driver,
439 				     brcmstb_gisb_arb_probe);
440 }
441 
442 module_init(brcm_gisb_driver_init);
443