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#define  ARB_ERR_CAP_CLEAR		(1 << 0)
34#define  ARB_ERR_CAP_STATUS_TIMEOUT	(1 << 12)
35#define  ARB_ERR_CAP_STATUS_TEA		(1 << 11)
36#define  ARB_ERR_CAP_STATUS_BS_SHIFT	(1 << 2)
37#define  ARB_ERR_CAP_STATUS_BS_MASK	0x3c
38#define  ARB_ERR_CAP_STATUS_WRITE	(1 << 1)
39#define  ARB_ERR_CAP_STATUS_VALID	(1 << 0)
40
41enum {
42	ARB_TIMER,
43	ARB_ERR_CAP_CLR,
44	ARB_ERR_CAP_HI_ADDR,
45	ARB_ERR_CAP_ADDR,
46	ARB_ERR_CAP_DATA,
47	ARB_ERR_CAP_STATUS,
48	ARB_ERR_CAP_MASTER,
49};
50
51static const int gisb_offsets_bcm7038[] = {
52	[ARB_TIMER]		= 0x00c,
53	[ARB_ERR_CAP_CLR]	= 0x0c4,
54	[ARB_ERR_CAP_HI_ADDR]	= -1,
55	[ARB_ERR_CAP_ADDR]	= 0x0c8,
56	[ARB_ERR_CAP_DATA]	= 0x0cc,
57	[ARB_ERR_CAP_STATUS]	= 0x0d0,
58	[ARB_ERR_CAP_MASTER]	= -1,
59};
60
61static const int gisb_offsets_bcm7400[] = {
62	[ARB_TIMER]		= 0x00c,
63	[ARB_ERR_CAP_CLR]	= 0x0c8,
64	[ARB_ERR_CAP_HI_ADDR]	= -1,
65	[ARB_ERR_CAP_ADDR]	= 0x0cc,
66	[ARB_ERR_CAP_DATA]	= 0x0d0,
67	[ARB_ERR_CAP_STATUS]	= 0x0d4,
68	[ARB_ERR_CAP_MASTER]	= 0x0d8,
69};
70
71static const int gisb_offsets_bcm7435[] = {
72	[ARB_TIMER]		= 0x00c,
73	[ARB_ERR_CAP_CLR]	= 0x168,
74	[ARB_ERR_CAP_HI_ADDR]	= -1,
75	[ARB_ERR_CAP_ADDR]	= 0x16c,
76	[ARB_ERR_CAP_DATA]	= 0x170,
77	[ARB_ERR_CAP_STATUS]	= 0x174,
78	[ARB_ERR_CAP_MASTER]	= 0x178,
79};
80
81static const int gisb_offsets_bcm7445[] = {
82	[ARB_TIMER]		= 0x008,
83	[ARB_ERR_CAP_CLR]	= 0x7e4,
84	[ARB_ERR_CAP_HI_ADDR]	= 0x7e8,
85	[ARB_ERR_CAP_ADDR]	= 0x7ec,
86	[ARB_ERR_CAP_DATA]	= 0x7f0,
87	[ARB_ERR_CAP_STATUS]	= 0x7f4,
88	[ARB_ERR_CAP_MASTER]	= 0x7f8,
89};
90
91struct brcmstb_gisb_arb_device {
92	void __iomem	*base;
93	const int	*gisb_offsets;
94	struct mutex	lock;
95	struct list_head next;
96	u32 valid_mask;
97	const char *master_names[sizeof(u32) * BITS_PER_BYTE];
98	u32 saved_timeout;
99};
100
101static LIST_HEAD(brcmstb_gisb_arb_device_list);
102
103static u32 gisb_read(struct brcmstb_gisb_arb_device *gdev, int reg)
104{
105	int offset = gdev->gisb_offsets[reg];
106
107	/* return 1 if the hardware doesn't have ARB_ERR_CAP_MASTER */
108	if (offset == -1)
109		return 1;
110
111	return ioread32(gdev->base + offset);
112}
113
114static void gisb_write(struct brcmstb_gisb_arb_device *gdev, u32 val, int reg)
115{
116	int offset = gdev->gisb_offsets[reg];
117
118	if (offset == -1)
119		return;
120	iowrite32(val, gdev->base + reg);
121}
122
123static ssize_t gisb_arb_get_timeout(struct device *dev,
124				    struct device_attribute *attr,
125				    char *buf)
126{
127	struct platform_device *pdev = to_platform_device(dev);
128	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
129	u32 timeout;
130
131	mutex_lock(&gdev->lock);
132	timeout = gisb_read(gdev, ARB_TIMER);
133	mutex_unlock(&gdev->lock);
134
135	return sprintf(buf, "%d", timeout);
136}
137
138static ssize_t gisb_arb_set_timeout(struct device *dev,
139				    struct device_attribute *attr,
140				    const char *buf, size_t count)
141{
142	struct platform_device *pdev = to_platform_device(dev);
143	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
144	int val, ret;
145
146	ret = kstrtoint(buf, 10, &val);
147	if (ret < 0)
148		return ret;
149
150	if (val == 0 || val >= 0xffffffff)
151		return -EINVAL;
152
153	mutex_lock(&gdev->lock);
154	gisb_write(gdev, val, ARB_TIMER);
155	mutex_unlock(&gdev->lock);
156
157	return count;
158}
159
160static const char *
161brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
162						u32 masters)
163{
164	u32 mask = gdev->valid_mask & masters;
165
166	if (hweight_long(mask) != 1)
167		return NULL;
168
169	return gdev->master_names[ffs(mask) - 1];
170}
171
172static int brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device *gdev,
173					const char *reason)
174{
175	u32 cap_status;
176	unsigned long arb_addr;
177	u32 master;
178	const char *m_name;
179	char m_fmt[11];
180
181	cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
182
183	/* Invalid captured address, bail out */
184	if (!(cap_status & ARB_ERR_CAP_STATUS_VALID))
185		return 1;
186
187	/* Read the address and master */
188	arb_addr = gisb_read(gdev, ARB_ERR_CAP_ADDR) & 0xffffffff;
189#if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))
190	arb_addr |= (u64)gisb_read(gdev, ARB_ERR_CAP_HI_ADDR) << 32;
191#endif
192	master = gisb_read(gdev, ARB_ERR_CAP_MASTER);
193
194	m_name = brcmstb_gisb_master_to_str(gdev, master);
195	if (!m_name) {
196		snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
197		m_name = m_fmt;
198	}
199
200	pr_crit("%s: %s at 0x%lx [%c %s], core: %s\n",
201		__func__, reason, arb_addr,
202		cap_status & ARB_ERR_CAP_STATUS_WRITE ? 'W' : 'R',
203		cap_status & ARB_ERR_CAP_STATUS_TIMEOUT ? "timeout" : "",
204		m_name);
205
206	/* clear the GISB error */
207	gisb_write(gdev, ARB_ERR_CAP_CLEAR, ARB_ERR_CAP_CLR);
208
209	return 0;
210}
211
212#ifdef CONFIG_ARM
213static int brcmstb_bus_error_handler(unsigned long addr, unsigned int fsr,
214				     struct pt_regs *regs)
215{
216	int ret = 0;
217	struct brcmstb_gisb_arb_device *gdev;
218
219	/* iterate over each GISB arb registered handlers */
220	list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
221		ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
222	/*
223	 * If it was an imprecise abort, then we need to correct the
224	 * return address to be _after_ the instruction.
225	*/
226	if (fsr & (1 << 10))
227		regs->ARM_pc += 4;
228
229	return ret;
230}
231#endif
232
233static irqreturn_t brcmstb_gisb_timeout_handler(int irq, void *dev_id)
234{
235	brcmstb_gisb_arb_decode_addr(dev_id, "timeout");
236
237	return IRQ_HANDLED;
238}
239
240static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
241{
242	brcmstb_gisb_arb_decode_addr(dev_id, "target abort");
243
244	return IRQ_HANDLED;
245}
246
247static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
248		gisb_arb_get_timeout, gisb_arb_set_timeout);
249
250static struct attribute *gisb_arb_sysfs_attrs[] = {
251	&dev_attr_gisb_arb_timeout.attr,
252	NULL,
253};
254
255static struct attribute_group gisb_arb_sysfs_attr_group = {
256	.attrs = gisb_arb_sysfs_attrs,
257};
258
259static const struct of_device_id brcmstb_gisb_arb_of_match[] = {
260	{ .compatible = "brcm,gisb-arb",         .data = gisb_offsets_bcm7445 },
261	{ .compatible = "brcm,bcm7445-gisb-arb", .data = gisb_offsets_bcm7445 },
262	{ .compatible = "brcm,bcm7435-gisb-arb", .data = gisb_offsets_bcm7435 },
263	{ .compatible = "brcm,bcm7400-gisb-arb", .data = gisb_offsets_bcm7400 },
264	{ .compatible = "brcm,bcm7038-gisb-arb", .data = gisb_offsets_bcm7038 },
265	{ },
266};
267
268static int __init brcmstb_gisb_arb_probe(struct platform_device *pdev)
269{
270	struct device_node *dn = pdev->dev.of_node;
271	struct brcmstb_gisb_arb_device *gdev;
272	const struct of_device_id *of_id;
273	struct resource *r;
274	int err, timeout_irq, tea_irq;
275	unsigned int num_masters, j = 0;
276	int i, first, last;
277
278	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
279	timeout_irq = platform_get_irq(pdev, 0);
280	tea_irq = platform_get_irq(pdev, 1);
281
282	gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
283	if (!gdev)
284		return -ENOMEM;
285
286	mutex_init(&gdev->lock);
287	INIT_LIST_HEAD(&gdev->next);
288
289	gdev->base = devm_ioremap_resource(&pdev->dev, r);
290	if (IS_ERR(gdev->base))
291		return PTR_ERR(gdev->base);
292
293	of_id = of_match_node(brcmstb_gisb_arb_of_match, dn);
294	if (!of_id) {
295		pr_err("failed to look up compatible string\n");
296		return -EINVAL;
297	}
298	gdev->gisb_offsets = of_id->data;
299
300	err = devm_request_irq(&pdev->dev, timeout_irq,
301				brcmstb_gisb_timeout_handler, 0, pdev->name,
302				gdev);
303	if (err < 0)
304		return err;
305
306	err = devm_request_irq(&pdev->dev, tea_irq,
307				brcmstb_gisb_tea_handler, 0, pdev->name,
308				gdev);
309	if (err < 0)
310		return err;
311
312	/* If we do not have a valid mask, assume all masters are enabled */
313	if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
314				&gdev->valid_mask))
315		gdev->valid_mask = 0xffffffff;
316
317	/* Proceed with reading the litteral names if we agree on the
318	 * number of masters
319	 */
320	num_masters = of_property_count_strings(dn,
321			"brcm,gisb-arb-master-names");
322	if (hweight_long(gdev->valid_mask) == num_masters) {
323		first = ffs(gdev->valid_mask) - 1;
324		last = fls(gdev->valid_mask) - 1;
325
326		for (i = first; i < last; i++) {
327			if (!(gdev->valid_mask & BIT(i)))
328				continue;
329
330			of_property_read_string_index(dn,
331					"brcm,gisb-arb-master-names", j,
332					&gdev->master_names[i]);
333			j++;
334		}
335	}
336
337	err = sysfs_create_group(&pdev->dev.kobj, &gisb_arb_sysfs_attr_group);
338	if (err)
339		return err;
340
341	platform_set_drvdata(pdev, gdev);
342
343	list_add_tail(&gdev->next, &brcmstb_gisb_arb_device_list);
344
345#ifdef CONFIG_ARM
346	hook_fault_code(22, brcmstb_bus_error_handler, SIGBUS, 0,
347			"imprecise external abort");
348#endif
349
350	dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
351			gdev->base, timeout_irq, tea_irq);
352
353	return 0;
354}
355
356#ifdef CONFIG_PM_SLEEP
357static int brcmstb_gisb_arb_suspend(struct device *dev)
358{
359	struct platform_device *pdev = to_platform_device(dev);
360	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
361
362	gdev->saved_timeout = gisb_read(gdev, ARB_TIMER);
363
364	return 0;
365}
366
367/* Make sure we provide the same timeout value that was configured before, and
368 * do this before the GISB timeout interrupt handler has any chance to run.
369 */
370static int brcmstb_gisb_arb_resume_noirq(struct device *dev)
371{
372	struct platform_device *pdev = to_platform_device(dev);
373	struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
374
375	gisb_write(gdev, gdev->saved_timeout, ARB_TIMER);
376
377	return 0;
378}
379#else
380#define brcmstb_gisb_arb_suspend       NULL
381#define brcmstb_gisb_arb_resume_noirq  NULL
382#endif
383
384static const struct dev_pm_ops brcmstb_gisb_arb_pm_ops = {
385	.suspend	= brcmstb_gisb_arb_suspend,
386	.resume_noirq	= brcmstb_gisb_arb_resume_noirq,
387};
388
389static struct platform_driver brcmstb_gisb_arb_driver = {
390	.driver = {
391		.name	= "brcm-gisb-arb",
392		.of_match_table = brcmstb_gisb_arb_of_match,
393		.pm	= &brcmstb_gisb_arb_pm_ops,
394	},
395};
396
397static int __init brcm_gisb_driver_init(void)
398{
399	return platform_driver_probe(&brcmstb_gisb_arb_driver,
400				     brcmstb_gisb_arb_probe);
401}
402
403module_init(brcm_gisb_driver_init);
404