1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
4 *
5 * Authors:
6 * Serge Semin <Sergey.Semin@baikalelectronics.ru>
7 *
8 * Baikal-T1 AXI-bus driver
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/types.h>
14#include <linux/bitfield.h>
15#include <linux/device.h>
16#include <linux/atomic.h>
17#include <linux/regmap.h>
18#include <linux/platform_device.h>
19#include <linux/mfd/syscon.h>
20#include <linux/interrupt.h>
21#include <linux/io.h>
22#include <linux/nmi.h>
23#include <linux/of.h>
24#include <linux/clk.h>
25#include <linux/reset.h>
26#include <linux/sysfs.h>
27
28#define BT1_AXI_WERRL 0x110
29#define BT1_AXI_WERRH 0x114
30#define BT1_AXI_WERRH_TYPE BIT(23)
31#define BT1_AXI_WERRH_ADDR_FLD 24
32#define BT1_AXI_WERRH_ADDR_MASK GENMASK(31, BT1_AXI_WERRH_ADDR_FLD)
33
34/*
35 * struct bt1_axi - Baikal-T1 AXI-bus private data
36 * @dev: Pointer to the device structure.
37 * @qos_regs: AXI Interconnect QoS tuning registers.
38 * @sys_regs: Baikal-T1 System Controller registers map.
39 * @irq: Errors IRQ number.
40 * @aclk: AXI reference clock.
41 * @arst: AXI Interconnect reset line.
42 * @count: Number of errors detected.
43 */
44struct bt1_axi {
45 struct device *dev;
46
47 void __iomem *qos_regs;
48 struct regmap *sys_regs;
49 int irq;
50
51 struct clk *aclk;
52
53 struct reset_control *arst;
54
55 atomic_t count;
56};
57
58static irqreturn_t bt1_axi_isr(int irq, void *data)
59{
60 struct bt1_axi *axi = data;
61 u32 low = 0, high = 0;
62
63 regmap_read(map: axi->sys_regs, BT1_AXI_WERRL, val: &low);
64 regmap_read(map: axi->sys_regs, BT1_AXI_WERRH, val: &high);
65
66 dev_crit_ratelimited(axi->dev,
67 "AXI-bus fault %d: %s at 0x%x%08x\n",
68 atomic_inc_return(&axi->count),
69 high & BT1_AXI_WERRH_TYPE ? "no slave" : "slave protocol error",
70 high, low);
71
72 /*
73 * Print backtrace on each CPU. This might be pointless if the fault
74 * has happened on the same CPU as the IRQ handler is executed or
75 * the other core proceeded further execution despite the error.
76 * But if it's not, by looking at the trace we would get straight to
77 * the cause of the problem.
78 */
79 trigger_all_cpu_backtrace();
80
81 return IRQ_HANDLED;
82}
83
84static void bt1_axi_clear_data(void *data)
85{
86 struct bt1_axi *axi = data;
87 struct platform_device *pdev = to_platform_device(axi->dev);
88
89 platform_set_drvdata(pdev, NULL);
90}
91
92static struct bt1_axi *bt1_axi_create_data(struct platform_device *pdev)
93{
94 struct device *dev = &pdev->dev;
95 struct bt1_axi *axi;
96 int ret;
97
98 axi = devm_kzalloc(dev, size: sizeof(*axi), GFP_KERNEL);
99 if (!axi)
100 return ERR_PTR(error: -ENOMEM);
101
102 ret = devm_add_action(dev, bt1_axi_clear_data, axi);
103 if (ret) {
104 dev_err(dev, "Can't add AXI EHB data clear action\n");
105 return ERR_PTR(error: ret);
106 }
107
108 axi->dev = dev;
109 atomic_set(v: &axi->count, i: 0);
110 platform_set_drvdata(pdev, data: axi);
111
112 return axi;
113}
114
115static int bt1_axi_request_regs(struct bt1_axi *axi)
116{
117 struct platform_device *pdev = to_platform_device(axi->dev);
118 struct device *dev = axi->dev;
119
120 axi->sys_regs = syscon_regmap_lookup_by_phandle(np: dev->of_node, property: "syscon");
121 if (IS_ERR(ptr: axi->sys_regs)) {
122 dev_err(dev, "Couldn't find syscon registers\n");
123 return PTR_ERR(ptr: axi->sys_regs);
124 }
125
126 axi->qos_regs = devm_platform_ioremap_resource_byname(pdev, name: "qos");
127 if (IS_ERR(ptr: axi->qos_regs))
128 dev_err(dev, "Couldn't map AXI-bus QoS registers\n");
129
130 return PTR_ERR_OR_ZERO(ptr: axi->qos_regs);
131}
132
133static int bt1_axi_request_rst(struct bt1_axi *axi)
134{
135 int ret;
136
137 axi->arst = devm_reset_control_get_optional_exclusive(dev: axi->dev, id: "arst");
138 if (IS_ERR(ptr: axi->arst))
139 return dev_err_probe(dev: axi->dev, err: PTR_ERR(ptr: axi->arst),
140 fmt: "Couldn't get reset control line\n");
141
142 ret = reset_control_deassert(rstc: axi->arst);
143 if (ret)
144 dev_err(axi->dev, "Failed to deassert the reset line\n");
145
146 return ret;
147}
148
149static void bt1_axi_disable_clk(void *data)
150{
151 struct bt1_axi *axi = data;
152
153 clk_disable_unprepare(clk: axi->aclk);
154}
155
156static int bt1_axi_request_clk(struct bt1_axi *axi)
157{
158 int ret;
159
160 axi->aclk = devm_clk_get(dev: axi->dev, id: "aclk");
161 if (IS_ERR(ptr: axi->aclk))
162 return dev_err_probe(dev: axi->dev, err: PTR_ERR(ptr: axi->aclk),
163 fmt: "Couldn't get AXI Interconnect clock\n");
164
165 ret = clk_prepare_enable(clk: axi->aclk);
166 if (ret) {
167 dev_err(axi->dev, "Couldn't enable the AXI clock\n");
168 return ret;
169 }
170
171 ret = devm_add_action_or_reset(axi->dev, bt1_axi_disable_clk, axi);
172 if (ret)
173 dev_err(axi->dev, "Can't add AXI clock disable action\n");
174
175 return ret;
176}
177
178static int bt1_axi_request_irq(struct bt1_axi *axi)
179{
180 struct platform_device *pdev = to_platform_device(axi->dev);
181 int ret;
182
183 axi->irq = platform_get_irq(pdev, 0);
184 if (axi->irq < 0)
185 return axi->irq;
186
187 ret = devm_request_irq(dev: axi->dev, irq: axi->irq, handler: bt1_axi_isr, IRQF_SHARED,
188 devname: "bt1-axi", dev_id: axi);
189 if (ret)
190 dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n");
191
192 return ret;
193}
194
195static ssize_t count_show(struct device *dev,
196 struct device_attribute *attr, char *buf)
197{
198 struct bt1_axi *axi = dev_get_drvdata(dev);
199
200 return scnprintf(buf, PAGE_SIZE, fmt: "%d\n", atomic_read(v: &axi->count));
201}
202static DEVICE_ATTR_RO(count);
203
204static ssize_t inject_error_show(struct device *dev,
205 struct device_attribute *attr, char *buf)
206{
207 return scnprintf(buf, PAGE_SIZE, fmt: "Error injection: bus unaligned\n");
208}
209
210static ssize_t inject_error_store(struct device *dev,
211 struct device_attribute *attr,
212 const char *data, size_t count)
213{
214 struct bt1_axi *axi = dev_get_drvdata(dev);
215
216 /*
217 * Performing unaligned read from the memory will cause the CM2 bus
218 * error while unaligned writing - the AXI bus write error handled
219 * by this driver.
220 */
221 if (sysfs_streq(s1: data, s2: "bus"))
222 readb(addr: axi->qos_regs);
223 else if (sysfs_streq(s1: data, s2: "unaligned"))
224 writeb(val: 0, addr: axi->qos_regs);
225 else
226 return -EINVAL;
227
228 return count;
229}
230static DEVICE_ATTR_RW(inject_error);
231
232static struct attribute *bt1_axi_sysfs_attrs[] = {
233 &dev_attr_count.attr,
234 &dev_attr_inject_error.attr,
235 NULL
236};
237ATTRIBUTE_GROUPS(bt1_axi_sysfs);
238
239static void bt1_axi_remove_sysfs(void *data)
240{
241 struct bt1_axi *axi = data;
242
243 device_remove_groups(dev: axi->dev, groups: bt1_axi_sysfs_groups);
244}
245
246static int bt1_axi_init_sysfs(struct bt1_axi *axi)
247{
248 int ret;
249
250 ret = device_add_groups(dev: axi->dev, groups: bt1_axi_sysfs_groups);
251 if (ret) {
252 dev_err(axi->dev, "Failed to add sysfs files group\n");
253 return ret;
254 }
255
256 ret = devm_add_action_or_reset(axi->dev, bt1_axi_remove_sysfs, axi);
257 if (ret)
258 dev_err(axi->dev, "Can't add AXI EHB sysfs remove action\n");
259
260 return ret;
261}
262
263static int bt1_axi_probe(struct platform_device *pdev)
264{
265 struct bt1_axi *axi;
266 int ret;
267
268 axi = bt1_axi_create_data(pdev);
269 if (IS_ERR(ptr: axi))
270 return PTR_ERR(ptr: axi);
271
272 ret = bt1_axi_request_regs(axi);
273 if (ret)
274 return ret;
275
276 ret = bt1_axi_request_rst(axi);
277 if (ret)
278 return ret;
279
280 ret = bt1_axi_request_clk(axi);
281 if (ret)
282 return ret;
283
284 ret = bt1_axi_request_irq(axi);
285 if (ret)
286 return ret;
287
288 ret = bt1_axi_init_sysfs(axi);
289 if (ret)
290 return ret;
291
292 return 0;
293}
294
295static const struct of_device_id bt1_axi_of_match[] = {
296 { .compatible = "baikal,bt1-axi" },
297 { }
298};
299MODULE_DEVICE_TABLE(of, bt1_axi_of_match);
300
301static struct platform_driver bt1_axi_driver = {
302 .probe = bt1_axi_probe,
303 .driver = {
304 .name = "bt1-axi",
305 .of_match_table = bt1_axi_of_match
306 }
307};
308module_platform_driver(bt1_axi_driver);
309
310MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
311MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver");
312

source code of linux/drivers/bus/bt1-axi.c