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 */
44 struct 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
bt1_axi_isr(int irq,void * data)58 static 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(axi->sys_regs, BT1_AXI_WERRL, &low);
64 regmap_read(axi->sys_regs, BT1_AXI_WERRH, &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
bt1_axi_clear_data(void * data)84 static 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
bt1_axi_create_data(struct platform_device * pdev)92 static 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, sizeof(*axi), GFP_KERNEL);
99 if (!axi)
100 return ERR_PTR(-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(ret);
106 }
107
108 axi->dev = dev;
109 atomic_set(&axi->count, 0);
110 platform_set_drvdata(pdev, axi);
111
112 return axi;
113 }
114
bt1_axi_request_regs(struct bt1_axi * axi)115 static 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(dev->of_node, "syscon");
121 if (IS_ERR(axi->sys_regs)) {
122 dev_err(dev, "Couldn't find syscon registers\n");
123 return PTR_ERR(axi->sys_regs);
124 }
125
126 axi->qos_regs = devm_platform_ioremap_resource_byname(pdev, "qos");
127 if (IS_ERR(axi->qos_regs))
128 dev_err(dev, "Couldn't map AXI-bus QoS registers\n");
129
130 return PTR_ERR_OR_ZERO(axi->qos_regs);
131 }
132
bt1_axi_request_rst(struct bt1_axi * axi)133 static int bt1_axi_request_rst(struct bt1_axi *axi)
134 {
135 int ret;
136
137 axi->arst = devm_reset_control_get_optional_exclusive(axi->dev, "arst");
138 if (IS_ERR(axi->arst))
139 return dev_err_probe(axi->dev, PTR_ERR(axi->arst),
140 "Couldn't get reset control line\n");
141
142 ret = reset_control_deassert(axi->arst);
143 if (ret)
144 dev_err(axi->dev, "Failed to deassert the reset line\n");
145
146 return ret;
147 }
148
bt1_axi_request_clk(struct bt1_axi * axi)149 static int bt1_axi_request_clk(struct bt1_axi *axi)
150 {
151 axi->aclk = devm_clk_get_enabled(axi->dev, "aclk");
152 if (IS_ERR(axi->aclk))
153 return dev_err_probe(axi->dev, PTR_ERR(axi->aclk),
154 "Couldn't get AXI Interconnect clock\n");
155
156 return 0;
157 }
158
bt1_axi_request_irq(struct bt1_axi * axi)159 static int bt1_axi_request_irq(struct bt1_axi *axi)
160 {
161 struct platform_device *pdev = to_platform_device(axi->dev);
162 int ret;
163
164 axi->irq = platform_get_irq(pdev, 0);
165 if (axi->irq < 0)
166 return axi->irq;
167
168 ret = devm_request_irq(axi->dev, axi->irq, bt1_axi_isr, IRQF_SHARED,
169 "bt1-axi", axi);
170 if (ret)
171 dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n");
172
173 return ret;
174 }
175
count_show(struct device * dev,struct device_attribute * attr,char * buf)176 static ssize_t count_show(struct device *dev,
177 struct device_attribute *attr, char *buf)
178 {
179 struct bt1_axi *axi = dev_get_drvdata(dev);
180
181 return scnprintf(buf, PAGE_SIZE, "%d\n", atomic_read(&axi->count));
182 }
183 static DEVICE_ATTR_RO(count);
184
inject_error_show(struct device * dev,struct device_attribute * attr,char * buf)185 static ssize_t inject_error_show(struct device *dev,
186 struct device_attribute *attr, char *buf)
187 {
188 return scnprintf(buf, PAGE_SIZE, "Error injection: bus unaligned\n");
189 }
190
inject_error_store(struct device * dev,struct device_attribute * attr,const char * data,size_t count)191 static ssize_t inject_error_store(struct device *dev,
192 struct device_attribute *attr,
193 const char *data, size_t count)
194 {
195 struct bt1_axi *axi = dev_get_drvdata(dev);
196
197 /*
198 * Performing unaligned read from the memory will cause the CM2 bus
199 * error while unaligned writing - the AXI bus write error handled
200 * by this driver.
201 */
202 if (sysfs_streq(data, "bus"))
203 readb(axi->qos_regs);
204 else if (sysfs_streq(data, "unaligned"))
205 writeb(0, axi->qos_regs);
206 else
207 return -EINVAL;
208
209 return count;
210 }
211 static DEVICE_ATTR_RW(inject_error);
212
213 static struct attribute *bt1_axi_sysfs_attrs[] = {
214 &dev_attr_count.attr,
215 &dev_attr_inject_error.attr,
216 NULL
217 };
218 ATTRIBUTE_GROUPS(bt1_axi_sysfs);
219
bt1_axi_remove_sysfs(void * data)220 static void bt1_axi_remove_sysfs(void *data)
221 {
222 struct bt1_axi *axi = data;
223
224 device_remove_groups(axi->dev, bt1_axi_sysfs_groups);
225 }
226
bt1_axi_init_sysfs(struct bt1_axi * axi)227 static int bt1_axi_init_sysfs(struct bt1_axi *axi)
228 {
229 int ret;
230
231 ret = device_add_groups(axi->dev, bt1_axi_sysfs_groups);
232 if (ret) {
233 dev_err(axi->dev, "Failed to add sysfs files group\n");
234 return ret;
235 }
236
237 ret = devm_add_action_or_reset(axi->dev, bt1_axi_remove_sysfs, axi);
238 if (ret)
239 dev_err(axi->dev, "Can't add AXI EHB sysfs remove action\n");
240
241 return ret;
242 }
243
bt1_axi_probe(struct platform_device * pdev)244 static int bt1_axi_probe(struct platform_device *pdev)
245 {
246 struct bt1_axi *axi;
247 int ret;
248
249 axi = bt1_axi_create_data(pdev);
250 if (IS_ERR(axi))
251 return PTR_ERR(axi);
252
253 ret = bt1_axi_request_regs(axi);
254 if (ret)
255 return ret;
256
257 ret = bt1_axi_request_rst(axi);
258 if (ret)
259 return ret;
260
261 ret = bt1_axi_request_clk(axi);
262 if (ret)
263 return ret;
264
265 ret = bt1_axi_request_irq(axi);
266 if (ret)
267 return ret;
268
269 ret = bt1_axi_init_sysfs(axi);
270 if (ret)
271 return ret;
272
273 return 0;
274 }
275
276 static const struct of_device_id bt1_axi_of_match[] = {
277 { .compatible = "baikal,bt1-axi" },
278 { }
279 };
280 MODULE_DEVICE_TABLE(of, bt1_axi_of_match);
281
282 static struct platform_driver bt1_axi_driver = {
283 .probe = bt1_axi_probe,
284 .driver = {
285 .name = "bt1-axi",
286 .of_match_table = bt1_axi_of_match
287 }
288 };
289 module_platform_driver(bt1_axi_driver);
290
291 MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
292 MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver");
293