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 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 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 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 } 114 115 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 } 132 133 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 } 148 149 static void bt1_axi_disable_clk(void *data) 150 { 151 struct bt1_axi *axi = data; 152 153 clk_disable_unprepare(axi->aclk); 154 } 155 156 static int bt1_axi_request_clk(struct bt1_axi *axi) 157 { 158 int ret; 159 160 axi->aclk = devm_clk_get(axi->dev, "aclk"); 161 if (IS_ERR(axi->aclk)) 162 return dev_err_probe(axi->dev, PTR_ERR(axi->aclk), 163 "Couldn't get AXI Interconnect clock\n"); 164 165 ret = clk_prepare_enable(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 } 177 178 static 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(axi->dev, axi->irq, bt1_axi_isr, IRQF_SHARED, 188 "bt1-axi", axi); 189 if (ret) 190 dev_err(axi->dev, "Couldn't request AXI EHB IRQ\n"); 191 192 return ret; 193 } 194 195 static 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, "%d\n", atomic_read(&axi->count)); 201 } 202 static DEVICE_ATTR_RO(count); 203 204 static ssize_t inject_error_show(struct device *dev, 205 struct device_attribute *attr, char *buf) 206 { 207 return scnprintf(buf, PAGE_SIZE, "Error injection: bus unaligned\n"); 208 } 209 210 static 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(data, "bus")) 222 readb(axi->qos_regs); 223 else if (sysfs_streq(data, "unaligned")) 224 writeb(0, axi->qos_regs); 225 else 226 return -EINVAL; 227 228 return count; 229 } 230 static DEVICE_ATTR_RW(inject_error); 231 232 static struct attribute *bt1_axi_sysfs_attrs[] = { 233 &dev_attr_count.attr, 234 &dev_attr_inject_error.attr, 235 NULL 236 }; 237 ATTRIBUTE_GROUPS(bt1_axi_sysfs); 238 239 static void bt1_axi_remove_sysfs(void *data) 240 { 241 struct bt1_axi *axi = data; 242 243 device_remove_groups(axi->dev, bt1_axi_sysfs_groups); 244 } 245 246 static int bt1_axi_init_sysfs(struct bt1_axi *axi) 247 { 248 int ret; 249 250 ret = device_add_groups(axi->dev, 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 } 262 263 static 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(axi)) 270 return PTR_ERR(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 } 294 295 static const struct of_device_id bt1_axi_of_match[] = { 296 { .compatible = "baikal,bt1-axi" }, 297 { } 298 }; 299 MODULE_DEVICE_TABLE(of, bt1_axi_of_match); 300 301 static 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 }; 308 module_platform_driver(bt1_axi_driver); 309 310 MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>"); 311 MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver"); 312