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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC4 *5 * Authors:6 * Serge Semin <Sergey.Semin@baikalelectronics.ru>7 *8 * Baikal-T1 AXI-bus driver9 */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 0x11029#define BT1_AXI_WERRH 0x11430#define BT1_AXI_WERRH_TYPE BIT(23)31#define BT1_AXI_WERRH_ADDR_FLD 2432#define BT1_AXI_WERRH_ADDR_MASK GENMASK(31, BT1_AXI_WERRH_ADDR_FLD)33 34/*35 * struct bt1_axi - Baikal-T1 AXI-bus private data36 * @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(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 fault74 * has happened on the same CPU as the IRQ handler is executed or75 * the other core proceeded further execution despite the error.76 * But if it's not, by looking at the trace we would get straight to77 * 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, 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 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(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 133static 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 149static 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 159static 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 176static 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}183static DEVICE_ATTR_RO(count);184 185static 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 191static 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 bus199 * error while unaligned writing - the AXI bus write error handled200 * 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 else207 return -EINVAL;208 209 return count;210}211static DEVICE_ATTR_RW(inject_error);212 213static struct attribute *bt1_axi_sysfs_attrs[] = {214 &dev_attr_count.attr,215 &dev_attr_inject_error.attr,216 NULL217};218ATTRIBUTE_GROUPS(bt1_axi_sysfs);219 220static 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 227static 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 244static 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 276static const struct of_device_id bt1_axi_of_match[] = {277 { .compatible = "baikal,bt1-axi" },278 { }279};280MODULE_DEVICE_TABLE(of, bt1_axi_of_match);281 282static struct platform_driver bt1_axi_driver = {283 .probe = bt1_axi_probe,284 .driver = {285 .name = "bt1-axi",286 .of_match_table = bt1_axi_of_match287 }288};289module_platform_driver(bt1_axi_driver);290 291MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");292MODULE_DESCRIPTION("Baikal-T1 AXI-bus driver");293