drivers/bus/brcmstb_gisb.c

   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
  27 #ifdef CONFIG_ARM
  28 #include <asm/bug.h>
  29 #include <asm/signal.h>
  30 #endif
  31
  32 #define ARB_TIMER                       0x008
  33 #define ARB_ERR_CAP_CLR                 0x7e4
  34 #define  ARB_ERR_CAP_CLEAR              (1 << 0)
  35 #define ARB_ERR_CAP_HI_ADDR             0x7e8
  36 #define ARB_ERR_CAP_ADDR                0x7ec
  37 #define ARB_ERR_CAP_DATA                0x7f0
  38 #define ARB_ERR_CAP_STATUS              0x7f4
  39 #define  ARB_ERR_CAP_STATUS_TIMEOUT     (1 << 12)
  40 #define  ARB_ERR_CAP_STATUS_TEA         (1 << 11)
  41 #define  ARB_ERR_CAP_STATUS_BS_SHIFT    (1 << 2)
  42 #define  ARB_ERR_CAP_STATUS_BS_MASK     0x3c
  43 #define  ARB_ERR_CAP_STATUS_WRITE       (1 << 1)
  44 #define  ARB_ERR_CAP_STATUS_VALID       (1 << 0)
  45 #define ARB_ERR_CAP_MASTER              0x7f8
  46
  47 struct brcmstb_gisb_arb_device {
  48         void __iomem    *base;
  49         struct mutex    lock;
  50         struct list_head next;
  51         u32 valid_mask;
  52         const char *master_names[sizeof(u32) * BITS_PER_BYTE];
  53 };
  54
  55 static LIST_HEAD(brcmstb_gisb_arb_device_list);
  56
  57 static u32 gisb_read(struct brcmstb_gisb_arb_device *gdev, int reg)
  58 {
  59         return ioread32(gdev->base + reg);
  60 }
  61
  62 static void gisb_write(struct brcmstb_gisb_arb_device *gdev, u32 val, int reg)
  63 {
  64         iowrite32(val, gdev->base + reg);
  65 }
  66
  67 static ssize_t gisb_arb_get_timeout(struct device *dev,
  68                                     struct device_attribute *attr,
  69                                     char *buf)
  70 {
  71         struct platform_device *pdev = to_platform_device(dev);
  72         struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
  73         u32 timeout;
  74
  75         mutex_lock(&gdev->lock);
  76         timeout = gisb_read(gdev, ARB_TIMER);
  77         mutex_unlock(&gdev->lock);
  78
  79         return sprintf(buf, "%d", timeout);
  80 }
  81
  82 static ssize_t gisb_arb_set_timeout(struct device *dev,
  83                                     struct device_attribute *attr,
  84                                     const char *buf, size_t count)
  85 {
  86         struct platform_device *pdev = to_platform_device(dev);
  87         struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
  88         int val, ret;
  89
  90         ret = kstrtoint(buf, 10, &val);
  91         if (ret < 0)
  92                 return ret;
  93
  94         if (val == 0 || val >= 0xffffffff)
  95                 return -EINVAL;
  96
  97         mutex_lock(&gdev->lock);
  98         gisb_write(gdev, val, ARB_TIMER);
  99         mutex_unlock(&gdev->lock);
 100
 101         return count;
 102 }
 103
 104 static const char *
 105 brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
 106                                                 u32 masters)
 107 {
 108         u32 mask = gdev->valid_mask & masters;
 109
 110         if (hweight_long(mask) != 1)
 111                 return NULL;
 112
 113         return gdev->master_names[ffs(mask) - 1];
 114 }
 115
 116 static int brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device *gdev,
 117                                         const char *reason)
 118 {
 119         u32 cap_status;
 120         unsigned long arb_addr;
 121         u32 master;
 122         const char *m_name;
 123         char m_fmt[11];
 124
 125         cap_status = gisb_read(gdev, ARB_ERR_CAP_STATUS);
 126
 127         /* Invalid captured address, bail out */
 128         if (!(cap_status & ARB_ERR_CAP_STATUS_VALID))
 129                 return 1;
 130
 131         /* Read the address and master */
 132         arb_addr = gisb_read(gdev, ARB_ERR_CAP_ADDR) & 0xffffffff;
 133 #if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))
 134         arb_addr |= (u64)gisb_read(gdev, ARB_ERR_CAP_HI_ADDR) << 32;
 135 #endif
 136         master = gisb_read(gdev, ARB_ERR_CAP_MASTER);
 137
 138         m_name = brcmstb_gisb_master_to_str(gdev, master);
 139         if (!m_name) {
 140                 snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
 141                 m_name = m_fmt;
 142         }
 143
 144         pr_crit("%s: %s at 0x%lx [%c %s], core: %s\n",
 145                 __func__, reason, arb_addr,
 146                 cap_status & ARB_ERR_CAP_STATUS_WRITE ? 'W' : 'R',
 147                 cap_status & ARB_ERR_CAP_STATUS_TIMEOUT ? "timeout" : "",
 148                 m_name);
 149
 150         /* clear the GISB error */
 151         gisb_write(gdev, ARB_ERR_CAP_CLEAR, ARB_ERR_CAP_CLR);
 152
 153         return 0;
 154 }
 155
 156 #ifdef CONFIG_ARM
 157 static int brcmstb_bus_error_handler(unsigned long addr, unsigned int fsr,
 158                                      struct pt_regs *regs)
 159 {
 160         int ret = 0;
 161         struct brcmstb_gisb_arb_device *gdev;
 162
 163         /* iterate over each GISB arb registered handlers */
 164         list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
 165                 ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
 166         /*
 167          * If it was an imprecise abort, then we need to correct the
 168          * return address to be _after_ the instruction.
 169         */
 170         if (fsr & (1 << 10))
 171                 regs->ARM_pc += 4;
 172
 173         return ret;
 174 }
 175
 176 void __init brcmstb_hook_fault_code(void)
 177 {
 178         hook_fault_code(22, brcmstb_bus_error_handler, SIGBUS, 0,
 179                         "imprecise external abort");
 180 }
 181 #endif
 182
 183 static irqreturn_t brcmstb_gisb_timeout_handler(int irq, void *dev_id)
 184 {
 185         brcmstb_gisb_arb_decode_addr(dev_id, "timeout");
 186
 187         return IRQ_HANDLED;
 188 }
 189
 190 static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
 191 {
 192         brcmstb_gisb_arb_decode_addr(dev_id, "target abort");
 193
 194         return IRQ_HANDLED;
 195 }
 196
 197 static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
 198                 gisb_arb_get_timeout, gisb_arb_set_timeout);
 199
 200 static struct attribute *gisb_arb_sysfs_attrs[] = {
 201         &dev_attr_gisb_arb_timeout.attr,
 202         NULL,
 203 };
 204
 205 static struct attribute_group gisb_arb_sysfs_attr_group = {
 206         .attrs = gisb_arb_sysfs_attrs,
 207 };
 208
 209 static int brcmstb_gisb_arb_probe(struct platform_device *pdev)
 210 {
 211         struct device_node *dn = pdev->dev.of_node;
 212         struct brcmstb_gisb_arb_device *gdev;
 213         struct resource *r;
 214         int err, timeout_irq, tea_irq;
 215         unsigned int num_masters, j = 0;
 216         int i, first, last;
 217
 218         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 219         timeout_irq = platform_get_irq(pdev, 0);
 220         tea_irq = platform_get_irq(pdev, 1);
 221
 222         gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
 223         if (!gdev)
 224                 return -ENOMEM;
 225
 226         mutex_init(&gdev->lock);
 227         INIT_LIST_HEAD(&gdev->next);
 228
 229         gdev->base = devm_ioremap_resource(&pdev->dev, r);
 230         if (IS_ERR(gdev->base))
 231                 return PTR_ERR(gdev->base);
 232
 233         err = devm_request_irq(&pdev->dev, timeout_irq,
 234                                 brcmstb_gisb_timeout_handler, 0, pdev->name,
 235                                 gdev);
 236         if (err < 0)
 237                 return err;
 238
 239         err = devm_request_irq(&pdev->dev, tea_irq,
 240                                 brcmstb_gisb_tea_handler, 0, pdev->name,
 241                                 gdev);
 242         if (err < 0)
 243                 return err;
 244
 245         /* If we do not have a valid mask, assume all masters are enabled */
 246         if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
 247                                 &gdev->valid_mask))
 248                 gdev->valid_mask = 0xffffffff;
 249
 250         /* Proceed with reading the litteral names if we agree on the
 251          * number of masters
 252          */
 253         num_masters = of_property_count_strings(dn,
 254                         "brcm,gisb-arb-master-names");
 255         if (hweight_long(gdev->valid_mask) == num_masters) {
 256                 first = ffs(gdev->valid_mask) - 1;
 257                 last = fls(gdev->valid_mask) - 1;
 258
 259                 for (i = first; i < last; i++) {
 260                         if (!(gdev->valid_mask & BIT(i)))
 261                                 continue;
 262
 263                         of_property_read_string_index(dn,
 264                                         "brcm,gisb-arb-master-names", j,
 265                                         &gdev->master_names[i]);
 266                         j++;
 267                 }
 268         }
 269
 270         err = sysfs_create_group(&pdev->dev.kobj, &gisb_arb_sysfs_attr_group);
 271         if (err)
 272                 return err;
 273
 274         platform_set_drvdata(pdev, gdev);
 275
 276         list_add_tail(&gdev->next, &brcmstb_gisb_arb_device_list);
 277
 278         dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
 279                         gdev->base, timeout_irq, tea_irq);
 280
 281         return 0;
 282 }
 283
 284 static const struct of_device_id brcmstb_gisb_arb_of_match[] = {
 285         { .compatible = "brcm,gisb-arb" },
 286         { },
 287 };
 288
 289 static struct platform_driver brcmstb_gisb_arb_driver = {
 290         .probe  = brcmstb_gisb_arb_probe,
 291         .driver = {
 292                 .name   = "brcm-gisb-arb",
 293                 .owner  = THIS_MODULE,
 294                 .of_match_table = brcmstb_gisb_arb_of_match,
 295         },
 296 };
 297
 298 static int __init brcm_gisb_driver_init(void)
 299 {
 300         return platform_driver_register(&brcmstb_gisb_arb_driver);
 301 }
 302
 303 module_init(brcm_gisb_driver_init);