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