3 files changed, 298 insertions, 0 deletions

diff --git a/drivers/bus/Kconfig b/drivers/bus/Kconfig
index 552373c4e362..d40d155f4234 100644
--- a/drivers/bus/Kconfig
+++ b/drivers/bus/Kconfig
@@ -4,6 +4,14 @@
 
 menu "Bus devices"
 
+config BRCMSTB_GISB_ARB
+        bool "Broadcom STB GISB bus arbiter"
+        depends on ARM
+        help
+          Driver for the Broadcom Set Top Box System-on-a-chip internal bus
+          arbiter. This driver provides timeout and target abort error handling
+          and internal bus master decoding.
+
 config IMX_WEIM
         bool "Freescale EIM DRIVER"
         depends on ARCH_MXC
diff --git a/drivers/bus/Makefile b/drivers/bus/Makefile
index 8947bdd0de8b..41fa45b3f061 100644
--- a/drivers/bus/Makefile
+++ b/drivers/bus/Makefile
@@ -2,6 +2,7 @@
 # Makefile for the bus drivers.
 #
 
+obj-$(CONFIG_BRCMSTB_GISB_ARB)  += brcmstb_gisb.o
 obj-$(CONFIG_IMX_WEIM)  += imx-weim.o
 obj-$(CONFIG_MVEBU_MBUS) += mvebu-mbus.o
 obj-$(CONFIG_OMAP_OCP2SCP)      += omap-ocp2scp.o
diff --git a/drivers/bus/brcmstb_gisb.c b/drivers/bus/brcmstb_gisb.c
new file mode 100644
index 000000000000..6159b7752a64
--- /dev/null
+++ b/drivers/bus/brcmstb_gisb.c
@@ -0,0 +1,289 @@
+/*
+ * Copyright (C) 2014 Broadcom Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/sysfs.h>
+#include <linux/io.h>
+#include <linux/string.h>
+#include <linux/device.h>
+#include <linux/list.h>
+#include <linux/of.h>
+#include <linux/bitops.h>
+
+#include <asm/bug.h>
+#include <asm/signal.h>
+
+#define ARB_TIMER                       0x008
+#define ARB_ERR_CAP_CLR                 0x7e4
+#define  ARB_ERR_CAP_CLEAR              (1 << 0)
+#define ARB_ERR_CAP_HI_ADDR             0x7e8
+#define ARB_ERR_CAP_ADDR                0x7ec
+#define ARB_ERR_CAP_DATA                0x7f0
+#define ARB_ERR_CAP_STATUS              0x7f4
+#define  ARB_ERR_CAP_STATUS_TIMEOUT     (1 << 12)
+#define  ARB_ERR_CAP_STATUS_TEA         (1 << 11)
+#define  ARB_ERR_CAP_STATUS_BS_SHIFT    (1 << 2)
+#define  ARB_ERR_CAP_STATUS_BS_MASK     0x3c
+#define  ARB_ERR_CAP_STATUS_WRITE       (1 << 1)
+#define  ARB_ERR_CAP_STATUS_VALID       (1 << 0)
+#define ARB_ERR_CAP_MASTER              0x7f8
+
+struct brcmstb_gisb_arb_device {
+        void __iomem    *base;
+        struct mutex    lock;
+        struct list_head next;
+        u32 valid_mask;
+        const char *master_names[sizeof(u32) * BITS_PER_BYTE];
+};
+
+static LIST_HEAD(brcmstb_gisb_arb_device_list);
+
+static ssize_t gisb_arb_get_timeout(struct device *dev,
+                                    struct device_attribute *attr,
+                                    char *buf)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
+        u32 timeout;
+
+        mutex_lock(&gdev->lock);
+        timeout = ioread32(gdev->base + ARB_TIMER);
+        mutex_unlock(&gdev->lock);
+
+        return sprintf(buf, "%d", timeout);
+}
+
+static ssize_t gisb_arb_set_timeout(struct device *dev,
+                                    struct device_attribute *attr,
+                                    const char *buf, size_t count)
+{
+        struct platform_device *pdev = to_platform_device(dev);
+        struct brcmstb_gisb_arb_device *gdev = platform_get_drvdata(pdev);
+        int val, ret;
+
+        ret = kstrtoint(buf, 10, &val);
+        if (ret < 0)
+                return ret;
+
+        if (val == 0 || val >= 0xffffffff)
+                return -EINVAL;
+
+        mutex_lock(&gdev->lock);
+        iowrite32(val, gdev->base + ARB_TIMER);
+        mutex_unlock(&gdev->lock);
+
+        return count;
+}
+
+static const char *
+brcmstb_gisb_master_to_str(struct brcmstb_gisb_arb_device *gdev,
+                                                u32 masters)
+{
+        u32 mask = gdev->valid_mask & masters;
+
+        if (hweight_long(mask) != 1)
+                return NULL;
+
+        return gdev->master_names[ffs(mask) - 1];
+}
+
+static int brcmstb_gisb_arb_decode_addr(struct brcmstb_gisb_arb_device *gdev,
+                                        const char *reason)
+{
+        u32 cap_status;
+        unsigned long arb_addr;
+        u32 master;
+        const char *m_name;
+        char m_fmt[11];
+
+        cap_status = ioread32(gdev->base + ARB_ERR_CAP_STATUS);
+
+        /* Invalid captured address, bail out */
+        if (!(cap_status & ARB_ERR_CAP_STATUS_VALID))
+                return 1;
+
+        /* Read the address and master */
+        arb_addr = ioread32(gdev->base + ARB_ERR_CAP_ADDR) & 0xffffffff;
+#if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT))
+        arb_addr |= (u64)ioread32(gdev->base + ARB_ERR_CAP_HI_ADDR) << 32;
+#endif
+        master = ioread32(gdev->base + ARB_ERR_CAP_MASTER);
+
+        m_name = brcmstb_gisb_master_to_str(gdev, master);
+        if (!m_name) {
+                snprintf(m_fmt, sizeof(m_fmt), "0x%08x", master);
+                m_name = m_fmt;
+        }
+
+        pr_crit("%s: %s at 0x%lx [%c %s], core: %s\n",
+                __func__, reason, arb_addr,
+                cap_status & ARB_ERR_CAP_STATUS_WRITE ? 'W' : 'R',
+                cap_status & ARB_ERR_CAP_STATUS_TIMEOUT ? "timeout" : "",
+                m_name);
+
+        /* clear the GISB error */
+        iowrite32(ARB_ERR_CAP_CLEAR, gdev->base + ARB_ERR_CAP_CLR);
+
+        return 0;
+}
+
+static int brcmstb_bus_error_handler(unsigned long addr, unsigned int fsr,
+                                     struct pt_regs *regs)
+{
+        int ret = 0;
+        struct brcmstb_gisb_arb_device *gdev;
+
+        /* iterate over each GISB arb registered handlers */
+        list_for_each_entry(gdev, &brcmstb_gisb_arb_device_list, next)
+                ret |= brcmstb_gisb_arb_decode_addr(gdev, "bus error");
+        /*
+         * If it was an imprecise abort, then we need to correct the
+         * return address to be _after_ the instruction.
+        */
+        if (fsr & (1 << 10))
+                regs->ARM_pc += 4;
+
+        return ret;
+}
+
+void __init brcmstb_hook_fault_code(void)
+{
+        hook_fault_code(22, brcmstb_bus_error_handler, SIGBUS, 0,
+                        "imprecise external abort");
+}
+
+static irqreturn_t brcmstb_gisb_timeout_handler(int irq, void *dev_id)
+{
+        brcmstb_gisb_arb_decode_addr(dev_id, "timeout");
+
+        return IRQ_HANDLED;
+}
+
+static irqreturn_t brcmstb_gisb_tea_handler(int irq, void *dev_id)
+{
+        brcmstb_gisb_arb_decode_addr(dev_id, "target abort");
+
+        return IRQ_HANDLED;
+}
+
+static DEVICE_ATTR(gisb_arb_timeout, S_IWUSR | S_IRUGO,
+                gisb_arb_get_timeout, gisb_arb_set_timeout);
+
+static struct attribute *gisb_arb_sysfs_attrs[] = {
+        &dev_attr_gisb_arb_timeout.attr,
+        NULL,
+};
+
+static struct attribute_group gisb_arb_sysfs_attr_group = {
+        .attrs = gisb_arb_sysfs_attrs,
+};
+
+static int brcmstb_gisb_arb_probe(struct platform_device *pdev)
+{
+        struct device_node *dn = pdev->dev.of_node;
+        struct brcmstb_gisb_arb_device *gdev;
+        struct resource *r;
+        int err, timeout_irq, tea_irq;
+        unsigned int num_masters, j = 0;
+        int i, first, last;
+
+        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+        timeout_irq = platform_get_irq(pdev, 0);
+        tea_irq = platform_get_irq(pdev, 1);
+
+        gdev = devm_kzalloc(&pdev->dev, sizeof(*gdev), GFP_KERNEL);
+        if (!gdev)
+                return -ENOMEM;
+
+        mutex_init(&gdev->lock);
+        INIT_LIST_HEAD(&gdev->next);
+
+        gdev->base = devm_request_and_ioremap(&pdev->dev, r);
+        if (!gdev->base)
+                return -ENOMEM;
+
+        err = devm_request_irq(&pdev->dev, timeout_irq,
+                                brcmstb_gisb_timeout_handler, 0, pdev->name,
+                                gdev);
+        if (err < 0)
+                return err;
+
+        err = devm_request_irq(&pdev->dev, tea_irq,
+                                brcmstb_gisb_tea_handler, 0, pdev->name,
+                                gdev);
+        if (err < 0)
+                return err;
+
+        /* If we do not have a valid mask, assume all masters are enabled */
+        if (of_property_read_u32(dn, "brcm,gisb-arb-master-mask",
+                                &gdev->valid_mask))
+                gdev->valid_mask = 0xffffffff;
+
+        /* Proceed with reading the litteral names if we agree on the
+         * number of masters
+         */
+        num_masters = of_property_count_strings(dn,
+                        "brcm,gisb-arb-master-names");
+        if (hweight_long(gdev->valid_mask) == num_masters) {
+                first = ffs(gdev->valid_mask) - 1;
+                last = fls(gdev->valid_mask) - 1;
+
+                for (i = first; i < last; i++) {
+                        if (!(gdev->valid_mask & BIT(i)))
+                                continue;
+
+                        of_property_read_string_index(dn,
+                                        "brcm,gisb-arb-master-names", j,
+                                        &gdev->master_names[i]);
+                        j++;
+                }
+        }
+
+        err = sysfs_create_group(&pdev->dev.kobj, &gisb_arb_sysfs_attr_group);
+        if (err)
+                return err;
+
+        platform_set_drvdata(pdev, gdev);
+
+        list_add_tail(&gdev->next, &brcmstb_gisb_arb_device_list);
+
+        dev_info(&pdev->dev, "registered mem: %p, irqs: %d, %d\n",
+                        gdev->base, timeout_irq, tea_irq);
+
+        return 0;
+}
+
+static const struct of_device_id brcmstb_gisb_arb_of_match[] = {
+        { .compatible = "brcm,gisb-arb" },
+        { },
+};
+
+static struct platform_driver brcmstb_gisb_arb_driver = {
+        .probe  = brcmstb_gisb_arb_probe,
+        .driver = {
+                .name   = "brcm-gisb-arb",
+                .owner  = THIS_MODULE,
+                .of_match_table = brcmstb_gisb_arb_of_match,
+        },
+};
+
+static int __init brcm_gisb_driver_init(void)
+{
+        return platform_driver_register(&brcmstb_gisb_arb_driver);
+}
+
+module_init(brcm_gisb_driver_init);