MIPS: ralink: add illegal access driver

These SoCs have a special irq that fires upon an illegal memmory access.

Signed-off-by: John Crispin <blogic@openwrt.org>
Patchwork: http://patchwork.linux-mips.org/patch/8003/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

2 files changed, 89 insertions, 0 deletions

diff --git a/arch/mips/ralink/Makefile b/arch/mips/ralink/Makefile
index 2c09c8aa0ae2..833fa677e6b8 100644
--- a/arch/mips/ralink/Makefile
+++ b/arch/mips/ralink/Makefile
@@ -10,6 +10,8 @@ obj-y := prom.o of.o reset.o clk.o irq.o timer.o
 
 obj-$(CONFIG_CLKEVT_RT3352) += cevt-rt3352.o
 
+obj-$(CONFIG_RALINK_ILL_ACC) += ill_acc.o
+
 obj-$(CONFIG_SOC_RT288X) += rt288x.o
 obj-$(CONFIG_SOC_RT305X) += rt305x.o
 obj-$(CONFIG_SOC_RT3883) += rt3883.o
diff --git a/arch/mips/ralink/ill_acc.c b/arch/mips/ralink/ill_acc.c
new file mode 100644
index 000000000000..e20b02e3ae28
--- /dev/null
+++ b/arch/mips/ralink/ill_acc.c
@@ -0,0 +1,87 @@
+/*
+ * 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.
+ *
+ * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+ */
+
+#include <linux/interrupt.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+
+#include <asm/mach-ralink/ralink_regs.h>
+
+#define REG_ILL_ACC_ADDR        0x10
+#define REG_ILL_ACC_TYPE        0x14
+
+#define ILL_INT_STATUS          BIT(31)
+#define ILL_ACC_WRITE           BIT(30)
+#define ILL_ACC_LEN_M           0xff
+#define ILL_ACC_OFF_M           0xf
+#define ILL_ACC_OFF_S           16
+#define ILL_ACC_ID_M            0x7
+#define ILL_ACC_ID_S            8
+
+#define DRV_NAME                "ill_acc"
+
+static const char * const ill_acc_ids[] = {
+        "cpu", "dma", "ppe", "pdma rx", "pdma tx", "pci/e", "wmac", "usb",
+};
+
+static irqreturn_t ill_acc_irq_handler(int irq, void *_priv)
+{
+        struct device *dev = (struct device *) _priv;
+        u32 addr = rt_memc_r32(REG_ILL_ACC_ADDR);
+        u32 type = rt_memc_r32(REG_ILL_ACC_TYPE);
+
+        dev_err(dev, "illegal %s access from %s - addr:0x%08x offset:%d len:%d\n",
+                (type & ILL_ACC_WRITE) ? ("write") : ("read"),
+                ill_acc_ids[(type >> ILL_ACC_ID_S) & ILL_ACC_ID_M],
+                addr, (type >> ILL_ACC_OFF_S) & ILL_ACC_OFF_M,
+                type & ILL_ACC_LEN_M);
+
+        rt_memc_w32(REG_ILL_ACC_TYPE, REG_ILL_ACC_TYPE);
+
+        return IRQ_HANDLED;
+}
+
+static int __init ill_acc_of_setup(void)
+{
+        struct platform_device *pdev;
+        struct device_node *np;
+        int irq;
+
+        /* somehow this driver breaks on RT5350 */
+        if (of_machine_is_compatible("ralink,rt5350-soc"))
+                return -EINVAL;
+
+        np = of_find_compatible_node(NULL, NULL, "ralink,rt3050-memc");
+        if (!np)
+                return -EINVAL;
+
+        pdev = of_find_device_by_node(np);
+        if (!pdev) {
+                pr_err("%s: failed to lookup pdev\n", np->name);
+                return -EINVAL;
+        }
+
+        irq = irq_of_parse_and_map(np, 0);
+        if (!irq) {
+                dev_err(&pdev->dev, "failed to get irq\n");
+                return -EINVAL;
+        }
+
+        if (request_irq(irq, ill_acc_irq_handler, 0, "ill_acc", &pdev->dev)) {
+                dev_err(&pdev->dev, "failed to request irq\n");
+                return -EINVAL;
+        }
+
+        rt_memc_w32(ILL_INT_STATUS, REG_ILL_ACC_TYPE);
+
+        dev_info(&pdev->dev, "irq registered\n");
+
+        return 0;
+}
+
+arch_initcall(ill_acc_of_setup);