ARM: imx: replace imx6q_restart() with mxc_restart()

The imx6q_restart() works fine with normal reboot but will run into
problem with emergency reboot like sysrq-b.  In that case, of_iomap()
gets called from interrupt context and hence triggers the BUG_ON in
__get_vm_area_node().

Actually, since commit c1e31d1 (ARM: imx: create
mxc_arch_reset_init_dt() for DT boot), imx6q/dl should try to use
mxc_restart() by calling mxc_arch_reset_init_dt() beforehand, where
things like of_iomap() can be done.

The patch updates mxc_restart() a little bit to get it work for imx6q/dl
and kill imx6q_restart() completely.

Reported-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
(cherry picked from commit 87a84b69824d7fd63b20f3bc98d75c0238b8e7d0)

Conflicts:

	arch/arm/mach-imx/mach-imx6q.c

Signed-off-by: Robin Gong <b38343@freescale.com>

3 files changed, 11 insertions, 56 deletions

diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h
index ac2251da4316..ccab418fa3fc 100644
--- a/arch/arm/mach-imx/common.h
+++ b/arch/arm/mach-imx/common.h
@@ -132,7 +132,11 @@ static inline void imx_scu_standby_enable(void) {}
 extern void imx6_pm_map_io(void);
 extern void imx6_suspend(void);
 extern void imx_src_init(void);
+#ifdef CONFIG_HAVE_IMX_SRC
 extern void imx_src_prepare_restart(void);
+#else
+static inline void imx_src_prepare_restart(void) {}
+#endif
 extern void imx_gpc_init(void);
 extern void imx_gpc_pre_suspend(bool arm_power_off);
 extern void imx_gpc_post_resume(void);
diff --git a/arch/arm/mach-imx/mach-imx6q.c b/arch/arm/mach-imx/mach-imx6q.c
index aac2ab57fafa..f24c231ce38a 100644
--- a/arch/arm/mach-imx/mach-imx6q.c
+++ b/arch/arm/mach-imx/mach-imx6q.c
@@ -16,7 +16,6 @@
 #include <linux/clkdev.h>
 #include <linux/clocksource.h>
 #include <linux/cpu.h>
-#include <linux/delay.h>
 #include <linux/export.h>
 #include <linux/gpio.h>
 #include <linux/init.h>
@@ -43,60 +42,6 @@
 #include "cpuidle.h"
 #include "hardware.h"
 
-static void imx6q_restart(char mode, const char *cmd)
-{
-        struct device_node *np;
-        void __iomem *wdog_base;
-        u32 wdog_source = 1; /* use WDOG1 default */
-        unsigned int value;
-
-        np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-gpc");
-        if (np)
-                of_property_read_u32(np, "fsl,wdog-reset", &wdog_source);
-        pr_info("Use WDOG%d as reset source\n", wdog_source);
-
-        np = of_find_compatible_node(NULL, NULL, "fsl,imx6q-wdt");
-        wdog_base = of_iomap(np, 0);
-        if (!wdog_base)
-                goto soft;
-
-        imx_src_prepare_restart();
-
-        if (wdog_source == 2) {
-                /*
-                 * Some boards  use WDOG2 to reset external pmic in bypass mode,
-                 * so do WDOG2 reset here. Do not set SRS,since we will
-                 * trigger external POR later. Use WDOG1 to reset in ldo-enable
-                 * mode.
-                 */
-                np = of_find_compatible_node(np, NULL, "fsl,imx6q-wdt");
-                wdog_base = of_iomap(np, 0);
-                if (!wdog_base) {
-                        pr_warn("Not found wdt2, please check your dts!\n");
-                        goto soft;
-                }
-                value = 0x14;
-        } else {
-                value = (1 << 2);
-        }
-        /* enable wdog */
-        writew_relaxed(value, wdog_base);
-        /* write twice to ensure the request will not get ignored */
-        writew_relaxed(value, wdog_base);
-
-        /* wait for reset to assert ... */
-        mdelay(500);
-
-        pr_err("Watchdog reset failed to assert reset\n");
-
-        /* delay to allow the serial port to show the message */
-        mdelay(50);
-
-soft:
-        /* we'll take a jump through zero as a poor second */
-        soft_restart(0);
-}
-
 static struct flexcan_platform_data flexcan_pdata[2];
 static int flexcan_en_gpio;
 static int flexcan_stby_gpio;
@@ -395,6 +340,7 @@ static void __init imx6q_init_machine(void)
 {
         struct device *parent;
 
+        mxc_arch_reset_init_dt();
         parent = imx_soc_device_init();
         if (parent == NULL)
                 pr_warn("failed to initialize soc device\n");
@@ -566,5 +512,5 @@ DT_MACHINE_START(IMX6Q, "Freescale i.MX6 Quad/DualLite (Device Tree)")
         .init_machine   = imx6q_init_machine,
         .init_late      = imx6q_init_late,
         .dt_compat      = imx6q_dt_compat,
-        .restart        = imx6q_restart,
+        .restart        = mxc_restart,
 MACHINE_END
diff --git a/arch/arm/mach-imx/system.c b/arch/arm/mach-imx/system.c
index 5fc35ca82dad..ab4f7fa3d4da 100644
--- a/arch/arm/mach-imx/system.c
+++ b/arch/arm/mach-imx/system.c
@@ -42,6 +42,9 @@ void mxc_restart(char mode, const char *cmd)
 {
         unsigned int wcr_enable;
 
+        if (cpu_is_imx6q() || cpu_is_imx6dl())
+                imx_src_prepare_restart();
+
         if (wdog_clk)
                 clk_enable(wdog_clk);
 
@@ -52,6 +55,8 @@ void mxc_restart(char mode, const char *cmd)
 
         /* Assert SRS signal */
         __raw_writew(wcr_enable, wdog_base);
+        /* write twice to ensure the request will not get ignored */
+        __raw_writew(wcr_enable, wdog_base);
 
         /* wait for reset to assert... */
         mdelay(500);