clk: samsung: register restart handlers for s3c2412 and s3c2443

S3C2412, S3C2443 and their derivatives contain a special software-reset
register in their system-controller.

Therefore register a restart handler for those.

Tested on a s3c2416-based board, s3c2412 compile-tested.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

2 files changed, 48 insertions, 0 deletions

diff --git a/drivers/clk/samsung/clk-s3c2412.c b/drivers/clk/samsung/clk-s3c2412.c
index 34af09f6a155..2ceedaf8ce18 100644
--- a/drivers/clk/samsung/clk-s3c2412.c
+++ b/drivers/clk/samsung/clk-s3c2412.c
@@ -14,6 +14,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/syscore_ops.h>
+#include <linux/reboot.h>
 
 #include <dt-bindings/clock/s3c2412.h>
 
@@ -26,6 +27,7 @@
 #define CLKCON          0x0c
 #define CLKDIVN         0x14
 #define CLKSRC          0x1c
+#define SWRST           0x30
 
 /* list of PLLs to be registered */
 enum s3c2412_plls {
@@ -204,6 +206,28 @@ struct samsung_clock_alias s3c2412_aliases[] __initdata = {
         ALIAS(MSYSCLK, NULL, "fclk"),
 };
 
+static int s3c2412_restart(struct notifier_block *this,
+                           unsigned long mode, void *cmd)
+{
+        /* errata "Watch-dog/Software Reset Problem" specifies that
+         * this reset must be done with the SYSCLK sourced from
+         * EXTCLK instead of FOUT to avoid a glitch in the reset
+         * mechanism.
+         *
+         * See the watchdog section of the S3C2412 manual for more
+         * information on this fix.
+         */
+
+        __raw_writel(0x00, reg_base + CLKSRC);
+        __raw_writel(0x533C2412, reg_base + SWRST);
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block s3c2412_restart_handler = {
+        .notifier_call = s3c2412_restart,
+        .priority = 129,
+};
+
 /*
  * fixed rate clocks generated outside the soc
  * Only necessary until the devicetree-move is complete
@@ -233,6 +257,7 @@ void __init s3c2412_common_clk_init(struct device_node *np, unsigned long xti_f,
                                     unsigned long ext_f, void __iomem *base)
 {
         struct samsung_clk_provider *ctx;
+        int ret;
         reg_base = base;
 
         if (np) {
@@ -267,6 +292,10 @@ void __init s3c2412_common_clk_init(struct device_node *np, unsigned long xti_f,
         s3c2412_clk_sleep_init();
 
         samsung_clk_of_add_provider(np, ctx);
+
+        ret = register_restart_handler(&s3c2412_restart_handler);
+        if (ret)
+                pr_warn("cannot register restart handler, %d\n", ret);
 }
 
 static void __init s3c2412_clk_init(struct device_node *np)
diff --git a/drivers/clk/samsung/clk-s3c2443.c b/drivers/clk/samsung/clk-s3c2443.c
index c92f853fca9f..0c3c182b902a 100644
--- a/drivers/clk/samsung/clk-s3c2443.c
+++ b/drivers/clk/samsung/clk-s3c2443.c
@@ -14,6 +14,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/syscore_ops.h>
+#include <linux/reboot.h>
 
 #include <dt-bindings/clock/s3c2443.h>
 
@@ -33,6 +34,7 @@
 #define HCLKCON         0x30
 #define PCLKCON         0x34
 #define SCLKCON         0x38
+#define SWRST           0x44
 
 /* the soc types */
 enum supported_socs {
@@ -354,6 +356,18 @@ struct samsung_clock_alias s3c2450_aliases[] __initdata = {
         ALIAS(PCLK_I2C1, "s3c2410-i2c.1", "i2c"),
 };
 
+static int s3c2443_restart(struct notifier_block *this,
+                           unsigned long mode, void *cmd)
+{
+        __raw_writel(0x533c2443, reg_base + SWRST);
+        return NOTIFY_DONE;
+}
+
+static struct notifier_block s3c2443_restart_handler = {
+        .notifier_call = s3c2443_restart,
+        .priority = 129,
+};
+
 /*
  * fixed rate clocks generated outside the soc
  * Only necessary until the devicetree-move is complete
@@ -378,6 +392,7 @@ void __init s3c2443_common_clk_init(struct device_node *np, unsigned long xti_f,
                                     void __iomem *base)
 {
         struct samsung_clk_provider *ctx;
+        int ret;
         reg_base = base;
 
         if (np) {
@@ -447,6 +462,10 @@ void __init s3c2443_common_clk_init(struct device_node *np, unsigned long xti_f,
         s3c2443_clk_sleep_init();
 
         samsung_clk_of_add_provider(np, ctx);
+
+        ret = register_restart_handler(&s3c2443_restart_handler);
+        if (ret)
+                pr_warn("cannot register restart handler, %d\n", ret);
 }
 
 static void __init s3c2416_clk_init(struct device_node *np)