[PATCH v5.1 10/7] clk: samsung: register restart handlers for s3c2412 and s3c2443

Heiko Stübner
2014-08-02T20:08:27Z

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>
[ Guenter Roeck: Updated to latest API version]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
changes since v5:
- increase priority to 129, as all Samsung platforms can use the watchdog
reset, but it might be nice to use the more specialized reset method
where it is available.

drivers/clk/samsung/clk-s3c2412.c | 29 +++++++++++++++++++++++++++++
drivers/clk/samsung/clk-s3c2443.c | 19 +++++++++++++++++++
2 files changed, 48 insertions(+)

diff --git a/drivers/clk/samsung/clk-s3c2412.c b/drivers/clk/samsung/clk-s3c2412.c
index 23e4313..456439d 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) {
@@ -265,6 +290,10 @@ void __init s3c2412_common_clk_init(struct device_node *np, unsigned long xti_f,
ARRAY_SIZE(s3c2412_aliases));

s3c2412_clk_sleep_init();
+
+ 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 c4bbdab..3c35db7 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) {
@@ -445,6 +460,10 @@ void __init s3c2443_common_clk_init(struct device_node *np, unsigned long xti_f,
}

s3c2443_clk_sleep_init();
+
+ 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)
--
2.0.1