diff mbox

[RFC,2/3] clk: samsung: register restart notifiers for s3c2412 and s3c2443

Message ID 1436436.XH2jFxzQOf@diego (mailing list archive)
State New, archived
Headers show

Commit Message

Heiko Stuebner July 6, 2014, 6:43 p.m. UTC 
S3C2412, S3C2443 and their derivatives contain a special software-reset
register in their system-controller.

Therefore register a restart-notifier for those.

Tested on a s3c2416-based board, s3c2412 compile-tested.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
 drivers/clk/samsung/clk-s3c2412.c | 28 ++++++++++++++++++++++++++++
 drivers/clk/samsung/clk-s3c2443.c | 18 ++++++++++++++++++
 2 files changed, 46 insertions(+)

Comments

Tomasz Figa July 8, 2014, 2:24 p.m. UTC | #1 
Hi Heiko,

On 06.07.2014 20:43, Heiko Stübner wrote:
> S3C2412, S3C2443 and their derivatives contain a special software-reset
> register in their system-controller.
> 
> Therefore register a restart-notifier for those.

I wonder if we really need to differentiate between these SoCs instead
of just using the watchdog reset for all of them. If there is no reason
to prefer software reset, then some code could be removed and things
would be more unified.

Best regards,
Tomasz
Guenter Roeck July 8, 2014, 4:23 p.m. UTC | #2 
On Tue, Jul 08, 2014 at 04:24:34PM +0200, Tomasz Figa wrote:
> Hi Heiko,
> 
> On 06.07.2014 20:43, Heiko Stübner wrote:
> > S3C2412, S3C2443 and their derivatives contain a special software-reset
> > register in their system-controller.
> > 
> > Therefore register a restart-notifier for those.
> 
> I wonder if we really need to differentiate between these SoCs instead
> of just using the watchdog reset for all of them. If there is no reason
> to prefer software reset, then some code could be removed and things
> would be more unified.
> 
Depends if the other method is always available. If not, it might make sense
to register this handler with lower priority to have a fallback.

Guenter
diff mbox

Patch

diff --git a/drivers/clk/samsung/clk-s3c2412.c b/drivers/clk/samsung/clk-s3c2412.c
index 23e4313..840f9bd 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 +206,27 @@  struct samsung_clock_alias s3c2412_aliases[] __initdata = {
 	ALIAS(MSYSCLK, NULL, "fclk"),
 };
 
+static int s3c2412_restart_notify(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_notifier = {
+	.notifier_call = s3c2412_restart_notify,
+};
+
 /*
  * fixed rate clocks generated outside the soc
  * Only necessary until the devicetree-move is complete
@@ -233,6 +256,7 @@  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 +289,10 @@  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_notifier(&s3c2412_restart_notifier);
+	if (ret)
+		pr_warn("cannot register restart notifier, %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..0be33cc 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 +356,17 @@  struct samsung_clock_alias s3c2450_aliases[] __initdata = {
 	ALIAS(PCLK_I2C1, "s3c2410-i2c.1", "i2c"),
 };
 
+static int s3c2443_restart_notify(struct notifier_block *this,
+				  unsigned long mode, void *cmd)
+{
+	__raw_writel(0x533c2443, reg_base + SWRST);
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block s3c2443_restart_notifier = {
+	.notifier_call = s3c2443_restart_notify,
+};
+
 /*
  * fixed rate clocks generated outside the soc
  * Only necessary until the devicetree-move is complete
@@ -378,6 +391,7 @@  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 +459,10 @@  void __init s3c2443_common_clk_init(struct device_node *np, unsigned long xti_f,
 	}
 
 	s3c2443_clk_sleep_init();
+
+	ret = register_restart_notifier(&s3c2443_restart_notifier);
+	if (ret)
+		pr_warn("cannot register restart notifier, %d\n", ret);
 }
 
 static void __init s3c2416_clk_init(struct device_node *np)