Re: [PATCH v7 10/11] clk: samsung: register restart handlers for s3c2412 and s3c2443

[Mike Turquette <mturquette@linaro.org>]

Quoting Guenter Roeck (2014-08-19 17:45:37)
> From: Heiko Stübner <heiko@sntech.de>
> 
> 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>

Acked-by: Mike Turquette <mturquette@linaro.org>

> ---
> v7: Added patch to series.
> 
>  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 34af09f..2ceedaf 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 c92f853..0c3c182 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)
> -- 
> 1.9.1
> 
> --
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