[PATCH] ARM: tegra: Support reboot modes

[Alexandre Courbot]

On Wed, May 7, 2014 at 12:04 AM, Thierry Reding
<thierry.reding at gmail.com> wrote:
> From: Thierry Reding <treding at nvidia.com>
>
> The boot ROM on Tegra SoCs supports booting into forced recovery mode
> (RCM) by setting a bit in the PMC scratch register 0. Similarily, the
> Android bootloader examines some of the bits in this register to disable
> autoboot or enter recovery mode.
>
> Support these modes by setting the corresponding bits depending on the
> specified reboot command (forced-recovery, bootloader, recovery). Recent
> systemd-based distributions allow this to be specified using an optional
> argument to the reboot command.

Tested-by: Alexandre Courbot <acourbot at nvidia.com>

Thanks, that's quite helpful, especially with Jetson TK1!

>
> Signed-off-by: Thierry Reding <treding at nvidia.com>
> ---
>  arch/arm/mach-tegra/pmc.c | 24 ++++++++++++++++++++++++
>  1 file changed, 24 insertions(+)
>
> diff --git a/arch/arm/mach-tegra/pmc.c b/arch/arm/mach-tegra/pmc.c
> index fb7920201ab4..7c7123e7557b 100644
> --- a/arch/arm/mach-tegra/pmc.c
> +++ b/arch/arm/mach-tegra/pmc.c
> @@ -41,6 +41,14 @@
>  #define PMC_REMOVE_CLAMPING            0x34
>  #define PMC_PWRGATE_STATUS             0x38
>
> +#define PMC_SCRATCH0                   0x50
> +#define PMC_SCRATCH0_MODE_RECOVERY     (1 << 31)
> +#define PMC_SCRATCH0_MODE_BOOTLOADER   (1 << 30)
> +#define PMC_SCRATCH0_MODE_RCM          (1 << 1)
> +#define PMC_SCRATCH0_MODE_MASK         (PMC_SCRATCH0_MODE_RECOVERY | \
> +                                        PMC_SCRATCH0_MODE_BOOTLOADER | \
> +                                        PMC_SCRATCH0_MODE_RCM)
> +
>  #define PMC_CPUPWRGOOD_TIMER   0xc8
>  #define PMC_CPUPWROFF_TIMER    0xcc
>
> @@ -165,6 +173,22 @@ void tegra_pmc_restart(enum reboot_mode mode, const char *cmd)
>  {
>         u32 val;
>
> +       val = tegra_pmc_readl(PMC_SCRATCH0);
> +       val &= ~PMC_SCRATCH0_MODE_MASK;
> +
> +       if (cmd) {
> +               if (strcmp(cmd, "recovery") == 0)
> +                       val |= PMC_SCRATCH0_MODE_RECOVERY;
> +
> +               if (strcmp(cmd, "bootloader") == 0)
> +                       val |= PMC_SCRATCH0_MODE_BOOTLOADER;
> +
> +               if (strcmp(cmd, "forced-recovery") == 0)
> +                       val |= PMC_SCRATCH0_MODE_RCM;
> +       }
> +
> +       tegra_pmc_writel(val, PMC_SCRATCH0);
> +
>         val = tegra_pmc_readl(0);
>         val |= 0x10;
>         tegra_pmc_writel(val, 0);
> --
> 1.9.2
>