[PATCH linux dev-4.10] ARM: aspeed: Release UART1 from reset for all platforms

[Xo Wang]

On Mon, Jul 3, 2017 at 6:10 PM, Joel Stanley <joel at jms.id.au> wrote:
> This workaround was in place for Zaius. Make it common to all
> platforms as the held-in-reset behaviour breaks the Linux tty layer
> where users expect the existence of a device to mean it is usable.
>
> Signed-off-by: Joel Stanley <joel at jms.id.au>
> ---
>  arch/arm/mach-aspeed/aspeed.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/arch/arm/mach-aspeed/aspeed.c b/arch/arm/mach-aspeed/aspeed.c
> index 420a8d0344da..d3eb9e7c2d8b 100644
> --- a/arch/arm/mach-aspeed/aspeed.c
> +++ b/arch/arm/mach-aspeed/aspeed.c
> @@ -173,14 +173,6 @@ static void __init do_zaius_setup(void)
>         /* Set pin high */
>         reg = readl(AST_IO(AST_BASE_GPIO | 0x00));
>         writel(reg | phy_reset_mask, AST_IO(AST_BASE_GPIO | 0x00));
> -
> -       /* Disable default behavior of UART1 being held in reset by LPCRST#.
> -        * By releasing UART1 from being controlled by LPC reset, it becomes
> -        * immediately available regardless of the host being up.
> -        */
> -       reg = readl(AST_IO(AST_BASE_LPC | 0x98));
> -       /* Clear "Enable UART1 reset source from LPC" */
> -       writel(reg & ~BIT(4), AST_IO(AST_BASE_LPC | 0x98));
>  }
>
>  static void __init do_witherspoon_setup(void)
> @@ -254,6 +246,14 @@ static void __init aspeed_init_early(void)
>          */
>         writel(0x001fdff3, AST_IO(AST_BASE_SCU | 0x9c));
>
> +       /* Disable default behavior of UART1 being held in reset by LPCRST#.
> +        * By releasing UART1 from being controlled by LPC reset, it becomes
> +        * immediately available regardless of the host being up.
> +        */
> +       reg = readl(AST_IO(AST_BASE_LPC | 0x98));
> +       /* Clear "Enable UART1 reset source from LPC" */
> +       writel(reg & ~BIT(4), AST_IO(AST_BASE_LPC | 0x98));
> +
>         /*
>          * Temporary setup of AST registers until pinmux driver is complete
>          */
> --
> 2.13.2
>

Reviewed-by: Xo Wang <xow at google.com>