From: Fabio Estevam <festevam@xxxxxxxxx>
Sent: Thursday 2nd May 2019 13:30
> Since commit 1e434b703248 ("ARM: imx: update the cpu power up timing
> setting on i.mx6sx") some characters loss is noticed on i.MX6ULL UART
> as reported by Christoph Niedermaier.
>
> The intention of such commit was to increase the SW2ISO field for i.MX6SX
> only, but since cpuidle-imx6sx is also used on i.MX6UL/i.MX6ULL this caused
> unintended side effects on other SoCs.
>
> Fix this problem by keeping the original SW2ISO value for i.MX6UL/i.MX6ULL
> and only increase SW2ISO in the i.MX6SX case.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 1e434b703248 ("ARM: imx: update the cpu power up timing setting on
> i.mx6sx")
> Reported-by: Christoph Niedermaier <cniedermaier@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Fabio Estevam <festevam@xxxxxxxxx>
> ---
> arch/arm/mach-imx/cpuidle-imx6sx.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-imx/cpuidle-imx6sx.c b/arch/arm/mach-imx/cpuidle-imx6sx.c
> index fd0053e47a15..57cb9c763222 100644
> --- a/arch/arm/mach-imx/cpuidle-imx6sx.c
> +++ b/arch/arm/mach-imx/cpuidle-imx6sx.c
> @@ -15,6 +15,7 @@
>
> #include "common.h"
> #include "cpuidle.h"
> +#include "hardware.h"
>
> static int imx6sx_idle_finish(unsigned long val)
> {
> @@ -99,8 +100,12 @@ static struct cpuidle_driver imx6sx_cpuidle_driver = {
> .safe_state_index = 0,
> };
>
> +#define SW2ISO_ORIGINAL 0x2
> +#define SW2ISO_IMX6SX 0xf
> int __init imx6sx_cpuidle_init(void)
> {
> + u32 sw2iso = SW2ISO_ORIGINAL;
> +
> imx6_set_int_mem_clk_lpm(true);
> imx6_enable_rbc(false);
> imx_gpc_set_l2_mem_power_in_lpm(false);
> @@ -110,7 +115,9 @@ int __init imx6sx_cpuidle_init(void)
> * except for power up sw2iso which need to be
> * larger than LDO ramp up time.
> */
> - imx_gpc_set_arm_power_up_timing(0xf, 1);
> + if (cpu_is_imx6sx())
> + sw2iso = SW2ISO_IMX6SX;
> + imx_gpc_set_arm_power_up_timing(sw2iso, 1);
> imx_gpc_set_arm_power_down_timing(1, 1);
>
> return cpuidle_register(&imx6sx_cpuidle_driver, NULL);
>
Tested-by: Christoph Niedermaier <cniedermaier@xxxxxxxxxxxxxxxxxx>
Best regards,
