[PATCH 3/6] ARM: imx: Add weak default reset_cpu()

[Marek Vasut]

On 8/8/23 21:17, Fabio Estevam wrote:
> Hi Marek,
> 
> On Mon, Jun 26, 2023 at 5:53 AM Marek Vasut <marex at denx.de> wrote:
>>
>> Add weak default reset_cpu() implementation needed by e.g. panic().
>>
>> Signed-off-by: Marek Vasut <marex at denx.de>
>> ---
>> Cc: "NXP i.MX U-Boot Team" <uboot-imx at nxp.com>
>> Cc: Fabio Estevam <festevam at gmail.com>
>> Cc: Stefano Babic <sbabic at denx.de>
>> ---
>>   arch/arm/mach-imx/cpu.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/arch/arm/mach-imx/cpu.c b/arch/arm/mach-imx/cpu.c
>> index 702cfc33275..488638c9058 100644
>> --- a/arch/arm/mach-imx/cpu.c
>> +++ b/arch/arm/mach-imx/cpu.c
>> @@ -510,3 +510,7 @@ char nxp_board_rev_string(void)
>>          return (*rev + nxp_board_rev() - 1);
>>   }
>>   #endif
>> +
>> +__weak void reset_cpu(void)
>> +{
>> +}
> 
> This patch causes the 'reset' command to not reset the imx7d-sdb and
> smegw01 boards anymore.
> 
> If I do the change below, the board resets again:
> 
> diff --git a/drivers/watchdog/imx_watchdog.c b/drivers/watchdog/imx_watchdog.c
> index 894158b304a7..709e437c8bd0 100644
> --- a/drivers/watchdog/imx_watchdog.c
> +++ b/drivers/watchdog/imx_watchdog.c
> @@ -44,7 +44,7 @@ static void imx_watchdog_expire_now(struct
> watchdog_regs *wdog, bool ext_reset)
> 
>   #if !defined(CONFIG_IMX_WATCHDOG) || \
>       (defined(CONFIG_IMX_WATCHDOG) && !CONFIG_IS_ENABLED(WDT))
> -void __attribute__((weak)) reset_cpu(void)
> +void reset_cpu(void)
>   {
>    struct watchdog_regs *wdog = (struct watchdog_regs *)WDOG1_BASE_ADDR;
> 
> Is this a correct fix?

No, this will likely fail on other machines which will now define two 
"strong" reset_cpu() functions. Drivers should really not provide any 
reset_cpu() implementation at all (except maybe for sysreset drivers), 
all that reset_cpu() should be in arch/ .

I think the proper fix is to use drivers/sysreset/sysreset_watchdog.c to 
expire that imx watchdog and cause a reset.