Re: [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 <ma...@denx.de> wrote:

Add weak default reset_cpu() implementation needed by e.g. panic().

Signed-off-by: Marek Vasut <ma...@denx.de>
---
Cc: "NXP i.MX U-Boot Team" <uboot-...@nxp.com>
Cc: Fabio Estevam <feste...@gmail.com>
Cc: Stefano Babic <sba...@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.