Re: [PATCH 2/2] arch: arm: imx: detect secondary boot

["Sascha Hauer" <s.hauer@pengutronix.de>]

On 2026-05-20 10:33, Fabian Pfitzner wrote:
> Integrate support to detect secondary boot on imx machines.
> Copy the logic for detection from the uboot-imx project[1].
> 
> The information will be stored in the `bootsource_instance_index`
> variable.
> 
> [1] https://github.com/nxp-imx/uboot-imx/blob/99518e6b6f20cb6a2bf19115e355db9f58100af8/arch/arm/mach-imx/imx8m/soc.c#L792
> 
> Signed-off-by: Fabian Pfitzner <f.pfitzner@pengutronix.de>
> ---
>  arch/arm/mach-imx/boot.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 52 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/boot.c b/arch/arm/mach-imx/boot.c
> index 3fea22d05f3bfdf2fe9caa6767e1c7c5ea3ced00..a35a1acc2e71231236d3dd5008523f6c66912000 100644
> --- a/arch/arm/mach-imx/boot.c
> +++ b/arch/arm/mach-imx/boot.c
> @@ -26,6 +26,8 @@
>  
>  #include <soc/fsl/fsl_udc.h>
>  
> +int imx8m_detect_secondary_image_boot(void);

It should be either static without forward declaration or exported with
the declaration in a header file.

> +
>  static void
>  imx_boot_save_loc(void (*get_boot_source)(enum bootsource *, int *))
>  {
> @@ -35,6 +37,10 @@ imx_boot_save_loc(void (*get_boot_source)(enum bootsource *, int *))
>  	get_boot_source(&src, &instance);
>  
>  	bootsource_set(src, instance);
> +
> +	int index = imx8m_detect_secondary_image_boot();

You assume you are running on i.MX8M here which is not necessarily the
case.

> +
> +	bootsource_set_instance_index(index);
>  }
>  
>  
> @@ -756,3 +762,49 @@ void imx8mn_get_boot_source(enum bootsource *src, int *instance)
>  
>  void imx8mn_boot_save_loc(void)
>  	__alias(imx8mp_boot_save_loc);
> +
> +int imx8m_detect_secondary_image_boot(void)
> +{
> +	u32 *rom_log_addr = (u32 *)0x9e0;
> +	u32 *rom_log;
> +	u8 event_id;
> +	int i, boot_secondary = 0;
> +
> +	/* If the ROM event log pointer is not valid. */
> +	if (*rom_log_addr < 0x900000 || *rom_log_addr >= 0xb00000 ||
> +	    *rom_log_addr & 0x3)
> +		return -EINVAL;

We have imx8m_get_bootrom_log() which handles different cases like we
are in PBL/EL3 or in barebox proper. Why not use it here?

I wonder how this works at all because you are derefencing the ROM which
is inside the faulting zero page. I would assume barebox crashes here
when this is called from barebox proper.

> +
> +	/* Parse the ROM event ID version 2 log */
> +	rom_log = (u32 *)(uintptr_t)(*rom_log_addr);
> +	for (i = 0; i < 128; i++) {
> +		event_id = rom_log[i] >> 24;

We already have defines for this, see arch/arm/mach-imx/bootrom-cmd.c

Sascha

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