[PATCH v2 1/3] imx8mp-evk: Add support for booting via USB

[Ahmad Fatoum]

On 13.08.21 17:22, Uwe Kleine-König wrote:

S-o-b missing.

> ---
>  arch/arm/boards/nxp-imx8mp-evk/lowlevel.c | 27 +++++++++++++++++++++++
>  arch/arm/mach-imx/boot.c                  |  4 +++-
>  include/asm-generic/sections.h            |  1 +
>  3 files changed, 31 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c b/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c
> index 3298ded5866d..1fb7899198d6 100644
> --- a/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c
> +++ b/arch/arm/boards/nxp-imx8mp-evk/lowlevel.c
> @@ -99,6 +99,30 @@ static int power_init_board(void)
>  	return 0;
>  }
>  
> +/* read piggydata via a bootrom callback and place it behind our copy in SDRAM */
> +static int imx8m_bootrom_load_image(void)
> +{
> +	int (*download_image)(u8 *dest, u32 offset, u32 size, u32 xor) = *(void **)0x988;

Would be nice to have this in a header, e.g.

extern struct imx8mp_bootrom_ops {
	/* ... */
	int (*download_image)(u8 *dest, u32 offset, u32 size, u32 xor);
} *imx8mp_bootrom_ops = (void *)0x988;

> +	size_t count = __piggydata_end - __piggydata_start;
> +	char *p = (char *)MX8M_ATF_BL33_BASE_ADDR + (__piggydata_start - __image_start);
> +
> +	while (count) {
> +		size_t chunksize = min(count, (size_t)1024);
> +		int ret;
> +
> +		ret = download_image(p, 0, chunksize, (uintptr_t)p ^ chunksize);
> +		if (ret != 0xf0) {
> +			pr_err("Failed to load piggy data (ret = %x)\n", ret);
> +			return -EIO;
> +		}
> +
> +		p += chunksize;
> +		count -= chunksize;
> +	}
> +
> +	return 0;
> +}
> +
>  extern struct dram_timing_info imx8mp_evk_dram_timing;
>  
>  static void start_atf(void)
> @@ -125,6 +149,9 @@ static void start_atf(void)
>  	case BOOTSOURCE_MMC:
>  		imx8mp_esdhc_load_image(instance, false);
>  		break;
> +	case BOOTSOURCE_SERIAL:
> +		imx8m_bootrom_load_image();
> +		break;
>  	default:
>  		printf("Unhandled bootsource BOOTSOURCE_%d\n", src);
>  		hang();
> diff --git a/arch/arm/mach-imx/boot.c b/arch/arm/mach-imx/boot.c
> index 2b66bbf71eb1..7c1d49291045 100644
> --- a/arch/arm/mach-imx/boot.c
> +++ b/arch/arm/mach-imx/boot.c
> @@ -495,10 +495,12 @@ static void __imx7_get_boot_source(enum bootsource *src, int *instance,
>  	case 5:
>  		*src = BOOTSOURCE_NOR;
>  		break;
> -	case 15:
> +	case 14: /* observed on i.MX8MP for USB "serial" booting */
> +	case 15: /* observed on i.MX8MM for USB "serial" booting */
>  		*src = BOOTSOURCE_SERIAL;
>  		break;
>  	default:
> +		*src = BOOTSOURCE_UNKNOWN;
>  		break;
>  	}
>  }
> diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
> index 870bff21f668..597c4951ea5e 100644
> --- a/include/asm-generic/sections.h
> +++ b/include/asm-generic/sections.h
> @@ -9,6 +9,7 @@ extern char _end[];
>  extern char __image_start[];
>  extern char __image_end[];
>  extern char __piggydata_start[];
> +extern char __piggydata_end[];

Other code normally uses __image_end, but it seems __piggydata_end should be
equal to it. I'd prefer __image_end, because conceptually, you want to copy
off the rest of the image (which happens to be just the piggy data)

@Rouven, The sha sum is at the end of the image, right?
Would this be included this way?

>  extern void *_barebox_image_size;
>  extern void *_barebox_bare_init_size;
>  extern void *_barebox_pbl_size;
> 


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