Re: [PATCH 2/2] ARM: i.MX: riotboard: rewrite lowlevel.c

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

Hi,

On 5/8/26 4:43 PM, Fabian Pflug wrote:
> Make use of the imx6q_barebox_entry instead of calling
> barebox_arm_entry directly, which allows us to profit from optional
> OP-TEE loading in this function.

maybe change commit message title to

ARM: i.MX: riotboard: switch to imx6q_barebox_entry

?

> Always setup UART, in case OP-TEE gets integrated, which will crash if
> the UART is not configured correctly and debug is enabled.
> Since now a bit more functions are called, we use
> relocate_to_current_adr instead of get_runtime_offset.
> 
> This should not change behaviour of current implementations, but makes
> way for OP-TEE implementations.
> 
> Signed-off-by: Fabian Pflug <f.pflug@pengutronix.de>
> ---
>  arch/arm/boards/embest-riotboard/lowlevel.c | 37 ++++++++++++++++++-----------
>  1 file changed, 23 insertions(+), 14 deletions(-)
> 
> diff --git a/arch/arm/boards/embest-riotboard/lowlevel.c b/arch/arm/boards/embest-riotboard/lowlevel.c
> index f1b37c2aa0..e44fb3582e 100644
> --- a/arch/arm/boards/embest-riotboard/lowlevel.c
> +++ b/arch/arm/boards/embest-riotboard/lowlevel.c
> @@ -11,26 +11,35 @@
>  #include <asm/cache.h>
>  #include <asm/mmu.h>
>  #include <mach/imx/imx6.h>
> +#include <mach/imx/iomux-mx6.h>
> +#include <mach/imx/esdctl.h>
>  
>  extern char __dtb_imx6s_riotboard_start[];
>  
> -ENTRY_FUNCTION(start_imx6s_riotboard, r0, r1, r2)
> +static noinline void setup_riotboard_uart(void)
>  {
> -	void *fdt;
> +	void __iomem *iomuxbase = IOMEM(MX6_IOMUXC_BASE_ADDR);
>  
> -	imx6_cpu_lowlevel_init();
> +	writel(0x4, iomuxbase + 0x016c);
> +
> +	imx6_ungate_all_peripherals();
> +	// if uart ist not set-up, then OP-TEE will fail if debugging is enabled.
> +	imx6_uart_setup(IOMEM(MX6_UART2_BASE_ADDR));
>  
>  	if (IS_ENABLED(CONFIG_DEBUG_LL)) {
> -		/*
> -		 * CONFIG_DEBUG_IMX6Q_UART=y
> -		 * CONFIG_DEBUG_IMX_UART_PORT=2
> -		 */
> -		writel(0x4, 0x020e016c);
> -		imx6_ungate_all_peripherals();
> -		imx6_uart_setup_ll();
> -		putc_ll('a');
> +		pbl_set_putc(imx_uart_putc, IOMEM(MX6_UART2_BASE_ADDR));
> +		putc_ll('>');
>  	}
> -
> -	fdt = __dtb_imx6s_riotboard_start + get_runtime_offset();
> -	barebox_arm_entry(0x10000000, SZ_1G, fdt);

Move

  imx6q_barebox_entry(__dtb_imx6s_riotboard_start);

here.

> +}
> +
> +ENTRY_FUNCTION(start_imx6s_riotboard, r0, r1, r2)
> +{
> +	imx6_cpu_lowlevel_init();
> +
> +	relocate_to_current_adr();
> +	setup_c();
> +
> +	setup_riotboard_uart();

Rename to continue_imx6s_riotboard() or similar.

> +
> +	imx6q_barebox_entry(__dtb_imx6s_riotboard_start);

Illegal reference to global variable in function that does relocation,
move it into the noinline function above.

Cheers,
Ahmad

>  }
> 

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