Re: [PATCH master] ARM: i.MX8M: romapi: reserve scratch space

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

On 05.09.23 16:26, Ahmad Fatoum wrote:
> We have 32K of RAM at the end of the initial memory, where a
> prebootloader can place data for future use. i.MX8M is currently the
> only user and currently uses it to save the ROM API log, which is
> located in SRAM and is inaccessible by the time barebox proper runs
> in EL2. This area was so far not reserved, which can lead to clobbering
> it when chainloading barebox. Avoid this by requesting the region.

Please only apply after <20230905093210.2067770-1-m.felsch@pengutronix.de>,
otherwise a chainloaded barebox on systems with >6G would end up completely
in >4G space, which triggers a bug that will be fixed separately (but is
worked around by Marco's patch above).

> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  arch/arm/mach-imx/romapi.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/arm/mach-imx/romapi.c b/arch/arm/mach-imx/romapi.c
> index 2fd803b0d998..aef0ff0534c9 100644
> --- a/arch/arm/mach-imx/romapi.c
> +++ b/arch/arm/mach-imx/romapi.c
> @@ -10,6 +10,8 @@
>  #include <mach/imx/xload.h>
>  #include <asm/barebox-arm.h>
>  #include <zero_page.h>
> +#include <memory.h>
> +#include <init.h>
>  #include <pbl.h>
>  
>  static int imx8m_bootrom_load(struct rom_api *rom_api, void *adr, size_t size)
> @@ -84,6 +86,14 @@ const u32 *imx8m_get_bootrom_log(void)
>  	return NULL;
>  }
>  
> +static int imx8m_reserve_scratch_area(void)
> +{
> +	return PTR_ERR_OR_ZERO(request_sdram_region("scratch area",
> +				    (ulong)arm_mem_scratch_get(),
> +				    sizeof(struct imx_scratch_space)));
> +}
> +device_initcall(imx8m_reserve_scratch_area);
> +
>  void imx8m_save_bootrom_log(void *dest)
>  {
>  	const u32 *rom_log;

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