[U-Boot] [PATCH] mach-stm32: Fix MPU region size dedicated to SDRAM for STM32F4

[Patrick DELAUNAY]

Hi Patrice,

> -----Original Message-----
> From: Patrice CHOTARD <patrice.chotard at st.com>
> Sent: mardi 25 juin 2019 10:08
> To: u-boot at lists.denx.de
> Cc: Patrice CHOTARD <patrice.chotard at st.com>; Patrick DELAUNAY
> <patrick.delaunay at st.com>; U-Boot STM32 <uboot-stm32 at st-md-
> mailman.stormreply.com>; Albert Aribaud <albert.u.boot at aribaud.net>; Vikas
> MANOCHA <vikas.manocha at st.com>
> Subject: [PATCH] mach-stm32: Fix MPU region size dedicated to SDRAM for
> STM32F4
> Importance: High
> 
> The MPU region dedicated for SDRAM for STM32F4 SoCs family was set to
> 16MB, but STM32F429 Evaluation board have 32MB of SDRAM.
> 
> When kernel starts, only first 16MB of SDRAM are configured with XN (eXecute
> Never) bit disabled, whereas kernel is using 32MB.
> 
> It fixes the following user land exception on STM32F429 Evaluation board :
> 
> [    1.713002] VFS: Mounted root (ext4 filesystem) readonly on device 179:2.
> [    1.722605] devtmpfs: mounted
> [    1.733057] Freeing unused kernel memory: 72K
> [    1.737622] This architecture does not have kernel memory protection.
> [    1.744070] Run /sbin/init as init process
> [    1.906850]
> [    1.906850] Unhandled exception: IPSR = 00000004 LR = fffffffd
> [    1.914282] CPU: 0 PID: 1 Comm: init Not tainted 5.1.0-00002-gcf9ca5719954 #6
> [    1.921433] Hardware name: STM32 (Device Tree Support)
> [    1.926601] PC is at 0x1a00b64
> [    1.929642] LR is at   (null)
> [    1.932669] pc : [<01a00b64>]    lr : [<00000000>]    psr: 01000000
> [    1.938993] sp : 01a5cfb0  ip : 00000000  fp : 00000000
> [    1.944269] r10: 01a43b00  r9 : 00000000  r8 : 00000000
> [    1.949564] r7 : 00000000  r6 : 00000000  r5 : 00000000  r4 : 00000000
> [    1.956168] r3 : 00000000  r2 : 00000000  r1 : 00000000  r0 : 00000000
> [    1.962701] xPSR: 01000000
> [    1.965506] CPU: 0 PID: 1 Comm: init Not tainted 5.1.0-00002-gcf9ca5719954 #6
> [    1.972658] Hardware name: STM32 (Device Tree Support)
> [    1.978132] [<0000c009>] (unwind_backtrace) from [<0000b24f>]
> (show_stack+0xb/0xc)
> [    1.986024] [<0000b24f>] (show_stack) from [<0000b947>]
> (__invalid_entry+0x4b/0x4c)
> 
> Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
> ---
> 
>  arch/arm/mach-stm32/soc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm/mach-stm32/soc.c b/arch/arm/mach-stm32/soc.c index
> 6ae31d3a1f..77bb18638f 100644
> --- a/arch/arm/mach-stm32/soc.c
> +++ b/arch/arm/mach-stm32/soc.c
> @@ -18,7 +18,7 @@ int arch_cpu_init(void)
>  		 */
>  #if defined(CONFIG_STM32F4)
>  		{ 0x00000000, REGION_0, XN_DIS, PRIV_RW_USR_RW,
> -		O_I_WB_RD_WR_ALLOC, REGION_16MB },
> +		O_I_WB_RD_WR_ALLOC, REGION_32MB },

For these boards, SYSCFG_MEMRMP.MEM_MODE = 0x4

./arch/arm/dts/stm32429i-eval-u-boot.dtsi:41:			st,mem_remap = <4>;
./arch/arm/dts/stm32f469-disco-u-boot.dtsi:41:			st,mem_remap = <4>;

=> 100: FMC/SDRAM Bank 1 mapped at 0x0000 0000

So size when remap shoul be 512MB here to be ready with greter SDRAM size ?
And only if remap is requested ?

Else internal FLASH is used (000: Main Flash memory mapped at 0x0000 0000)
=> max Size is 2MB  ?

>  #endif
> 
>  		{ 0x90000000, REGION_1, XN_DIS, PRIV_RW_USR_RW,
> --
> 2.17.1

Regards

Patrick