[U-Boot] [PATCH] mach-stm32: Fix mpu region's attribute for STM32H7

[Vikas MANOCHA]

Hi Patrice,

Cheers,
Vikas

> -----Original Message-----
> From: Patrice CHOTARD
> Sent: Tuesday, November 14, 2017 12:41 AM
> To: Vikas MANOCHA <vikas.manocha at st.com>; u-boot at lists.denx.de; albert.u.boot at aribaud.net; sjg at chromium.org
> Cc: Patrick DELAUNAY <patrick.delaunay at st.com>; Christophe KERELLO <christophe.kerello at st.com>
> Subject: Re: [PATCH] mach-stm32: Fix mpu region's attribute for STM32H7
> 
> Hi Vikas
> 
> On 11/14/2017 03:16 AM, Vikas MANOCHA wrote:
> > Hi Patrice,
> >
> >> -----Original Message-----
> >> From: Patrice CHOTARD
> >> Sent: Monday, November 13, 2017 8:26 AM
> >> To: u-boot at lists.denx.de; albert.u.boot at aribaud.net;
> >> sjg at chromium.org; Vikas MANOCHA <vikas.manocha at st.com>
> >> Cc: Patrice CHOTARD <patrice.chotard at st.com>; Patrick DELAUNAY
> >> <patrick.delaunay at st.com>; Christophe KERELLO
> >> <christophe.kerello at st.com>
> >> Subject: [PATCH] mach-stm32: Fix mpu region's attribute for STM32H7
> >>
> >> From: Patrice Chotard <patrice.chotard at st.com>
> >>
> >> The SDRAM region was setup with the wrong attributes.
> >> It must be set to :
> >>    _ XN_EN (Execution of an instruction fetched from this region permitted)
> >>    _ O_I_WB_RD_WR_ALLOC (Outer and inner write-back, write and read
> >> allocate)
> >>
> >
> > H7 mpu configuration seems same as F7, can we have one config for F7 & H7.
> 
> Between F7 and H7, there is one difference regarding the F7's region 3 which is not needed on H7 because FMC/QSPI registers are
> located inside H7's region 2.

Yes, that’s correct. Any way we can handle it at one place.
In any case, for easy maintenance let's keep the same configuration/code for two with this above exception.

> 
> Just one question about F7's region 1, why is it only 512MB and not 1GB long, to include ITCM and DTCM area ? (see Embedded SRAM
> chapter of
> RM0385 Reference manual)

because 512MB (0x2000_0000) is size of armv7m code area.

Cheers,
Vikas

> 
> Nevertheless, i just notice that for H7, i can remove region 1 which overlaps region 0 with exactly the same attribute.
> 
> Thanks
> 
> >
> >> This fixes hard fault when trying to load and execute kernel linux in this area.
> >>
> >> Signed-off-by: Patrice Chotard <patrice.chotard at st.com>
> >
> > In any case,
> > Reviewed-by: Vikas Manocha <vikas.manocha at st.com>
> >
> > Cheers,
> > Vikas
> >
> >> ---
> >>   arch/arm/mach-stm32/stm32h7/soc.c | 9 ++++++---
> >>   1 file changed, 6 insertions(+), 3 deletions(-)
> >>
> >> diff --git a/arch/arm/mach-stm32/stm32h7/soc.c
> >> b/arch/arm/mach-stm32/stm32h7/soc.c
> >> index 692dbcc..e0d3f11 100644
> >> --- a/arch/arm/mach-stm32/stm32h7/soc.c
> >> +++ b/arch/arm/mach-stm32/stm32h7/soc.c
> >> @@ -30,9 +30,12 @@ int arch_cpu_init(void)
> >>   		{ 0x00000000, REGION_0, XN_DIS, PRIV_RW_USR_RW,
> >>   		O_I_WB_RD_WR_ALLOC, REGION_4GB },
> >>
> >> -		/* Code area, executable & strongly ordered */
> >> -		{ 0xD0000000, REGION_1, XN_EN, PRIV_RW_USR_RW,
> >> -		STRONG_ORDER, REGION_8MB },
> >> +		/*
> >> +		 * Code area, executable, Outer and inner write-back,
> >> +		 * no write allocate
> >> +		 */
> >> +		{ 0xD0000000, REGION_1, XN_DIS, PRIV_RW_USR_RW,
> >> +		O_I_WB_RD_WR_ALLOC, REGION_32MB },
> >>
> >>   		/* Device area in all H7 : Not executable */
> >>   		{ 0x40000000, REGION_2, XN_EN, PRIV_RW_USR_RW,
> >> --
> >> 1.9.1
> >