[RFC PATCH 06/10] FWU: STM32MP1: Add support to read boot index from backup register

[Sughosh Ganu]

hi Patrick,

On Tue, 7 Dec 2021 at 19:57, Patrick DELAUNAY <patrick.delaunay at foss.st.com>
wrote:

> Hi Sughosh,
>
> On 11/25/21 8:01 AM, Sughosh Ganu wrote:
> > The FWU Multi Bank Update feature allows the platform to boot the
> > firmware images from one of the partitions(banks). The first stage
> > bootloader(fsbl) passes the value of the boot index, i.e. the bank
> > from which the firmware images were booted from to U-Boot. On the
> > STM32MP157C-DK2 board, this value is passed through one of the SoC's
> > backup register. Add a function to read the boot index value from the
> > backup register.
> >
> > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > ---
> >   arch/arm/mach-stm32mp/include/mach/stm32.h | 1 +
> >   board/st/stm32mp1/stm32mp1.c               | 7 +++++++
> >   include/fwu_metadata.h                     | 1 +
> >   3 files changed, 9 insertions(+)
> >
> > diff --git a/arch/arm/mach-stm32mp/include/mach/stm32.h
> b/arch/arm/mach-stm32mp/include/mach/stm32.h
> > index c11a9903f2..21ed9f12e4 100644
> > --- a/arch/arm/mach-stm32mp/include/mach/stm32.h
> > +++ b/arch/arm/mach-stm32mp/include/mach/stm32.h
> > @@ -97,6 +97,7 @@ enum boot_device {
> >   #define TAMP_BACKUP_REGISTER(x)             (STM32_TAMP_BASE + 0x100 +
> 4 * x)
> >   #define TAMP_BACKUP_MAGIC_NUMBER    TAMP_BACKUP_REGISTER(4)
> >   #define TAMP_BACKUP_BRANCH_ADDRESS  TAMP_BACKUP_REGISTER(5)
> > +#define TAMP_FWU_BOOT_IDX            TAMP_BACKUP_REGISTER(10)
>
> The used TAMP register need to be aligned with TF-A BL2, offset = 10 to
> be confirmed
>

Yes, the same register is being used in tf-a BL2 to pass the boot index.
The patch for this support is being reviewed in tf-a[1].

-sughosh

[1] - https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/12577


>
>
> >   #define TAMP_COPRO_RSC_TBL_ADDRESS  TAMP_BACKUP_REGISTER(17)
> >   #define TAMP_COPRO_STATE            TAMP_BACKUP_REGISTER(18)
> >   #define TAMP_BOOT_CONTEXT           TAMP_BACKUP_REGISTER(20)
> > diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
> > index a6884d2772..32bba71289 100644
> > --- a/board/st/stm32mp1/stm32mp1.c
> > +++ b/board/st/stm32mp1/stm32mp1.c
> > @@ -990,6 +990,13 @@ int fwu_plat_get_blk_desc(struct blk_desc **desc)
> >       return 0;
> >   }
> >
> > +void fwu_plat_get_bootidx(void *boot_idx)
> > +{
> > +     u32 *bootidx = boot_idx;
> > +
> > +     *bootidx = readl(TAMP_FWU_BOOT_IDX);
> > +}
> > +
> >   struct fwu_metadata_ops *get_plat_fwu_metadata_ops(void)
> >   {
> >       if (CONFIG_IS_ENABLED(TARGET_ST_STM32MP15x) &&
> > diff --git a/include/fwu_metadata.h b/include/fwu_metadata.h
> > index 6a5e814ab6..44f06f4c6a 100644
> > --- a/include/fwu_metadata.h
> > +++ b/include/fwu_metadata.h
> > @@ -124,5 +124,6 @@ int fwu_get_metadata(struct fwu_metadata **metadata);
> >
> >   int fwu_plat_get_update_index(u32 *update_idx);
> >   int fwu_plat_get_blk_desc(struct blk_desc **desc);
> > +void fwu_plat_get_bootidx(void *boot_idx);
> >
> >   #endif /* _FWU_METADATA_H_ */
>
>
> Regards
>
>
> Patrick
>
>