On Mon, 2026-11-02 at 10:31 -0600, David Lechner wrote:
> On 10/30/26 3:57 AM, Steffen Dirkwinkel wrote:
> > From: Steffen Dirkwinkel <[email protected]>
>
> A couple things in addition to Carlo's comments...
>
> >
> > Running through spl without the dcache is very slow, especially when
> > hashing or checking signatures.
> >
> > Time from the SPL banner to entering BL31 on an MT8370 module loading a
> > 2.7 MB FIT with SHA-256 hashes from SPI NOR, two boots each:
> >
> > FIT caches off caches on
> > unsigned 864.0 / 864.3 ms 95.8 / 95.8 ms
> > RSA-3072 signature 1903.3 / 1903.8 ms 142.0 / 142.0 ms
> >
> > Signed-off-by: Steffen Dirkwinkel <[email protected]>
> > ---
> > arch/arm/mach-mediatek/mt8188/init.c | 14 ++++++++++++++
> > arch/arm/mach-mediatek/spl.c | 7 +++++++
> > 2 files changed, 21 insertions(+)
> >
> > diff --git a/arch/arm/mach-mediatek/mt8188/init.c
> > b/arch/arm/mach-mediatek/mt8188/init.c
> > index b2cdec8c2189..2e6aa041c38f 100644
> > --- a/arch/arm/mach-mediatek/mt8188/init.c
> > +++ b/arch/arm/mach-mediatek/mt8188/init.c
> > @@ -6,6 +6,7 @@
> > * Chris-QJ Chen <[email protected]>
> > */
> >
> > +#include <cpu_func.h>
> > #include <asm/global_data.h>
> > #include <asm/system.h>
> > #include <dm/uclass.h>
> > @@ -47,3 +48,16 @@ int print_cpuinfo(void)
> > printf("CPU: MediaTek MT8188\n");
> > return 0;
> > }
> > +
> > +#if IS_ENABLED(CONFIG_XPL_BUILD) && !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)
> > +/* Early page tables, in DRAM unused by SPL and by U-Boot before
> > relocation */
> > +#define MT8188_EARLY_TLB_ADDR 0x4e000000
> > +
> > +/* Initialize the MMU and activate the data cache in SPL */
> > +void mtk_spl_enable_caches(void)
> > +{
> > + gd->arch.tlb_addr = MT8188_EARLY_TLB_ADDR;
> > + gd->arch.tlb_size = PGTABLE_SIZE;
> > + dcache_enable();
>
> Why not also icache?
I tested it and it didn't really help (boot wasn't faster). But it's cleaner to
have both on, I'll do it in the next version.
>
> > +}
> > +#endif
> > diff --git a/arch/arm/mach-mediatek/spl.c b/arch/arm/mach-mediatek/spl.c
> > index 125ebcd784fe..8073101e3ef6 100644
> > --- a/arch/arm/mach-mediatek/spl.c
> > +++ b/arch/arm/mach-mediatek/spl.c
> > @@ -14,10 +14,17 @@ __weak int mtk_soc_early_init(void)
> > return 0;
> > }
> >
> > +__weak void mtk_spl_enable_caches(void)
> > +{
> > +}
>
> Can we make this a config option instead of a weak function so that we don't
> have to implement the same function on every board?
>
> > +
> > void board_init_f(ulong dummy)
> > {
> > int ret;
> >
> > + /* enable caches early */
> > + mtk_spl_enable_caches();
> > +
> > ret = spl_early_init();
> > if (ret)
> > hang();
> >
