| Message ID | 1479653838-3574-13-git-send-email-andre.przywara@arm.com |
|---|---|
| State | Superseded |
| Delegated to: | Jagannadha Sutradharudu Teki |
| Headers | show |
On 20/11/2016 15:57, Andre Przywara wrote: > The Allwinner A64 SoC starts execution in AArch32 mode, and both > the boot ROM and Allwinner's boot0 keep running in this mode. > So U-Boot gets entered in 32-bit, although we want it to run in AArch64. > > By using a "magic" instruction, which happens to be an almost-NOP in > AArch64 and a branch in AArch32, we differentiate between being > entered in 64-bit or 32-bit mode. > If in 64-bit mode, we proceed with the branch to reset, but in 32-bit > mode we trigger an RMR write to bring the core into AArch64/EL3 and > re-enter U-Boot at CONFIG_SYS_TEXT_BASE. > This allows a 64-bit U-Boot to be both entered in 32 and 64-bit mode, > so we can use the same start code for the SPL and the U-Boot proper. > > Signed-off-by: Andre Przywara <andre.przywara@arm.com> > --- > arch/arm/include/asm/arch-sunxi/boot0.h | 27 +++++++++++++++++++++++++++ > board/sunxi/Kconfig | 5 +++++ > 2 files changed, 32 insertions(+) > > diff --git a/arch/arm/include/asm/arch-sunxi/boot0.h b/arch/arm/include/asm/arch-sunxi/boot0.h > index 6a13db5..c31a2af 100644 > --- a/arch/arm/include/asm/arch-sunxi/boot0.h > +++ b/arch/arm/include/asm/arch-sunxi/boot0.h > @@ -4,6 +4,33 @@ > * SPDX-License-Identifier: GPL-2.0+ > */ > > +#if defined(CONFIG_RESERVE_ALLWINNER_BOOT0_HEADER) > /* reserve space for BOOT0 header information */ > b reset > .space 1532 > +#elif defined(CONFIG_ARM_BOOT_HOOK_RMR) > +/* switch into AArch64 if needed */ > + tst x0, x0 // this is "b #0x84" in ARM > + b reset > + .space 0x7c > + .word 0xe3a01617 // mov r1, #0x1700000 > + .word 0xe38110a0 // orr r1, r1, #0xa0 Is this address guaranteed to stay the same for newer chips? Maybe it'd be better to use a pc-relative load and put it in as .word like you do below for the text base address. Alex > + .word 0xe59f0020 // ldr r0, [pc, #32] > + .word 0xe5810000 // str r0, [r1] > + .word 0xf57ff04f // dsb sy > + .word 0xf57ff06f // isb sy > + .word 0xee1c0f50 // mrc 15, 0, r0, cr12, cr0, {2} > + .word 0xe3800003 // orr r0, r0, #3 > + .word 0xee0c0f50 // mcr 15, 0, r0, cr12, cr0, {2} > + .word 0xf57ff06f // isb sy > + .word 0xe320f003 // wfi > + .word 0xeafffffd // b @wfi > +#ifdef CONFIG_SPL_BUILD > + .word CONFIG_SPL_TEXT_BASE > +#else > + .word CONFIG_SYS_TEXT_BASE > +#endif > +#else > +/* normal execution */ > + b reset > +#endif > diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig > index 0cd57a2..ba72e76 100644 > --- a/board/sunxi/Kconfig > +++ b/board/sunxi/Kconfig > @@ -142,6 +142,11 @@ config RESERVE_ALLWINNER_BOOT0_HEADER > blob relies on this information to load and execute U-Boot. > Only needed on 64-bit Allwinner boards so far when using boot0. > > +config ARM_BOOT_HOOK_RMR > + bool > + default y if ARM64 > + select ENABLE_ARM_SOC_BOOT0_HOOK > + > config DRAM_TYPE > int "sunxi dram type" > depends on MACH_SUN8I_A83T >
Hi, On 21/11/16 16:34, Alexander Graf wrote: > > > On 20/11/2016 15:57, Andre Przywara wrote: >> The Allwinner A64 SoC starts execution in AArch32 mode, and both >> the boot ROM and Allwinner's boot0 keep running in this mode. >> So U-Boot gets entered in 32-bit, although we want it to run in AArch64. >> >> By using a "magic" instruction, which happens to be an almost-NOP in >> AArch64 and a branch in AArch32, we differentiate between being >> entered in 64-bit or 32-bit mode. >> If in 64-bit mode, we proceed with the branch to reset, but in 32-bit >> mode we trigger an RMR write to bring the core into AArch64/EL3 and >> re-enter U-Boot at CONFIG_SYS_TEXT_BASE. >> This allows a 64-bit U-Boot to be both entered in 32 and 64-bit mode, >> so we can use the same start code for the SPL and the U-Boot proper. >> >> Signed-off-by: Andre Przywara <andre.przywara@arm.com> >> --- >> arch/arm/include/asm/arch-sunxi/boot0.h | 27 +++++++++++++++++++++++++++ >> board/sunxi/Kconfig | 5 +++++ >> 2 files changed, 32 insertions(+) >> >> diff --git a/arch/arm/include/asm/arch-sunxi/boot0.h >> b/arch/arm/include/asm/arch-sunxi/boot0.h >> index 6a13db5..c31a2af 100644 >> --- a/arch/arm/include/asm/arch-sunxi/boot0.h >> +++ b/arch/arm/include/asm/arch-sunxi/boot0.h >> @@ -4,6 +4,33 @@ >> * SPDX-License-Identifier: GPL-2.0+ >> */ >> >> +#if defined(CONFIG_RESERVE_ALLWINNER_BOOT0_HEADER) >> /* reserve space for BOOT0 header information */ >> b reset >> .space 1532 >> +#elif defined(CONFIG_ARM_BOOT_HOOK_RMR) >> +/* switch into AArch64 if needed */ >> + tst x0, x0 // this is "b #0x84" in ARM >> + b reset >> + .space 0x7c >> + .word 0xe3a01617 // mov r1, #0x1700000 >> + .word 0xe38110a0 // orr r1, r1, #0xa0 > > Is this address guaranteed to stay the same for newer chips? AW and stay the same? ;-) > Maybe it'd > be better to use a pc-relative load and put it in as .word like you do > below for the text base address. Yes, good plan. Cheers, Andre > > > Alex > >> + .word 0xe59f0020 // ldr r0, [pc, #32] >> + .word 0xe5810000 // str r0, [r1] >> + .word 0xf57ff04f // dsb sy >> + .word 0xf57ff06f // isb sy >> + .word 0xee1c0f50 // mrc 15, 0, r0, cr12, cr0, {2} >> + .word 0xe3800003 // orr r0, r0, #3 >> + .word 0xee0c0f50 // mcr 15, 0, r0, cr12, cr0, {2} >> + .word 0xf57ff06f // isb sy >> + .word 0xe320f003 // wfi >> + .word 0xeafffffd // b @wfi >> +#ifdef CONFIG_SPL_BUILD >> + .word CONFIG_SPL_TEXT_BASE >> +#else >> + .word CONFIG_SYS_TEXT_BASE >> +#endif >> +#else >> +/* normal execution */ >> + b reset >> +#endif >> diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig >> index 0cd57a2..ba72e76 100644 >> --- a/board/sunxi/Kconfig >> +++ b/board/sunxi/Kconfig >> @@ -142,6 +142,11 @@ config RESERVE_ALLWINNER_BOOT0_HEADER >> blob relies on this information to load and execute U-Boot. >> Only needed on 64-bit Allwinner boards so far when using boot0. >> >> +config ARM_BOOT_HOOK_RMR >> + bool >> + default y if ARM64 >> + select ENABLE_ARM_SOC_BOOT0_HOOK >> + >> config DRAM_TYPE >> int "sunxi dram type" >> depends on MACH_SUN8I_A83T >>
diff --git a/arch/arm/include/asm/arch-sunxi/boot0.h b/arch/arm/include/asm/arch-sunxi/boot0.h index 6a13db5..c31a2af 100644 --- a/arch/arm/include/asm/arch-sunxi/boot0.h +++ b/arch/arm/include/asm/arch-sunxi/boot0.h @@ -4,6 +4,33 @@ * SPDX-License-Identifier: GPL-2.0+ */ +#if defined(CONFIG_RESERVE_ALLWINNER_BOOT0_HEADER) /* reserve space for BOOT0 header information */ b reset .space 1532 +#elif defined(CONFIG_ARM_BOOT_HOOK_RMR) +/* switch into AArch64 if needed */ + tst x0, x0 // this is "b #0x84" in ARM + b reset + .space 0x7c + .word 0xe3a01617 // mov r1, #0x1700000 + .word 0xe38110a0 // orr r1, r1, #0xa0 + .word 0xe59f0020 // ldr r0, [pc, #32] + .word 0xe5810000 // str r0, [r1] + .word 0xf57ff04f // dsb sy + .word 0xf57ff06f // isb sy + .word 0xee1c0f50 // mrc 15, 0, r0, cr12, cr0, {2} + .word 0xe3800003 // orr r0, r0, #3 + .word 0xee0c0f50 // mcr 15, 0, r0, cr12, cr0, {2} + .word 0xf57ff06f // isb sy + .word 0xe320f003 // wfi + .word 0xeafffffd // b @wfi +#ifdef CONFIG_SPL_BUILD + .word CONFIG_SPL_TEXT_BASE +#else + .word CONFIG_SYS_TEXT_BASE +#endif +#else +/* normal execution */ + b reset +#endif diff --git a/board/sunxi/Kconfig b/board/sunxi/Kconfig index 0cd57a2..ba72e76 100644 --- a/board/sunxi/Kconfig +++ b/board/sunxi/Kconfig @@ -142,6 +142,11 @@ config RESERVE_ALLWINNER_BOOT0_HEADER blob relies on this information to load and execute U-Boot. Only needed on 64-bit Allwinner boards so far when using boot0. +config ARM_BOOT_HOOK_RMR + bool + default y if ARM64 + select ENABLE_ARM_SOC_BOOT0_HOOK + config DRAM_TYPE int "sunxi dram type" depends on MACH_SUN8I_A83T
The Allwinner A64 SoC starts execution in AArch32 mode, and both the boot ROM and Allwinner's boot0 keep running in this mode. So U-Boot gets entered in 32-bit, although we want it to run in AArch64. By using a "magic" instruction, which happens to be an almost-NOP in AArch64 and a branch in AArch32, we differentiate between being entered in 64-bit or 32-bit mode. If in 64-bit mode, we proceed with the branch to reset, but in 32-bit mode we trigger an RMR write to bring the core into AArch64/EL3 and re-enter U-Boot at CONFIG_SYS_TEXT_BASE. This allows a 64-bit U-Boot to be both entered in 32 and 64-bit mode, so we can use the same start code for the SPL and the U-Boot proper. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- arch/arm/include/asm/arch-sunxi/boot0.h | 27 +++++++++++++++++++++++++++ board/sunxi/Kconfig | 5 +++++ 2 files changed, 32 insertions(+)