diff options
| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2015-03-23 00:07:31 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.masahiro@socionext.com> | 2015-03-24 00:15:55 +0900 |
| commit | 62118b7b0183d29755a101a6a5b88dee11c5f94b (patch) | |
| tree | 5d7c5d8ab6e240b95793dc11706a376844e6f25d /arch/arm/mach-uniphier/lowlevel_init.S | |
| parent | 4d13b1b708b8c31c0e22d7f31f05dde4b3961621 (diff) | |
| download | u-boot-62118b7b0183d29755a101a6a5b88dee11c5f94b.tar.gz | |
ARM: UniPhier: optimize kicking secondary CPUs code
Currently, the secondary CPU(s) are kicked three times:
Boot ROM ---(kick)--> SPL ---(kick)--> U-boot ---(kick)--> Linux.
It makes the boot sequence very complicated.
This commit merges the first and the second kicks, so the secondary
CPU(s) can directly jump from SPL to Linux.
arch/arm/mach-uniphier/smp.S is no longer necessary.
Linux boot test passed.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'arch/arm/mach-uniphier/lowlevel_init.S')
| -rw-r--r-- | arch/arm/mach-uniphier/lowlevel_init.S | 42 |
1 files changed, 36 insertions, 6 deletions
diff --git a/arch/arm/mach-uniphier/lowlevel_init.S b/arch/arm/mach-uniphier/lowlevel_init.S index 4a23ea4d56..825b160762 100644 --- a/arch/arm/mach-uniphier/lowlevel_init.S +++ b/arch/arm/mach-uniphier/lowlevel_init.S @@ -48,6 +48,25 @@ ENTRY(lowlevel_init) bl enable_mmu #ifdef CONFIG_UNIPHIER_SMP +secondary_startup: + /* + * Entry point for secondary CPUs + * + * The Boot ROM has already enabled MMU for the secondary CPUs as well + * as for the primary one. The MMU table embedded in the Boot ROM + * prohibits the DRAM access, so it is impossible to bring the + * secondary CPUs into DRAM directly. They must jump here into SPL, + * which is run on L2 cache. + * + * Boot Sequence + * [primary CPU] [secondary CPUs] + * start from Boot ROM start from Boot ROM + * jump to SPL sleep in Boot ROM + * kick secondaries ---(sev)---> jump to SPL + * jump to U-Boot main sleep in SPL + * jump to Linux + * kick secondaries ---(sev)---> jump to Linux + */ /* * ACTLR (Auxiliary Control Register) for Cortex-A9 * bit[9] Parity on @@ -68,17 +87,28 @@ ENTRY(lowlevel_init) and r0, r0, #0x3 cmp r0, #0x0 beq primary_cpu - ldr r1, =ROM_BOOT_ROMRSV2 + /* only for secondary CPUs */ + ldr r1, =ROM_BOOT_ROMRSV2 @ The last data access to L2 cache + mrc p15, 0, r0, c1, c0, 0 @ SCTLR (System Control Register) + orr r0, r0, #CR_I @ Enable ICache + bic r0, r0, #(CR_C | CR_M) @ MMU and Dcache must be disabled + mcr p15, 0, r0, c1, c0, 0 @ before jumping to Linux mov r0, #0 str r0, [r1] -0: wfe - ldr r0, [r1] + b 1f + /* + * L2 cache is shared among all the CPUs and it might be disabled by + * the primary one. Before that, the following 5 lines must be cached + * on the Icaches of the secondary CPUs. + */ +0: wfe @ kicked by Linux +1: ldr r0, [r1] cmp r0, #0 - beq 0b - bx r0 @ r0: entry point of U-Boot main for the secondary CPU + bxne r0 @ r0: Linux entry for secondary CPUs + b 0b primary_cpu: ldr r1, =ROM_BOOT_ROMRSV2 - ldr r0, =_start @ entry for the secondary CPU + ldr r0, =secondary_startup str r0, [r1] ldr r0, [r1] @ make sure str is complete before sev sev @ kick the secondary CPU |