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| author | Masahiro Yamada <yamada.masahiro@socionext.com> | 2016-06-27 10:31:05 (GMT) |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2016-07-14 22:22:16 (GMT) |
| commit | 6b6024eadb96bc471643bd183fe940fb657bef83 (patch) | |
| tree | 35c09153ac815289e395ddbf7678587c0232c114 /arch/arm/cpu/armv8/start.S | |
| parent | 3a592a1349ac3961b0f4f2db0a8d9f128225d897 (diff) | |
| download | u-boot-fsl-qoriq-6b6024eadb96bc471643bd183fe940fb657bef83.tar.xz | |
arm64: add better and more generic spin-table support
There are two enable methods supported by ARM64 Linux; psci and
spin-table. The latter is simpler and helpful for quick SoC bring
up. My main motivation for this patch is to improve the spin-table
support, which allows us to boot an ARMv8 system without the ARM
Trusted Firmware.
Currently, we have multi-entry code in arch/arm/cpu/armv8/start.S
and the spin-table is supported in a really ad-hoc way, and I see
some problems:
- We must hard-code CPU_RELEASE_ADDR so that it matches the
"cpu-release-addr" property in the DT that comes from the
kernel tree.
- The Documentation/arm64/booting.txt in Linux requires that
the release address must be zero-initialized, but it is not
cared by the common code in U-Boot. We must do it in a board
function.
- There is no systematic way to protect the spin-table code from
the kernel. We are supposed to do it in a board specific manner,
but it is difficult to predict where the spin-table code will be
located after the relocation. So, it also makes difficult to
hard-code /memreserve/ in the DT of the kernel.
So, here is a patch to solve those problems; the DT is run-time
modified to reserve the spin-table code (+ cpu-release-addr).
Also, the "cpu-release-addr" property is set to an appropriate
address after the relocation, which means we no longer need the
hard-coded CPU_RELEASE_ADDR.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Diffstat (limited to 'arch/arm/cpu/armv8/start.S')
| -rw-r--r-- | arch/arm/cpu/armv8/start.S | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/arm/cpu/armv8/start.S b/arch/arm/cpu/armv8/start.S index 670e323..67edf94 100644 --- a/arch/arm/cpu/armv8/start.S +++ b/arch/arm/cpu/armv8/start.S @@ -94,7 +94,11 @@ reset: /* Processor specific initialization */ bl lowlevel_init -#ifdef CONFIG_ARMV8_MULTIENTRY +#if CONFIG_IS_ENABLED(ARMV8_SPIN_TABLE) + branch_if_master x0, x1, master_cpu + b spin_table_secondary_jump + /* never return */ +#elif defined(CONFIG_ARMV8_MULTIENTRY) branch_if_master x0, x1, master_cpu /* @@ -106,10 +110,8 @@ slave_cpu: ldr x0, [x1] cbz x0, slave_cpu br x0 /* branch to the given address */ -master_cpu: - /* On the master CPU */ #endif /* CONFIG_ARMV8_MULTIENTRY */ - +master_cpu: bl _main #ifdef CONFIG_SYS_RESET_SCTRL |