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author | Akshay Saraswat <akshay.s@samsung.com> | 2015-02-20 13:27:12 +0530 |
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committer | Minkyu Kang <mk7.kang@samsung.com> | 2015-02-28 18:03:46 +0900 |
commit | ac0d98cd557e0939bd0f10ff68e2e648a74bbea6 (patch) | |
tree | ff8fee5d3b87261254d1fea5f3c4461b47f984f8 /arch/x86 | |
parent | 1a8aae9b946d707d5dd2b1616e9c9c80c3daf178 (diff) | |
download | u-boot-imx-ac0d98cd557e0939bd0f10ff68e2e648a74bbea6.zip u-boot-imx-ac0d98cd557e0939bd0f10ff68e2e648a74bbea6.tar.gz u-boot-imx-ac0d98cd557e0939bd0f10ff68e2e648a74bbea6.tar.bz2 |
Exynos542x: CPU: Power down all secondary cores
This patch adds code to shutdown secondary cores.
When U-boot comes up, all secondary cores appear powered on,
which is undesirable and causes side effects while
initializing these cores in kernel.
Secondary core power down happens in following steps:
Step-1: After Exynos power-on, primary core starts executing first.
Step-2: In iROM code every core has to check 2 flags i.e.
addresses 0x02020028 & 0x02020004.
Step-3: Initially 0x02020028 is 0 for all cores and 0x02020004 has a
jump address for primary core and 0 for all secondary cores.
Step-4: Therefore, primary core follows normal iROM execution and jumps
to BL1 eventually, whereas all secondary cores enter WFE.
Step-5: When primary core comes into function secondary_cores_configure,
it puts pointer to function power_down_core into 0x02020004
and provides DSB and SEV for all cores so that they may come out
of WFE and jump to power_down_core function.
Step-6: And ultimately because of power_down_core all
secondary cores shut-down.
Signed-off-by: Kimoon Kim <kimoon.kim@samsung.com>
Signed-off-by: Akshay Saraswat <akshay.s@samsung.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
Diffstat (limited to 'arch/x86')
0 files changed, 0 insertions, 0 deletions