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| author | Joseph Lo <josephl@nvidia.com> | 2013-08-12 09:40:04 (GMT) |
|---|---|---|
| committer | Stephen Warren <swarren@nvidia.com> | 2013-08-12 19:30:11 (GMT) |
| commit | e7a932b1961c3936c7ae5b8d1628f39dc50a746d (patch) | |
| tree | 757f5862da9fad0e10185382f9a9bbaca4723579 /arch/arm/mach-tegra/sleep.h | |
| parent | 95872f427eca73b19ac9466c25afd9bb876dc1aa (diff) | |
| download | linux-e7a932b1961c3936c7ae5b8d1628f39dc50a746d.tar.xz | |
ARM: tegra: add LP1 suspend support for Tegra30
The LP1 suspend mode will power off the CPU, clock gated the PLLs and put
SDRAM to self-refresh mode. Any interrupt can wake up device from LP1. The
sequence when LP1 suspending:
* tunning off L1 data cache and the MMU
* storing some EMC registers, DPD (deep power down) status, clk source of
mselect and SCLK burst policy
* putting SDRAM into self-refresh
* switching CPU to CLK_M (12MHz OSC)
* tunning off PLLM, PLLP, PLLA, PLLC and PLLX
* switching SCLK to CLK_S (32KHz OSC)
* shutting off the CPU rail
The sequence of LP1 resuming:
* re-enabling PLLM, PLLP, PLLA, PLLC and PLLX
* restoring the clk source of mselect and SCLK burst policy
* setting up CCLK burst policy to PLLX
* restoring DPD status and some EMC registers
* resuming SDRAM to normal mode
* jumping to the "tegra_resume" from PMC_SCRATCH41
Due to the SDRAM will be put into self-refresh mode, the low level
procedures of LP1 suspending and resuming should be copied to
TEGRA_IRAM_CODE_AREA (TEGRA_IRAM_BASE + SZ_4K) when suspending. Before
restoring the CPU context when resuming, the SDRAM needs to be switched
back to normal mode. And the PLLs need to be re-enabled, SCLK burst policy
be restored, CCLK burst policy be set in PLLX. Then jumping to
"tegra_resume" that was expected to be stored in PMC_SCRATCH41 to restore
CPU context and back to kernel.
Based on the work by: Scott Williams <scwilliams@nvidia.com>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Diffstat (limited to 'arch/arm/mach-tegra/sleep.h')
| -rw-r--r-- | arch/arm/mach-tegra/sleep.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/mach-tegra/sleep.h b/arch/arm/mach-tegra/sleep.h index e907e40..a4edbb3 100644 --- a/arch/arm/mach-tegra/sleep.h +++ b/arch/arm/mach-tegra/sleep.h @@ -46,6 +46,14 @@ #define TEGRA_FLUSH_CACHE_ALL 1 #ifdef __ASSEMBLY__ +/* waits until the microsecond counter (base) is > rn */ +.macro wait_until, rn, base, tmp + add \rn, \rn, #1 +1001: ldr \tmp, [\base] + cmp \tmp, \rn + bmi 1001b +.endm + /* returns the offset of the flow controller halt register for a cpu */ .macro cpu_to_halt_reg rd, rcpu cmp \rcpu, #0 |