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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 * putting SDRAM into self-refresh * storing some EMC registers and SCLK burst policy * switching CPU to CLK_M (12MHz OSC) * switching SCLK to CLK_S (32KHz OSC) * tunning off PLLM, PLLP and PLLC * shutting off the CPU rail The sequence of LP1 resuming: * re-enabling PLLM, PLLP, and PLLC * restoring some EMC registers and SCLK burst policy * setting up CCLK burst policy to PLLP * 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 PLLP. 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: Colin Cross <ccross@android.com> Gary King <gking@nvidia.com> Signed-off-by: Joseph Lo <josephl@nvidia.com> Signed-off-by: Stephen Warren <swarren@nvidia.com>
35 lines
1.0 KiB
C
35 lines
1.0 KiB
C
/*
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* Copyright (c) 2013, NVIDIA Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kernel.h>
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#include "pm.h"
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#ifdef CONFIG_PM_SLEEP
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extern u32 tegra20_iram_start, tegra20_iram_end;
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extern void tegra20_sleep_core_finish(unsigned long);
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void tegra20_lp1_iram_hook(void)
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{
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tegra_lp1_iram.start_addr = &tegra20_iram_start;
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tegra_lp1_iram.end_addr = &tegra20_iram_end;
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}
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void tegra20_sleep_core_init(void)
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{
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tegra_sleep_core_finish = tegra20_sleep_core_finish;
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}
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#endif
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