linux/arch/arm/mach-tegra/sleep.S
Joseph Lo e7a932b196 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>
2013-08-12 13:30:11 -06:00

162 lines
3.8 KiB
ArmAsm

/*
* arch/arm/mach-tegra/sleep.S
*
* Copyright (c) 2010-2011, NVIDIA Corporation.
* Copyright (c) 2011, Google, Inc.
*
* Author: Colin Cross <ccross@android.com>
* Gary King <gking@nvidia.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/cache.h>
#include <asm/cp15.h>
#include <asm/hardware/cache-l2x0.h>
#include "iomap.h"
#include "flowctrl.h"
#include "sleep.h"
#define CLK_RESET_CCLK_BURST 0x20
#define CLK_RESET_CCLK_DIVIDER 0x24
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PM_SLEEP)
/*
* tegra_disable_clean_inv_dcache
*
* disable, clean & invalidate the D-cache
*
* Corrupted registers: r1-r3, r6, r8, r9-r11
*/
ENTRY(tegra_disable_clean_inv_dcache)
stmfd sp!, {r0, r4-r5, r7, r9-r11, lr}
dmb @ ensure ordering
/* Disable the D-cache */
mrc p15, 0, r2, c1, c0, 0
bic r2, r2, #CR_C
mcr p15, 0, r2, c1, c0, 0
isb
/* Flush the D-cache */
cmp r0, #TEGRA_FLUSH_CACHE_ALL
blne v7_flush_dcache_louis
bleq v7_flush_dcache_all
/* Trun off coherency */
exit_smp r4, r5
ldmfd sp!, {r0, r4-r5, r7, r9-r11, pc}
ENDPROC(tegra_disable_clean_inv_dcache)
#endif
#ifdef CONFIG_PM_SLEEP
/*
* tegra_init_l2_for_a15
*
* set up the correct L2 cache data RAM latency
*/
ENTRY(tegra_init_l2_for_a15)
mrc p15, 0, r0, c0, c0, 5
ubfx r0, r0, #8, #4
tst r0, #1 @ only need for cluster 0
bne _exit_init_l2_a15
mrc p15, 0x1, r0, c9, c0, 2
and r0, r0, #7
cmp r0, #2
bicne r0, r0, #7
orrne r0, r0, #2
mcrne p15, 0x1, r0, c9, c0, 2
_exit_init_l2_a15:
mov pc, lr
ENDPROC(tegra_init_l2_for_a15)
/*
* tegra_sleep_cpu_finish(unsigned long v2p)
*
* enters suspend in LP2 by turning off the mmu and jumping to
* tegra?_tear_down_cpu
*/
ENTRY(tegra_sleep_cpu_finish)
mov r4, r0
/* Flush and disable the L1 data cache */
mov r0, #TEGRA_FLUSH_CACHE_ALL
bl tegra_disable_clean_inv_dcache
mov r0, r4
mov32 r6, tegra_tear_down_cpu
ldr r1, [r6]
add r1, r1, r0
mov32 r3, tegra_shut_off_mmu
add r3, r3, r0
mov r0, r1
mov pc, r3
ENDPROC(tegra_sleep_cpu_finish)
/*
* tegra_shut_off_mmu
*
* r0 = physical address to jump to with mmu off
*
* called with VA=PA mapping
* turns off MMU, icache, dcache and branch prediction
*/
.align L1_CACHE_SHIFT
.pushsection .idmap.text, "ax"
ENTRY(tegra_shut_off_mmu)
mrc p15, 0, r3, c1, c0, 0
movw r2, #CR_I | CR_Z | CR_C | CR_M
bic r3, r3, r2
dsb
mcr p15, 0, r3, c1, c0, 0
isb
#ifdef CONFIG_CACHE_L2X0
/* Disable L2 cache */
check_cpu_part_num 0xc09, r9, r10
movweq r2, #:lower16:(TEGRA_ARM_PERIF_BASE + 0x3000)
movteq r2, #:upper16:(TEGRA_ARM_PERIF_BASE + 0x3000)
moveq r3, #0
streq r3, [r2, #L2X0_CTRL]
#endif
mov pc, r0
ENDPROC(tegra_shut_off_mmu)
.popsection
/*
* tegra_switch_cpu_to_pllp
*
* In LP2 the normal cpu clock pllx will be turned off. Switch the CPU to pllp
*/
ENTRY(tegra_switch_cpu_to_pllp)
/* in LP2 idle (SDRAM active), set the CPU burst policy to PLLP */
mov32 r5, TEGRA_CLK_RESET_BASE
mov r0, #(2 << 28) @ burst policy = run mode
orr r0, r0, #(4 << 4) @ use PLLP in run mode burst
str r0, [r5, #CLK_RESET_CCLK_BURST]
mov r0, #0
str r0, [r5, #CLK_RESET_CCLK_DIVIDER]
mov pc, lr
ENDPROC(tegra_switch_cpu_to_pllp)
#endif