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/*
* Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
* 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 and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/proc-fns.h>
#include <asm/cp15.h>
#include "sleep.h"
#include "flowctrl.h"
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PM_SLEEP)
/*
* tegra20_hotplug_shutdown(void)
*
* puts the current cpu in reset
* should never return
*/
ENTRY(tegra20_hotplug_shutdown)
/* Put this CPU down */
cpu_id r0
bl tegra20_cpu_shutdown
mov pc, lr @ should never get here
ENDPROC(tegra20_hotplug_shutdown)
/*
* tegra20_cpu_shutdown(int cpu)
*
* r0 is cpu to reset
*
* puts the specified CPU in wait-for-event mode on the flow controller
* and puts the CPU in reset
* can be called on the current cpu or another cpu
* if called on the current cpu, does not return
* MUST NOT BE CALLED FOR CPU 0.
*
* corrupts r0-r3, r12
*/
ENTRY(tegra20_cpu_shutdown)
cmp r0, #0
moveq pc, lr @ must not be called for CPU 0
cpu_to_halt_reg r1, r0
ldr r3, =TEGRA_FLOW_CTRL_VIRT
mov r2, #FLOW_CTRL_WAITEVENT | FLOW_CTRL_JTAG_RESUME
str r2, [r3, r1] @ put flow controller in wait event mode
ldr r2, [r3, r1]
isb
dsb
movw r1, 0x1011
mov r1, r1, lsl r0
ldr r3, =TEGRA_CLK_RESET_VIRT
str r1, [r3, #0x340] @ put slave CPU in reset
isb
dsb
cpu_id r3
cmp r3, r0
beq .
mov pc, lr
ENDPROC(tegra20_cpu_shutdown)
#endif
#ifdef CONFIG_PM_SLEEP
/*
* tegra_pen_lock
*
* spinlock implementation with no atomic test-and-set and no coherence
* using Peterson's algorithm on strongly-ordered registers
* used to synchronize a cpu waking up from wfi with entering lp2 on idle
*
* The reference link of Peterson's algorithm:
* http://en.wikipedia.org/wiki/Peterson's_algorithm
*
* SCRATCH37 = r1 = !turn (inverted from Peterson's algorithm)
* on cpu 0:
* r2 = flag[0] (in SCRATCH38)
* r3 = flag[1] (in SCRATCH39)
* on cpu1:
* r2 = flag[1] (in SCRATCH39)
* r3 = flag[0] (in SCRATCH38)
*
* must be called with MMU on
* corrupts r0-r3, r12
*/
ENTRY(tegra_pen_lock)
mov32 r3, TEGRA_PMC_VIRT
cpu_id r0
add r1, r3, #PMC_SCRATCH37
cmp r0, #0
addeq r2, r3, #PMC_SCRATCH38
addeq r3, r3, #PMC_SCRATCH39
addne r2, r3, #PMC_SCRATCH39
addne r3, r3, #PMC_SCRATCH38
mov r12, #1
str r12, [r2] @ flag[cpu] = 1
dsb
str r12, [r1] @ !turn = cpu
1: dsb
ldr r12, [r3]
cmp r12, #1 @ flag[!cpu] == 1?
ldreq r12, [r1]
cmpeq r12, r0 @ !turn == cpu?
beq 1b @ while !turn == cpu && flag[!cpu] == 1
mov pc, lr @ locked
ENDPROC(tegra_pen_lock)
ENTRY(tegra_pen_unlock)
dsb
mov32 r3, TEGRA_PMC_VIRT
cpu_id r0
cmp r0, #0
addeq r2, r3, #PMC_SCRATCH38
addne r2, r3, #PMC_SCRATCH39
mov r12, #0
str r12, [r2]
mov pc, lr
ENDPROC(tegra_pen_unlock)
/*
* tegra20_cpu_clear_resettable(void)
*
* Called to clear the "resettable soon" flag in PMC_SCRATCH41 when
* it is expected that the secondary CPU will be idle soon.
*/
ENTRY(tegra20_cpu_clear_resettable)
mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
mov r12, #CPU_NOT_RESETTABLE
str r12, [r1]
mov pc, lr
ENDPROC(tegra20_cpu_clear_resettable)
/*
* tegra20_cpu_set_resettable_soon(void)
*
* Called to set the "resettable soon" flag in PMC_SCRATCH41 when
* it is expected that the secondary CPU will be idle soon.
*/
ENTRY(tegra20_cpu_set_resettable_soon)
mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
mov r12, #CPU_RESETTABLE_SOON
str r12, [r1]
mov pc, lr
ENDPROC(tegra20_cpu_set_resettable_soon)
/*
* tegra20_sleep_cpu_secondary_finish(unsigned long v2p)
*
* Enters WFI on secondary CPU by exiting coherency.
*/
ENTRY(tegra20_sleep_cpu_secondary_finish)
stmfd sp!, {r4-r11, lr}
mrc p15, 0, r11, c1, c0, 1 @ save actlr before exiting coherency
/* Flush and disable the L1 data cache */
bl tegra_disable_clean_inv_dcache
mov32 r0, TEGRA_PMC_VIRT + PMC_SCRATCH41
mov r3, #CPU_RESETTABLE
str r3, [r0]
bl cpu_do_idle
/*
* cpu may be reset while in wfi, which will return through
* tegra_resume to cpu_resume
* or interrupt may wake wfi, which will return here
* cpu state is unchanged - MMU is on, cache is on, coherency
* is off, and the data cache is off
*
* r11 contains the original actlr
*/
bl tegra_pen_lock
mov32 r3, TEGRA_PMC_VIRT
add r0, r3, #PMC_SCRATCH41
mov r3, #CPU_NOT_RESETTABLE
str r3, [r0]
bl tegra_pen_unlock
/* Re-enable the data cache */
mrc p15, 0, r10, c1, c0, 0
orr r10, r10, #CR_C
mcr p15, 0, r10, c1, c0, 0
isb
mcr p15, 0, r11, c1, c0, 1 @ reenable coherency
/* Invalidate the TLBs & BTAC */
mov r1, #0
mcr p15, 0, r1, c8, c3, 0 @ invalidate shared TLBs
mcr p15, 0, r1, c7, c1, 6 @ invalidate shared BTAC
dsb
isb
/* the cpu was running with coherency disabled,
* caches may be out of date */
bl v7_flush_kern_cache_louis
ldmfd sp!, {r4 - r11, pc}
ENDPROC(tegra20_sleep_cpu_secondary_finish)
#endif
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