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![Arnd Bergmann](/assets/img/avatar_default.png)
When building a kernel for multiple CPU architecture levels, cpu_do_idle() is a macro for an indirect function call, which cannot be called from assembly code as Tegra does. Adding a trivial C wrapper for this function lets us build a tegra kernel with ARMv6 support enabled. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Joseph Lo <josephl@nvidia.com> Cc: Stephen Warren <swarren@nvidia.com>
277 lines
6.6 KiB
ArmAsm
277 lines
6.6 KiB
ArmAsm
/*
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* Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
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* Copyright (c) 2011, Google, Inc.
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*
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* Author: Colin Cross <ccross@android.com>
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* Gary King <gking@nvidia.com>
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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/linkage.h>
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#include <asm/assembler.h>
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#include <asm/proc-fns.h>
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#include <asm/cp15.h>
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#include "sleep.h"
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#include "flowctrl.h"
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#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_PM_SLEEP)
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/*
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* tegra20_hotplug_shutdown(void)
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*
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* puts the current cpu in reset
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* should never return
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*/
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ENTRY(tegra20_hotplug_shutdown)
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/* Put this CPU down */
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cpu_id r0
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bl tegra20_cpu_shutdown
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mov pc, lr @ should never get here
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ENDPROC(tegra20_hotplug_shutdown)
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/*
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* tegra20_cpu_shutdown(int cpu)
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*
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* r0 is cpu to reset
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*
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* puts the specified CPU in wait-for-event mode on the flow controller
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* and puts the CPU in reset
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* can be called on the current cpu or another cpu
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* if called on the current cpu, does not return
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* MUST NOT BE CALLED FOR CPU 0.
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*
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* corrupts r0-r3, r12
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*/
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ENTRY(tegra20_cpu_shutdown)
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cmp r0, #0
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moveq pc, lr @ must not be called for CPU 0
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mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
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mov r12, #CPU_RESETTABLE
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str r12, [r1]
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cpu_to_halt_reg r1, r0
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ldr r3, =TEGRA_FLOW_CTRL_VIRT
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mov r2, #FLOW_CTRL_WAITEVENT | FLOW_CTRL_JTAG_RESUME
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str r2, [r3, r1] @ put flow controller in wait event mode
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ldr r2, [r3, r1]
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isb
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dsb
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movw r1, 0x1011
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mov r1, r1, lsl r0
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ldr r3, =TEGRA_CLK_RESET_VIRT
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str r1, [r3, #0x340] @ put slave CPU in reset
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isb
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dsb
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cpu_id r3
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cmp r3, r0
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beq .
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mov pc, lr
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ENDPROC(tegra20_cpu_shutdown)
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#endif
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#ifdef CONFIG_PM_SLEEP
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/*
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* tegra_pen_lock
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*
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* spinlock implementation with no atomic test-and-set and no coherence
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* using Peterson's algorithm on strongly-ordered registers
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* used to synchronize a cpu waking up from wfi with entering lp2 on idle
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*
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* The reference link of Peterson's algorithm:
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* http://en.wikipedia.org/wiki/Peterson's_algorithm
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*
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* SCRATCH37 = r1 = !turn (inverted from Peterson's algorithm)
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* on cpu 0:
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* r2 = flag[0] (in SCRATCH38)
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* r3 = flag[1] (in SCRATCH39)
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* on cpu1:
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* r2 = flag[1] (in SCRATCH39)
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* r3 = flag[0] (in SCRATCH38)
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*
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* must be called with MMU on
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* corrupts r0-r3, r12
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*/
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ENTRY(tegra_pen_lock)
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mov32 r3, TEGRA_PMC_VIRT
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cpu_id r0
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add r1, r3, #PMC_SCRATCH37
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cmp r0, #0
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addeq r2, r3, #PMC_SCRATCH38
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addeq r3, r3, #PMC_SCRATCH39
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addne r2, r3, #PMC_SCRATCH39
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addne r3, r3, #PMC_SCRATCH38
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mov r12, #1
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str r12, [r2] @ flag[cpu] = 1
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dsb
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str r12, [r1] @ !turn = cpu
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1: dsb
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ldr r12, [r3]
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cmp r12, #1 @ flag[!cpu] == 1?
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ldreq r12, [r1]
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cmpeq r12, r0 @ !turn == cpu?
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beq 1b @ while !turn == cpu && flag[!cpu] == 1
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mov pc, lr @ locked
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ENDPROC(tegra_pen_lock)
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ENTRY(tegra_pen_unlock)
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dsb
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mov32 r3, TEGRA_PMC_VIRT
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cpu_id r0
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cmp r0, #0
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addeq r2, r3, #PMC_SCRATCH38
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addne r2, r3, #PMC_SCRATCH39
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mov r12, #0
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str r12, [r2]
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mov pc, lr
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ENDPROC(tegra_pen_unlock)
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/*
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* tegra20_cpu_clear_resettable(void)
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*
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* Called to clear the "resettable soon" flag in PMC_SCRATCH41 when
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* it is expected that the secondary CPU will be idle soon.
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*/
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ENTRY(tegra20_cpu_clear_resettable)
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mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
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mov r12, #CPU_NOT_RESETTABLE
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str r12, [r1]
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mov pc, lr
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ENDPROC(tegra20_cpu_clear_resettable)
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/*
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* tegra20_cpu_set_resettable_soon(void)
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*
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* Called to set the "resettable soon" flag in PMC_SCRATCH41 when
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* it is expected that the secondary CPU will be idle soon.
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*/
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ENTRY(tegra20_cpu_set_resettable_soon)
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mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
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mov r12, #CPU_RESETTABLE_SOON
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str r12, [r1]
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mov pc, lr
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ENDPROC(tegra20_cpu_set_resettable_soon)
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/*
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* tegra20_cpu_is_resettable_soon(void)
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*
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* Returns true if the "resettable soon" flag in PMC_SCRATCH41 has been
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* set because it is expected that the secondary CPU will be idle soon.
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*/
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ENTRY(tegra20_cpu_is_resettable_soon)
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mov32 r1, TEGRA_PMC_VIRT + PMC_SCRATCH41
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ldr r12, [r1]
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cmp r12, #CPU_RESETTABLE_SOON
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moveq r0, #1
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movne r0, #0
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mov pc, lr
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ENDPROC(tegra20_cpu_is_resettable_soon)
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/*
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* tegra20_sleep_cpu_secondary_finish(unsigned long v2p)
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*
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* Enters WFI on secondary CPU by exiting coherency.
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*/
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ENTRY(tegra20_sleep_cpu_secondary_finish)
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stmfd sp!, {r4-r11, lr}
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mrc p15, 0, r11, c1, c0, 1 @ save actlr before exiting coherency
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/* Flush and disable the L1 data cache */
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bl tegra_disable_clean_inv_dcache
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mov32 r0, TEGRA_PMC_VIRT + PMC_SCRATCH41
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mov r3, #CPU_RESETTABLE
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str r3, [r0]
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bl tegra_cpu_do_idle
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/*
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* cpu may be reset while in wfi, which will return through
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* tegra_resume to cpu_resume
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* or interrupt may wake wfi, which will return here
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* cpu state is unchanged - MMU is on, cache is on, coherency
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* is off, and the data cache is off
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*
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* r11 contains the original actlr
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*/
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bl tegra_pen_lock
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mov32 r3, TEGRA_PMC_VIRT
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add r0, r3, #PMC_SCRATCH41
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mov r3, #CPU_NOT_RESETTABLE
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str r3, [r0]
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bl tegra_pen_unlock
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/* Re-enable the data cache */
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mrc p15, 0, r10, c1, c0, 0
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orr r10, r10, #CR_C
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mcr p15, 0, r10, c1, c0, 0
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isb
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mcr p15, 0, r11, c1, c0, 1 @ reenable coherency
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/* Invalidate the TLBs & BTAC */
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mov r1, #0
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mcr p15, 0, r1, c8, c3, 0 @ invalidate shared TLBs
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mcr p15, 0, r1, c7, c1, 6 @ invalidate shared BTAC
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dsb
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isb
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/* the cpu was running with coherency disabled,
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* caches may be out of date */
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bl v7_flush_kern_cache_louis
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ldmfd sp!, {r4 - r11, pc}
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ENDPROC(tegra20_sleep_cpu_secondary_finish)
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/*
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* tegra20_tear_down_cpu
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*
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* Switches the CPU cluster to PLL-P and enters sleep.
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*/
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ENTRY(tegra20_tear_down_cpu)
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bl tegra_switch_cpu_to_pllp
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b tegra20_enter_sleep
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ENDPROC(tegra20_tear_down_cpu)
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/*
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* tegra20_enter_sleep
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*
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* uses flow controller to enter sleep state
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* executes from IRAM with SDRAM in selfrefresh when target state is LP0 or LP1
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* executes from SDRAM with target state is LP2
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*/
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tegra20_enter_sleep:
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mov32 r6, TEGRA_FLOW_CTRL_BASE
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mov r0, #FLOW_CTRL_WAIT_FOR_INTERRUPT
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orr r0, r0, #FLOW_CTRL_HALT_CPU_IRQ | FLOW_CTRL_HALT_CPU_FIQ
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cpu_id r1
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cpu_to_halt_reg r1, r1
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str r0, [r6, r1]
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dsb
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ldr r0, [r6, r1] /* memory barrier */
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halted:
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dsb
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wfe /* CPU should be power gated here */
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isb
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b halted
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#endif
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