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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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fff94cd9f5
As noted by Russell King, the sleep code path is not
elegant and makes use of leaving items on the stack
between calls.
Change the code that does the following:
if (s3c_cpu_save(regs_save) == 0) {
flush_cache_all();
S3C_PMDBG("preparing to sleep\n");
pm_cpu_sleep();
}
to simply call s3c_cpu_save, and let that do the
necessary calls to quiesce and sleep the system.
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
159 lines
4.1 KiB
ArmAsm
159 lines
4.1 KiB
ArmAsm
/* linux/arch/arm/plat-s3c24xx/sleep.S
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*
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* Copyright (c) 2004 Simtec Electronics
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* Ben Dooks <ben@simtec.co.uk>
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*
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* S3C2410 Power Manager (Suspend-To-RAM) support
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*
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* Based on PXA/SA1100 sleep code by:
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* Nicolas Pitre, (c) 2002 Monta Vista Software Inc
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* Cliff Brake, (c) 2001
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for 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, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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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 <mach/hardware.h>
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#include <mach/map.h>
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#include <mach/regs-gpio.h>
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#include <mach/regs-clock.h>
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#include <mach/regs-mem.h>
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#include <plat/regs-serial.h>
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/* CONFIG_DEBUG_RESUME is dangerous if your bootloader does not
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* reset the UART configuration, only enable if you really need this!
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*/
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//#define CONFIG_DEBUG_RESUME
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.text
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/* s3c_cpu_save
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*
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* entry:
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* r0 = save address (virtual addr of s3c_sleep_save_phys)
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*/
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ENTRY(s3c_cpu_save)
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stmfd sp!, { r4 - r12, lr }
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@@ store co-processor registers
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mrc p15, 0, r4, c13, c0, 0 @ PID
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mrc p15, 0, r5, c3, c0, 0 @ Domain ID
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mrc p15, 0, r6, c2, c0, 0 @ translation table base address
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mrc p15, 0, r7, c1, c0, 0 @ control register
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stmia r0, { r4 - r13 }
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@@ write our state back to RAM
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bl s3c_pm_cb_flushcache
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@@ jump to final code to send system to sleep
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ldr r0, =pm_cpu_sleep
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@@ldr pc, [ r0 ]
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ldr r0, [ r0 ]
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mov pc, r0
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@@ return to the caller, after having the MMU
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@@ turned on, this restores the last bits from the
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@@ stack
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resume_with_mmu:
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ldmfd sp!, { r4 - r12, pc }
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.ltorg
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@@ the next bits sit in the .data segment, even though they
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@@ happen to be code... the s3c_sleep_save_phys needs to be
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@@ accessed by the resume code before it can restore the MMU.
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@@ This means that the variable has to be close enough for the
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@@ code to read it... since the .text segment needs to be RO,
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@@ the data segment can be the only place to put this code.
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.data
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.global s3c_sleep_save_phys
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s3c_sleep_save_phys:
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.word 0
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/* sleep magic, to allow the bootloader to check for an valid
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* image to resume to. Must be the first word before the
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* s3c_cpu_resume entry.
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*/
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.word 0x2bedf00d
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/* s3c_cpu_resume
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*
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* resume code entry for bootloader to call
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*
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* we must put this code here in the data segment as we have no
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* other way of restoring the stack pointer after sleep, and we
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* must not write to the code segment (code is read-only)
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*/
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ENTRY(s3c_cpu_resume)
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mov r0, #PSR_I_BIT | PSR_F_BIT | SVC_MODE
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msr cpsr_c, r0
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@@ load UART to allow us to print the two characters for
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@@ resume debug
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mov r2, #S3C24XX_PA_UART & 0xff000000
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orr r2, r2, #S3C24XX_PA_UART & 0xff000
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#if 0
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/* SMDK2440 LED set */
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mov r14, #S3C24XX_PA_GPIO
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ldr r12, [ r14, #0x54 ]
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bic r12, r12, #3<<4
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orr r12, r12, #1<<7
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str r12, [ r14, #0x54 ]
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#endif
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#ifdef CONFIG_DEBUG_RESUME
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mov r3, #'L'
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strb r3, [ r2, #S3C2410_UTXH ]
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1001:
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ldrb r14, [ r3, #S3C2410_UTRSTAT ]
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tst r14, #S3C2410_UTRSTAT_TXE
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beq 1001b
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#endif /* CONFIG_DEBUG_RESUME */
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mov r1, #0
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mcr p15, 0, r1, c8, c7, 0 @@ invalidate I & D TLBs
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mcr p15, 0, r1, c7, c7, 0 @@ invalidate I & D caches
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ldr r0, s3c_sleep_save_phys @ address of restore block
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ldmia r0, { r4 - r13 }
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mcr p15, 0, r4, c13, c0, 0 @ PID
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mcr p15, 0, r5, c3, c0, 0 @ Domain ID
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mcr p15, 0, r6, c2, c0, 0 @ translation table base
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#ifdef CONFIG_DEBUG_RESUME
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mov r3, #'R'
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strb r3, [ r2, #S3C2410_UTXH ]
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#endif
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ldr r2, =resume_with_mmu
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mcr p15, 0, r7, c1, c0, 0 @ turn on MMU, etc
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nop @ second-to-last before mmu
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mov pc, r2 @ go back to virtual address
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.ltorg
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