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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/arm/mach-s3c2410/sleep.S
downloadconfigs-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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+/* linux/arch/arm/mach-s3c2410/sleep.S
+ *
+ * Copyright (c) 2004 Simtec Electronics
+ * Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2410 Power Manager (Suspend-To-RAM) support
+ *
+ * Based on PXA/SA1100 sleep code by:
+ * Nicolas Pitre, (c) 2002 Monta Vista Software Inc
+ * Cliff Brake, (c) 2001
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <linux/config.h>
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <asm/hardware.h>
+#include <asm/arch/map.h>
+
+#include <asm/arch/regs-gpio.h>
+#include <asm/arch/regs-clock.h>
+#include <asm/arch/regs-mem.h>
+#include <asm/arch/regs-serial.h>
+
+/* CONFIG_DEBUG_RESUME is dangerous if your bootloader does not
+ * reset the UART configuration, only enable if you really need this!
+*/
+//#define CONFIG_DEBUG_RESUME
+
+ .text
+
+ /* s3c2410_cpu_suspend
+ *
+ * put the cpu into sleep mode
+ *
+ * entry:
+ * r0 = sleep save block
+ */
+
+ENTRY(s3c2410_cpu_suspend)
+ stmfd sp!, { r4 - r12, lr }
+
+ @@ store co-processor registers
+
+ mrc p15, 0, r4, c15, c1, 0 @ CP access register
+ mrc p15, 0, r5, c13, c0, 0 @ PID
+ mrc p15, 0, r6, c3, c0, 0 @ Domain ID
+ mrc p15, 0, r7, c2, c0, 0 @ translation table base address
+ mrc p15, 0, r8, c2, c0, 0 @ auxiliary control register
+ mrc p15, 0, r9, c1, c0, 0 @ control register
+
+ stmia r0, { r4 - r13 }
+
+ @@ flush the caches to ensure everything is back out to
+ @@ SDRAM before the core powers down
+
+ bl arm920_flush_kern_cache_all
+
+ @@ prepare cpu to sleep
+
+ ldr r4, =S3C2410_REFRESH
+ ldr r5, =S3C2410_MISCCR
+ ldr r6, =S3C2410_CLKCON
+ ldr r7, [ r4 ] @ get REFRESH (and ensure in TLB)
+ ldr r8, [ r5 ] @ get MISCCR (and ensure in TLB)
+ ldr r9, [ r6 ] @ get CLKCON (and ensure in TLB)
+
+ orr r7, r7, #S3C2410_REFRESH_SELF @ SDRAM sleep command
+ orr r8, r8, #S3C2410_MISCCR_SDSLEEP @ SDRAM power-down signals
+ orr r9, r9, #S3C2410_CLKCON_POWER @ power down command
+
+ teq pc, #0 @ first as a trial-run to load cache
+ bl s3c2410_do_sleep
+ teq r0, r0 @ now do it for real
+ b s3c2410_do_sleep @
+
+ @@ align next bit of code to cache line
+ .align 8
+s3c2410_do_sleep:
+ streq r7, [ r4 ] @ SDRAM sleep command
+ streq r8, [ r5 ] @ SDRAM power-down config
+ streq r9, [ r6 ] @ CPU sleep
+1: beq 1b
+ mov pc, r14
+
+ @@ return to the caller, after having the MMU
+ @@ turned on, this restores the last bits from the
+ @@ stack
+resume_with_mmu:
+ ldmfd sp!, { r4 - r12, pc }
+
+ .ltorg
+
+ @@ the next bits sit in the .data segment, even though they
+ @@ happen to be code... the s3c2410_sleep_save_phys needs to be
+ @@ accessed by the resume code before it can restore the MMU.
+ @@ This means that the variable has to be close enough for the
+ @@ code to read it... since the .text segment needs to be RO,
+ @@ the data segment can be the only place to put this code.
+
+ .data
+
+ .global s3c2410_sleep_save_phys
+s3c2410_sleep_save_phys:
+ .word 0
+
+ /* s3c2410_cpu_resume
+ *
+ * resume code entry for bootloader to call
+ *
+ * we must put this code here in the data segment as we have no
+ * other way of restoring the stack pointer after sleep, and we
+ * must not write to the code segment (code is read-only)
+ */
+
+ENTRY(s3c2410_cpu_resume)
+ mov r0, #PSR_I_BIT | PSR_F_BIT | MODE_SVC
+ msr cpsr_c, r0
+
+ @@ load UART to allow us to print the two characters for
+ @@ resume debug
+
+ mov r2, #S3C2410_PA_UART & 0xff000000
+ orr r2, r2, #S3C2410_PA_UART & 0xff000
+
+#if 0
+ /* SMDK2440 LED set */
+ mov r14, #S3C2410_PA_GPIO
+ ldr r12, [ r14, #0x54 ]
+ bic r12, r12, #3<<4
+ orr r12, r12, #1<<7
+ str r12, [ r14, #0x54 ]
+#endif
+
+#ifdef CONFIG_DEBUG_RESUME
+ mov r3, #'L'
+ strb r3, [ r2, #S3C2410_UTXH ]
+1001:
+ ldrb r14, [ r3, #S3C2410_UTRSTAT ]
+ tst r14, #S3C2410_UTRSTAT_TXE
+ beq 1001b
+#endif /* CONFIG_DEBUG_RESUME */
+
+ mov r1, #0
+ mcr p15, 0, r1, c8, c7, 0 @@ invalidate I & D TLBs
+ mcr p15, 0, r1, c7, c7, 0 @@ invalidate I & D caches
+
+ ldr r0, s3c2410_sleep_save_phys @ address of restore block
+ ldmia r0, { r4 - r13 }
+
+ mcr p15, 0, r4, c15, c1, 0 @ CP access register
+ mcr p15, 0, r5, c13, c0, 0 @ PID
+ mcr p15, 0, r6, c3, c0, 0 @ Domain ID
+ mcr p15, 0, r7, c2, c0, 0 @ translation table base
+ mcr p15, 0, r8, c1, c1, 0 @ auxilliary control
+
+#ifdef CONFIG_DEBUG_RESUME
+ mov r3, #'R'
+ strb r3, [ r2, #S3C2410_UTXH ]
+#endif
+
+ ldr r2, =resume_with_mmu
+ mcr p15, 0, r9, c1, c0, 0 @ turn on MMU, etc
+ nop @ second-to-last before mmu
+ mov pc, r2 @ go back to virtual address
+
+ .ltorg