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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/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_save
+ *
+ * save enough of the CPU state to allow us to re-start
+ * pm.c code. as we store items like the sp/lr, we will
+ * end up returning from this function when the cpu resumes
+ * so the return value is set to mark this.
+ *
+ * This arangement means we avoid having to flush the cache
+ * from this code.
+ *
+ * entry:
+ * r0 = pointer to save block
+ *
+ * exit:
+ * r0 = 0 => we stored everything
+ * 1 => resumed from sleep
+ */
+
+ENTRY(s3c2410_cpu_save)
+ stmfd sp!, { r4 - r12, lr }
+
+ @@ store co-processor registers
+
+ mrc p15, 0, r4, c13, c0, 0 @ PID
+ mrc p15, 0, r5, c3, c0, 0 @ Domain ID
+ mrc p15, 0, r6, c2, c0, 0 @ translation table base address
+ mrc p15, 0, r7, c1, c0, 0 @ control register
+
+ stmia r0, { r4 - r13 }
+
+ mov r0, #0
+ ldmfd sp, { r4 - r12, pc }
+
+ @@ return to the caller, after having the MMU
+ @@ turned on, this restores the last bits from the
+ @@ stack
+resume_with_mmu:
+ mov r0, #1
+ 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 | SVC_MODE
+ msr cpsr_c, r0
+
+ @@ load UART to allow us to print the two characters for
+ @@ resume debug
+
+ mov r2, #S3C24XX_PA_UART & 0xff000000
+ orr r2, r2, #S3C24XX_PA_UART & 0xff000
+
+#if 0
+ /* SMDK2440 LED set */
+ mov r14, #S3C24XX_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, c13, c0, 0 @ PID
+ mcr p15, 0, r5, c3, c0, 0 @ Domain ID
+ mcr p15, 0, r6, c2, c0, 0 @ translation table base
+
+#ifdef CONFIG_DEBUG_RESUME
+ mov r3, #'R'
+ strb r3, [ r2, #S3C2410_UTXH ]
+#endif
+
+ ldr r2, =resume_with_mmu
+ mcr p15, 0, r7, c1, c0, 0 @ turn on MMU, etc
+ nop @ second-to-last before mmu
+ mov pc, r2 @ go back to virtual address
+
+ .ltorg