[ARM] S3C64XX: Initial support for PM (suspend to RAM)

Add the initial support for the S3C64XX based systems to use
suspend-to-RAM to sleep.

Includes basic debugging for use with the SMDK6410 usign the
LEDs on the baseboard.

Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 144 insertions, 0 deletions

diff --git a/arch/arm/plat-s3c64xx/sleep.S b/arch/arm/plat-s3c64xx/sleep.S
new file mode 100644
index 000000000000..8e71fe90a373
--- /dev/null
+++ b/arch/arm/plat-s3c64xx/sleep.S
@@ -0,0 +1,144 @@
+/* linux/0arch/arm/plat-s3c64xx/sleep.S
+ *
+ * Copyright 2008 Openmoko, Inc.
+ * Copyright 2008 Simtec Electronics
+ *	Ben Dooks <ben@simtec.co.uk>
+ *	http://armlinux.simtec.co.uk/
+ *
+ * S3C64XX CPU sleep code
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <mach/map.h>
+
+#undef S3C64XX_VA_GPIO
+#define S3C64XX_VA_GPIO (0x0)
+
+#include <plat/regs-gpio.h>
+#include <plat/gpio-bank-n.h>
+
+#define LL_UART (S3C_PA_UART + (0x400 * CONFIG_S3C_LOWLEVEL_UART_PORT))
+
+	.text
+
+	/* s3c_cpu_save
+	 *
+	 * Save enough processor state to allow the restart of the pm.c
+	 * code after resume.
+	 *
+	 * entry:
+	 *	r0 = pointer to the save block
+	*/
+
+ENTRY(s3c_cpu_save)
+	stmfd	sp!, { r4 - r12, lr }
+
+	mrc	p15, 0, r4, c13, c0, 0	@ FCSE/PID
+	mrc	p15, 0, r5, c3, c0, 0	@ Domain ID
+	mrc	p15, 0, r6, c2, c0, 0	@ Translation Table BASE0
+	mrc	p15, 0, r7, c2, c0, 1	@ Translation Table BASE1
+	mrc	p15, 0, r8, c2, c0, 2	@ Translation Table Control
+	mrc	p15, 0, r9, c1, c0, 0	@ Control register
+	mrc	p15, 0, r10, c1, c0, 1	@ Auxiliary control register
+	mrc	p15, 0, r11, c1, c0, 2	@ Co-processor access controls
+
+	stmia	r0, { r4 - r13 }	@ Save CP registers and SP
+
+	@@ save our state to ram
+	bl	s3c_pm_cb_flushcache
+
+	@@ call final suspend code
+	ldr	r0, =pm_cpu_sleep
+	ldr	pc, [r0]
+	
+	@@ return to the caller, after the MMU is turned on.
+	@@ restore the last bits of the stack and return.
+resume_with_mmu:
+	ldmfd	sp!, { r4 - r12, pc }	@ return, from sp from s3c_cpu_save
+
+	.data
+
+	/* the next bit is code, but it requires easy access to the
+	 * s3c_sleep_save_phys data before the MMU is switched on, so
+	 * we store the code that needs this variable in the .data where
+	 * the value can be written to (the .text segment is RO).
+	*/
+
+	.global	s3c_sleep_save_phys
+s3c_sleep_save_phys:
+	.word	0
+
+	/* Sleep magic, the word before the resume entry point so that the
+	 * bootloader can check for a resumeable image. */
+
+	.word	0x2bedf00d
+
+	/* s3c_cpu_reusme
+	 *
+	 * This is the entry point, stored by whatever method the bootloader
+	 * requires to get the kernel runnign again. This code expects to be
+	 * entered with no caches live and the MMU disabled. It will then
+	 * restore the MMU and other basic CP registers saved and restart
+	 * the kernel C code to finish the resume code.
+	*/
+
+ENTRY(s3c_cpu_resume)
+	msr	cpsr_c, #PSR_I_BIT | PSR_F_BIT | SVC_MODE
+	ldr	r2, =LL_UART		/* for debug */
+
+#ifdef CONFIG_S3C_PM_DEBUG_LED_SMDK
+	/* Initialise the GPIO state if we are debugging via the SMDK LEDs,
+	 * as the uboot version supplied resets these to inputs during the
+	 * resume checks.
+	*/
+
+	ldr	r3, =S3C64XX_PA_GPIO
+	ldr	r0, [ r3, #S3C64XX_GPNCON ]
+	bic	r0, r0, #(S3C64XX_GPN_CONMASK(12) | S3C64XX_GPN_CONMASK(13) | \
+			  S3C64XX_GPN_CONMASK(14) | S3C64XX_GPN_CONMASK(15))
+	orr	r0, r0, #(S3C64XX_GPN_OUTPUT(12) | S3C64XX_GPN_OUTPUT(13) | \
+			  S3C64XX_GPN_OUTPUT(14) | S3C64XX_GPN_OUTPUT(15))
+	str	r0, [ r3, #S3C64XX_GPNCON ]
+
+	ldr	r0, [ r3, #S3C64XX_GPNDAT ]
+	bic	r0, r0, #0xf << 12			@ GPN12..15
+	orr	r0, r0, #1 << 15			@ GPN15
+	str	r0, [ r3, #S3C64XX_GPNDAT ]
+#endif
+
+	/* __v6_setup from arch/arm/mm/proc-v6.S, ensure that the caches
+	 * are thoroughly cleaned just in case the bootloader didn't do it
+	 * for us. */
+	mov	r0, #0
+	mcr	p15, 0, r0, c7, c14, 0		@ clean+invalidate D cache
+	mcr	p15, 0, r0, c7, c5, 0		@ invalidate I cache
+	mcr	p15, 0, r0, c7, c15, 0		@ clean+invalidate cache
+	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer
+	@@mcr	p15, 0, r0, c8, c7, 0		@ invalidate I + D TLBs
+	@@mcr	p15, 0, r0, c7, c7, 0		@ Invalidate I + D caches
+
+	ldr	r0, s3c_sleep_save_phys
+	ldmia	r0, { r4 - r13 }
+
+	mcr	p15, 0, r4, c13, c0, 0	@ FCSE/PID
+	mcr	p15, 0, r5, c3, c0, 0	@ Domain ID
+	mcr	p15, 0, r6, c2, c0, 0	@ Translation Table BASE0
+	mcr	p15, 0, r7, c2, c0, 1	@ Translation Table BASE1
+	mcr	p15, 0, r8, c2, c0, 2	@ Translation Table Control
+	mcr	p15, 0, r10, c1, c0, 1	@ Auxiliary control register
+
+	mov	r0, #0			@ restore copro access controls
+	mcr	p15, 0, r11, c1, c0, 2	@ Co-processor access controls
+	mcr 	p15, 0, r0, c7, c5, 4
+
+	ldr	r2, =resume_with_mmu
+	mcr	p15, 0, r9, c1, c0, 0		/* turn mmu back on */
+	nop
+	mov	pc, r2				/* jump back */
+
+	.end