ARM: LPC32XX: System suspend support

Support for system suspend and resume

Signed-off-by: Kevin Wells <wellsk40@gmail.com>

1 files changed, 151 insertions, 0 deletions

diff --git a/arch/arm/mach-lpc32xx/suspend.S b/arch/arm/mach-lpc32xx/suspend.S
new file mode 100644
index 000000000000..374f9f07fe48
--- /dev/null
+++ b/arch/arm/mach-lpc32xx/suspend.S
@@ -0,0 +1,151 @@
+/*
+ * arch/arm/mach-lpc32xx/suspend.S
+ *
+ * Original authors: Dmitry Chigirev, Vitaly Wool <source@mvista.com>
+ * Modified by Kevin Wells <kevin.wells@nxp.com>
+ *
+ * 2005 (c) MontaVista Software, Inc. This file is licensed under
+ * the terms of the GNU General Public License version 2. This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ */
+#include <linux/linkage.h>
+#include <asm/assembler.h>
+#include <mach/platform.h>
+#include <mach/hardware.h>
+
+/* Using named register defines makes the code easier to follow */
+#define WORK1_REG			r0
+#define WORK2_REG			r1
+#define SAVED_HCLK_DIV_REG		r2
+#define SAVED_HCLK_PLL_REG		r3
+#define SAVED_DRAM_CLKCTRL_REG		r4
+#define SAVED_PWR_CTRL_REG		r5
+#define CLKPWRBASE_REG			r6
+#define EMCBASE_REG			r7
+
+#define LPC32XX_EMC_STATUS_OFFS		0x04
+#define LPC32XX_EMC_STATUS_BUSY		0x1
+#define LPC32XX_EMC_STATUS_SELF_RFSH	0x4
+
+#define LPC32XX_CLKPWR_PWR_CTRL_OFFS	0x44
+#define LPC32XX_CLKPWR_HCLK_DIV_OFFS	0x40
+#define LPC32XX_CLKPWR_HCLKPLL_CTRL_OFFS 0x58
+
+#define CLKPWR_PCLK_DIV_MASK		0xFFFFFE7F
+
+	.text
+
+ENTRY(lpc32xx_sys_suspend)
+	@ Save a copy of the used registers in IRAM, r0 is corrupted
+	adr	r0, tmp_stack_end
+	stmfd	r0!, {r3 - r7, sp, lr}
+
+	@ Load a few common register addresses
+	adr	WORK1_REG, reg_bases
+	ldr	CLKPWRBASE_REG, [WORK1_REG, #0]
+	ldr	EMCBASE_REG, [WORK1_REG, #4]
+
+	ldr	SAVED_PWR_CTRL_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+	orr	WORK1_REG, SAVED_PWR_CTRL_REG, #LPC32XX_CLKPWR_SDRAM_SELF_RFSH
+
+	@ Wait for SDRAM busy status to go busy and then idle
+	@ This guarantees a small windows where DRAM isn't busy
+1:
+	ldr	WORK2_REG, [EMCBASE_REG, #LPC32XX_EMC_STATUS_OFFS]
+	and	WORK2_REG, WORK2_REG, #LPC32XX_EMC_STATUS_BUSY
+	cmp	WORK2_REG, #LPC32XX_EMC_STATUS_BUSY
+	bne	1b @ Branch while idle
+2:
+	ldr	WORK2_REG, [EMCBASE_REG, #LPC32XX_EMC_STATUS_OFFS]
+	and	WORK2_REG, WORK2_REG, #LPC32XX_EMC_STATUS_BUSY
+	cmp	WORK2_REG, #LPC32XX_EMC_STATUS_BUSY
+	beq	2b @ Branch until idle
+
+	@ Setup self-refresh with support for manual exit of
+	@ self-refresh mode
+	str	WORK1_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+	orr	WORK2_REG, WORK1_REG, #LPC32XX_CLKPWR_UPD_SDRAM_SELF_RFSH
+	str	WORK2_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+	str	WORK1_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+
+	@ Wait for self-refresh acknowledge, clocks to the DRAM device
+	@ will automatically stop on start of self-refresh
+3:
+	ldr	WORK2_REG, [EMCBASE_REG, #LPC32XX_EMC_STATUS_OFFS]
+	and	WORK2_REG, WORK2_REG, #LPC32XX_EMC_STATUS_SELF_RFSH
+	cmp	WORK2_REG, #LPC32XX_EMC_STATUS_SELF_RFSH
+	bne	3b @ Branch until self-refresh mode starts
+
+	@ Enter direct-run mode from run mode
+	bic	WORK1_REG, WORK1_REG, #LPC32XX_CLKPWR_SELECT_RUN_MODE
+	str	WORK1_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+
+	@ Safe disable of DRAM clock in EMC block, prevents DDR sync
+	@ issues on restart
+	ldr	SAVED_HCLK_DIV_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_HCLK_DIV_OFFS]
+	and	WORK2_REG, SAVED_HCLK_DIV_REG, #CLKPWR_PCLK_DIV_MASK
+	str	WORK2_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_HCLK_DIV_OFFS]
+
+	@ Save HCLK PLL state and disable HCLK PLL
+	ldr	SAVED_HCLK_PLL_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_HCLKPLL_CTRL_OFFS]
+	bic	WORK2_REG, SAVED_HCLK_PLL_REG, #LPC32XX_CLKPWR_HCLKPLL_POWER_UP
+	str	WORK2_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_HCLKPLL_CTRL_OFFS]
+
+	@ Enter stop mode until an enabled event occurs
+	orr	WORK1_REG, WORK1_REG, #LPC32XX_CLKPWR_STOP_MODE_CTRL
+	str	WORK1_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+	.rept 9
+	nop
+	.endr
+
+	@ Clear stop status
+	bic	WORK1_REG, WORK1_REG, #LPC32XX_CLKPWR_STOP_MODE_CTRL
+
+	@ Restore original HCLK PLL value and wait for PLL lock
+	str	SAVED_HCLK_PLL_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_HCLKPLL_CTRL_OFFS]
+4:
+	ldr	WORK2_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_HCLKPLL_CTRL_OFFS]
+	and	WORK2_REG, WORK2_REG, #LPC32XX_CLKPWR_HCLKPLL_PLL_STS
+	bne	4b
+
+	@ Re-enter run mode with self-refresh flag cleared, but no DRAM
+	@ update yet. DRAM is still in self-refresh
+	str	SAVED_PWR_CTRL_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+
+	@ Restore original DRAM clock mode to restore DRAM clocks
+	str	SAVED_HCLK_DIV_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_HCLK_DIV_OFFS]
+
+	@ Clear self-refresh mode
+	orr	WORK1_REG, SAVED_PWR_CTRL_REG,\
+		#LPC32XX_CLKPWR_UPD_SDRAM_SELF_RFSH
+	str	WORK1_REG, [CLKPWRBASE_REG, #LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+	str	SAVED_PWR_CTRL_REG, [CLKPWRBASE_REG,\
+		#LPC32XX_CLKPWR_PWR_CTRL_OFFS]
+
+	@ Wait for EMC to clear self-refresh mode
+5:
+	ldr	WORK2_REG, [EMCBASE_REG, #LPC32XX_EMC_STATUS_OFFS]
+	and	WORK2_REG, WORK2_REG, #LPC32XX_EMC_STATUS_SELF_RFSH
+	bne	5b @ Branch until self-refresh has exited
+
+	@ restore regs and return
+	adr	r0, tmp_stack
+	ldmfd	r0!, {r3 - r7, sp, pc}
+
+reg_bases:
+	.long	IO_ADDRESS(LPC32XX_CLK_PM_BASE)
+	.long	IO_ADDRESS(LPC32XX_EMC_BASE)
+
+tmp_stack:
+	.long	0, 0, 0, 0, 0, 0, 0
+tmp_stack_end:
+
+ENTRY(lpc32xx_sys_suspend_sz)
+	.word	. - lpc32xx_sys_suspend