ARM: LPC32XX: System suspend support
Support for system suspend and resume
Signed-off-by: Kevin Wells <wellsk40@gmail.com>
diff --git a/arch/arm/mach-lpc32xx/suspend.S b/arch/arm/mach-lpc32xx/suspend.S
new file mode 100644
index 0000000..374f9f0
--- /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