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author | Kevin Wells <wellsk40@gmail.com> | 2010-07-27 08:35:56 -0700 |
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committer | Kevin Wells <wellsk40@gmail.com> | 2010-07-27 08:35:56 -0700 |
commit | 3c0e1947d9c171649f3bde13d1010ac6d7ce09c1 (patch) | |
tree | 2cd113b5d28f11dd7c6e3125abbe50ef35de83e9 | |
parent | c4a0208fff6cba5c7e22166ad7209322eab16bb3 (diff) | |
download | linux-3c0e1947d9c171649f3bde13d1010ac6d7ce09c1.tar.bz2 |
ARM: LPC32XX: System suspend support
Support for system suspend and resume
Signed-off-by: Kevin Wells <wellsk40@gmail.com>
-rw-r--r-- | arch/arm/mach-lpc32xx/pm.c | 146 | ||||
-rw-r--r-- | arch/arm/mach-lpc32xx/suspend.S | 151 |
2 files changed, 297 insertions, 0 deletions
diff --git a/arch/arm/mach-lpc32xx/pm.c b/arch/arm/mach-lpc32xx/pm.c new file mode 100644 index 000000000000..a6e2aed9a49f --- /dev/null +++ b/arch/arm/mach-lpc32xx/pm.c @@ -0,0 +1,146 @@ +/* + * arch/arm/mach-lpc32xx/pm.c + * + * Original authors: Vitaly Wool, Dmitry Chigirev <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. + */ + +/* + * LPC32XX CPU and system power management + * + * The LCP32XX has three CPU modes for controlling system power: run, + * direct-run, and halt modes. When switching between halt and run modes, + * the CPU transistions through direct-run mode. For Linux, direct-run + * mode is not used in normal operation. Halt mode is used when the + * system is fully suspended. + * + * Run mode: + * The ARM CPU clock (HCLK_PLL), HCLK bus clock, and PCLK bus clocks are + * derived from the HCLK PLL. The HCLK and PCLK bus rates are divided from + * the HCLK_PLL rate. Linux runs in this mode. + * + * Direct-run mode: + * The ARM CPU clock, HCLK bus clock, and PCLK bus clocks are driven from + * SYSCLK. SYSCLK is usually around 13MHz, but may vary based on SYSCLK + * source or the frequency of the main oscillator. In this mode, the + * HCLK_PLL can be safely enabled, changed, or disabled. + * + * Halt mode: + * SYSCLK is gated off and the CPU and system clocks are halted. + * Peripherals based on the 32KHz oscillator clock (ie, RTC, touch, + * key scanner, etc.) still operate if enabled. In this state, an enabled + * system event (ie, GPIO state change, RTC match, key press, etc.) will + * wake the system up back into direct-run mode. + * + * DRAM refresh + * DRAM clocking and refresh are slightly different for systems with DDR + * DRAM or regular SDRAM devices. If SDRAM is used in the system, the + * SDRAM will still be accessible in direct-run mode. In DDR based systems, + * a transistion to direct-run mode will stop all DDR accesses (no clocks). + * Because of this, the code to switch power modes and the code to enter + * and exit DRAM self-refresh modes must not be executed in DRAM. A small + * section of IRAM is used instead for this. + * + * Suspend is handled with the following logic: + * Backup a small area of IRAM used for the suspend code + * Copy suspend code to IRAM + * Transfer control to code in IRAM + * Places DRAMs in self-refresh mode + * Enter direct-run mode + * Save state of HCLK_PLL PLL + * Disable HCLK_PLL PLL + * Enter halt mode - CPU and buses will stop + * System enters direct-run mode when an enabled event occurs + * HCLK PLL state is restored + * Run mode is entered + * DRAMS are placed back into normal mode + * Code execution returns from IRAM + * IRAM code are used for suspend is restored + * Suspend mode is exited + */ + +#include <linux/suspend.h> +#include <linux/io.h> +#include <linux/slab.h> + +#include <asm/cacheflush.h> + +#include <mach/hardware.h> +#include <mach/platform.h> +#include "common.h" +#include "clock.h" + +#define TEMP_IRAM_AREA IO_ADDRESS(LPC32XX_IRAM_BASE) + +/* + * Both STANDBY and MEM suspend states are handled the same with no + * loss of CPU or memory state + */ +static int lpc32xx_pm_enter(suspend_state_t state) +{ + int (*lpc32xx_suspend_ptr) (void); + void *iram_swap_area; + + /* Allocate some space for temporary IRAM storage */ + iram_swap_area = kmalloc(lpc32xx_sys_suspend_sz, GFP_KERNEL); + if (!iram_swap_area) { + printk(KERN_ERR + "PM Suspend: cannot allocate memory to save portion " + "of SRAM\n"); + return -ENOMEM; + } + + /* Backup a small area of IRAM used for the suspend code */ + memcpy(iram_swap_area, (void *) TEMP_IRAM_AREA, + lpc32xx_sys_suspend_sz); + + /* + * Copy code to suspend system into IRAM. The suspend code + * needs to run from IRAM as DRAM may no longer be available + * when the PLL is stopped. + */ + memcpy((void *) TEMP_IRAM_AREA, &lpc32xx_sys_suspend, + lpc32xx_sys_suspend_sz); + flush_icache_range((unsigned long)TEMP_IRAM_AREA, + (unsigned long)(TEMP_IRAM_AREA) + lpc32xx_sys_suspend_sz); + + /* Transfer to suspend code in IRAM */ + lpc32xx_suspend_ptr = (void *) TEMP_IRAM_AREA; + flush_cache_all(); + (void) lpc32xx_suspend_ptr(); + + /* Restore original IRAM contents */ + memcpy((void *) TEMP_IRAM_AREA, iram_swap_area, + lpc32xx_sys_suspend_sz); + + kfree(iram_swap_area); + + return 0; +} + +static struct platform_suspend_ops lpc32xx_pm_ops = { + .valid = suspend_valid_only_mem, + .enter = lpc32xx_pm_enter, +}; + +#define EMC_DYN_MEM_CTRL_OFS 0x20 +#define EMC_SRMMC (1 << 3) +#define EMC_CTRL_REG io_p2v(LPC32XX_EMC_BASE + EMC_DYN_MEM_CTRL_OFS) +static int __init lpc32xx_pm_init(void) +{ + /* + * Setup SDRAM self-refresh clock to automatically disable o + * start of self-refresh. This only needs to be done once. + */ + __raw_writel(__raw_readl(EMC_CTRL_REG) | EMC_SRMMC, EMC_CTRL_REG); + + suspend_set_ops(&lpc32xx_pm_ops); + + return 0; +} +arch_initcall(lpc32xx_pm_init); 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 |