diff options
Diffstat (limited to 'kernel/arch/arm/mach-at91/pm.c')
| -rw-r--r-- | kernel/arch/arm/mach-at91/pm.c | 447 |
1 files changed, 447 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-at91/pm.c b/kernel/arch/arm/mach-at91/pm.c new file mode 100644 index 000000000..5062699cb --- /dev/null +++ b/kernel/arch/arm/mach-at91/pm.c @@ -0,0 +1,447 @@ +/* + * arch/arm/mach-at91/pm.c + * AT91 Power Management + * + * Copyright (C) 2005 David Brownell + * + * 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. + */ + +#include <linux/gpio.h> +#include <linux/suspend.h> +#include <linux/sched.h> +#include <linux/proc_fs.h> +#include <linux/genalloc.h> +#include <linux/interrupt.h> +#include <linux/sysfs.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/of_address.h> +#include <linux/platform_device.h> +#include <linux/io.h> +#include <linux/clk/at91_pmc.h> + +#include <asm/irq.h> +#include <linux/atomic.h> +#include <asm/mach/time.h> +#include <asm/mach/irq.h> +#include <asm/fncpy.h> +#include <asm/cacheflush.h> + +#include "generic.h" +#include "pm.h" + +/* + * FIXME: this is needed to communicate between the pinctrl driver and + * the PM implementation in the machine. Possibly part of the PM + * implementation should be moved down into the pinctrl driver and get + * called as part of the generic suspend/resume path. + */ +extern void at91_pinctrl_gpio_suspend(void); +extern void at91_pinctrl_gpio_resume(void); + +static struct { + unsigned long uhp_udp_mask; + int memctrl; +} at91_pm_data; + +void __iomem *at91_ramc_base[2]; + +static int at91_pm_valid_state(suspend_state_t state) +{ + switch (state) { + case PM_SUSPEND_ON: + case PM_SUSPEND_STANDBY: + case PM_SUSPEND_MEM: + return 1; + + default: + return 0; + } +} + + +static suspend_state_t target_state; + +/* + * Called after processes are frozen, but before we shutdown devices. + */ +static int at91_pm_begin(suspend_state_t state) +{ + target_state = state; + return 0; +} + +/* + * Verify that all the clocks are correct before entering + * slow-clock mode. + */ +static int at91_pm_verify_clocks(void) +{ + unsigned long scsr; + int i; + + scsr = at91_pmc_read(AT91_PMC_SCSR); + + /* USB must not be using PLLB */ + if ((scsr & at91_pm_data.uhp_udp_mask) != 0) { + pr_err("AT91: PM - Suspend-to-RAM with USB still active\n"); + return 0; + } + + /* PCK0..PCK3 must be disabled, or configured to use clk32k */ + for (i = 0; i < 4; i++) { + u32 css; + + if ((scsr & (AT91_PMC_PCK0 << i)) == 0) + continue; + + css = at91_pmc_read(AT91_PMC_PCKR(i)) & AT91_PMC_CSS; + if (css != AT91_PMC_CSS_SLOW) { + pr_err("AT91: PM - Suspend-to-RAM with PCK%d src %d\n", i, css); + return 0; + } + } + + return 1; +} + +/* + * Call this from platform driver suspend() to see how deeply to suspend. + * For example, some controllers (like OHCI) need one of the PLL clocks + * in order to act as a wakeup source, and those are not available when + * going into slow clock mode. + * + * REVISIT: generalize as clk_will_be_available(clk)? Other platforms have + * the very same problem (but not using at91 main_clk), and it'd be better + * to add one generic API rather than lots of platform-specific ones. + */ +int at91_suspend_entering_slow_clock(void) +{ + return (target_state == PM_SUSPEND_MEM); +} +EXPORT_SYMBOL(at91_suspend_entering_slow_clock); + +static void (*at91_suspend_sram_fn)(void __iomem *pmc, void __iomem *ramc0, + void __iomem *ramc1, int memctrl); + +extern void at91_pm_suspend_in_sram(void __iomem *pmc, void __iomem *ramc0, + void __iomem *ramc1, int memctrl); +extern u32 at91_pm_suspend_in_sram_sz; + +static void at91_pm_suspend(suspend_state_t state) +{ + unsigned int pm_data = at91_pm_data.memctrl; + + pm_data |= (state == PM_SUSPEND_MEM) ? + AT91_PM_MODE(AT91_PM_SLOW_CLOCK) : 0; + + flush_cache_all(); + outer_disable(); + + at91_suspend_sram_fn(at91_pmc_base, at91_ramc_base[0], + at91_ramc_base[1], pm_data); + + outer_resume(); +} + +static int at91_pm_enter(suspend_state_t state) +{ + at91_pinctrl_gpio_suspend(); + + switch (state) { + /* + * Suspend-to-RAM is like STANDBY plus slow clock mode, so + * drivers must suspend more deeply, the master clock switches + * to the clk32k and turns off the main oscillator + */ + case PM_SUSPEND_MEM: + /* + * Ensure that clocks are in a valid state. + */ + if (!at91_pm_verify_clocks()) + goto error; + + at91_pm_suspend(state); + + break; + + /* + * STANDBY mode has *all* drivers suspended; ignores irqs not + * marked as 'wakeup' event sources; and reduces DRAM power. + * But otherwise it's identical to PM_SUSPEND_ON: cpu idle, and + * nothing fancy done with main or cpu clocks. + */ + case PM_SUSPEND_STANDBY: + at91_pm_suspend(state); + break; + + case PM_SUSPEND_ON: + cpu_do_idle(); + break; + + default: + pr_debug("AT91: PM - bogus suspend state %d\n", state); + goto error; + } + +error: + target_state = PM_SUSPEND_ON; + + at91_pinctrl_gpio_resume(); + return 0; +} + +/* + * Called right prior to thawing processes. + */ +static void at91_pm_end(void) +{ + target_state = PM_SUSPEND_ON; +} + + +static const struct platform_suspend_ops at91_pm_ops = { + .valid = at91_pm_valid_state, + .begin = at91_pm_begin, + .enter = at91_pm_enter, + .end = at91_pm_end, +}; + +static struct platform_device at91_cpuidle_device = { + .name = "cpuidle-at91", +}; + +static void at91_pm_set_standby(void (*at91_standby)(void)) +{ + if (at91_standby) + at91_cpuidle_device.dev.platform_data = at91_standby; +} + +/* + * The AT91RM9200 goes into self-refresh mode with this command, and will + * terminate self-refresh automatically on the next SDRAM access. + * + * Self-refresh mode is exited as soon as a memory access is made, but we don't + * know for sure when that happens. However, we need to restore the low-power + * mode if it was enabled before going idle. Restoring low-power mode while + * still in self-refresh is "not recommended", but seems to work. + */ +static void at91rm9200_standby(void) +{ + u32 lpr = at91_ramc_read(0, AT91RM9200_SDRAMC_LPR); + + asm volatile( + "b 1f\n\t" + ".align 5\n\t" + "1: mcr p15, 0, %0, c7, c10, 4\n\t" + " str %0, [%1, %2]\n\t" + " str %3, [%1, %4]\n\t" + " mcr p15, 0, %0, c7, c0, 4\n\t" + " str %5, [%1, %2]" + : + : "r" (0), "r" (at91_ramc_base[0]), "r" (AT91RM9200_SDRAMC_LPR), + "r" (1), "r" (AT91RM9200_SDRAMC_SRR), + "r" (lpr)); +} + +/* We manage both DDRAM/SDRAM controllers, we need more than one value to + * remember. + */ +static void at91_ddr_standby(void) +{ + /* Those two values allow us to delay self-refresh activation + * to the maximum. */ + u32 lpr0, lpr1 = 0; + u32 saved_lpr0, saved_lpr1 = 0; + + if (at91_ramc_base[1]) { + saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR); + lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB; + lpr1 |= AT91_DDRSDRC_LPCB_SELF_REFRESH; + } + + saved_lpr0 = at91_ramc_read(0, AT91_DDRSDRC_LPR); + lpr0 = saved_lpr0 & ~AT91_DDRSDRC_LPCB; + lpr0 |= AT91_DDRSDRC_LPCB_SELF_REFRESH; + + /* self-refresh mode now */ + at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0); + if (at91_ramc_base[1]) + at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1); + + cpu_do_idle(); + + at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0); + if (at91_ramc_base[1]) + at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1); +} + +/* We manage both DDRAM/SDRAM controllers, we need more than one value to + * remember. + */ +static void at91sam9_sdram_standby(void) +{ + u32 lpr0, lpr1 = 0; + u32 saved_lpr0, saved_lpr1 = 0; + + if (at91_ramc_base[1]) { + saved_lpr1 = at91_ramc_read(1, AT91_SDRAMC_LPR); + lpr1 = saved_lpr1 & ~AT91_SDRAMC_LPCB; + lpr1 |= AT91_SDRAMC_LPCB_SELF_REFRESH; + } + + saved_lpr0 = at91_ramc_read(0, AT91_SDRAMC_LPR); + lpr0 = saved_lpr0 & ~AT91_SDRAMC_LPCB; + lpr0 |= AT91_SDRAMC_LPCB_SELF_REFRESH; + + /* self-refresh mode now */ + at91_ramc_write(0, AT91_SDRAMC_LPR, lpr0); + if (at91_ramc_base[1]) + at91_ramc_write(1, AT91_SDRAMC_LPR, lpr1); + + cpu_do_idle(); + + at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr0); + if (at91_ramc_base[1]) + at91_ramc_write(1, AT91_SDRAMC_LPR, saved_lpr1); +} + +static const struct of_device_id ramc_ids[] __initconst = { + { .compatible = "atmel,at91rm9200-sdramc", .data = at91rm9200_standby }, + { .compatible = "atmel,at91sam9260-sdramc", .data = at91sam9_sdram_standby }, + { .compatible = "atmel,at91sam9g45-ddramc", .data = at91_ddr_standby }, + { .compatible = "atmel,sama5d3-ddramc", .data = at91_ddr_standby }, + { /*sentinel*/ } +}; + +static __init void at91_dt_ramc(void) +{ + struct device_node *np; + const struct of_device_id *of_id; + int idx = 0; + const void *standby = NULL; + + for_each_matching_node_and_match(np, ramc_ids, &of_id) { + at91_ramc_base[idx] = of_iomap(np, 0); + if (!at91_ramc_base[idx]) + panic(pr_fmt("unable to map ramc[%d] cpu registers\n"), idx); + + if (!standby) + standby = of_id->data; + + idx++; + } + + if (!idx) + panic(pr_fmt("unable to find compatible ram controller node in dtb\n")); + + if (!standby) { + pr_warn("ramc no standby function available\n"); + return; + } + + at91_pm_set_standby(standby); +} + +static void __init at91_pm_sram_init(void) +{ + struct gen_pool *sram_pool; + phys_addr_t sram_pbase; + unsigned long sram_base; + struct device_node *node; + struct platform_device *pdev = NULL; + + for_each_compatible_node(node, NULL, "mmio-sram") { + pdev = of_find_device_by_node(node); + if (pdev) { + of_node_put(node); + break; + } + } + + if (!pdev) { + pr_warn("%s: failed to find sram device!\n", __func__); + return; + } + + sram_pool = dev_get_gen_pool(&pdev->dev); + if (!sram_pool) { + pr_warn("%s: sram pool unavailable!\n", __func__); + return; + } + + sram_base = gen_pool_alloc(sram_pool, at91_pm_suspend_in_sram_sz); + if (!sram_base) { + pr_warn("%s: unable to alloc sram!\n", __func__); + return; + } + + sram_pbase = gen_pool_virt_to_phys(sram_pool, sram_base); + at91_suspend_sram_fn = __arm_ioremap_exec(sram_pbase, + at91_pm_suspend_in_sram_sz, false); + if (!at91_suspend_sram_fn) { + pr_warn("SRAM: Could not map\n"); + return; + } + + /* Copy the pm suspend handler to SRAM */ + at91_suspend_sram_fn = fncpy(at91_suspend_sram_fn, + &at91_pm_suspend_in_sram, at91_pm_suspend_in_sram_sz); +} + +static void __init at91_pm_init(void) +{ + at91_pm_sram_init(); + + if (at91_cpuidle_device.dev.platform_data) + platform_device_register(&at91_cpuidle_device); + + if (at91_suspend_sram_fn) + suspend_set_ops(&at91_pm_ops); + else + pr_info("AT91: PM not supported, due to no SRAM allocated\n"); +} + +void __init at91rm9200_pm_init(void) +{ + at91_dt_ramc(); + + /* + * AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. + */ + at91_ramc_write(0, AT91RM9200_SDRAMC_LPR, 0); + + at91_pm_data.uhp_udp_mask = AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP; + at91_pm_data.memctrl = AT91_MEMCTRL_MC; + + at91_pm_init(); +} + +void __init at91sam9260_pm_init(void) +{ + at91_dt_ramc(); + at91_pm_data.memctrl = AT91_MEMCTRL_SDRAMC; + at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP; + return at91_pm_init(); +} + +void __init at91sam9g45_pm_init(void) +{ + at91_dt_ramc(); + at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP; + at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR; + return at91_pm_init(); +} + +void __init at91sam9x5_pm_init(void) +{ + at91_dt_ramc(); + at91_pm_data.uhp_udp_mask = AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP; + at91_pm_data.memctrl = AT91_MEMCTRL_DDRSDR; + return at91_pm_init(); +} |