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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/arm/mach-at91/pm.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/arm/mach-at91/pm.c')
-rw-r--r--arch/arm/mach-at91/pm.c327
1 files changed, 327 insertions, 0 deletions
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
new file mode 100644
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+++ b/arch/arm/mach-at91/pm.c
@@ -0,0 +1,327 @@
+/*
+ * 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/interrupt.h>
+#include <linux/sysfs.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+#include <asm/irq.h>
+#include <linux/atomic.h>
+#include <asm/mach/time.h>
+#include <asm/mach/irq.h>
+
+#include <mach/at91_pmc.h>
+#include <mach/cpu.h>
+
+#include "generic.h"
+#include "pm.h"
+
+/*
+ * Show the reason for the previous system reset.
+ */
+
+#include <mach/at91_rstc.h>
+#include <mach/at91_shdwc.h>
+
+static void __init show_reset_status(void)
+{
+ static char reset[] __initdata = "reset";
+
+ static char general[] __initdata = "general";
+ static char wakeup[] __initdata = "wakeup";
+ static char watchdog[] __initdata = "watchdog";
+ static char software[] __initdata = "software";
+ static char user[] __initdata = "user";
+ static char unknown[] __initdata = "unknown";
+
+ static char signal[] __initdata = "signal";
+ static char rtc[] __initdata = "rtc";
+ static char rtt[] __initdata = "rtt";
+ static char restore[] __initdata = "power-restored";
+
+ char *reason, *r2 = reset;
+ u32 reset_type, wake_type;
+
+ if (!at91_shdwc_base || !at91_rstc_base)
+ return;
+
+ reset_type = at91_rstc_read(AT91_RSTC_SR) & AT91_RSTC_RSTTYP;
+ wake_type = at91_shdwc_read(AT91_SHDW_SR);
+
+ switch (reset_type) {
+ case AT91_RSTC_RSTTYP_GENERAL:
+ reason = general;
+ break;
+ case AT91_RSTC_RSTTYP_WAKEUP:
+ /* board-specific code enabled the wakeup sources */
+ reason = wakeup;
+
+ /* "wakeup signal" */
+ if (wake_type & AT91_SHDW_WAKEUP0)
+ r2 = signal;
+ else {
+ r2 = reason;
+ if (wake_type & AT91_SHDW_RTTWK) /* rtt wakeup */
+ reason = rtt;
+ else if (wake_type & AT91_SHDW_RTCWK) /* rtc wakeup */
+ reason = rtc;
+ else if (wake_type == 0) /* power-restored wakeup */
+ reason = restore;
+ else /* unknown wakeup */
+ reason = unknown;
+ }
+ break;
+ case AT91_RSTC_RSTTYP_WATCHDOG:
+ reason = watchdog;
+ break;
+ case AT91_RSTC_RSTTYP_SOFTWARE:
+ reason = software;
+ break;
+ case AT91_RSTC_RSTTYP_USER:
+ reason = user;
+ break;
+ default:
+ reason = unknown;
+ break;
+ }
+ pr_info("AT91: Starting after %s %s\n", reason, r2);
+}
+
+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_sys_read(AT91_PMC_SCSR);
+
+ /* USB must not be using PLLB */
+ if (cpu_is_at91rm9200()) {
+ if ((scsr & (AT91RM9200_PMC_UHP | AT91RM9200_PMC_UDP)) != 0) {
+ pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
+ return 0;
+ }
+ } else if (cpu_is_at91sam9260() || cpu_is_at91sam9261() || cpu_is_at91sam9263()
+ || cpu_is_at91sam9g20() || cpu_is_at91sam9g10()) {
+ if ((scsr & (AT91SAM926x_PMC_UHP | AT91SAM926x_PMC_UDP)) != 0) {
+ pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
+ return 0;
+ }
+ } else if (cpu_is_at91cap9()) {
+ if ((scsr & AT91CAP9_PMC_UHP) != 0) {
+ pr_err("AT91: PM - Suspend-to-RAM with USB still active\n");
+ return 0;
+ }
+ }
+
+#ifdef CONFIG_AT91_PROGRAMMABLE_CLOCKS
+ /* 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_sys_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;
+ }
+ }
+#endif
+
+ 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 (*slow_clock)(void);
+
+#ifdef CONFIG_AT91_SLOW_CLOCK
+extern void at91_slow_clock(void);
+extern u32 at91_slow_clock_sz;
+#endif
+
+
+static int at91_pm_enter(suspend_state_t state)
+{
+ u32 saved_lpr;
+ at91_gpio_suspend();
+ at91_irq_suspend();
+
+ pr_debug("AT91: PM - wake mask %08x, pm state %d\n",
+ /* remember all the always-wake irqs */
+ (at91_sys_read(AT91_PMC_PCSR)
+ | (1 << AT91_ID_FIQ)
+ | (1 << AT91_ID_SYS)
+ | (at91_extern_irq))
+ & at91_aic_read(AT91_AIC_IMR),
+ state);
+
+ switch (state) {
+ /*
+ * Suspend-to-RAM is like STANDBY plus slow clock mode, so
+ * drivers must suspend more deeply: only the master clock
+ * controller may be using the main oscillator.
+ */
+ case PM_SUSPEND_MEM:
+ /*
+ * Ensure that clocks are in a valid state.
+ */
+ if (!at91_pm_verify_clocks())
+ goto error;
+
+ /*
+ * Enter slow clock mode by switching over to clk32k and
+ * turning off the main oscillator; reverse on wakeup.
+ */
+ if (slow_clock) {
+#ifdef CONFIG_AT91_SLOW_CLOCK
+ /* copy slow_clock handler to SRAM, and call it */
+ memcpy(slow_clock, at91_slow_clock, at91_slow_clock_sz);
+#endif
+ slow_clock();
+ break;
+ } else {
+ pr_info("AT91: PM - no slow clock mode enabled ...\n");
+ /* FALLTHROUGH leaving master clock alone */
+ }
+
+ /*
+ * 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:
+ /*
+ * NOTE: the Wait-for-Interrupt instruction needs to be
+ * in icache so no SDRAM accesses are needed until the
+ * wakeup IRQ occurs and self-refresh is terminated.
+ * For ARM 926 based chips, this requirement is weaker
+ * as at91sam9 can access a RAM in self-refresh mode.
+ */
+ asm volatile ( "mov r0, #0\n\t"
+ "b 1f\n\t"
+ ".align 5\n\t"
+ "1: mcr p15, 0, r0, c7, c10, 4\n\t"
+ : /* no output */
+ : /* no input */
+ : "r0");
+ saved_lpr = sdram_selfrefresh_enable();
+ wait_for_interrupt_enable();
+ sdram_selfrefresh_disable(saved_lpr);
+ break;
+
+ case PM_SUSPEND_ON:
+ cpu_do_idle();
+ break;
+
+ default:
+ pr_debug("AT91: PM - bogus suspend state %d\n", state);
+ goto error;
+ }
+
+ pr_debug("AT91: PM - wakeup %08x\n",
+ at91_aic_read(AT91_AIC_IPR) & at91_aic_read(AT91_AIC_IMR));
+
+error:
+ target_state = PM_SUSPEND_ON;
+ at91_irq_resume();
+ at91_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 int __init at91_pm_init(void)
+{
+#ifdef CONFIG_AT91_SLOW_CLOCK
+ slow_clock = (void *) (AT91_IO_VIRT_BASE - at91_slow_clock_sz);
+#endif
+
+ pr_info("AT91: Power Management%s\n", (slow_clock ? " (with slow clock mode)" : ""));
+
+#ifdef CONFIG_ARCH_AT91RM9200
+ /* AT91RM9200 SDRAM low-power mode cannot be used with self-refresh. */
+ at91_sys_write(AT91_SDRAMC_LPR, 0);
+#endif
+
+ suspend_set_ops(&at91_pm_ops);
+
+ show_reset_status();
+ return 0;
+}
+arch_initcall(at91_pm_init);