avr32: Power Management support ("standby" and "mem" modes)
Implement Standby support. In this mode, we'll suspend all drivers,
put the SDRAM in self-refresh mode and switch off the HSB bus
("frozen" mode.)
Implement Suspend-to-mem support. In this mode, we suspend all
drivers, put the SDRAM into self-refresh mode and switch off all
internal clocks except the 32 kHz oscillator ("stop" mode.)
The lowest-level suspend code runs from a small portion of SRAM
allocated at startup time. This gets rid of a small potential race
with the SDRAM where we might try to enter self-refresh mode in the
middle of an icache burst. We also relocate all interrupt and
exception handlers to SRAM during the small window when we enter and
exit the low-power modes.
We don't need to do any special tricks to start and stop the PLL. The
main clock is automatically gated by hardware until the PLL is stable.
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index e8ee5fa..45d63c9 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -205,6 +205,11 @@
menu "Power management options"
+source "kernel/power/Kconfig"
+
+config ARCH_SUSPEND_POSSIBLE
+ def_bool y
+
menu "CPU Frequency scaling"
source "drivers/cpufreq/Kconfig"
diff --git a/arch/avr32/mach-at32ap/Makefile b/arch/avr32/mach-at32ap/Makefile
index cb44182..d5018e2 100644
--- a/arch/avr32/mach-at32ap/Makefile
+++ b/arch/avr32/mach-at32ap/Makefile
@@ -1,3 +1,8 @@
obj-y += pdc.o clock.o intc.o extint.o pio.o hsmc.o
obj-$(CONFIG_CPU_AT32AP700X) += at32ap700x.o pm-at32ap700x.o
obj-$(CONFIG_CPU_FREQ_AT32AP) += cpufreq.o
+obj-$(CONFIG_PM) += pm.o
+
+ifeq ($(CONFIG_PM_DEBUG),y)
+CFLAGS_pm.o += -DDEBUG
+endif
diff --git a/arch/avr32/mach-at32ap/intc.c b/arch/avr32/mach-at32ap/intc.c
index 644a3fb..994c4545 100644
--- a/arch/avr32/mach-at32ap/intc.c
+++ b/arch/avr32/mach-at32ap/intc.c
@@ -22,6 +22,10 @@
void __iomem *regs;
struct irq_chip chip;
struct sys_device sysdev;
+#ifdef CONFIG_PM
+ unsigned long suspend_ipr;
+ unsigned long saved_ipr[64];
+#endif
};
extern struct platform_device at32_intc0_device;
@@ -138,8 +142,56 @@
panic("Interrupt controller initialization failed!\n");
}
+#ifdef CONFIG_PM
+void intc_set_suspend_handler(unsigned long offset)
+{
+ intc0.suspend_ipr = offset;
+}
+
+static int intc_suspend(struct sys_device *sdev, pm_message_t state)
+{
+ struct intc *intc = container_of(sdev, struct intc, sysdev);
+ int i;
+
+ if (unlikely(!irqs_disabled())) {
+ pr_err("intc_suspend: called with interrupts enabled\n");
+ return -EINVAL;
+ }
+
+ if (unlikely(!intc->suspend_ipr)) {
+ pr_err("intc_suspend: suspend_ipr not initialized\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < 64; i++) {
+ intc->saved_ipr[i] = intc_readl(intc, INTPR0 + 4 * i);
+ intc_writel(intc, INTPR0 + 4 * i, intc->suspend_ipr);
+ }
+
+ return 0;
+}
+
+static int intc_resume(struct sys_device *sdev)
+{
+ struct intc *intc = container_of(sdev, struct intc, sysdev);
+ int i;
+
+ WARN_ON(!irqs_disabled());
+
+ for (i = 0; i < 64; i++)
+ intc_writel(intc, INTPR0 + 4 * i, intc->saved_ipr[i]);
+
+ return 0;
+}
+#else
+#define intc_suspend NULL
+#define intc_resume NULL
+#endif
+
static struct sysdev_class intc_class = {
- .name = "intc",
+ .name = "intc",
+ .suspend = intc_suspend,
+ .resume = intc_resume,
};
static int __init intc_init_sysdev(void)
diff --git a/arch/avr32/mach-at32ap/pm-at32ap700x.S b/arch/avr32/mach-at32ap/pm-at32ap700x.S
index 949e248..0a53ad3 100644
--- a/arch/avr32/mach-at32ap/pm-at32ap700x.S
+++ b/arch/avr32/mach-at32ap/pm-at32ap700x.S
@@ -12,6 +12,12 @@
#include <asm/thread_info.h>
#include <asm/arch/pm.h>
+#include "pm.h"
+#include "sdramc.h"
+
+/* Same as 0xfff00000 but fits in a 21 bit signed immediate */
+#define PM_BASE -0x100000
+
.section .bss, "wa", @nobits
.global disable_idle_sleep
.type disable_idle_sleep, @object
@@ -64,3 +70,105 @@
unmask_interrupts
retal r12
.size cpu_idle_skip_sleep, . - cpu_idle_skip_sleep
+
+#ifdef CONFIG_PM
+ .section .init.text, "ax", @progbits
+
+ .global pm_exception
+ .type pm_exception, @function
+pm_exception:
+ /*
+ * Exceptions are masked when we switch to this handler, so
+ * we'll only get "unrecoverable" exceptions (offset 0.)
+ */
+ sub r12, pc, . - .Lpanic_msg
+ lddpc pc, .Lpanic_addr
+
+ .align 2
+.Lpanic_addr:
+ .long panic
+.Lpanic_msg:
+ .asciz "Unrecoverable exception during suspend\n"
+ .size pm_exception, . - pm_exception
+
+ .global pm_irq0
+ .type pm_irq0, @function
+pm_irq0:
+ /* Disable interrupts and return after the sleep instruction */
+ mfsr r9, SYSREG_RSR_INT0
+ mtsr SYSREG_RAR_INT0, r8
+ sbr r9, SYSREG_GM_OFFSET
+ mtsr SYSREG_RSR_INT0, r9
+ rete
+
+ /*
+ * void cpu_enter_standby(unsigned long sdramc_base)
+ *
+ * Enter PM_SUSPEND_STANDBY mode. At this point, all drivers
+ * are suspended and interrupts are disabled. Interrupts
+ * marked as 'wakeup' event sources may still come along and
+ * get us out of here.
+ *
+ * The SDRAM will be put into self-refresh mode (which does
+ * not require a clock from the CPU), and the CPU will be put
+ * into "frozen" mode (HSB bus stopped). The SDRAM controller
+ * will automatically bring the SDRAM into normal mode on the
+ * first access, and the power manager will automatically
+ * start the HSB and CPU clocks upon a wakeup event.
+ *
+ * This code uses the same "skip sleep" technique as above.
+ * It is very important that we jump directly to
+ * cpu_after_sleep after the sleep instruction since that's
+ * where we'll end up if the interrupt handler decides that we
+ * need to skip the sleep instruction.
+ */
+ .global pm_standby
+ .type pm_standby, @function
+pm_standby:
+ /*
+ * interrupts are already masked at this point, and EVBA
+ * points to pm_exception above.
+ */
+ ld.w r10, r12[SDRAMC_LPR]
+ sub r8, pc, . - 1f /* return address for irq handler */
+ mov r11, SDRAMC_LPR_LPCB_SELF_RFR
+ bfins r10, r11, 0, 2 /* LPCB <- self Refresh */
+ sync 0 /* flush write buffer */
+ st.w r12[SDRAMC_LPR], r11 /* put SDRAM in self-refresh mode */
+ ld.w r11, r12[SDRAMC_LPR]
+ unmask_interrupts
+ sleep CPU_SLEEP_FROZEN
+1: mask_interrupts
+ retal r12
+ .size pm_standby, . - pm_standby
+
+ .global pm_suspend_to_ram
+ .type pm_suspend_to_ram, @function
+pm_suspend_to_ram:
+ /*
+ * interrupts are already masked at this point, and EVBA
+ * points to pm_exception above.
+ */
+ mov r11, 0
+ cache r11[2], 8 /* clean all dcache lines */
+ sync 0 /* flush write buffer */
+ ld.w r10, r12[SDRAMC_LPR]
+ sub r8, pc, . - 1f /* return address for irq handler */
+ mov r11, SDRAMC_LPR_LPCB_SELF_RFR
+ bfins r10, r11, 0, 2 /* LPCB <- self refresh */
+ st.w r12[SDRAMC_LPR], r10 /* put SDRAM in self-refresh mode */
+ ld.w r11, r12[SDRAMC_LPR]
+
+ unmask_interrupts
+ sleep CPU_SLEEP_STOP
+1: mask_interrupts
+
+ retal r12
+ .size pm_suspend_to_ram, . - pm_suspend_to_ram
+
+ .global pm_sram_end
+ .type pm_sram_end, @function
+pm_sram_end:
+ .size pm_sram_end, 0
+
+#endif /* CONFIG_PM */
diff --git a/arch/avr32/mach-at32ap/pm.c b/arch/avr32/mach-at32ap/pm.c
new file mode 100644
index 0000000..0b76432
--- /dev/null
+++ b/arch/avr32/mach-at32ap/pm.c
@@ -0,0 +1,245 @@
+/*
+ * AVR32 AP Power Management
+ *
+ * Copyright (C) 2008 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+#include <linux/io.h>
+#include <linux/suspend.h>
+#include <linux/vmalloc.h>
+
+#include <asm/cacheflush.h>
+#include <asm/sysreg.h>
+
+#include <asm/arch/pm.h>
+#include <asm/arch/sram.h>
+
+/* FIXME: This is only valid for AP7000 */
+#define SDRAMC_BASE 0xfff03800
+
+#include "sdramc.h"
+
+#define SRAM_PAGE_FLAGS (SYSREG_BIT(TLBELO_D) | SYSREG_BF(SZ, 1) \
+ | SYSREG_BF(AP, 3) | SYSREG_BIT(G))
+
+
+static unsigned long pm_sram_start;
+static size_t pm_sram_size;
+static struct vm_struct *pm_sram_area;
+
+static void (*avr32_pm_enter_standby)(unsigned long sdramc_base);
+static void (*avr32_pm_enter_str)(unsigned long sdramc_base);
+
+/*
+ * Must be called with interrupts disabled. Exceptions will be masked
+ * on return (i.e. all exceptions will be "unrecoverable".)
+ */
+static void *avr32_pm_map_sram(void)
+{
+ unsigned long vaddr;
+ unsigned long page_addr;
+ u32 tlbehi;
+ u32 mmucr;
+
+ vaddr = (unsigned long)pm_sram_area->addr;
+ page_addr = pm_sram_start & PAGE_MASK;
+
+ /*
+ * Mask exceptions and grab the first TLB entry. We won't be
+ * needing it while sleeping.
+ */
+ asm volatile("ssrf %0" : : "i"(SYSREG_EM_OFFSET) : "memory");
+
+ mmucr = sysreg_read(MMUCR);
+ tlbehi = sysreg_read(TLBEHI);
+ sysreg_write(MMUCR, SYSREG_BFINS(DRP, 0, mmucr));
+
+ tlbehi = SYSREG_BF(ASID, SYSREG_BFEXT(ASID, tlbehi));
+ tlbehi |= vaddr & PAGE_MASK;
+ tlbehi |= SYSREG_BIT(TLBEHI_V);
+
+ sysreg_write(TLBELO, page_addr | SRAM_PAGE_FLAGS);
+ sysreg_write(TLBEHI, tlbehi);
+ __builtin_tlbw();
+
+ return (void *)(vaddr + pm_sram_start - page_addr);
+}
+
+/*
+ * Must be called with interrupts disabled. Exceptions will be
+ * unmasked on return.
+ */
+static void avr32_pm_unmap_sram(void)
+{
+ u32 mmucr;
+ u32 tlbehi;
+ u32 tlbarlo;
+
+ /* Going to update TLB entry at index 0 */
+ mmucr = sysreg_read(MMUCR);
+ tlbehi = sysreg_read(TLBEHI);
+ sysreg_write(MMUCR, SYSREG_BFINS(DRP, 0, mmucr));
+
+ /* Clear the "valid" bit */
+ tlbehi = SYSREG_BF(ASID, SYSREG_BFEXT(ASID, tlbehi));
+ sysreg_write(TLBEHI, tlbehi);
+
+ /* Mark it as "not accessed" */
+ tlbarlo = sysreg_read(TLBARLO);
+ sysreg_write(TLBARLO, tlbarlo | 0x80000000U);
+
+ /* Update the TLB */
+ __builtin_tlbw();
+
+ /* Unmask exceptions */
+ asm volatile("csrf %0" : : "i"(SYSREG_EM_OFFSET) : "memory");
+}
+
+static int avr32_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 int avr32_pm_enter(suspend_state_t state)
+{
+ u32 lpr_saved;
+ u32 evba_saved;
+ void *sram;
+
+ switch (state) {
+ case PM_SUSPEND_STANDBY:
+ sram = avr32_pm_map_sram();
+
+ /* Switch to in-sram exception handlers */
+ evba_saved = sysreg_read(EVBA);
+ sysreg_write(EVBA, (unsigned long)sram);
+
+ /*
+ * Save the LPR register so that we can re-enable
+ * SDRAM Low Power mode on resume.
+ */
+ lpr_saved = sdramc_readl(LPR);
+ pr_debug("%s: Entering standby...\n", __func__);
+ avr32_pm_enter_standby(SDRAMC_BASE);
+ sdramc_writel(LPR, lpr_saved);
+
+ /* Switch back to regular exception handlers */
+ sysreg_write(EVBA, evba_saved);
+
+ avr32_pm_unmap_sram();
+ break;
+
+ case PM_SUSPEND_MEM:
+ sram = avr32_pm_map_sram();
+
+ /* Switch to in-sram exception handlers */
+ evba_saved = sysreg_read(EVBA);
+ sysreg_write(EVBA, (unsigned long)sram);
+
+ /*
+ * Save the LPR register so that we can re-enable
+ * SDRAM Low Power mode on resume.
+ */
+ lpr_saved = sdramc_readl(LPR);
+ pr_debug("%s: Entering suspend-to-ram...\n", __func__);
+ avr32_pm_enter_str(SDRAMC_BASE);
+ sdramc_writel(LPR, lpr_saved);
+
+ /* Switch back to regular exception handlers */
+ sysreg_write(EVBA, evba_saved);
+
+ avr32_pm_unmap_sram();
+ break;
+
+ case PM_SUSPEND_ON:
+ pr_debug("%s: Entering idle...\n", __func__);
+ cpu_enter_idle();
+ break;
+
+ default:
+ pr_debug("%s: Invalid suspend state %d\n", __func__, state);
+ goto out;
+ }
+
+ pr_debug("%s: wakeup\n", __func__);
+
+out:
+ return 0;
+}
+
+static struct platform_suspend_ops avr32_pm_ops = {
+ .valid = avr32_pm_valid_state,
+ .enter = avr32_pm_enter,
+};
+
+static unsigned long avr32_pm_offset(void *symbol)
+{
+ extern u8 pm_exception[];
+
+ return (unsigned long)symbol - (unsigned long)pm_exception;
+}
+
+static int __init avr32_pm_init(void)
+{
+ extern u8 pm_exception[];
+ extern u8 pm_irq0[];
+ extern u8 pm_standby[];
+ extern u8 pm_suspend_to_ram[];
+ extern u8 pm_sram_end[];
+ void *dst;
+
+ /*
+ * To keep things simple, we depend on not needing more than a
+ * single page.
+ */
+ pm_sram_size = avr32_pm_offset(pm_sram_end);
+ if (pm_sram_size > PAGE_SIZE)
+ goto err;
+
+ pm_sram_start = sram_alloc(pm_sram_size);
+ if (!pm_sram_start)
+ goto err_alloc_sram;
+
+ /* Grab a virtual area we can use later on. */
+ pm_sram_area = get_vm_area(pm_sram_size, VM_IOREMAP);
+ if (!pm_sram_area)
+ goto err_vm_area;
+ pm_sram_area->phys_addr = pm_sram_start;
+
+ local_irq_disable();
+ dst = avr32_pm_map_sram();
+ memcpy(dst, pm_exception, pm_sram_size);
+ flush_dcache_region(dst, pm_sram_size);
+ invalidate_icache_region(dst, pm_sram_size);
+ avr32_pm_unmap_sram();
+ local_irq_enable();
+
+ avr32_pm_enter_standby = dst + avr32_pm_offset(pm_standby);
+ avr32_pm_enter_str = dst + avr32_pm_offset(pm_suspend_to_ram);
+ intc_set_suspend_handler(avr32_pm_offset(pm_irq0));
+
+ suspend_set_ops(&avr32_pm_ops);
+
+ printk("AVR32 AP Power Management enabled\n");
+
+ return 0;
+
+err_vm_area:
+ sram_free(pm_sram_start, pm_sram_size);
+err_alloc_sram:
+err:
+ pr_err("AVR32 Power Management initialization failed\n");
+ return -ENOMEM;
+}
+arch_initcall(avr32_pm_init);
diff --git a/arch/avr32/mach-at32ap/sdramc.h b/arch/avr32/mach-at32ap/sdramc.h
new file mode 100644
index 0000000..66eeaed
--- /dev/null
+++ b/arch/avr32/mach-at32ap/sdramc.h
@@ -0,0 +1,76 @@
+/*
+ * Register definitions for the AT32AP SDRAM Controller
+ *
+ * Copyright (C) 2008 Atmel Corporation
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ */
+
+/* Register offsets */
+#define SDRAMC_MR 0x0000
+#define SDRAMC_TR 0x0004
+#define SDRAMC_CR 0x0008
+#define SDRAMC_HSR 0x000c
+#define SDRAMC_LPR 0x0010
+#define SDRAMC_IER 0x0014
+#define SDRAMC_IDR 0x0018
+#define SDRAMC_IMR 0x001c
+#define SDRAMC_ISR 0x0020
+#define SDRAMC_MDR 0x0024
+
+/* MR - Mode Register */
+#define SDRAMC_MR_MODE_NORMAL ( 0 << 0)
+#define SDRAMC_MR_MODE_NOP ( 1 << 0)
+#define SDRAMC_MR_MODE_BANKS_PRECHARGE ( 2 << 0)
+#define SDRAMC_MR_MODE_LOAD_MODE ( 3 << 0)
+#define SDRAMC_MR_MODE_AUTO_REFRESH ( 4 << 0)
+#define SDRAMC_MR_MODE_EXT_LOAD_MODE ( 5 << 0)
+#define SDRAMC_MR_MODE_POWER_DOWN ( 6 << 0)
+
+/* CR - Configuration Register */
+#define SDRAMC_CR_NC_8_BITS ( 0 << 0)
+#define SDRAMC_CR_NC_9_BITS ( 1 << 0)
+#define SDRAMC_CR_NC_10_BITS ( 2 << 0)
+#define SDRAMC_CR_NC_11_BITS ( 3 << 0)
+#define SDRAMC_CR_NR_11_BITS ( 0 << 2)
+#define SDRAMC_CR_NR_12_BITS ( 1 << 2)
+#define SDRAMC_CR_NR_13_BITS ( 2 << 2)
+#define SDRAMC_CR_NB_2_BANKS ( 0 << 4)
+#define SDRAMC_CR_NB_4_BANKS ( 1 << 4)
+#define SDRAMC_CR_CAS(x) ((x) << 5)
+#define SDRAMC_CR_DBW_32_BITS ( 0 << 7)
+#define SDRAMC_CR_DBW_16_BITS ( 1 << 7)
+#define SDRAMC_CR_TWR(x) ((x) << 8)
+#define SDRAMC_CR_TRC(x) ((x) << 12)
+#define SDRAMC_CR_TRP(x) ((x) << 16)
+#define SDRAMC_CR_TRCD(x) ((x) << 20)
+#define SDRAMC_CR_TRAS(x) ((x) << 24)
+#define SDRAMC_CR_TXSR(x) ((x) << 28)
+
+/* HSR - High Speed Register */
+#define SDRAMC_HSR_DA ( 1 << 0)
+
+/* LPR - Low Power Register */
+#define SDRAMC_LPR_LPCB_INHIBIT ( 0 << 0)
+#define SDRAMC_LPR_LPCB_SELF_RFR ( 1 << 0)
+#define SDRAMC_LPR_LPCB_PDOWN ( 2 << 0)
+#define SDRAMC_LPR_LPCB_DEEP_PDOWN ( 3 << 0)
+#define SDRAMC_LPR_PASR(x) ((x) << 4)
+#define SDRAMC_LPR_TCSR(x) ((x) << 8)
+#define SDRAMC_LPR_DS(x) ((x) << 10)
+#define SDRAMC_LPR_TIMEOUT(x) ((x) << 12)
+
+/* IER/IDR/IMR/ISR - Interrupt Enable/Disable/Mask/Status Register */
+#define SDRAMC_ISR_RES ( 1 << 0)
+
+/* MDR - Memory Device Register */
+#define SDRAMC_MDR_MD_SDRAM ( 0 << 0)
+#define SDRAMC_MDR_MD_LOW_PWR_SDRAM ( 1 << 0)
+
+/* Register access macros */
+#define sdramc_readl(reg) \
+ __raw_readl((void __iomem __force *)SDRAMC_BASE + SDRAMC_##reg)
+#define sdramc_writel(reg, value) \
+ __raw_writel(value, (void __iomem __force *)SDRAMC_BASE + SDRAMC_##reg)
diff --git a/include/asm-avr32/arch-at32ap/pm.h b/include/asm-avr32/arch-at32ap/pm.h
index 356e430..979b355 100644
--- a/include/asm-avr32/arch-at32ap/pm.h
+++ b/include/asm-avr32/arch-at32ap/pm.h
@@ -19,6 +19,7 @@
#ifndef __ASSEMBLY__
extern void cpu_enter_idle(void);
+extern void cpu_enter_standby(unsigned long sdramc_base);
extern bool disable_idle_sleep;
@@ -43,6 +44,8 @@
else
cpu_enter_idle();
}
+
+void intc_set_suspend_handler(unsigned long offset);
#endif
#endif /* __ASM_AVR32_ARCH_PM_H */
diff --git a/include/asm-avr32/thread_info.h b/include/asm-avr32/thread_info.h
index 07049f6..df68631 100644
--- a/include/asm-avr32/thread_info.h
+++ b/include/asm-avr32/thread_info.h
@@ -88,6 +88,7 @@
#define TIF_MEMDIE 6
#define TIF_RESTORE_SIGMASK 7 /* restore signal mask in do_signal */
#define TIF_CPU_GOING_TO_SLEEP 8 /* CPU is entering sleep 0 mode */
+#define TIF_FREEZE 29
#define TIF_DEBUG 30 /* debugging enabled */
#define TIF_USERSPACE 31 /* true if FS sets userspace */