diff options
Diffstat (limited to 'kernel/arch/arm/mach-mvebu/pm.c')
| -rw-r--r-- | kernel/arch/arm/mach-mvebu/pm.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/kernel/arch/arm/mach-mvebu/pm.c b/kernel/arch/arm/mach-mvebu/pm.c new file mode 100644 index 000000000..6573a8f11 --- /dev/null +++ b/kernel/arch/arm/mach-mvebu/pm.c @@ -0,0 +1,218 @@ +/* + * Suspend/resume support. Currently supporting Armada XP only. + * + * Copyright (C) 2014 Marvell + * + * Thomas Petazzoni <thomas.petazzoni@free-electrons.com> + * + * 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/cpu_pm.h> +#include <linux/delay.h> +#include <linux/gpio.h> +#include <linux/io.h> +#include <linux/kernel.h> +#include <linux/mbus.h> +#include <linux/of_address.h> +#include <linux/suspend.h> +#include <asm/cacheflush.h> +#include <asm/outercache.h> +#include <asm/suspend.h> + +#include "coherency.h" +#include "pmsu.h" + +#define SDRAM_CONFIG_OFFS 0x0 +#define SDRAM_CONFIG_SR_MODE_BIT BIT(24) +#define SDRAM_OPERATION_OFFS 0x18 +#define SDRAM_OPERATION_SELF_REFRESH 0x7 +#define SDRAM_DLB_EVICTION_OFFS 0x30c +#define SDRAM_DLB_EVICTION_THRESHOLD_MASK 0xff + +static void (*mvebu_board_pm_enter)(void __iomem *sdram_reg, u32 srcmd); +static void __iomem *sdram_ctrl; + +static int mvebu_pm_powerdown(unsigned long data) +{ + u32 reg, srcmd; + + flush_cache_all(); + outer_flush_all(); + + /* + * Issue a Data Synchronization Barrier instruction to ensure + * that all state saving has been completed. + */ + dsb(); + + /* Flush the DLB and wait ~7 usec */ + reg = readl(sdram_ctrl + SDRAM_DLB_EVICTION_OFFS); + reg &= ~SDRAM_DLB_EVICTION_THRESHOLD_MASK; + writel(reg, sdram_ctrl + SDRAM_DLB_EVICTION_OFFS); + + udelay(7); + + /* Set DRAM in battery backup mode */ + reg = readl(sdram_ctrl + SDRAM_CONFIG_OFFS); + reg &= ~SDRAM_CONFIG_SR_MODE_BIT; + writel(reg, sdram_ctrl + SDRAM_CONFIG_OFFS); + + /* Prepare to go to self-refresh */ + + srcmd = readl(sdram_ctrl + SDRAM_OPERATION_OFFS); + srcmd &= ~0x1F; + srcmd |= SDRAM_OPERATION_SELF_REFRESH; + + mvebu_board_pm_enter(sdram_ctrl + SDRAM_OPERATION_OFFS, srcmd); + + return 0; +} + +#define BOOT_INFO_ADDR 0x3000 +#define BOOT_MAGIC_WORD 0xdeadb002 +#define BOOT_MAGIC_LIST_END 0xffffffff + +/* + * Those registers are accessed before switching the internal register + * base, which is why we hardcode the 0xd0000000 base address, the one + * used by the SoC out of reset. + */ +#define MBUS_WINDOW_12_CTRL 0xd00200b0 +#define MBUS_INTERNAL_REG_ADDRESS 0xd0020080 + +#define SDRAM_WIN_BASE_REG(x) (0x20180 + (0x8*x)) +#define SDRAM_WIN_CTRL_REG(x) (0x20184 + (0x8*x)) + +static phys_addr_t mvebu_internal_reg_base(void) +{ + struct device_node *np; + __be32 in_addr[2]; + + np = of_find_node_by_name(NULL, "internal-regs"); + BUG_ON(!np); + + /* + * Ask the DT what is the internal register address on this + * platform. In the mvebu-mbus DT binding, 0xf0010000 + * corresponds to the internal register window. + */ + in_addr[0] = cpu_to_be32(0xf0010000); + in_addr[1] = 0x0; + + return of_translate_address(np, in_addr); +} + +static void mvebu_pm_store_bootinfo(void) +{ + u32 *store_addr; + phys_addr_t resume_pc; + + store_addr = phys_to_virt(BOOT_INFO_ADDR); + resume_pc = virt_to_phys(armada_370_xp_cpu_resume); + + /* + * The bootloader expects the first two words to be a magic + * value (BOOT_MAGIC_WORD), followed by the address of the + * resume code to jump to. Then, it expects a sequence of + * (address, value) pairs, which can be used to restore the + * value of certain registers. This sequence must end with the + * BOOT_MAGIC_LIST_END magic value. + */ + + writel(BOOT_MAGIC_WORD, store_addr++); + writel(resume_pc, store_addr++); + + /* + * Some platforms remap their internal register base address + * to 0xf1000000. However, out of reset, window 12 starts at + * 0xf0000000 and ends at 0xf7ffffff, which would overlap with + * the internal registers. Therefore, disable window 12. + */ + writel(MBUS_WINDOW_12_CTRL, store_addr++); + writel(0x0, store_addr++); + + /* + * Set the internal register base address to the value + * expected by Linux, as read from the Device Tree. + */ + writel(MBUS_INTERNAL_REG_ADDRESS, store_addr++); + writel(mvebu_internal_reg_base(), store_addr++); + + /* + * Ask the mvebu-mbus driver to store the SDRAM window + * configuration, which has to be restored by the bootloader + * before re-entering the kernel on resume. + */ + store_addr += mvebu_mbus_save_cpu_target(store_addr); + + writel(BOOT_MAGIC_LIST_END, store_addr); +} + +static int mvebu_pm_enter(suspend_state_t state) +{ + if (state != PM_SUSPEND_MEM) + return -EINVAL; + + cpu_pm_enter(); + + mvebu_pm_store_bootinfo(); + cpu_suspend(0, mvebu_pm_powerdown); + + outer_resume(); + + mvebu_v7_pmsu_idle_exit(); + + set_cpu_coherent(); + + cpu_pm_exit(); + + return 0; +} + +static const struct platform_suspend_ops mvebu_pm_ops = { + .enter = mvebu_pm_enter, + .valid = suspend_valid_only_mem, +}; + +int mvebu_pm_init(void (*board_pm_enter)(void __iomem *sdram_reg, u32 srcmd)) +{ + struct device_node *np; + struct resource res; + + if (!of_machine_is_compatible("marvell,armadaxp")) + return -ENODEV; + + np = of_find_compatible_node(NULL, NULL, + "marvell,armada-xp-sdram-controller"); + if (!np) + return -ENODEV; + + if (of_address_to_resource(np, 0, &res)) { + of_node_put(np); + return -ENODEV; + } + + if (!request_mem_region(res.start, resource_size(&res), + np->full_name)) { + of_node_put(np); + return -EBUSY; + } + + sdram_ctrl = ioremap(res.start, resource_size(&res)); + if (!sdram_ctrl) { + release_mem_region(res.start, resource_size(&res)); + of_node_put(np); + return -ENOMEM; + } + + of_node_put(np); + + mvebu_board_pm_enter = board_pm_enter; + + suspend_set_ops(&mvebu_pm_ops); + + return 0; +} |