diff options
Diffstat (limited to 'arch/arm/mach-davinci/cpuidle.c')
| -rw-r--r-- | arch/arm/mach-davinci/cpuidle.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/arch/arm/mach-davinci/cpuidle.c b/arch/arm/mach-davinci/cpuidle.c new file mode 100644 index 00000000000..97a90f36fc9 --- /dev/null +++ b/arch/arm/mach-davinci/cpuidle.c @@ -0,0 +1,197 @@ +/* + * CPU idle for DaVinci SoCs + * + * Copyright (C) 2009 Texas Instruments Incorporated. http://www.ti.com/ + * + * Derived from Marvell Kirkwood CPU idle code + * (arch/arm/mach-kirkwood/cpuidle.c) + * + * 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/kernel.h> +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/cpuidle.h> +#include <linux/io.h> +#include <asm/proc-fns.h> + +#include <mach/cpuidle.h> + +#define DAVINCI_CPUIDLE_MAX_STATES 2 + +struct davinci_ops { + void (*enter) (u32 flags); + void (*exit) (u32 flags); + u32 flags; +}; + +/* fields in davinci_ops.flags */ +#define DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN BIT(0) + +static struct cpuidle_driver davinci_idle_driver = { + .name = "cpuidle-davinci", + .owner = THIS_MODULE, +}; + +static DEFINE_PER_CPU(struct cpuidle_device, davinci_cpuidle_device); +static void __iomem *ddr2_reg_base; + +#define DDR2_SDRCR_OFFSET 0xc +#define DDR2_SRPD_BIT BIT(23) +#define DDR2_LPMODEN_BIT BIT(31) + +static void davinci_save_ddr_power(int enter, bool pdown) +{ + u32 val; + + val = __raw_readl(ddr2_reg_base + DDR2_SDRCR_OFFSET); + + if (enter) { + if (pdown) + val |= DDR2_SRPD_BIT; + else + val &= ~DDR2_SRPD_BIT; + val |= DDR2_LPMODEN_BIT; + } else { + val &= ~(DDR2_SRPD_BIT | DDR2_LPMODEN_BIT); + } + + __raw_writel(val, ddr2_reg_base + DDR2_SDRCR_OFFSET); +} + +static void davinci_c2state_enter(u32 flags) +{ + davinci_save_ddr_power(1, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); +} + +static void davinci_c2state_exit(u32 flags) +{ + davinci_save_ddr_power(0, !!(flags & DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN)); +} + +static struct davinci_ops davinci_states[DAVINCI_CPUIDLE_MAX_STATES] = { + [1] = { + .enter = davinci_c2state_enter, + .exit = davinci_c2state_exit, + }, +}; + +/* Actual code that puts the SoC in different idle states */ +static int davinci_enter_idle(struct cpuidle_device *dev, + struct cpuidle_state *state) +{ + struct davinci_ops *ops = cpuidle_get_statedata(state); + struct timeval before, after; + int idle_time; + + local_irq_disable(); + do_gettimeofday(&before); + + if (ops && ops->enter) + ops->enter(ops->flags); + /* Wait for interrupt state */ + cpu_do_idle(); + if (ops && ops->exit) + ops->exit(ops->flags); + + do_gettimeofday(&after); + local_irq_enable(); + idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC + + (after.tv_usec - before.tv_usec); + return idle_time; +} + +static int __init davinci_cpuidle_probe(struct platform_device *pdev) +{ + int ret; + struct cpuidle_device *device; + struct davinci_cpuidle_config *pdata = pdev->dev.platform_data; + struct resource *ddr2_regs; + resource_size_t len; + + device = &per_cpu(davinci_cpuidle_device, smp_processor_id()); + + if (!pdata) { + dev_err(&pdev->dev, "cannot get platform data\n"); + return -ENOENT; + } + + ddr2_regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!ddr2_regs) { + dev_err(&pdev->dev, "cannot get DDR2 controller register base"); + return -ENODEV; + } + + len = resource_size(ddr2_regs); + + ddr2_regs = request_mem_region(ddr2_regs->start, len, ddr2_regs->name); + if (!ddr2_regs) + return -EBUSY; + + ddr2_reg_base = ioremap(ddr2_regs->start, len); + if (!ddr2_reg_base) { + ret = -ENOMEM; + goto ioremap_fail; + } + + ret = cpuidle_register_driver(&davinci_idle_driver); + if (ret) { + dev_err(&pdev->dev, "failed to register driver\n"); + goto driver_register_fail; + } + + /* Wait for interrupt state */ + device->states[0].enter = davinci_enter_idle; + device->states[0].exit_latency = 1; + device->states[0].target_residency = 10000; + device->states[0].flags = CPUIDLE_FLAG_TIME_VALID; + strcpy(device->states[0].name, "WFI"); + strcpy(device->states[0].desc, "Wait for interrupt"); + + /* Wait for interrupt and DDR self refresh state */ + device->states[1].enter = davinci_enter_idle; + device->states[1].exit_latency = 10; + device->states[1].target_residency = 10000; + device->states[1].flags = CPUIDLE_FLAG_TIME_VALID; + strcpy(device->states[1].name, "DDR SR"); + strcpy(device->states[1].desc, "WFI and DDR Self Refresh"); + if (pdata->ddr2_pdown) + davinci_states[1].flags |= DAVINCI_CPUIDLE_FLAGS_DDR2_PWDN; + cpuidle_set_statedata(&device->states[1], &davinci_states[1]); + + device->state_count = DAVINCI_CPUIDLE_MAX_STATES; + + ret = cpuidle_register_device(device); + if (ret) { + dev_err(&pdev->dev, "failed to register device\n"); + goto device_register_fail; + } + + return 0; + +device_register_fail: + cpuidle_unregister_driver(&davinci_idle_driver); +driver_register_fail: + iounmap(ddr2_reg_base); +ioremap_fail: + release_mem_region(ddr2_regs->start, len); + return ret; +} + +static struct platform_driver davinci_cpuidle_driver = { + .driver = { + .name = "cpuidle-davinci", + .owner = THIS_MODULE, + }, +}; + +static int __init davinci_cpuidle_init(void) +{ + return platform_driver_probe(&davinci_cpuidle_driver, + davinci_cpuidle_probe); +} +device_initcall(davinci_cpuidle_init); + |