diff options
Diffstat (limited to 'arch/arm/mach-omap2/omap-mpuss-lowpower.c')
| -rw-r--r-- | arch/arm/mach-omap2/omap-mpuss-lowpower.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/omap-mpuss-lowpower.c b/arch/arm/mach-omap2/omap-mpuss-lowpower.c new file mode 100644 index 000000000000..867fee51e42c --- /dev/null +++ b/arch/arm/mach-omap2/omap-mpuss-lowpower.c @@ -0,0 +1,248 @@ +/* + * OMAP MPUSS low power code + * + * Copyright (C) 2011 Texas Instruments, Inc. + * Santosh Shilimkar <santosh.shilimkar@ti.com> + * + * OMAP4430 MPUSS mainly consists of dual Cortex-A9 with per-CPU + * Local timer and Watchdog, GIC, SCU, PL310 L2 cache controller, + * CPU0 and CPU1 LPRM modules. + * CPU0, CPU1 and MPUSS each have there own power domain and + * hence multiple low power combinations of MPUSS are possible. + * + * The CPU0 and CPU1 can't support Closed switch Retention (CSWR) + * because the mode is not supported by hw constraints of dormant + * mode. While waking up from the dormant mode, a reset signal + * to the Cortex-A9 processor must be asserted by the external + * power controller. + * + * With architectural inputs and hardware recommendations, only + * below modes are supported from power gain vs latency point of view. + * + * CPU0 CPU1 MPUSS + * ---------------------------------------------- + * ON ON ON + * ON(Inactive) OFF ON(Inactive) + * OFF OFF CSWR + * OFF OFF OSWR (*TBD) + * OFF OFF OFF* (*TBD) + * ---------------------------------------------- + * + * Note: CPU0 is the master core and it is the last CPU to go down + * and first to wake-up when MPUSS low power states are excercised + * + * + * 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/io.h> +#include <linux/errno.h> +#include <linux/linkage.h> +#include <linux/smp.h> + +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm/smp_scu.h> +#include <asm/system.h> +#include <asm/pgalloc.h> +#include <asm/suspend.h> + +#include <plat/omap44xx.h> + +#include "common.h" +#include "omap4-sar-layout.h" +#include "pm.h" +#include "powerdomain.h" + +#ifdef CONFIG_SMP + +struct omap4_cpu_pm_info { + struct powerdomain *pwrdm; + void __iomem *scu_sar_addr; + void __iomem *wkup_sar_addr; +}; + +static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info); + +/* + * Program the wakeup routine address for the CPU0 and CPU1 + * used for OFF or DORMANT wakeup. + */ +static inline void set_cpu_wakeup_addr(unsigned int cpu_id, u32 addr) +{ + struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id); + + __raw_writel(addr, pm_info->wkup_sar_addr); +} + +/* + * Set the CPUx powerdomain's previous power state + */ +static inline void set_cpu_next_pwrst(unsigned int cpu_id, + unsigned int power_state) +{ + struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id); + + pwrdm_set_next_pwrst(pm_info->pwrdm, power_state); +} + +/* + * Read CPU's previous power state + */ +static inline unsigned int read_cpu_prev_pwrst(unsigned int cpu_id) +{ + struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id); + + return pwrdm_read_prev_pwrst(pm_info->pwrdm); +} + +/* + * Clear the CPUx powerdomain's previous power state + */ +static inline void clear_cpu_prev_pwrst(unsigned int cpu_id) +{ + struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id); + + pwrdm_clear_all_prev_pwrst(pm_info->pwrdm); +} + +/* + * Store the SCU power status value to scratchpad memory + */ +static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state) +{ + struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id); + u32 scu_pwr_st; + + switch (cpu_state) { + case PWRDM_POWER_RET: + scu_pwr_st = SCU_PM_DORMANT; + break; + case PWRDM_POWER_OFF: + scu_pwr_st = SCU_PM_POWEROFF; + break; + case PWRDM_POWER_ON: + case PWRDM_POWER_INACTIVE: + default: + scu_pwr_st = SCU_PM_NORMAL; + break; + } + + __raw_writel(scu_pwr_st, pm_info->scu_sar_addr); +} + +/** + * omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function + * The purpose of this function is to manage low power programming + * of OMAP4 MPUSS subsystem + * @cpu : CPU ID + * @power_state: Low power state. + */ +int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state) +{ + unsigned int save_state = 0; + unsigned int wakeup_cpu; + + if (omap_rev() == OMAP4430_REV_ES1_0) + return -ENXIO; + + switch (power_state) { + case PWRDM_POWER_ON: + case PWRDM_POWER_INACTIVE: + save_state = 0; + break; + case PWRDM_POWER_OFF: + save_state = 1; + break; + case PWRDM_POWER_RET: + default: + /* + * CPUx CSWR is invalid hardware state. Also CPUx OSWR + * doesn't make much scense, since logic is lost and $L1 + * needs to be cleaned because of coherency. This makes + * CPUx OSWR equivalent to CPUX OFF and hence not supported + */ + WARN_ON(1); + return -ENXIO; + } + + clear_cpu_prev_pwrst(cpu); + set_cpu_next_pwrst(cpu, power_state); + set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume)); + scu_pwrst_prepare(cpu, power_state); + + /* + * Call low level function with targeted low power state. + */ + cpu_suspend(save_state, omap4_finish_suspend); + + /* + * Restore the CPUx power state to ON otherwise CPUx + * power domain can transitions to programmed low power + * state while doing WFI outside the low powe code. On + * secure devices, CPUx does WFI which can result in + * domain transition + */ + wakeup_cpu = smp_processor_id(); + set_cpu_next_pwrst(wakeup_cpu, PWRDM_POWER_ON); + + return 0; +} + +/* + * Initialise OMAP4 MPUSS + */ +int __init omap4_mpuss_init(void) +{ + struct omap4_cpu_pm_info *pm_info; + void __iomem *sar_base = omap4_get_sar_ram_base(); + + if (omap_rev() == OMAP4430_REV_ES1_0) { + WARN(1, "Power Management not supported on OMAP4430 ES1.0\n"); + return -ENODEV; + } + + /* Initilaise per CPU PM information */ + pm_info = &per_cpu(omap4_pm_info, 0x0); + pm_info->scu_sar_addr = sar_base + SCU_OFFSET0; + pm_info->wkup_sar_addr = sar_base + CPU0_WAKEUP_NS_PA_ADDR_OFFSET; + pm_info->pwrdm = pwrdm_lookup("cpu0_pwrdm"); + if (!pm_info->pwrdm) { + pr_err("Lookup failed for CPU0 pwrdm\n"); + return -ENODEV; + } + + /* Clear CPU previous power domain state */ + pwrdm_clear_all_prev_pwrst(pm_info->pwrdm); + + /* Initialise CPU0 power domain state to ON */ + pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON); + + pm_info = &per_cpu(omap4_pm_info, 0x1); + pm_info->scu_sar_addr = sar_base + SCU_OFFSET1; + pm_info->wkup_sar_addr = sar_base + CPU1_WAKEUP_NS_PA_ADDR_OFFSET; + pm_info->pwrdm = pwrdm_lookup("cpu1_pwrdm"); + if (!pm_info->pwrdm) { + pr_err("Lookup failed for CPU1 pwrdm\n"); + return -ENODEV; + } + + /* Clear CPU previous power domain state */ + pwrdm_clear_all_prev_pwrst(pm_info->pwrdm); + + /* Initialise CPU1 power domain state to ON */ + pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON); + + /* Save device type on scratchpad for low level code to use */ + if (omap_type() != OMAP2_DEVICE_TYPE_GP) + __raw_writel(1, sar_base + OMAP_TYPE_OFFSET); + else + __raw_writel(0, sar_base + OMAP_TYPE_OFFSET); + + return 0; +} + +#endif |