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