arch/arm/mach-omap2/omap-mpuss-lowpower.c

   1 /*
   2  * OMAP MPUSS low power code
   3  *
   4  * Copyright (C) 2011 Texas Instruments, Inc.
   5  *      Santosh Shilimkar <santosh.shilimkar@ti.com>
   6  *
   7  * OMAP4430 MPUSS mainly consists of dual Cortex-A9 with per-CPU
   8  * Local timer and Watchdog, GIC, SCU, PL310 L2 cache controller,
   9  * CPU0 and CPU1 LPRM modules.
  10  * CPU0, CPU1 and MPUSS each have there own power domain and
  11  * hence multiple low power combinations of MPUSS are possible.
  12  *
  13  * The CPU0 and CPU1 can't support Closed switch Retention (CSWR)
  14  * because the mode is not supported by hw constraints of dormant
  15  * mode. While waking up from the dormant mode, a reset  signal
  16  * to the Cortex-A9 processor must be asserted by the external
  17  * power controller.
  18  *
  19  * With architectural inputs and hardware recommendations, only
  20  * below modes are supported from power gain vs latency point of view.
  21  *
  22  *      CPU0            CPU1            MPUSS
  23  *      ----------------------------------------------
  24  *      ON              ON              ON
  25  *      ON(Inactive)    OFF             ON(Inactive)
  26  *      OFF             OFF             CSWR
  27  *      OFF             OFF             OSWR
  28  *      OFF             OFF             OFF(Device OFF *TBD)
  29  *      ----------------------------------------------
  30  *
  31  * Note: CPU0 is the master core and it is the last CPU to go down
  32  * and first to wake-up when MPUSS low power states are excercised
  33  *
  34  *
  35  * This program is free software; you can redistribute it and/or modify
  36  * it under the terms of the GNU General Public License version 2 as
  37  * published by the Free Software Foundation.
  38  */
  39
  40 #include <linux/kernel.h>
  41 #include <linux/io.h>
  42 #include <linux/errno.h>
  43 #include <linux/linkage.h>
  44 #include <linux/smp.h>
  45
  46 #include <asm/cacheflush.h>
  47 #include <asm/tlbflush.h>
  48 #include <asm/smp_scu.h>
  49 #include <asm/pgalloc.h>
  50 #include <asm/suspend.h>
  51 #include <asm/hardware/cache-l2x0.h>
  52
  53 #include "soc.h"
  54 #include "common.h"
  55 #include "omap44xx.h"
  56 #include "omap4-sar-layout.h"
  57 #include "pm.h"
  58 #include "prcm_mpu44xx.h"
  59 #include "prminst44xx.h"
  60 #include "prcm44xx.h"
  61 #include "prm44xx.h"
  62 #include "prm-regbits-44xx.h"
  63
  64 #ifdef CONFIG_SMP
  65
  66 struct omap4_cpu_pm_info {
  67         struct powerdomain *pwrdm;
  68         void __iomem *scu_sar_addr;
  69         void __iomem *wkup_sar_addr;
  70         void __iomem *l2x0_sar_addr;
  71         void (*secondary_startup)(void);
  72 };
  73
  74 static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
  75 static struct powerdomain *mpuss_pd;
  76 static void __iomem *sar_base;
  77
  78 /*
  79  * Program the wakeup routine address for the CPU0 and CPU1
  80  * used for OFF or DORMANT wakeup.
  81  */
  82 static inline void set_cpu_wakeup_addr(unsigned int cpu_id, u32 addr)
  83 {
  84         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
  85
  86         __raw_writel(addr, pm_info->wkup_sar_addr);
  87 }
  88
  89 /*
  90  * Store the SCU power status value to scratchpad memory
  91  */
  92 static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
  93 {
  94         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
  95         u32 scu_pwr_st;
  96
  97         switch (cpu_state) {
  98         case PWRDM_POWER_RET:
  99                 scu_pwr_st = SCU_PM_DORMANT;
 100                 break;
 101         case PWRDM_POWER_OFF:
 102                 scu_pwr_st = SCU_PM_POWEROFF;
 103                 break;
 104         case PWRDM_POWER_ON:
 105         case PWRDM_POWER_INACTIVE:
 106         default:
 107                 scu_pwr_st = SCU_PM_NORMAL;
 108                 break;
 109         }
 110
 111         __raw_writel(scu_pwr_st, pm_info->scu_sar_addr);
 112 }
 113
 114 /* Helper functions for MPUSS OSWR */
 115 static inline void mpuss_clear_prev_logic_pwrst(void)
 116 {
 117         u32 reg;
 118
 119         reg = omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
 120                 OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
 121         omap4_prminst_write_inst_reg(reg, OMAP4430_PRM_PARTITION,
 122                 OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
 123 }
 124
 125 static inline void cpu_clear_prev_logic_pwrst(unsigned int cpu_id)
 126 {
 127         u32 reg;
 128
 129         if (cpu_id) {
 130                 reg = omap4_prcm_mpu_read_inst_reg(OMAP4430_PRCM_MPU_CPU1_INST,
 131                                         OMAP4_RM_CPU1_CPU1_CONTEXT_OFFSET);
 132                 omap4_prcm_mpu_write_inst_reg(reg, OMAP4430_PRCM_MPU_CPU1_INST,
 133                                         OMAP4_RM_CPU1_CPU1_CONTEXT_OFFSET);
 134         } else {
 135                 reg = omap4_prcm_mpu_read_inst_reg(OMAP4430_PRCM_MPU_CPU0_INST,
 136                                         OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET);
 137                 omap4_prcm_mpu_write_inst_reg(reg, OMAP4430_PRCM_MPU_CPU0_INST,
 138                                         OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET);
 139         }
 140 }
 141
 142 /**
 143  * omap4_mpuss_read_prev_context_state:
 144  * Function returns the MPUSS previous context state
 145  */
 146 u32 omap4_mpuss_read_prev_context_state(void)
 147 {
 148         u32 reg;
 149
 150         reg = omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
 151                 OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
 152         reg &= OMAP4430_LOSTCONTEXT_DFF_MASK;
 153         return reg;
 154 }
 155
 156 /*
 157  * Store the CPU cluster state for L2X0 low power operations.
 158  */
 159 static void l2x0_pwrst_prepare(unsigned int cpu_id, unsigned int save_state)
 160 {
 161         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
 162
 163         __raw_writel(save_state, pm_info->l2x0_sar_addr);
 164 }
 165
 166 /*
 167  * Save the L2X0 AUXCTRL and POR value to SAR memory. Its used to
 168  * in every restore MPUSS OFF path.
 169  */
 170 #ifdef CONFIG_CACHE_L2X0
 171 static void save_l2x0_context(void)
 172 {
 173         u32 val;
 174         void __iomem *l2x0_base = omap4_get_l2cache_base();
 175
 176         val = __raw_readl(l2x0_base + L2X0_AUX_CTRL);
 177         __raw_writel(val, sar_base + L2X0_AUXCTRL_OFFSET);
 178         val = __raw_readl(l2x0_base + L2X0_PREFETCH_CTRL);
 179         __raw_writel(val, sar_base + L2X0_PREFETCH_CTRL_OFFSET);
 180 }
 181 #else
 182 static void save_l2x0_context(void)
 183 {}
 184 #endif
 185
 186 /**
 187  * omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
 188  * The purpose of this function is to manage low power programming
 189  * of OMAP4 MPUSS subsystem
 190  * @cpu : CPU ID
 191  * @power_state: Low power state.
 192  *
 193  * MPUSS states for the context save:
 194  * save_state =
 195  *      0 - Nothing lost and no need to save: MPUSS INACTIVE
 196  *      1 - CPUx L1 and logic lost: MPUSS CSWR
 197  *      2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
 198  *      3 - CPUx L1 and logic lost + GIC + L2 lost: DEVICE OFF
 199  */
 200 int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
 201 {
 202         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu);
 203         unsigned int save_state = 0;
 204         unsigned int wakeup_cpu;
 205
 206         if (omap_rev() == OMAP4430_REV_ES1_0)
 207                 return -ENXIO;
 208
 209         switch (power_state) {
 210         case PWRDM_POWER_ON:
 211         case PWRDM_POWER_INACTIVE:
 212                 save_state = 0;
 213                 break;
 214         case PWRDM_POWER_OFF:
 215                 save_state = 1;
 216                 break;
 217         case PWRDM_POWER_RET:
 218         default:
 219                 /*
 220                  * CPUx CSWR is invalid hardware state. Also CPUx OSWR
 221                  * doesn't make much scense, since logic is lost and $L1
 222                  * needs to be cleaned because of coherency. This makes
 223                  * CPUx OSWR equivalent to CPUX OFF and hence not supported
 224                  */
 225                 WARN_ON(1);
 226                 return -ENXIO;
 227         }
 228
 229         pwrdm_pre_transition(NULL);
 230
 231         /*
 232          * Check MPUSS next state and save interrupt controller if needed.
 233          * In MPUSS OSWR or device OFF, interrupt controller  contest is lost.
 234          */
 235         mpuss_clear_prev_logic_pwrst();
 236         if ((pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_RET) &&
 237                 (pwrdm_read_logic_retst(mpuss_pd) == PWRDM_POWER_OFF))
 238                 save_state = 2;
 239
 240         cpu_clear_prev_logic_pwrst(cpu);
 241         pwrdm_set_next_pwrst(pm_info->pwrdm, power_state);
 242         set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume));
 243         scu_pwrst_prepare(cpu, power_state);
 244         l2x0_pwrst_prepare(cpu, save_state);
 245
 246         /*
 247          * Call low level function  with targeted low power state.
 248          */
 249         if (save_state)
 250                 cpu_suspend(save_state, omap4_finish_suspend);
 251         else
 252                 omap4_finish_suspend(save_state);
 253
 254         /*
 255          * Restore the CPUx power state to ON otherwise CPUx
 256          * power domain can transitions to programmed low power
 257          * state while doing WFI outside the low powe code. On
 258          * secure devices, CPUx does WFI which can result in
 259          * domain transition
 260          */
 261         wakeup_cpu = smp_processor_id();
 262         pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 263
 264         pwrdm_post_transition(NULL);
 265
 266         return 0;
 267 }
 268
 269 /**
 270  * omap4_hotplug_cpu: OMAP4 CPU hotplug entry
 271  * @cpu : CPU ID
 272  * @power_state: CPU low power state.
 273  */
 274 int __cpuinit omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state)
 275 {
 276         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu);
 277         unsigned int cpu_state = 0;
 278
 279         if (omap_rev() == OMAP4430_REV_ES1_0)
 280                 return -ENXIO;
 281
 282         if (power_state == PWRDM_POWER_OFF)
 283                 cpu_state = 1;
 284
 285         pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
 286         pwrdm_set_next_pwrst(pm_info->pwrdm, power_state);
 287         set_cpu_wakeup_addr(cpu, virt_to_phys(pm_info->secondary_startup));
 288         scu_pwrst_prepare(cpu, power_state);
 289
 290         /*
 291          * CPU never retuns back if targeted power state is OFF mode.
 292          * CPU ONLINE follows normal CPU ONLINE ptah via
 293          * omap_secondary_startup().
 294          */
 295         omap4_finish_suspend(cpu_state);
 296
 297         pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 298         return 0;
 299 }
 300
 301
 302 /*
 303  * Initialise OMAP4 MPUSS
 304  */
 305 int __init omap4_mpuss_init(void)
 306 {
 307         struct omap4_cpu_pm_info *pm_info;
 308
 309         if (omap_rev() == OMAP4430_REV_ES1_0) {
 310                 WARN(1, "Power Management not supported on OMAP4430 ES1.0\n");
 311                 return -ENODEV;
 312         }
 313
 314         sar_base = omap4_get_sar_ram_base();
 315
 316         /* Initilaise per CPU PM information */
 317         pm_info = &per_cpu(omap4_pm_info, 0x0);
 318         pm_info->scu_sar_addr = sar_base + SCU_OFFSET0;
 319         pm_info->wkup_sar_addr = sar_base + CPU0_WAKEUP_NS_PA_ADDR_OFFSET;
 320         pm_info->l2x0_sar_addr = sar_base + L2X0_SAVE_OFFSET0;
 321         pm_info->pwrdm = pwrdm_lookup("cpu0_pwrdm");
 322         if (!pm_info->pwrdm) {
 323                 pr_err("Lookup failed for CPU0 pwrdm\n");
 324                 return -ENODEV;
 325         }
 326
 327         /* Clear CPU previous power domain state */
 328         pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
 329         cpu_clear_prev_logic_pwrst(0);
 330
 331         /* Initialise CPU0 power domain state to ON */
 332         pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 333
 334         pm_info = &per_cpu(omap4_pm_info, 0x1);
 335         pm_info->scu_sar_addr = sar_base + SCU_OFFSET1;
 336         pm_info->wkup_sar_addr = sar_base + CPU1_WAKEUP_NS_PA_ADDR_OFFSET;
 337         pm_info->l2x0_sar_addr = sar_base + L2X0_SAVE_OFFSET1;
 338         if (cpu_is_omap446x())
 339                 pm_info->secondary_startup = omap_secondary_startup_4460;
 340         else
 341                 pm_info->secondary_startup = omap_secondary_startup;
 342
 343         pm_info->pwrdm = pwrdm_lookup("cpu1_pwrdm");
 344         if (!pm_info->pwrdm) {
 345                 pr_err("Lookup failed for CPU1 pwrdm\n");
 346                 return -ENODEV;
 347         }
 348
 349         /* Clear CPU previous power domain state */
 350         pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
 351         cpu_clear_prev_logic_pwrst(1);
 352
 353         /* Initialise CPU1 power domain state to ON */
 354         pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 355
 356         mpuss_pd = pwrdm_lookup("mpu_pwrdm");
 357         if (!mpuss_pd) {
 358                 pr_err("Failed to lookup MPUSS power domain\n");
 359                 return -ENODEV;
 360         }
 361         pwrdm_clear_all_prev_pwrst(mpuss_pd);
 362         mpuss_clear_prev_logic_pwrst();
 363
 364         /* Save device type on scratchpad for low level code to use */
 365         if (omap_type() != OMAP2_DEVICE_TYPE_GP)
 366                 __raw_writel(1, sar_base + OMAP_TYPE_OFFSET);
 367         else
 368                 __raw_writel(0, sar_base + OMAP_TYPE_OFFSET);
 369
 370         save_l2x0_context();
 371
 372         return 0;
 373 }
 374
 375 #endif