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 "common.h"
  54 #include "omap44xx.h"
  55 #include "omap4-sar-layout.h"
  56 #include "pm.h"
  57 #include "prcm_mpu44xx.h"
  58 #include "prminst44xx.h"
  59 #include "prcm44xx.h"
  60 #include "prm44xx.h"
  61 #include "prm-regbits-44xx.h"
  62
  63 #ifdef CONFIG_SMP
  64
  65 struct omap4_cpu_pm_info {
  66         struct powerdomain *pwrdm;
  67         void __iomem *scu_sar_addr;
  68         void __iomem *wkup_sar_addr;
  69         void __iomem *l2x0_sar_addr;
  70 };
  71
  72 static DEFINE_PER_CPU(struct omap4_cpu_pm_info, omap4_pm_info);
  73 static struct powerdomain *mpuss_pd;
  74 static void __iomem *sar_base;
  75
  76 /*
  77  * Program the wakeup routine address for the CPU0 and CPU1
  78  * used for OFF or DORMANT wakeup.
  79  */
  80 static inline void set_cpu_wakeup_addr(unsigned int cpu_id, u32 addr)
  81 {
  82         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
  83
  84         __raw_writel(addr, pm_info->wkup_sar_addr);
  85 }
  86
  87 /*
  88  * Set the CPUx powerdomain's previous power state
  89  */
  90 static inline void set_cpu_next_pwrst(unsigned int cpu_id,
  91                                 unsigned int power_state)
  92 {
  93         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
  94
  95         pwrdm_set_next_pwrst(pm_info->pwrdm, power_state);
  96 }
  97
  98 /*
  99  * Read CPU's previous power state
 100  */
 101 static inline unsigned int read_cpu_prev_pwrst(unsigned int cpu_id)
 102 {
 103         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
 104
 105         return pwrdm_read_prev_pwrst(pm_info->pwrdm);
 106 }
 107
 108 /*
 109  * Clear the CPUx powerdomain's previous power state
 110  */
 111 static inline void clear_cpu_prev_pwrst(unsigned int cpu_id)
 112 {
 113         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
 114
 115         pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
 116 }
 117
 118 /*
 119  * Store the SCU power status value to scratchpad memory
 120  */
 121 static void scu_pwrst_prepare(unsigned int cpu_id, unsigned int cpu_state)
 122 {
 123         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
 124         u32 scu_pwr_st;
 125
 126         switch (cpu_state) {
 127         case PWRDM_POWER_RET:
 128                 scu_pwr_st = SCU_PM_DORMANT;
 129                 break;
 130         case PWRDM_POWER_OFF:
 131                 scu_pwr_st = SCU_PM_POWEROFF;
 132                 break;
 133         case PWRDM_POWER_ON:
 134         case PWRDM_POWER_INACTIVE:
 135         default:
 136                 scu_pwr_st = SCU_PM_NORMAL;
 137                 break;
 138         }
 139
 140         __raw_writel(scu_pwr_st, pm_info->scu_sar_addr);
 141 }
 142
 143 /* Helper functions for MPUSS OSWR */
 144 static inline void mpuss_clear_prev_logic_pwrst(void)
 145 {
 146         u32 reg;
 147
 148         reg = omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
 149                 OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
 150         omap4_prminst_write_inst_reg(reg, OMAP4430_PRM_PARTITION,
 151                 OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
 152 }
 153
 154 static inline void cpu_clear_prev_logic_pwrst(unsigned int cpu_id)
 155 {
 156         u32 reg;
 157
 158         if (cpu_id) {
 159                 reg = omap4_prcm_mpu_read_inst_reg(OMAP4430_PRCM_MPU_CPU1_INST,
 160                                         OMAP4_RM_CPU1_CPU1_CONTEXT_OFFSET);
 161                 omap4_prcm_mpu_write_inst_reg(reg, OMAP4430_PRCM_MPU_CPU1_INST,
 162                                         OMAP4_RM_CPU1_CPU1_CONTEXT_OFFSET);
 163         } else {
 164                 reg = omap4_prcm_mpu_read_inst_reg(OMAP4430_PRCM_MPU_CPU0_INST,
 165                                         OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET);
 166                 omap4_prcm_mpu_write_inst_reg(reg, OMAP4430_PRCM_MPU_CPU0_INST,
 167                                         OMAP4_RM_CPU0_CPU0_CONTEXT_OFFSET);
 168         }
 169 }
 170
 171 /**
 172  * omap4_mpuss_read_prev_context_state:
 173  * Function returns the MPUSS previous context state
 174  */
 175 u32 omap4_mpuss_read_prev_context_state(void)
 176 {
 177         u32 reg;
 178
 179         reg = omap4_prminst_read_inst_reg(OMAP4430_PRM_PARTITION,
 180                 OMAP4430_PRM_MPU_INST, OMAP4_RM_MPU_MPU_CONTEXT_OFFSET);
 181         reg &= OMAP4430_LOSTCONTEXT_DFF_MASK;
 182         return reg;
 183 }
 184
 185 /*
 186  * Store the CPU cluster state for L2X0 low power operations.
 187  */
 188 static void l2x0_pwrst_prepare(unsigned int cpu_id, unsigned int save_state)
 189 {
 190         struct omap4_cpu_pm_info *pm_info = &per_cpu(omap4_pm_info, cpu_id);
 191
 192         __raw_writel(save_state, pm_info->l2x0_sar_addr);
 193 }
 194
 195 /*
 196  * Save the L2X0 AUXCTRL and POR value to SAR memory. Its used to
 197  * in every restore MPUSS OFF path.
 198  */
 199 #ifdef CONFIG_CACHE_L2X0
 200 static void save_l2x0_context(void)
 201 {
 202         u32 val;
 203         void __iomem *l2x0_base = omap4_get_l2cache_base();
 204
 205         val = __raw_readl(l2x0_base + L2X0_AUX_CTRL);
 206         __raw_writel(val, sar_base + L2X0_AUXCTRL_OFFSET);
 207         val = __raw_readl(l2x0_base + L2X0_PREFETCH_CTRL);
 208         __raw_writel(val, sar_base + L2X0_PREFETCH_CTRL_OFFSET);
 209 }
 210 #else
 211 static void save_l2x0_context(void)
 212 {}
 213 #endif
 214
 215 /**
 216  * omap4_enter_lowpower: OMAP4 MPUSS Low Power Entry Function
 217  * The purpose of this function is to manage low power programming
 218  * of OMAP4 MPUSS subsystem
 219  * @cpu : CPU ID
 220  * @power_state: Low power state.
 221  *
 222  * MPUSS states for the context save:
 223  * save_state =
 224  *      0 - Nothing lost and no need to save: MPUSS INACTIVE
 225  *      1 - CPUx L1 and logic lost: MPUSS CSWR
 226  *      2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
 227  *      3 - CPUx L1 and logic lost + GIC + L2 lost: DEVICE OFF
 228  */
 229 int omap4_enter_lowpower(unsigned int cpu, unsigned int power_state)
 230 {
 231         unsigned int save_state = 0;
 232         unsigned int wakeup_cpu;
 233
 234         if (omap_rev() == OMAP4430_REV_ES1_0)
 235                 return -ENXIO;
 236
 237         switch (power_state) {
 238         case PWRDM_POWER_ON:
 239         case PWRDM_POWER_INACTIVE:
 240                 save_state = 0;
 241                 break;
 242         case PWRDM_POWER_OFF:
 243                 save_state = 1;
 244                 break;
 245         case PWRDM_POWER_RET:
 246         default:
 247                 /*
 248                  * CPUx CSWR is invalid hardware state. Also CPUx OSWR
 249                  * doesn't make much scense, since logic is lost and $L1
 250                  * needs to be cleaned because of coherency. This makes
 251                  * CPUx OSWR equivalent to CPUX OFF and hence not supported
 252                  */
 253                 WARN_ON(1);
 254                 return -ENXIO;
 255         }
 256
 257         pwrdm_pre_transition(NULL);
 258
 259         /*
 260          * Check MPUSS next state and save interrupt controller if needed.
 261          * In MPUSS OSWR or device OFF, interrupt controller  contest is lost.
 262          */
 263         mpuss_clear_prev_logic_pwrst();
 264         if ((pwrdm_read_next_pwrst(mpuss_pd) == PWRDM_POWER_RET) &&
 265                 (pwrdm_read_logic_retst(mpuss_pd) == PWRDM_POWER_OFF))
 266                 save_state = 2;
 267
 268         cpu_clear_prev_logic_pwrst(cpu);
 269         set_cpu_next_pwrst(cpu, power_state);
 270         set_cpu_wakeup_addr(cpu, virt_to_phys(omap4_cpu_resume));
 271         scu_pwrst_prepare(cpu, power_state);
 272         l2x0_pwrst_prepare(cpu, save_state);
 273
 274         /*
 275          * Call low level function  with targeted low power state.
 276          */
 277         cpu_suspend(save_state, omap4_finish_suspend);
 278
 279         /*
 280          * Restore the CPUx power state to ON otherwise CPUx
 281          * power domain can transitions to programmed low power
 282          * state while doing WFI outside the low powe code. On
 283          * secure devices, CPUx does WFI which can result in
 284          * domain transition
 285          */
 286         wakeup_cpu = smp_processor_id();
 287         set_cpu_next_pwrst(wakeup_cpu, PWRDM_POWER_ON);
 288
 289         pwrdm_post_transition(NULL);
 290
 291         return 0;
 292 }
 293
 294 /**
 295  * omap4_hotplug_cpu: OMAP4 CPU hotplug entry
 296  * @cpu : CPU ID
 297  * @power_state: CPU low power state.
 298  */
 299 int __cpuinit omap4_hotplug_cpu(unsigned int cpu, unsigned int power_state)
 300 {
 301         unsigned int cpu_state = 0;
 302
 303         if (omap_rev() == OMAP4430_REV_ES1_0)
 304                 return -ENXIO;
 305
 306         if (power_state == PWRDM_POWER_OFF)
 307                 cpu_state = 1;
 308
 309         clear_cpu_prev_pwrst(cpu);
 310         set_cpu_next_pwrst(cpu, power_state);
 311         set_cpu_wakeup_addr(cpu, virt_to_phys(omap_secondary_startup));
 312         scu_pwrst_prepare(cpu, power_state);
 313
 314         /*
 315          * CPU never retuns back if targeted power state is OFF mode.
 316          * CPU ONLINE follows normal CPU ONLINE ptah via
 317          * omap_secondary_startup().
 318          */
 319         omap4_finish_suspend(cpu_state);
 320
 321         set_cpu_next_pwrst(cpu, PWRDM_POWER_ON);
 322         return 0;
 323 }
 324
 325
 326 /*
 327  * Initialise OMAP4 MPUSS
 328  */
 329 int __init omap4_mpuss_init(void)
 330 {
 331         struct omap4_cpu_pm_info *pm_info;
 332
 333         if (omap_rev() == OMAP4430_REV_ES1_0) {
 334                 WARN(1, "Power Management not supported on OMAP4430 ES1.0\n");
 335                 return -ENODEV;
 336         }
 337
 338         sar_base = omap4_get_sar_ram_base();
 339
 340         /* Initilaise per CPU PM information */
 341         pm_info = &per_cpu(omap4_pm_info, 0x0);
 342         pm_info->scu_sar_addr = sar_base + SCU_OFFSET0;
 343         pm_info->wkup_sar_addr = sar_base + CPU0_WAKEUP_NS_PA_ADDR_OFFSET;
 344         pm_info->l2x0_sar_addr = sar_base + L2X0_SAVE_OFFSET0;
 345         pm_info->pwrdm = pwrdm_lookup("cpu0_pwrdm");
 346         if (!pm_info->pwrdm) {
 347                 pr_err("Lookup failed for CPU0 pwrdm\n");
 348                 return -ENODEV;
 349         }
 350
 351         /* Clear CPU previous power domain state */
 352         pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
 353         cpu_clear_prev_logic_pwrst(0);
 354
 355         /* Initialise CPU0 power domain state to ON */
 356         pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 357
 358         pm_info = &per_cpu(omap4_pm_info, 0x1);
 359         pm_info->scu_sar_addr = sar_base + SCU_OFFSET1;
 360         pm_info->wkup_sar_addr = sar_base + CPU1_WAKEUP_NS_PA_ADDR_OFFSET;
 361         pm_info->l2x0_sar_addr = sar_base + L2X0_SAVE_OFFSET1;
 362         pm_info->pwrdm = pwrdm_lookup("cpu1_pwrdm");
 363         if (!pm_info->pwrdm) {
 364                 pr_err("Lookup failed for CPU1 pwrdm\n");
 365                 return -ENODEV;
 366         }
 367
 368         /* Clear CPU previous power domain state */
 369         pwrdm_clear_all_prev_pwrst(pm_info->pwrdm);
 370         cpu_clear_prev_logic_pwrst(1);
 371
 372         /* Initialise CPU1 power domain state to ON */
 373         pwrdm_set_next_pwrst(pm_info->pwrdm, PWRDM_POWER_ON);
 374
 375         mpuss_pd = pwrdm_lookup("mpu_pwrdm");
 376         if (!mpuss_pd) {
 377                 pr_err("Failed to lookup MPUSS power domain\n");
 378                 return -ENODEV;
 379         }
 380         pwrdm_clear_all_prev_pwrst(mpuss_pd);
 381         mpuss_clear_prev_logic_pwrst();
 382
 383         /* Save device type on scratchpad for low level code to use */
 384         if (omap_type() != OMAP2_DEVICE_TYPE_GP)
 385                 __raw_writel(1, sar_base + OMAP_TYPE_OFFSET);
 386         else
 387                 __raw_writel(0, sar_base + OMAP_TYPE_OFFSET);
 388
 389         save_l2x0_context();
 390
 391         return 0;
 392 }
 393
 394 #endif