arch/arm/mach-bcm/platsmp-brcmstb.c

   1 /*
   2  * Broadcom STB CPU SMP and hotplug support for ARM
   3  *
   4  * Copyright (C) 2013-2014 Broadcom Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation version 2.
   9  *
  10  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  11  * kind, whether express or implied; without even the implied warranty
  12  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/errno.h>
  18 #include <linux/init.h>
  19 #include <linux/io.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/printk.h>
  24 #include <linux/regmap.h>
  25 #include <linux/smp.h>
  26 #include <linux/mfd/syscon.h>
  27
  28 #include <asm/cacheflush.h>
  29 #include <asm/cp15.h>
  30 #include <asm/mach-types.h>
  31 #include <asm/smp_plat.h>
  32
  33 enum {
  34         ZONE_MAN_CLKEN_MASK             = BIT(0),
  35         ZONE_MAN_RESET_CNTL_MASK        = BIT(1),
  36         ZONE_MAN_MEM_PWR_MASK           = BIT(4),
  37         ZONE_RESERVED_1_MASK            = BIT(5),
  38         ZONE_MAN_ISO_CNTL_MASK          = BIT(6),
  39         ZONE_MANUAL_CONTROL_MASK        = BIT(7),
  40         ZONE_PWR_DN_REQ_MASK            = BIT(9),
  41         ZONE_PWR_UP_REQ_MASK            = BIT(10),
  42         ZONE_BLK_RST_ASSERT_MASK        = BIT(12),
  43         ZONE_PWR_OFF_STATE_MASK         = BIT(25),
  44         ZONE_PWR_ON_STATE_MASK          = BIT(26),
  45         ZONE_DPG_PWR_STATE_MASK         = BIT(28),
  46         ZONE_MEM_PWR_STATE_MASK         = BIT(29),
  47         ZONE_RESET_STATE_MASK           = BIT(31),
  48         CPU0_PWR_ZONE_CTRL_REG          = 1,
  49         CPU_RESET_CONFIG_REG            = 2,
  50 };
  51
  52 static void __iomem *cpubiuctrl_block;
  53 static void __iomem *hif_cont_block;
  54 static u32 cpu0_pwr_zone_ctrl_reg;
  55 static u32 cpu_rst_cfg_reg;
  56 static u32 hif_cont_reg;
  57
  58 #ifdef CONFIG_HOTPLUG_CPU
  59 /*
  60  * We must quiesce a dying CPU before it can be killed by the boot CPU. Because
  61  * one or more cache may be disabled, we must flush to ensure coherency. We
  62  * cannot use traditionl completion structures or spinlocks as they rely on
  63  * coherency.
  64  */
  65 static DEFINE_PER_CPU_ALIGNED(int, per_cpu_sw_state);
  66
  67 static int per_cpu_sw_state_rd(u32 cpu)
  68 {
  69         sync_cache_r(SHIFT_PERCPU_PTR(&per_cpu_sw_state, per_cpu_offset(cpu)));
  70         return per_cpu(per_cpu_sw_state, cpu);
  71 }
  72
  73 static void per_cpu_sw_state_wr(u32 cpu, int val)
  74 {
  75         dmb();
  76         per_cpu(per_cpu_sw_state, cpu) = val;
  77         sync_cache_w(SHIFT_PERCPU_PTR(&per_cpu_sw_state, per_cpu_offset(cpu)));
  78 }
  79 #else
  80 static inline void per_cpu_sw_state_wr(u32 cpu, int val) { }
  81 #endif
  82
  83 static void __iomem *pwr_ctrl_get_base(u32 cpu)
  84 {
  85         void __iomem *base = cpubiuctrl_block + cpu0_pwr_zone_ctrl_reg;
  86         base += (cpu_logical_map(cpu) * 4);
  87         return base;
  88 }
  89
  90 static u32 pwr_ctrl_rd(u32 cpu)
  91 {
  92         void __iomem *base = pwr_ctrl_get_base(cpu);
  93         return readl_relaxed(base);
  94 }
  95
  96 static void pwr_ctrl_set(unsigned int cpu, u32 val, u32 mask)
  97 {
  98         void __iomem *base = pwr_ctrl_get_base(cpu);
  99         writel((readl(base) & mask) | val, base);
 100 }
 101
 102 static void pwr_ctrl_clr(unsigned int cpu, u32 val, u32 mask)
 103 {
 104         void __iomem *base = pwr_ctrl_get_base(cpu);
 105         writel((readl(base) & mask) & ~val, base);
 106 }
 107
 108 #define POLL_TMOUT_MS 500
 109 static int pwr_ctrl_wait_tmout(unsigned int cpu, u32 set, u32 mask)
 110 {
 111         const unsigned long timeo = jiffies + msecs_to_jiffies(POLL_TMOUT_MS);
 112         u32 tmp;
 113
 114         do {
 115                 tmp = pwr_ctrl_rd(cpu) & mask;
 116                 if (!set == !tmp)
 117                         return 0;
 118         } while (time_before(jiffies, timeo));
 119
 120         tmp = pwr_ctrl_rd(cpu) & mask;
 121         if (!set == !tmp)
 122                 return 0;
 123
 124         return -ETIMEDOUT;
 125 }
 126
 127 static void cpu_rst_cfg_set(u32 cpu, int set)
 128 {
 129         u32 val;
 130         val = readl_relaxed(cpubiuctrl_block + cpu_rst_cfg_reg);
 131         if (set)
 132                 val |= BIT(cpu_logical_map(cpu));
 133         else
 134                 val &= ~BIT(cpu_logical_map(cpu));
 135         writel_relaxed(val, cpubiuctrl_block + cpu_rst_cfg_reg);
 136 }
 137
 138 static void cpu_set_boot_addr(u32 cpu, unsigned long boot_addr)
 139 {
 140         const int reg_ofs = cpu_logical_map(cpu) * 8;
 141         writel_relaxed(0, hif_cont_block + hif_cont_reg + reg_ofs);
 142         writel_relaxed(boot_addr, hif_cont_block + hif_cont_reg + 4 + reg_ofs);
 143 }
 144
 145 static void brcmstb_cpu_boot(u32 cpu)
 146 {
 147         /* Mark this CPU as "up" */
 148         per_cpu_sw_state_wr(cpu, 1);
 149
 150         /*
 151          * Set the reset vector to point to the secondary_startup
 152          * routine
 153          */
 154         cpu_set_boot_addr(cpu, virt_to_phys(secondary_startup));
 155
 156         /* Unhalt the cpu */
 157         cpu_rst_cfg_set(cpu, 0);
 158 }
 159
 160 static void brcmstb_cpu_power_on(u32 cpu)
 161 {
 162         /*
 163          * The secondary cores power was cut, so we must go through
 164          * power-on initialization.
 165          */
 166         pwr_ctrl_set(cpu, ZONE_MAN_ISO_CNTL_MASK, 0xffffff00);
 167         pwr_ctrl_set(cpu, ZONE_MANUAL_CONTROL_MASK, -1);
 168         pwr_ctrl_set(cpu, ZONE_RESERVED_1_MASK, -1);
 169
 170         pwr_ctrl_set(cpu, ZONE_MAN_MEM_PWR_MASK, -1);
 171
 172         if (pwr_ctrl_wait_tmout(cpu, 1, ZONE_MEM_PWR_STATE_MASK))
 173                 panic("ZONE_MEM_PWR_STATE_MASK set timeout");
 174
 175         pwr_ctrl_set(cpu, ZONE_MAN_CLKEN_MASK, -1);
 176
 177         if (pwr_ctrl_wait_tmout(cpu, 1, ZONE_DPG_PWR_STATE_MASK))
 178                 panic("ZONE_DPG_PWR_STATE_MASK set timeout");
 179
 180         pwr_ctrl_clr(cpu, ZONE_MAN_ISO_CNTL_MASK, -1);
 181         pwr_ctrl_set(cpu, ZONE_MAN_RESET_CNTL_MASK, -1);
 182 }
 183
 184 static int brcmstb_cpu_get_power_state(u32 cpu)
 185 {
 186         int tmp = pwr_ctrl_rd(cpu);
 187         return (tmp & ZONE_RESET_STATE_MASK) ? 0 : 1;
 188 }
 189
 190 #ifdef CONFIG_HOTPLUG_CPU
 191
 192 static void brcmstb_cpu_die(u32 cpu)
 193 {
 194         v7_exit_coherency_flush(all);
 195
 196         per_cpu_sw_state_wr(cpu, 0);
 197
 198         /* Sit and wait to die */
 199         wfi();
 200
 201         /* We should never get here... */
 202         while (1)
 203                 ;
 204 }
 205
 206 static int brcmstb_cpu_kill(u32 cpu)
 207 {
 208         /*
 209          * Ordinarily, the hardware forbids power-down of CPU0 (which is good
 210          * because it is the boot CPU), but this is not true when using BPCM
 211          * manual mode.  Consequently, we must avoid turning off CPU0 here to
 212          * ensure that TI2C master reset will work.
 213          */
 214         if (cpu == 0) {
 215                 pr_warn("SMP: refusing to power off CPU0\n");
 216                 return 1;
 217         }
 218
 219         while (per_cpu_sw_state_rd(cpu))
 220                 ;
 221
 222         pwr_ctrl_set(cpu, ZONE_MANUAL_CONTROL_MASK, -1);
 223         pwr_ctrl_clr(cpu, ZONE_MAN_RESET_CNTL_MASK, -1);
 224         pwr_ctrl_clr(cpu, ZONE_MAN_CLKEN_MASK, -1);
 225         pwr_ctrl_set(cpu, ZONE_MAN_ISO_CNTL_MASK, -1);
 226         pwr_ctrl_clr(cpu, ZONE_MAN_MEM_PWR_MASK, -1);
 227
 228         if (pwr_ctrl_wait_tmout(cpu, 0, ZONE_MEM_PWR_STATE_MASK))
 229                 panic("ZONE_MEM_PWR_STATE_MASK clear timeout");
 230
 231         pwr_ctrl_clr(cpu, ZONE_RESERVED_1_MASK, -1);
 232
 233         if (pwr_ctrl_wait_tmout(cpu, 0, ZONE_DPG_PWR_STATE_MASK))
 234                 panic("ZONE_DPG_PWR_STATE_MASK clear timeout");
 235
 236         /* Flush pipeline before resetting CPU */
 237         mb();
 238
 239         /* Assert reset on the CPU */
 240         cpu_rst_cfg_set(cpu, 1);
 241
 242         return 1;
 243 }
 244
 245 #endif /* CONFIG_HOTPLUG_CPU */
 246
 247 static int __init setup_hifcpubiuctrl_regs(struct device_node *np)
 248 {
 249         int rc = 0;
 250         char *name;
 251         struct device_node *syscon_np = NULL;
 252
 253         name = "syscon-cpu";
 254
 255         syscon_np = of_parse_phandle(np, name, 0);
 256         if (!syscon_np) {
 257                 pr_err("can't find phandle %s\n", name);
 258                 rc = -EINVAL;
 259                 goto cleanup;
 260         }
 261
 262         cpubiuctrl_block = of_iomap(syscon_np, 0);
 263         if (!cpubiuctrl_block) {
 264                 pr_err("iomap failed for cpubiuctrl_block\n");
 265                 rc = -EINVAL;
 266                 goto cleanup;
 267         }
 268
 269         rc = of_property_read_u32_index(np, name, CPU0_PWR_ZONE_CTRL_REG,
 270                                         &cpu0_pwr_zone_ctrl_reg);
 271         if (rc) {
 272                 pr_err("failed to read 1st entry from %s property (%d)\n", name,
 273                         rc);
 274                 rc = -EINVAL;
 275                 goto cleanup;
 276         }
 277
 278         rc = of_property_read_u32_index(np, name, CPU_RESET_CONFIG_REG,
 279                                         &cpu_rst_cfg_reg);
 280         if (rc) {
 281                 pr_err("failed to read 2nd entry from %s property (%d)\n", name,
 282                         rc);
 283                 rc = -EINVAL;
 284                 goto cleanup;
 285         }
 286
 287 cleanup:
 288         of_node_put(syscon_np);
 289         return rc;
 290 }
 291
 292 static int __init setup_hifcont_regs(struct device_node *np)
 293 {
 294         int rc = 0;
 295         char *name;
 296         struct device_node *syscon_np = NULL;
 297
 298         name = "syscon-cont";
 299
 300         syscon_np = of_parse_phandle(np, name, 0);
 301         if (!syscon_np) {
 302                 pr_err("can't find phandle %s\n", name);
 303                 rc = -EINVAL;
 304                 goto cleanup;
 305         }
 306
 307         hif_cont_block = of_iomap(syscon_np, 0);
 308         if (!hif_cont_block) {
 309                 pr_err("iomap failed for hif_cont_block\n");
 310                 rc = -EINVAL;
 311                 goto cleanup;
 312         }
 313
 314         /* Offset is at top of hif_cont_block */
 315         hif_cont_reg = 0;
 316
 317 cleanup:
 318         of_node_put(syscon_np);
 319         return rc;
 320 }
 321
 322 static void __init brcmstb_cpu_ctrl_setup(unsigned int max_cpus)
 323 {
 324         int rc;
 325         struct device_node *np;
 326         char *name;
 327
 328         name = "brcm,brcmstb-smpboot";
 329         np = of_find_compatible_node(NULL, NULL, name);
 330         if (!np) {
 331                 pr_err("can't find compatible node %s\n", name);
 332                 return;
 333         }
 334
 335         rc = setup_hifcpubiuctrl_regs(np);
 336         if (rc)
 337                 return;
 338
 339         rc = setup_hifcont_regs(np);
 340         if (rc)
 341                 return;
 342 }
 343
 344 static int brcmstb_boot_secondary(unsigned int cpu, struct task_struct *idle)
 345 {
 346         /* Missing the brcm,brcmstb-smpboot DT node? */
 347         if (!cpubiuctrl_block || !hif_cont_block)
 348                 return -ENODEV;
 349
 350         /* Bring up power to the core if necessary */
 351         if (brcmstb_cpu_get_power_state(cpu) == 0)
 352                 brcmstb_cpu_power_on(cpu);
 353
 354         brcmstb_cpu_boot(cpu);
 355
 356         return 0;
 357 }
 358
 359 static const struct smp_operations brcmstb_smp_ops __initconst = {
 360         .smp_prepare_cpus       = brcmstb_cpu_ctrl_setup,
 361         .smp_boot_secondary     = brcmstb_boot_secondary,
 362 #ifdef CONFIG_HOTPLUG_CPU
 363         .cpu_kill               = brcmstb_cpu_kill,
 364         .cpu_die                = brcmstb_cpu_die,
 365 #endif
 366 };
 367
 368 CPU_METHOD_OF_DECLARE(brcmstb_smp, "brcm,brahma-b15", &brcmstb_smp_ops);