arch/arm/mach-exynos/platsmp.c

   1 /* linux/arch/arm/mach-exynos4/platsmp.c
   2  *
   3  * Copyright (c) 2010-2011 Samsung Electronics Co., Ltd.
   4  *              http://www.samsung.com
   5  *
   6  * Cloned from linux/arch/arm/mach-vexpress/platsmp.c
   7  *
   8  *  Copyright (C) 2002 ARM Ltd.
   9  *  All Rights Reserved
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License version 2 as
  13  * published by the Free Software Foundation.
  14 */
  15
  16 #include <linux/init.h>
  17 #include <linux/errno.h>
  18 #include <linux/delay.h>
  19 #include <linux/device.h>
  20 #include <linux/jiffies.h>
  21 #include <linux/smp.h>
  22 #include <linux/io.h>
  23 #include <linux/of_address.h>
  24
  25 #include <asm/cacheflush.h>
  26 #include <asm/smp_plat.h>
  27 #include <asm/smp_scu.h>
  28 #include <asm/firmware.h>
  29
  30 #include <plat/cpu.h>
  31
  32 #include "common.h"
  33 #include "regs-pmu.h"
  34
  35 extern void exynos4_secondary_startup(void);
  36
  37 static void __iomem *sysram_base_addr;
  38 void __iomem *sysram_ns_base_addr;
  39
  40 static void __init exynos_smp_prepare_sysram(void)
  41 {
  42         struct device_node *node;
  43
  44         for_each_compatible_node(node, NULL, "samsung,exynos4210-sysram") {
  45                 if (!of_device_is_available(node))
  46                         continue;
  47                 sysram_base_addr = of_iomap(node, 0);
  48                 break;
  49         }
  50
  51         for_each_compatible_node(node, NULL, "samsung,exynos4210-sysram-ns") {
  52                 if (!of_device_is_available(node))
  53                         continue;
  54                 sysram_ns_base_addr = of_iomap(node, 0);
  55                 break;
  56         }
  57 }
  58
  59 static inline void __iomem *cpu_boot_reg_base(void)
  60 {
  61         if (soc_is_exynos4210() && samsung_rev() == EXYNOS4210_REV_1_1)
  62                 return S5P_INFORM5;
  63         return sysram_base_addr;
  64 }
  65
  66 static inline void __iomem *cpu_boot_reg(int cpu)
  67 {
  68         void __iomem *boot_reg;
  69
  70         boot_reg = cpu_boot_reg_base();
  71         if (!boot_reg)
  72                 return ERR_PTR(-ENODEV);
  73         if (soc_is_exynos4412())
  74                 boot_reg += 4*cpu;
  75         else if (soc_is_exynos5420())
  76                 boot_reg += 4;
  77         return boot_reg;
  78 }
  79
  80 /*
  81  * Write pen_release in a way that is guaranteed to be visible to all
  82  * observers, irrespective of whether they're taking part in coherency
  83  * or not.  This is necessary for the hotplug code to work reliably.
  84  */
  85 static void write_pen_release(int val)
  86 {
  87         pen_release = val;
  88         smp_wmb();
  89         sync_cache_w(&pen_release);
  90 }
  91
  92 static void __iomem *scu_base_addr(void)
  93 {
  94         return (void __iomem *)(S5P_VA_SCU);
  95 }
  96
  97 static DEFINE_SPINLOCK(boot_lock);
  98
  99 static void exynos_secondary_init(unsigned int cpu)
 100 {
 101         /*
 102          * let the primary processor know we're out of the
 103          * pen, then head off into the C entry point
 104          */
 105         write_pen_release(-1);
 106
 107         /*
 108          * Synchronise with the boot thread.
 109          */
 110         spin_lock(&boot_lock);
 111         spin_unlock(&boot_lock);
 112 }
 113
 114 static int exynos_boot_secondary(unsigned int cpu, struct task_struct *idle)
 115 {
 116         unsigned long timeout;
 117         unsigned long phys_cpu = cpu_logical_map(cpu);
 118         int ret = -ENOSYS;
 119
 120         /*
 121          * Set synchronisation state between this boot processor
 122          * and the secondary one
 123          */
 124         spin_lock(&boot_lock);
 125
 126         /*
 127          * The secondary processor is waiting to be released from
 128          * the holding pen - release it, then wait for it to flag
 129          * that it has been released by resetting pen_release.
 130          *
 131          * Note that "pen_release" is the hardware CPU ID, whereas
 132          * "cpu" is Linux's internal ID.
 133          */
 134         write_pen_release(phys_cpu);
 135
 136         if (!(__raw_readl(S5P_ARM_CORE1_STATUS) & S5P_CORE_LOCAL_PWR_EN)) {
 137                 __raw_writel(S5P_CORE_LOCAL_PWR_EN,
 138                              S5P_ARM_CORE1_CONFIGURATION);
 139
 140                 timeout = 10;
 141
 142                 /* wait max 10 ms until cpu1 is on */
 143                 while ((__raw_readl(S5P_ARM_CORE1_STATUS)
 144                         & S5P_CORE_LOCAL_PWR_EN) != S5P_CORE_LOCAL_PWR_EN) {
 145                         if (timeout-- == 0)
 146                                 break;
 147
 148                         mdelay(1);
 149                 }
 150
 151                 if (timeout == 0) {
 152                         printk(KERN_ERR "cpu1 power enable failed");
 153                         spin_unlock(&boot_lock);
 154                         return -ETIMEDOUT;
 155                 }
 156         }
 157         /*
 158          * Send the secondary CPU a soft interrupt, thereby causing
 159          * the boot monitor to read the system wide flags register,
 160          * and branch to the address found there.
 161          */
 162
 163         timeout = jiffies + (1 * HZ);
 164         while (time_before(jiffies, timeout)) {
 165                 unsigned long boot_addr;
 166
 167                 smp_rmb();
 168
 169                 boot_addr = virt_to_phys(exynos4_secondary_startup);
 170
 171                 /*
 172                  * Try to set boot address using firmware first
 173                  * and fall back to boot register if it fails.
 174                  */
 175                 ret = call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr);
 176                 if (ret && ret != -ENOSYS)
 177                         goto fail;
 178                 if (ret == -ENOSYS) {
 179                         void __iomem *boot_reg = cpu_boot_reg(phys_cpu);
 180
 181                         if (IS_ERR(boot_reg)) {
 182                                 ret = PTR_ERR(boot_reg);
 183                                 goto fail;
 184                         }
 185                         __raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
 186                 }
 187
 188                 call_firmware_op(cpu_boot, phys_cpu);
 189
 190                 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
 191
 192                 if (pen_release == -1)
 193                         break;
 194
 195                 udelay(10);
 196         }
 197
 198         /*
 199          * now the secondary core is starting up let it run its
 200          * calibrations, then wait for it to finish
 201          */
 202 fail:
 203         spin_unlock(&boot_lock);
 204
 205         return pen_release != -1 ? ret : 0;
 206 }
 207
 208 /*
 209  * Initialise the CPU possible map early - this describes the CPUs
 210  * which may be present or become present in the system.
 211  */
 212
 213 static void __init exynos_smp_init_cpus(void)
 214 {
 215         void __iomem *scu_base = scu_base_addr();
 216         unsigned int i, ncores;
 217
 218         if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
 219                 ncores = scu_base ? scu_get_core_count(scu_base) : 1;
 220         else
 221                 /*
 222                  * CPU Nodes are passed thru DT and set_cpu_possible
 223                  * is set by "arm_dt_init_cpu_maps".
 224                  */
 225                 return;
 226
 227         /* sanity check */
 228         if (ncores > nr_cpu_ids) {
 229                 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
 230                         ncores, nr_cpu_ids);
 231                 ncores = nr_cpu_ids;
 232         }
 233
 234         for (i = 0; i < ncores; i++)
 235                 set_cpu_possible(i, true);
 236 }
 237
 238 static void __init exynos_smp_prepare_cpus(unsigned int max_cpus)
 239 {
 240         int i;
 241
 242         if (read_cpuid_part_number() == ARM_CPU_PART_CORTEX_A9)
 243                 scu_enable(scu_base_addr());
 244
 245         exynos_smp_prepare_sysram();
 246
 247         /*
 248          * Write the address of secondary startup into the
 249          * system-wide flags register. The boot monitor waits
 250          * until it receives a soft interrupt, and then the
 251          * secondary CPU branches to this address.
 252          *
 253          * Try using firmware operation first and fall back to
 254          * boot register if it fails.
 255          */
 256         for (i = 1; i < max_cpus; ++i) {
 257                 unsigned long phys_cpu;
 258                 unsigned long boot_addr;
 259                 int ret;
 260
 261                 phys_cpu = cpu_logical_map(i);
 262                 boot_addr = virt_to_phys(exynos4_secondary_startup);
 263
 264                 ret = call_firmware_op(set_cpu_boot_addr, phys_cpu, boot_addr);
 265                 if (ret && ret != -ENOSYS)
 266                         break;
 267                 if (ret == -ENOSYS) {
 268                         void __iomem *boot_reg = cpu_boot_reg(phys_cpu);
 269
 270                         if (IS_ERR(boot_reg))
 271                                 break;
 272                         __raw_writel(boot_addr, cpu_boot_reg(phys_cpu));
 273                 }
 274         }
 275 }
 276
 277 struct smp_operations exynos_smp_ops __initdata = {
 278         .smp_init_cpus          = exynos_smp_init_cpus,
 279         .smp_prepare_cpus       = exynos_smp_prepare_cpus,
 280         .smp_secondary_init     = exynos_secondary_init,
 281         .smp_boot_secondary     = exynos_boot_secondary,
 282 #ifdef CONFIG_HOTPLUG_CPU
 283         .cpu_die                = exynos_cpu_die,
 284 #endif
 285 };