arch/arm/mach-vexpress/platsmp.c

   1 /*
   2  *  linux/arch/arm/mach-vexpress/platsmp.c
   3  *
   4  *  Copyright (C) 2002 ARM Ltd.
   5  *  All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11 #include <linux/init.h>
  12 #include <linux/errno.h>
  13 #include <linux/smp.h>
  14 #include <linux/io.h>
  15 #include <linux/of_fdt.h>
  16
  17 #include <asm/smp_scu.h>
  18 #include <asm/hardware/gic.h>
  19 #include <asm/mach/map.h>
  20
  21 #include <mach/motherboard.h>
  22
  23 #include "core.h"
  24
  25 extern void versatile_secondary_startup(void);
  26
  27 #if defined(CONFIG_OF)
  28
  29 static enum {
  30         GENERIC_SCU,
  31         CORTEX_A9_SCU,
  32 } vexpress_dt_scu __initdata = GENERIC_SCU;
  33
  34 static struct map_desc vexpress_dt_cortex_a9_scu_map __initdata = {
  35         .virtual        = V2T_PERIPH,
  36         /* .pfn set in vexpress_dt_init_cortex_a9_scu() */
  37         .length         = SZ_128,
  38         .type           = MT_DEVICE,
  39 };
  40
  41 static void *vexpress_dt_cortex_a9_scu_base __initdata;
  42
  43 const static char *vexpress_dt_cortex_a9_match[] __initconst = {
  44         "arm,cortex-a5-scu",
  45         "arm,cortex-a9-scu",
  46         NULL
  47 };
  48
  49 static int __init vexpress_dt_find_scu(unsigned long node,
  50                 const char *uname, int depth, void *data)
  51 {
  52         if (of_flat_dt_match(node, vexpress_dt_cortex_a9_match)) {
  53                 phys_addr_t phys_addr;
  54                 __be32 *reg = of_get_flat_dt_prop(node, "reg", NULL);
  55
  56                 if (WARN_ON(!reg))
  57                         return -EINVAL;
  58
  59                 phys_addr = be32_to_cpup(reg);
  60                 vexpress_dt_scu = CORTEX_A9_SCU;
  61
  62                 vexpress_dt_cortex_a9_scu_map.pfn = __phys_to_pfn(phys_addr);
  63                 iotable_init(&vexpress_dt_cortex_a9_scu_map, 1);
  64                 vexpress_dt_cortex_a9_scu_base = ioremap(phys_addr, SZ_256);
  65                 if (WARN_ON(!vexpress_dt_cortex_a9_scu_base))
  66                         return -EFAULT;
  67         }
  68
  69         return 0;
  70 }
  71
  72 void __init vexpress_dt_smp_map_io(void)
  73 {
  74         if (initial_boot_params)
  75                 WARN_ON(of_scan_flat_dt(vexpress_dt_find_scu, NULL));
  76 }
  77
  78 static int __init vexpress_dt_cpus_num(unsigned long node, const char *uname,
  79                 int depth, void *data)
  80 {
  81         static int prev_depth = -1;
  82         static int nr_cpus = -1;
  83
  84         if (prev_depth > depth && nr_cpus > 0)
  85                 return nr_cpus;
  86
  87         if (nr_cpus < 0 && strcmp(uname, "cpus") == 0)
  88                 nr_cpus = 0;
  89
  90         if (nr_cpus >= 0) {
  91                 const char *device_type = of_get_flat_dt_prop(node,
  92                                 "device_type", NULL);
  93
  94                 if (device_type && strcmp(device_type, "cpu") == 0)
  95                         nr_cpus++;
  96         }
  97
  98         prev_depth = depth;
  99
 100         return 0;
 101 }
 102
 103 static void __init vexpress_dt_smp_init_cpus(void)
 104 {
 105         int ncores = 0, i;
 106
 107         switch (vexpress_dt_scu) {
 108         case GENERIC_SCU:
 109                 ncores = of_scan_flat_dt(vexpress_dt_cpus_num, NULL);
 110                 break;
 111         case CORTEX_A9_SCU:
 112                 ncores = scu_get_core_count(vexpress_dt_cortex_a9_scu_base);
 113                 break;
 114         default:
 115                 WARN_ON(1);
 116                 break;
 117         }
 118
 119         if (ncores < 2)
 120                 return;
 121
 122         if (ncores > nr_cpu_ids) {
 123                 pr_warn("SMP: %u cores greater than maximum (%u), clipping\n",
 124                                 ncores, nr_cpu_ids);
 125                 ncores = nr_cpu_ids;
 126         }
 127
 128         for (i = 0; i < ncores; ++i)
 129                 set_cpu_possible(i, true);
 130
 131         set_smp_cross_call(gic_raise_softirq);
 132 }
 133
 134 static void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
 135 {
 136         int i;
 137
 138         switch (vexpress_dt_scu) {
 139         case GENERIC_SCU:
 140                 for (i = 0; i < max_cpus; i++)
 141                         set_cpu_present(i, true);
 142                 break;
 143         case CORTEX_A9_SCU:
 144                 scu_enable(vexpress_dt_cortex_a9_scu_base);
 145                 break;
 146         default:
 147                 WARN_ON(1);
 148                 break;
 149         }
 150 }
 151
 152 #else
 153
 154 static void __init vexpress_dt_smp_init_cpus(void)
 155 {
 156         WARN_ON(1);
 157 }
 158
 159 void __init vexpress_dt_smp_prepare_cpus(unsigned int max_cpus)
 160 {
 161         WARN_ON(1);
 162 }
 163
 164 #endif
 165
 166 /*
 167  * Initialise the CPU possible map early - this describes the CPUs
 168  * which may be present or become present in the system.
 169  */
 170 void __init smp_init_cpus(void)
 171 {
 172         if (ct_desc)
 173                 ct_desc->init_cpu_map();
 174         else
 175                 vexpress_dt_smp_init_cpus();
 176
 177 }
 178
 179 void __init platform_smp_prepare_cpus(unsigned int max_cpus)
 180 {
 181         /*
 182          * Initialise the present map, which describes the set of CPUs
 183          * actually populated at the present time.
 184          */
 185         if (ct_desc)
 186                 ct_desc->smp_enable(max_cpus);
 187         else
 188                 vexpress_dt_smp_prepare_cpus(max_cpus);
 189
 190         /*
 191          * Write the address of secondary startup into the
 192          * system-wide flags register. The boot monitor waits
 193          * until it receives a soft interrupt, and then the
 194          * secondary CPU branches to this address.
 195          */
 196         v2m_flags_set(virt_to_phys(versatile_secondary_startup));
 197 }