arch/arm/mach-imx/platsmp.c

   1 /*
   2  * Copyright 2011 Freescale Semiconductor, Inc.
   3  * Copyright 2011 Linaro Ltd.
   4  *
   5  * The code contained herein is licensed under the GNU General Public
   6  * License. You may obtain a copy of the GNU General Public License
   7  * Version 2 or later at the following locations:
   8  *
   9  * http://www.opensource.org/licenses/gpl-license.html
  10  * http://www.gnu.org/copyleft/gpl.html
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/smp.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/page.h>
  17 #include <asm/smp_scu.h>
  18 #include <asm/mach/map.h>
  19
  20 #include "common.h"
  21 #include "hardware.h"
  22
  23 #define SCU_STANDBY_ENABLE      (1 << 5)
  24
  25 u32 g_diag_reg;
  26 static void __iomem *scu_base;
  27
  28 static struct map_desc scu_io_desc __initdata = {
  29         /* .virtual and .pfn are run-time assigned */
  30         .length         = SZ_4K,
  31         .type           = MT_DEVICE,
  32 };
  33
  34 void __init imx_scu_map_io(void)
  35 {
  36         unsigned long base;
  37
  38         /* Get SCU base */
  39         asm("mrc p15, 4, %0, c15, c0, 0" : "=r" (base));
  40
  41         scu_io_desc.virtual = IMX_IO_P2V(base);
  42         scu_io_desc.pfn = __phys_to_pfn(base);
  43         iotable_init(&scu_io_desc, 1);
  44
  45         scu_base = IMX_IO_ADDRESS(base);
  46 }
  47
  48 void imx_scu_standby_enable(void)
  49 {
  50         u32 val = readl_relaxed(scu_base);
  51
  52         val |= SCU_STANDBY_ENABLE;
  53         writel_relaxed(val, scu_base);
  54 }
  55
  56 static int imx_boot_secondary(unsigned int cpu, struct task_struct *idle)
  57 {
  58         imx_set_cpu_jump(cpu, v7_secondary_startup);
  59         imx_enable_cpu(cpu, true);
  60         return 0;
  61 }
  62
  63 /*
  64  * Initialise the CPU possible map early - this describes the CPUs
  65  * which may be present or become present in the system.
  66  */
  67 static void __init imx_smp_init_cpus(void)
  68 {
  69         int i, ncores;
  70
  71         ncores = scu_get_core_count(scu_base);
  72
  73         for (i = ncores; i < NR_CPUS; i++)
  74                 set_cpu_possible(i, false);
  75 }
  76
  77 void imx_smp_prepare(void)
  78 {
  79         scu_enable(scu_base);
  80 }
  81
  82 static void __init imx_smp_prepare_cpus(unsigned int max_cpus)
  83 {
  84         imx_smp_prepare();
  85
  86         /*
  87          * The diagnostic register holds the errata bits.  Mostly bootloader
  88          * does not bring up secondary cores, so that when errata bits are set
  89          * in bootloader, they are set only for boot cpu.  But on a SMP
  90          * configuration, it should be equally done on every single core.
  91          * Read the register from boot cpu here, and will replicate it into
  92          * secondary cores when booting them.
  93          */
  94         asm("mrc p15, 0, %0, c15, c0, 1" : "=r" (g_diag_reg) : : "cc");
  95         sync_cache_w(&g_diag_reg);
  96 }
  97
  98 struct smp_operations  imx_smp_ops __initdata = {
  99         .smp_init_cpus          = imx_smp_init_cpus,
 100         .smp_prepare_cpus       = imx_smp_prepare_cpus,
 101         .smp_boot_secondary     = imx_boot_secondary,
 102 #ifdef CONFIG_HOTPLUG_CPU
 103         .cpu_die                = imx_cpu_die,
 104         .cpu_kill               = imx_cpu_kill,
 105 #endif
 106 };