arch/arm/mach-zynq/platsmp.c

   1 /*
   2  * This file contains Xilinx specific SMP code, used to start up
   3  * the second processor.
   4  *
   5  * Copyright (C) 2011-2013 Xilinx
   6  *
   7  * based on linux/arch/arm/mach-realview/platsmp.c
   8  *
   9  * Copyright (C) 2002 ARM Ltd.
  10  *
  11  * This software is licensed under the terms of the GNU General Public
  12  * License version 2, as published by the Free Software Foundation, and
  13  * may be copied, distributed, and modified under those terms.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  */
  20
  21 #include <linux/export.h>
  22 #include <linux/jiffies.h>
  23 #include <linux/init.h>
  24 #include <linux/io.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/smp_scu.h>
  27 #include <linux/irqchip/arm-gic.h>
  28 #include "common.h"
  29
  30 /*
  31  * Store number of cores in the system
  32  * Because of scu_get_core_count() must be in __init section and can't
  33  * be called from zynq_cpun_start() because it is not in __init section.
  34  */
  35 static int ncores;
  36
  37 int zynq_cpun_start(u32 address, int cpu)
  38 {
  39         u32 trampoline_code_size = &zynq_secondary_trampoline_end -
  40                                                 &zynq_secondary_trampoline;
  41
  42         if (cpu > ncores) {
  43                 pr_warn("CPU No. is not available in the system\n");
  44                 return -1;
  45         }
  46
  47         /* MS: Expectation that SLCR are directly map and accessible */
  48         /* Not possible to jump to non aligned address */
  49         if (!(address & 3) && (!address || (address >= trampoline_code_size))) {
  50                 /* Store pointer to ioremap area which points to address 0x0 */
  51                 static u8 __iomem *zero;
  52                 u32 trampoline_size = &zynq_secondary_trampoline_jump -
  53                                                 &zynq_secondary_trampoline;
  54
  55                 zynq_slcr_cpu_stop(cpu);
  56                 if (address) {
  57                         if (__pa(PAGE_OFFSET)) {
  58                                 zero = ioremap(0, trampoline_code_size);
  59                                 if (!zero) {
  60                                         pr_warn("BOOTUP jump vectors not accessible\n");
  61                                         return -1;
  62                                 }
  63                         } else {
  64                                 zero = (__force u8 __iomem *)PAGE_OFFSET;
  65                         }
  66
  67                         /*
  68                         * This is elegant way how to jump to any address
  69                         * 0x0: Load address at 0x8 to r0
  70                         * 0x4: Jump by mov instruction
  71                         * 0x8: Jumping address
  72                         */
  73                         memcpy((__force void *)zero, &zynq_secondary_trampoline,
  74                                                         trampoline_size);
  75                         writel(address, zero + trampoline_size);
  76
  77                         flush_cache_all();
  78                         outer_flush_range(0, trampoline_code_size);
  79                         smp_wmb();
  80
  81                         if (__pa(PAGE_OFFSET))
  82                                 iounmap(zero);
  83                 }
  84                 zynq_slcr_cpu_start(cpu);
  85
  86                 return 0;
  87         }
  88
  89         pr_warn("Can't start CPU%d: Wrong starting address %x\n", cpu, address);
  90
  91         return -1;
  92 }
  93 EXPORT_SYMBOL(zynq_cpun_start);
  94
  95 static int zynq_boot_secondary(unsigned int cpu,
  96                                                 struct task_struct *idle)
  97 {
  98         return zynq_cpun_start(virt_to_phys(secondary_startup), cpu);
  99 }
 100
 101 /*
 102  * Initialise the CPU possible map early - this describes the CPUs
 103  * which may be present or become present in the system.
 104  */
 105 static void __init zynq_smp_init_cpus(void)
 106 {
 107         int i;
 108
 109         ncores = scu_get_core_count(zynq_scu_base);
 110
 111         for (i = 0; i < ncores && i < CONFIG_NR_CPUS; i++)
 112                 set_cpu_possible(i, true);
 113 }
 114
 115 static void __init zynq_smp_prepare_cpus(unsigned int max_cpus)
 116 {
 117         int i;
 118
 119         /*
 120          * Initialise the present map, which describes the set of CPUs
 121          * actually populated at the present time.
 122          */
 123         for (i = 0; i < max_cpus; i++)
 124                 set_cpu_present(i, true);
 125
 126         scu_enable(zynq_scu_base);
 127 }
 128
 129 struct smp_operations zynq_smp_ops __initdata = {
 130         .smp_init_cpus          = zynq_smp_init_cpus,
 131         .smp_prepare_cpus       = zynq_smp_prepare_cpus,
 132         .smp_boot_secondary     = zynq_boot_secondary,
 133 #ifdef CONFIG_HOTPLUG_CPU
 134         .cpu_die                = zynq_platform_cpu_die,
 135 #endif
 136 };