arch/arm/mach-sunxi/platsmp.c

   1 /*
   2  * SMP support for Allwinner SoCs
   3  *
   4  * Copyright (C) 2013 Maxime Ripard
   5  *
   6  * Maxime Ripard <maxime.ripard@free-electrons.com>
   7  *
   8  * Based on code
   9  *  Copyright (C) 2012-2013 Allwinner Ltd.
  10  *
  11  * This file is licensed under the terms of the GNU General Public
  12  * License version 2.  This program is licensed "as is" without any
  13  * warranty of any kind, whether express or implied.
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/init.h>
  18 #include <linux/io.h>
  19 #include <linux/memory.h>
  20 #include <linux/of.h>
  21 #include <linux/of_address.h>
  22 #include <linux/smp.h>
  23
  24 #define CPUCFG_CPU_PWR_CLAMP_STATUS_REG(cpu)    ((cpu) * 0x40 + 0x64)
  25 #define CPUCFG_CPU_RST_CTRL_REG(cpu)            (((cpu) + 1) * 0x40)
  26 #define CPUCFG_CPU_CTRL_REG(cpu)                (((cpu) + 1) * 0x40 + 0x04)
  27 #define CPUCFG_CPU_STATUS_REG(cpu)              (((cpu) + 1) * 0x40 + 0x08)
  28 #define CPUCFG_GEN_CTRL_REG                     0x184
  29 #define CPUCFG_PRIVATE0_REG                     0x1a4
  30 #define CPUCFG_PRIVATE1_REG                     0x1a8
  31 #define CPUCFG_DBG_CTL0_REG                     0x1e0
  32 #define CPUCFG_DBG_CTL1_REG                     0x1e4
  33
  34 #define PRCM_CPU_PWROFF_REG                     0x100
  35 #define PRCM_CPU_PWR_CLAMP_REG(cpu)             (((cpu) * 4) + 0x140)
  36
  37 static void __iomem *cpucfg_membase;
  38 static void __iomem *prcm_membase;
  39
  40 static DEFINE_SPINLOCK(cpu_lock);
  41
  42 static void __init sun6i_smp_prepare_cpus(unsigned int max_cpus)
  43 {
  44         struct device_node *node;
  45
  46         node = of_find_compatible_node(NULL, NULL, "allwinner,sun6i-a31-prcm");
  47         if (!node) {
  48                 pr_err("Missing A31 PRCM node in the device tree\n");
  49                 return;
  50         }
  51
  52         prcm_membase = of_iomap(node, 0);
  53         if (!prcm_membase) {
  54                 pr_err("Couldn't map A31 PRCM registers\n");
  55                 return;
  56         }
  57
  58         node = of_find_compatible_node(NULL, NULL,
  59                                        "allwinner,sun6i-a31-cpuconfig");
  60         if (!node) {
  61                 pr_err("Missing A31 CPU config node in the device tree\n");
  62                 return;
  63         }
  64
  65         cpucfg_membase = of_iomap(node, 0);
  66         if (!cpucfg_membase)
  67                 pr_err("Couldn't map A31 CPU config registers\n");
  68
  69 }
  70
  71 static int sun6i_smp_boot_secondary(unsigned int cpu,
  72                                     struct task_struct *idle)
  73 {
  74         u32 reg;
  75         int i;
  76
  77         if (!(prcm_membase && cpucfg_membase))
  78                 return -EFAULT;
  79
  80         spin_lock(&cpu_lock);
  81
  82         /* Set CPU boot address */
  83         writel(virt_to_phys(secondary_startup),
  84                cpucfg_membase + CPUCFG_PRIVATE0_REG);
  85
  86         /* Assert the CPU core in reset */
  87         writel(0, cpucfg_membase + CPUCFG_CPU_RST_CTRL_REG(cpu));
  88
  89         /* Assert the L1 cache in reset */
  90         reg = readl(cpucfg_membase + CPUCFG_GEN_CTRL_REG);
  91         writel(reg & ~BIT(cpu), cpucfg_membase + CPUCFG_GEN_CTRL_REG);
  92
  93         /* Disable external debug access */
  94         reg = readl(cpucfg_membase + CPUCFG_DBG_CTL1_REG);
  95         writel(reg & ~BIT(cpu), cpucfg_membase + CPUCFG_DBG_CTL1_REG);
  96
  97         /* Power up the CPU */
  98         for (i = 0; i <= 8; i++)
  99                 writel(0xff >> i, prcm_membase + PRCM_CPU_PWR_CLAMP_REG(cpu));
 100         mdelay(10);
 101
 102         /* Clear CPU power-off gating */
 103         reg = readl(prcm_membase + PRCM_CPU_PWROFF_REG);
 104         writel(reg & ~BIT(cpu), prcm_membase + PRCM_CPU_PWROFF_REG);
 105         mdelay(1);
 106
 107         /* Deassert the CPU core reset */
 108         writel(3, cpucfg_membase + CPUCFG_CPU_RST_CTRL_REG(cpu));
 109
 110         /* Enable back the external debug accesses */
 111         reg = readl(cpucfg_membase + CPUCFG_DBG_CTL1_REG);
 112         writel(reg | BIT(cpu), cpucfg_membase + CPUCFG_DBG_CTL1_REG);
 113
 114         spin_unlock(&cpu_lock);
 115
 116         return 0;
 117 }
 118
 119 static struct smp_operations sun6i_smp_ops __initdata = {
 120         .smp_prepare_cpus       = sun6i_smp_prepare_cpus,
 121         .smp_boot_secondary     = sun6i_smp_boot_secondary,
 122 };
 123 CPU_METHOD_OF_DECLARE(sun6i_smp, "allwinner,sun6i-a31", &sun6i_smp_ops);