arch/arm/mach-npcm/platsmp.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (c) 2018 Nuvoton Technology corporation.
   3 // Copyright 2018 Google, Inc.
   4
   5 #define pr_fmt(fmt) "nuvoton,npcm7xx-smp: " fmt
   6
   7 #include <linux/delay.h>
   8 #include <linux/device.h>
   9 #include <linux/smp.h>
  10 #include <linux/io.h>
  11 #include <linux/of.h>
  12 #include <linux/of_device.h>
  13 #include <linux/of_platform.h>
  14 #include <linux/of_address.h>
  15 #include <asm/cacheflush.h>
  16 #include <asm/smp.h>
  17 #include <asm/smp_plat.h>
  18 #include <asm/smp_scu.h>
  19
  20 #define NPCM7XX_SCRPAD_REG 0x13c
  21
  22 extern void npcm7xx_secondary_startup(void);
  23
  24 static int npcm7xx_smp_boot_secondary(unsigned int cpu,
  25                                       struct task_struct *idle)
  26 {
  27         struct device_node *gcr_np;
  28         void __iomem *gcr_base;
  29         int ret = 0;
  30
  31         gcr_np = of_find_compatible_node(NULL, NULL, "nuvoton,npcm750-gcr");
  32         if (!gcr_np) {
  33                 pr_err("no gcr device node\n");
  34                 ret = -ENODEV;
  35                 goto out;
  36         }
  37         gcr_base = of_iomap(gcr_np, 0);
  38         if (!gcr_base) {
  39                 pr_err("could not iomap gcr");
  40                 ret = -ENOMEM;
  41                 goto out;
  42         }
  43
  44         /* give boot ROM kernel start address. */
  45         iowrite32(__pa_symbol(npcm7xx_secondary_startup), gcr_base +
  46                   NPCM7XX_SCRPAD_REG);
  47         /* make sure the previous write is seen by all observers. */
  48         dsb_sev();
  49
  50         iounmap(gcr_base);
  51 out:
  52         return ret;
  53 }
  54
  55 static void __init npcm7xx_smp_prepare_cpus(unsigned int max_cpus)
  56 {
  57         struct device_node *scu_np;
  58         void __iomem *scu_base;
  59
  60         scu_np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
  61         if (!scu_np) {
  62                 pr_err("no scu device node\n");
  63                 return;
  64         }
  65         scu_base = of_iomap(scu_np, 0);
  66         if (!scu_base) {
  67                 pr_err("could not iomap scu");
  68                 return;
  69         }
  70
  71         scu_enable(scu_base);
  72
  73         iounmap(scu_base);
  74 }
  75
  76 static struct smp_operations npcm7xx_smp_ops __initdata = {
  77         .smp_prepare_cpus = npcm7xx_smp_prepare_cpus,
  78         .smp_boot_secondary = npcm7xx_smp_boot_secondary,
  79 };
  80
  81 CPU_METHOD_OF_DECLARE(npcm7xx_smp, "nuvoton,npcm750-smp", &npcm7xx_smp_ops);