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