arch/riscv/kernel/cpu_ops_sbi.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * HSM extension and cpu_ops implementation.
   4  *
   5  * Copyright (c) 2020 Western Digital Corporation or its affiliates.
   6  */
   7
   8 #include <linux/init.h>
   9 #include <linux/mm.h>
  10 #include <asm/cpu_ops.h>
  11 #include <asm/sbi.h>
  12 #include <asm/smp.h>
  13
  14 extern char secondary_start_sbi[];
  15 const struct cpu_operations cpu_ops_sbi;
  16
  17 static int sbi_hsm_hart_start(unsigned long hartid, unsigned long saddr,
  18                               unsigned long priv)
  19 {
  20         struct sbiret ret;
  21
  22         ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_START,
  23                         hartid, saddr, priv, 0, 0, 0);
  24         if (ret.error)
  25                 return sbi_err_map_linux_errno(ret.error);
  26         else
  27                 return 0;
  28 }
  29
  30 #ifdef CONFIG_HOTPLUG_CPU
  31 static int sbi_hsm_hart_stop(void)
  32 {
  33         struct sbiret ret;
  34
  35         ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STOP, 0, 0, 0, 0, 0, 0);
  36
  37         if (ret.error)
  38                 return sbi_err_map_linux_errno(ret.error);
  39         else
  40                 return 0;
  41 }
  42
  43 static int sbi_hsm_hart_get_status(unsigned long hartid)
  44 {
  45         struct sbiret ret;
  46
  47         ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_STATUS,
  48                         hartid, 0, 0, 0, 0, 0);
  49         if (ret.error)
  50                 return sbi_err_map_linux_errno(ret.error);
  51         else
  52                 return ret.value;
  53 }
  54 #endif
  55
  56 static int sbi_cpu_start(unsigned int cpuid, struct task_struct *tidle)
  57 {
  58         int rc;
  59         unsigned long boot_addr = __pa_symbol(secondary_start_sbi);
  60         int hartid = cpuid_to_hartid_map(cpuid);
  61
  62         cpu_update_secondary_bootdata(cpuid, tidle);
  63         rc = sbi_hsm_hart_start(hartid, boot_addr, 0);
  64
  65         return rc;
  66 }
  67
  68 static int sbi_cpu_prepare(unsigned int cpuid)
  69 {
  70         if (!cpu_ops_sbi.cpu_start) {
  71                 pr_err("cpu start method not defined for CPU [%d]\n", cpuid);
  72                 return -ENODEV;
  73         }
  74         return 0;
  75 }
  76
  77 #ifdef CONFIG_HOTPLUG_CPU
  78 static int sbi_cpu_disable(unsigned int cpuid)
  79 {
  80         if (!cpu_ops_sbi.cpu_stop)
  81                 return -EOPNOTSUPP;
  82         return 0;
  83 }
  84
  85 static void sbi_cpu_stop(void)
  86 {
  87         int ret;
  88
  89         ret = sbi_hsm_hart_stop();
  90         pr_crit("Unable to stop the cpu %u (%d)\n", smp_processor_id(), ret);
  91 }
  92
  93 static int sbi_cpu_is_stopped(unsigned int cpuid)
  94 {
  95         int rc;
  96         int hartid = cpuid_to_hartid_map(cpuid);
  97
  98         rc = sbi_hsm_hart_get_status(hartid);
  99
 100         if (rc == SBI_HSM_HART_STATUS_STOPPED)
 101                 return 0;
 102         return rc;
 103 }
 104 #endif
 105
 106 const struct cpu_operations cpu_ops_sbi = {
 107         .name           = "sbi",
 108         .cpu_prepare    = sbi_cpu_prepare,
 109         .cpu_start      = sbi_cpu_start,
 110 #ifdef CONFIG_HOTPLUG_CPU
 111         .cpu_disable    = sbi_cpu_disable,
 112         .cpu_stop       = sbi_cpu_stop,
 113         .cpu_is_stopped = sbi_cpu_is_stopped,
 114 #endif
 115 };