LXR linux/arch/riscv/kernel/cpu_ops

   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
  14extern char secondary_start_sbi[];
  15const struct cpu_operations cpu_ops_sbi;
  16
  17static 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
  31static 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
  43static 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
  56static 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
  68static 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
  78static int sbi_cpu_disable(unsigned int cpuid)
  79{
  80        if (!cpu_ops_sbi.cpu_stop)
  81                return -EOPNOTSUPP;
  82        return 0;
  83}
  84
  85static 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
  93static 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
 106const 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};
 116