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RISC-V: Use SBI SRST extension when available 

The SBI SRST extension provides a standard way to poweroff and
reboot the system irrespective to whether Linux RISC-V S-mode
is running natively (HS-mode) or inside Guest/VM (VS-mode).

The SBI SRST extension is available in the SBI v0.3 specification.
(Refer, https://github.com/riscv/riscv-sbi-doc/releases/tag/v0.3.0-rc1)

This patch extends Linux RISC-V SBI implementation to detect
and use SBI SRST extension.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Anup Patel 2021-06-09 17:43:22 +05:30 committed by Palmer Dabbelt
parent b0fd4b1bf9
commit b579dfe71a
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GPG Key ID: 2E1319F35FBB1889
2 changed files with 59 additions and 0 deletions
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24
arch/riscv/include/asm/sbi.h
View File

@ -27,6 +27,7 @@ enum sbi_ext_id {
SBI_EXT_IPI = 0x735049,
SBI_EXT_RFENCE = 0x52464E43,
SBI_EXT_HSM = 0x48534D,
SBI_EXT_SRST = 0x53525354,
};
enum sbi_ext_base_fid {
@ -70,6 +71,21 @@ enum sbi_hsm_hart_status {
SBI_HSM_HART_STATUS_STOP_PENDING,
};
enum sbi_ext_srst_fid {
SBI_EXT_SRST_RESET = 0,
};
enum sbi_srst_reset_type {
SBI_SRST_RESET_TYPE_SHUTDOWN = 0,
SBI_SRST_RESET_TYPE_COLD_REBOOT,
SBI_SRST_RESET_TYPE_WARM_REBOOT,
};
enum sbi_srst_reset_reason {
SBI_SRST_RESET_REASON_NONE = 0,
SBI_SRST_RESET_REASON_SYS_FAILURE,
};
#define SBI_SPEC_VERSION_DEFAULT 0x1
#define SBI_SPEC_VERSION_MAJOR_SHIFT 24
#define SBI_SPEC_VERSION_MAJOR_MASK 0x7f
@ -148,6 +164,14 @@ static inline unsigned long sbi_minor_version(void)
return sbi_spec_version & SBI_SPEC_VERSION_MINOR_MASK;
}
/* Make SBI version */
static inline unsigned long sbi_mk_version(unsigned long major,
unsigned long minor)
{
return ((major & SBI_SPEC_VERSION_MAJOR_MASK) <<
SBI_SPEC_VERSION_MAJOR_SHIFT) | minor;
}
int sbi_err_map_linux_errno(int err);
#else /* CONFIG_RISCV_SBI */
static inline int sbi_remote_fence_i(const unsigned long *hart_mask) { return -1; }

35
arch/riscv/kernel/sbi.c
View File

@ -7,6 +7,7 @@
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/reboot.h>
#include <asm/sbi.h>
#include <asm/smp.h>
@ -501,6 +502,32 @@ int sbi_remote_hfence_vvma_asid(const unsigned long *hart_mask,
}
EXPORT_SYMBOL(sbi_remote_hfence_vvma_asid);
static void sbi_srst_reset(unsigned long type, unsigned long reason)
{
sbi_ecall(SBI_EXT_SRST, SBI_EXT_SRST_RESET, type, reason,
0, 0, 0, 0);
pr_warn("%s: type=0x%lx reason=0x%lx failed\n",
__func__, type, reason);
}
static int sbi_srst_reboot(struct notifier_block *this,
unsigned long mode, void *cmd)
{
sbi_srst_reset((mode == REBOOT_WARM || mode == REBOOT_SOFT) ?
SBI_SRST_RESET_TYPE_WARM_REBOOT :
SBI_SRST_RESET_TYPE_COLD_REBOOT,
SBI_SRST_RESET_REASON_NONE);
return NOTIFY_DONE;
}
static struct notifier_block sbi_srst_reboot_nb;
static void sbi_srst_power_off(void)
{
sbi_srst_reset(SBI_SRST_RESET_TYPE_SHUTDOWN,
SBI_SRST_RESET_REASON_NONE);
}
/**
* sbi_probe_extension() - Check if an SBI extension ID is supported or not.
* @extid: The extension ID to be probed.
@ -608,6 +635,14 @@ void __init sbi_init(void)
} else {
__sbi_rfence = __sbi_rfence_v01;
}
if ((sbi_spec_version >= sbi_mk_version(0, 3)) &&
(sbi_probe_extension(SBI_EXT_SRST) > 0)) {
pr_info("SBI SRST extension detected\n");
pm_power_off = sbi_srst_power_off;
sbi_srst_reboot_nb.notifier_call = sbi_srst_reboot;
sbi_srst_reboot_nb.priority = 192;
register_restart_handler(&sbi_srst_reboot_nb);
}
} else {
__sbi_set_timer = __sbi_set_timer_v01;
__sbi_send_ipi = __sbi_send_ipi_v01;