On Mon, 01 Mar 2021 03:58:33 PST (-0800), Anup Patel wrote:
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 latest SBI v0.3-draft
specification at: https://github.com/riscv/riscv-sbi-doc.
This patch extends Linux RISC-V SBI implementation to detect
and use SBI SRST extension.
Signed-off-by: Anup Patel <anup.pa...@wdc.com>
---
arch/riscv/include/asm/sbi.h | 16 ++++++++++++++
arch/riscv/kernel/sbi.c | 41 +++++++++++++++++++++++++++++++++---
2 files changed, 54 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 99895d9c3bdd..8add0209c9c7 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -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
diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index f4a7db3d309e..49155588e56c 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -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.
@@ -577,22 +604,30 @@ void __init sbi_init(void)
sbi_get_firmware_id(), sbi_get_firmware_version());
if (sbi_probe_extension(SBI_EXT_TIME) > 0) {
__sbi_set_timer = __sbi_set_timer_v02;
- pr_info("SBI v0.2 TIME extension detected\n");
+ pr_info("SBI TIME extension detected\n");
} else {
__sbi_set_timer = __sbi_set_timer_v01;
}
if (sbi_probe_extension(SBI_EXT_IPI) > 0) {
__sbi_send_ipi = __sbi_send_ipi_v02;
- pr_info("SBI v0.2 IPI extension detected\n");
+ pr_info("SBI IPI extension detected\n");
These aren't really part of the reset stuff and should be split into a separate
patch.
} else {
__sbi_send_ipi = __sbi_send_ipi_v01;
}
if (sbi_probe_extension(SBI_EXT_RFENCE) > 0) {
__sbi_rfence = __sbi_rfence_v02;
- pr_info("SBI v0.2 RFENCE extension detected\n");
+ pr_info("SBI RFENCE extension detected\n");
} else {
__sbi_rfence = __sbi_rfence_v01;
}
+ if (sbi_probe_extension(SBI_EXT_SRST) > 0 &&
+ sbi_minor_version() >= 3) {
+ 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;
This is fine, but I don't want to take things for draft SBI versions until
they're at least tagged.
