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Message-ID: <tencent_B931BF1864B6AE8C674686ED9852ACFA0609@qq.com>
Date: Thu, 20 Jul 2023 08:23:19 +0800
From: Woody Zhang <woodylab@...mail.com>
To: Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>
Cc: Conor Dooley <conor@...nel.org>, linux-riscv@...ts.infradead.org,
linux-kernel@...r.kernel.org, Woody Zhang <woodylab@...mail.com>
Subject: [PATCH] riscv: add SBI SUSP extension support
RISC-V SBI spec 2.0 [1] introduces System Suspend Extension which can be
used to suspend the platform via SBI firmware.
This patch can be tested on Qemu with recent OpenSBI with
`system-suspend-test` enabled like [2] in DTB.
[1] https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/riscv-sbi.adoc
[2] https://github.com/woodyzhang666/qemu/commit/e4a5120133c1dc354e6ac437ec1f870f6c0f6d05
Signed-off-by: Woody Zhang <woodylab@...mail.com>
---
arch/riscv/include/asm/sbi.h | 10 ++++++++++
arch/riscv/kernel/sbi.c | 26 ++++++++++++++++++++++++++
2 files changed, 36 insertions(+)
diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
index 5b4a1bf5f439..3b04016da671 100644
--- a/arch/riscv/include/asm/sbi.h
+++ b/arch/riscv/include/asm/sbi.h
@@ -30,6 +30,7 @@ enum sbi_ext_id {
SBI_EXT_HSM = 0x48534D,
SBI_EXT_SRST = 0x53525354,
SBI_EXT_PMU = 0x504D55,
+ SBI_EXT_SUSP = 0x53555350,
/* Experimentals extensions must lie within this range */
SBI_EXT_EXPERIMENTAL_START = 0x08000000,
@@ -236,6 +237,15 @@ enum sbi_pmu_ctr_type {
/* Flags defined for counter stop function */
#define SBI_PMU_STOP_FLAG_RESET (1 << 0)
+enum sbi_ext_susp_fid {
+ SBI_EXT_SUSP_SYSTEM_SUSPEND = 0,
+};
+
+/* SBI suspend sleep types */
+enum sbi_susp_sleep_type {
+ SBI_SUSP_SLEEP_TYPE_SUSPEND = 0x0,
+};
+
#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 c672c8ba9a2a..9a68959f9f18 100644
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -9,8 +9,10 @@
#include <linux/init.h>
#include <linux/pm.h>
#include <linux/reboot.h>
+#include <linux/suspend.h>
#include <asm/sbi.h>
#include <asm/smp.h>
+#include <asm/suspend.h>
/* default SBI version is 0.1 */
unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT;
@@ -520,6 +522,26 @@ static void sbi_srst_power_off(void)
SBI_SRST_RESET_REASON_NONE);
}
+static int sbi_system_suspend(unsigned long arg,
+ unsigned long resume_entry, unsigned long context)
+{
+ struct sbiret ret = {0};
+
+ ret = sbi_ecall(SBI_EXT_SUSP, SBI_EXT_SUSP_SYSTEM_SUSPEND,
+ SBI_SUSP_SLEEP_TYPE_SUSPEND, resume_entry, context, 0, 0, 0);
+ return ret.error;
+}
+
+static int sbi_system_suspend_enter(suspend_state_t state)
+{
+ return cpu_suspend(0, sbi_system_suspend);
+}
+
+static const struct platform_suspend_ops sbi_suspend_ops = {
+ .valid = suspend_valid_only_mem,
+ .enter = sbi_system_suspend_enter,
+};
+
/**
* sbi_probe_extension() - Check if an SBI extension ID is supported or not.
* @extid: The extension ID to be probed.
@@ -624,6 +646,10 @@ void __init sbi_init(void)
sbi_srst_reboot_nb.priority = 192;
register_restart_handler(&sbi_srst_reboot_nb);
}
+ if (sbi_probe_extension(SBI_EXT_SUSP)) {
+ pr_info("SBI SUSP extension detected\n");
+ suspend_set_ops(&sbi_suspend_ops);
+ }
} else {
__sbi_set_timer = __sbi_set_timer_v01;
__sbi_send_ipi = __sbi_send_ipi_v01;
--
2.39.2
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