Merge patch series "RISC-V: ACPI: Add LPI support"
Sunil V L <sunilvl@ventanamicro.com> says:
This series adds support for Low Power Idle (LPI) on ACPI based
platforms.
LPI is described in the ACPI spec [1]. RISC-V FFH spec required to
enable this is available at [2].
[1] - https://uefi.org/specs/ACPI/6.5/08_Processor_Configuration_and_Control.html#lpi-low-power-idle-states
[2] - https://github.com/riscv-non-isa/riscv-acpi-ffh/releases/download/v/riscv-ffh.pdf
* b4-shazam-merge:
ACPI: Enable ACPI_PROCESSOR for RISC-V
ACPI: RISC-V: Add LPI driver
cpuidle: RISC-V: Move few functions to arch/riscv
Link: https://lore.kernel.org/r/20240118062930.245937-1-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
diff --git a/arch/riscv/include/asm/suspend.h b/arch/riscv/include/asm/suspend.h
index 02f8786..076f8a9 100644
--- a/arch/riscv/include/asm/suspend.h
+++ b/arch/riscv/include/asm/suspend.h
@@ -55,4 +55,7 @@
asmlinkage void hibernate_restore_image(unsigned long resume_satp, unsigned long satp_temp,
unsigned long cpu_resume);
asmlinkage int hibernate_core_restore_code(void);
+bool riscv_sbi_hsm_is_supported(void);
+bool riscv_sbi_suspend_state_is_valid(u32 state);
+int riscv_sbi_hart_suspend(u32 state);
#endif
diff --git a/arch/riscv/kernel/suspend.c b/arch/riscv/kernel/suspend.c
index 2395093..b20f2cb 100644
--- a/arch/riscv/kernel/suspend.c
+++ b/arch/riscv/kernel/suspend.c
@@ -128,4 +128,53 @@
}
arch_initcall(sbi_system_suspend_init);
+
+static int sbi_suspend_finisher(unsigned long suspend_type,
+ unsigned long resume_addr,
+ unsigned long opaque)
+{
+ struct sbiret ret;
+
+ ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
+ suspend_type, resume_addr, opaque, 0, 0, 0);
+
+ return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
+}
+
+int riscv_sbi_hart_suspend(u32 state)
+{
+ if (state & SBI_HSM_SUSP_NON_RET_BIT)
+ return cpu_suspend(state, sbi_suspend_finisher);
+ else
+ return sbi_suspend_finisher(state, 0, 0);
+}
+
+bool riscv_sbi_suspend_state_is_valid(u32 state)
+{
+ if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
+ state < SBI_HSM_SUSPEND_RET_PLATFORM)
+ return false;
+
+ if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
+ state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
+ return false;
+
+ return true;
+}
+
+bool riscv_sbi_hsm_is_supported(void)
+{
+ /*
+ * The SBI HSM suspend function is only available when:
+ * 1) SBI version is 0.3 or higher
+ * 2) SBI HSM extension is available
+ */
+ if (sbi_spec_version < sbi_mk_version(0, 3) ||
+ !sbi_probe_extension(SBI_EXT_HSM)) {
+ pr_info("HSM suspend not available\n");
+ return false;
+ }
+
+ return true;
+}
#endif /* CONFIG_RISCV_SBI */
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 3c3f803..1606eb6 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -286,7 +286,7 @@
config ACPI_PROCESSOR
tristate "Processor"
- depends on X86 || ARM64 || LOONGARCH
+ depends on X86 || ARM64 || LOONGARCH || RISCV
select ACPI_PROCESSOR_IDLE
select ACPI_CPU_FREQ_PSS if X86 || LOONGARCH
select THERMAL
diff --git a/drivers/acpi/riscv/Makefile b/drivers/acpi/riscv/Makefile
index 8b3b126e..7309d92 100644
--- a/drivers/acpi/riscv/Makefile
+++ b/drivers/acpi/riscv/Makefile
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
-obj-y += rhct.o
+obj-y += rhct.o
+obj-$(CONFIG_ACPI_PROCESSOR_IDLE) += cpuidle.o
diff --git a/drivers/acpi/riscv/cpuidle.c b/drivers/acpi/riscv/cpuidle.c
new file mode 100644
index 0000000..624f9bb
--- /dev/null
+++ b/drivers/acpi/riscv/cpuidle.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024, Ventana Micro Systems Inc
+ * Author: Sunil V L <sunilvl@ventanamicro.com>
+ *
+ */
+
+#include <linux/acpi.h>
+#include <acpi/processor.h>
+#include <linux/cpu_pm.h>
+#include <linux/cpuidle.h>
+#include <linux/suspend.h>
+#include <asm/cpuidle.h>
+#include <asm/sbi.h>
+#include <asm/suspend.h>
+
+#define RISCV_FFH_LPI_TYPE_MASK GENMASK_ULL(63, 60)
+#define RISCV_FFH_LPI_RSVD_MASK GENMASK_ULL(59, 32)
+
+#define RISCV_FFH_LPI_TYPE_SBI BIT_ULL(60)
+
+static int acpi_cpu_init_idle(unsigned int cpu)
+{
+ int i;
+ struct acpi_lpi_state *lpi;
+ struct acpi_processor *pr = per_cpu(processors, cpu);
+
+ if (unlikely(!pr || !pr->flags.has_lpi))
+ return -EINVAL;
+
+ if (!riscv_sbi_hsm_is_supported())
+ return -ENODEV;
+
+ if (pr->power.count <= 1)
+ return -ENODEV;
+
+ for (i = 1; i < pr->power.count; i++) {
+ u32 state;
+
+ lpi = &pr->power.lpi_states[i];
+
+ /*
+ * Validate Entry Method as per FFH spec.
+ * bits[63:60] should be 0x1
+ * bits[59:32] should be 0x0
+ * bits[31:0] represent a SBI power_state
+ */
+ if (((lpi->address & RISCV_FFH_LPI_TYPE_MASK) != RISCV_FFH_LPI_TYPE_SBI) ||
+ (lpi->address & RISCV_FFH_LPI_RSVD_MASK)) {
+ pr_warn("Invalid LPI entry method %#llx\n", lpi->address);
+ return -EINVAL;
+ }
+
+ state = lpi->address;
+ if (!riscv_sbi_suspend_state_is_valid(state)) {
+ pr_warn("Invalid SBI power state %#x\n", state);
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+int acpi_processor_ffh_lpi_probe(unsigned int cpu)
+{
+ return acpi_cpu_init_idle(cpu);
+}
+
+int acpi_processor_ffh_lpi_enter(struct acpi_lpi_state *lpi)
+{
+ u32 state = lpi->address;
+
+ if (state & SBI_HSM_SUSP_NON_RET_BIT)
+ return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_sbi_hart_suspend,
+ lpi->index,
+ state);
+ else
+ return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend,
+ lpi->index,
+ state);
+}
diff --git a/drivers/cpuidle/cpuidle-riscv-sbi.c b/drivers/cpuidle/cpuidle-riscv-sbi.c
index e8094fc..a6e123d 100644
--- a/drivers/cpuidle/cpuidle-riscv-sbi.c
+++ b/drivers/cpuidle/cpuidle-riscv-sbi.c
@@ -73,26 +73,6 @@
return data->available;
}
-static int sbi_suspend_finisher(unsigned long suspend_type,
- unsigned long resume_addr,
- unsigned long opaque)
-{
- struct sbiret ret;
-
- ret = sbi_ecall(SBI_EXT_HSM, SBI_EXT_HSM_HART_SUSPEND,
- suspend_type, resume_addr, opaque, 0, 0, 0);
-
- return (ret.error) ? sbi_err_map_linux_errno(ret.error) : 0;
-}
-
-static int sbi_suspend(u32 state)
-{
- if (state & SBI_HSM_SUSP_NON_RET_BIT)
- return cpu_suspend(state, sbi_suspend_finisher);
- else
- return sbi_suspend_finisher(state, 0, 0);
-}
-
static __cpuidle int sbi_cpuidle_enter_state(struct cpuidle_device *dev,
struct cpuidle_driver *drv, int idx)
{
@@ -100,9 +80,9 @@
u32 state = states[idx];
if (state & SBI_HSM_SUSP_NON_RET_BIT)
- return CPU_PM_CPU_IDLE_ENTER_PARAM(sbi_suspend, idx, state);
+ return CPU_PM_CPU_IDLE_ENTER_PARAM(riscv_sbi_hart_suspend, idx, state);
else
- return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(sbi_suspend,
+ return CPU_PM_CPU_IDLE_ENTER_RETENTION_PARAM(riscv_sbi_hart_suspend,
idx, state);
}
@@ -133,7 +113,7 @@
else
state = states[idx];
- ret = sbi_suspend(state) ? -1 : idx;
+ ret = riscv_sbi_hart_suspend(state) ? -1 : idx;
ct_cpuidle_exit();
@@ -206,17 +186,6 @@
{ },
};
-static bool sbi_suspend_state_is_valid(u32 state)
-{
- if (state > SBI_HSM_SUSPEND_RET_DEFAULT &&
- state < SBI_HSM_SUSPEND_RET_PLATFORM)
- return false;
- if (state > SBI_HSM_SUSPEND_NON_RET_DEFAULT &&
- state < SBI_HSM_SUSPEND_NON_RET_PLATFORM)
- return false;
- return true;
-}
-
static int sbi_dt_parse_state_node(struct device_node *np, u32 *state)
{
int err = of_property_read_u32(np, "riscv,sbi-suspend-param", state);
@@ -226,7 +195,7 @@
return err;
}
- if (!sbi_suspend_state_is_valid(*state)) {
+ if (!riscv_sbi_suspend_state_is_valid(*state)) {
pr_warn("Invalid SBI suspend state %#x\n", *state);
return -EINVAL;
}
@@ -607,16 +576,8 @@
int ret;
struct platform_device *pdev;
- /*
- * The SBI HSM suspend function is only available when:
- * 1) SBI version is 0.3 or higher
- * 2) SBI HSM extension is available
- */
- if ((sbi_spec_version < sbi_mk_version(0, 3)) ||
- !sbi_probe_extension(SBI_EXT_HSM)) {
- pr_info("HSM suspend not available\n");
+ if (!riscv_sbi_hsm_is_supported())
return 0;
- }
ret = platform_driver_register(&sbi_cpuidle_driver);
if (ret)
