Merge patch series "RISC-V: ACPI: Enable CPPC based cpufreq support"
Sunil V L <sunilvl@ventanamicro.com> says:
This series enables the support for "Collaborative Processor Performance
Control (CPPC) on ACPI based RISC-V platforms. It depends on the
encoding of CPPC registers as defined in RISC-V FFH spec [2].
CPPC 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#collaborative-processor-performance-control
[2] - https://github.com/riscv-non-isa/riscv-acpi-ffh/releases/download/v1.0.0/riscv-ffh.pdf
* b4-shazam-merge:
RISC-V: defconfig: Enable CONFIG_ACPI_CPPC_CPUFREQ
cpufreq: Move CPPC configs to common Kconfig and add RISC-V
ACPI: RISC-V: Add CPPC driver
Link: https://lore.kernel.org/r/20240208034414.22579-1-sunilvl@ventanamicro.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
diff --git a/arch/riscv/configs/defconfig b/arch/riscv/configs/defconfig
index 89a009a..fc0ec2e 100644
--- a/arch/riscv/configs/defconfig
+++ b/arch/riscv/configs/defconfig
@@ -44,6 +44,7 @@
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
CONFIG_CPU_FREQ_GOV_CONSERVATIVE=m
CONFIG_CPUFREQ_DT=y
+CONFIG_ACPI_CPPC_CPUFREQ=m
CONFIG_VIRTUALIZATION=y
CONFIG_KVM=m
CONFIG_ACPI=y
diff --git a/drivers/acpi/riscv/Makefile b/drivers/acpi/riscv/Makefile
index 7309d92..86b0925 100644
--- a/drivers/acpi/riscv/Makefile
+++ b/drivers/acpi/riscv/Makefile
@@ -1,3 +1,4 @@
# SPDX-License-Identifier: GPL-2.0-only
obj-y += rhct.o
obj-$(CONFIG_ACPI_PROCESSOR_IDLE) += cpuidle.o
+obj-$(CONFIG_ACPI_CPPC_LIB) += cppc.o
diff --git a/drivers/acpi/riscv/cppc.c b/drivers/acpi/riscv/cppc.c
new file mode 100644
index 0000000..4cdff38
--- /dev/null
+++ b/drivers/acpi/riscv/cppc.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Implement CPPC FFH helper routines for RISC-V.
+ *
+ * Copyright (C) 2024 Ventana Micro Systems Inc.
+ */
+
+#include <acpi/cppc_acpi.h>
+#include <asm/csr.h>
+#include <asm/sbi.h>
+
+#define SBI_EXT_CPPC 0x43505043
+
+/* CPPC interfaces defined in SBI spec */
+#define SBI_CPPC_PROBE 0x0
+#define SBI_CPPC_READ 0x1
+#define SBI_CPPC_READ_HI 0x2
+#define SBI_CPPC_WRITE 0x3
+
+/* RISC-V FFH definitions from RISC-V FFH spec */
+#define FFH_CPPC_TYPE(r) (((r) & GENMASK_ULL(63, 60)) >> 60)
+#define FFH_CPPC_SBI_REG(r) ((r) & GENMASK(31, 0))
+#define FFH_CPPC_CSR_NUM(r) ((r) & GENMASK(11, 0))
+
+#define FFH_CPPC_SBI 0x1
+#define FFH_CPPC_CSR 0x2
+
+struct sbi_cppc_data {
+ u64 val;
+ u32 reg;
+ struct sbiret ret;
+};
+
+static bool cppc_ext_present;
+
+static int __init sbi_cppc_init(void)
+{
+ if (sbi_spec_version >= sbi_mk_version(2, 0) &&
+ sbi_probe_extension(SBI_EXT_CPPC) > 0) {
+ pr_info("SBI CPPC extension detected\n");
+ cppc_ext_present = true;
+ } else {
+ pr_info("SBI CPPC extension NOT detected!!\n");
+ cppc_ext_present = false;
+ }
+
+ return 0;
+}
+device_initcall(sbi_cppc_init);
+
+static void sbi_cppc_read(void *read_data)
+{
+ struct sbi_cppc_data *data = (struct sbi_cppc_data *)read_data;
+
+ data->ret = sbi_ecall(SBI_EXT_CPPC, SBI_CPPC_READ,
+ data->reg, 0, 0, 0, 0, 0);
+}
+
+static void sbi_cppc_write(void *write_data)
+{
+ struct sbi_cppc_data *data = (struct sbi_cppc_data *)write_data;
+
+ data->ret = sbi_ecall(SBI_EXT_CPPC, SBI_CPPC_WRITE,
+ data->reg, data->val, 0, 0, 0, 0);
+}
+
+static void cppc_ffh_csr_read(void *read_data)
+{
+ struct sbi_cppc_data *data = (struct sbi_cppc_data *)read_data;
+
+ switch (data->reg) {
+ /* Support only TIME CSR for now */
+ case CSR_TIME:
+ data->ret.value = csr_read(CSR_TIME);
+ data->ret.error = 0;
+ break;
+ default:
+ data->ret.error = -EINVAL;
+ break;
+ }
+}
+
+static void cppc_ffh_csr_write(void *write_data)
+{
+ struct sbi_cppc_data *data = (struct sbi_cppc_data *)write_data;
+
+ data->ret.error = -EINVAL;
+}
+
+/*
+ * Refer to drivers/acpi/cppc_acpi.c for the description of the functions
+ * below.
+ */
+bool cpc_ffh_supported(void)
+{
+ return true;
+}
+
+int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val)
+{
+ struct sbi_cppc_data data;
+
+ if (WARN_ON_ONCE(irqs_disabled()))
+ return -EPERM;
+
+ if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_SBI) {
+ if (!cppc_ext_present)
+ return -EINVAL;
+
+ data.reg = FFH_CPPC_SBI_REG(reg->address);
+
+ smp_call_function_single(cpu, sbi_cppc_read, &data, 1);
+
+ *val = data.ret.value;
+
+ return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
+ } else if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_CSR) {
+ data.reg = FFH_CPPC_CSR_NUM(reg->address);
+
+ smp_call_function_single(cpu, cppc_ffh_csr_read, &data, 1);
+
+ *val = data.ret.value;
+
+ return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
+ }
+
+ return -EINVAL;
+}
+
+int cpc_write_ffh(int cpu, struct cpc_reg *reg, u64 val)
+{
+ struct sbi_cppc_data data;
+
+ if (WARN_ON_ONCE(irqs_disabled()))
+ return -EPERM;
+
+ if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_SBI) {
+ if (!cppc_ext_present)
+ return -EINVAL;
+
+ data.reg = FFH_CPPC_SBI_REG(reg->address);
+ data.val = val;
+
+ smp_call_function_single(cpu, sbi_cppc_write, &data, 1);
+
+ return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
+ } else if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_CSR) {
+ data.reg = FFH_CPPC_CSR_NUM(reg->address);
+ data.val = val;
+
+ smp_call_function_single(cpu, cppc_ffh_csr_write, &data, 1);
+
+ return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
+ }
+
+ return -EINVAL;
+}
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index 35efb53..94e55c4 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -302,4 +302,33 @@
which are capable of changing the CPU's frequency dynamically.
endif
+
+config ACPI_CPPC_CPUFREQ
+ tristate "CPUFreq driver based on the ACPI CPPC spec"
+ depends on ACPI_PROCESSOR
+ depends on ARM || ARM64 || RISCV
+ select ACPI_CPPC_LIB
+ help
+ This adds a CPUFreq driver which uses CPPC methods
+ as described in the ACPIv5.1 spec. CPPC stands for
+ Collaborative Processor Performance Controls. It
+ is based on an abstract continuous scale of CPU
+ performance values which allows the remote power
+ processor to flexibly optimize for power and
+ performance. CPPC relies on power management firmware
+ support for its operation.
+
+ If in doubt, say N.
+
+config ACPI_CPPC_CPUFREQ_FIE
+ bool "Frequency Invariance support for CPPC cpufreq driver"
+ depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY
+ depends on ARM || ARM64 || RISCV
+ default y
+ help
+ This extends frequency invariance support in the CPPC cpufreq driver,
+ by using CPPC delivered and reference performance counters.
+
+ If in doubt, say N.
+
endmenu
diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm
index f911606..987b3d9 100644
--- a/drivers/cpufreq/Kconfig.arm
+++ b/drivers/cpufreq/Kconfig.arm
@@ -3,32 +3,6 @@
# ARM CPU Frequency scaling drivers
#
-config ACPI_CPPC_CPUFREQ
- tristate "CPUFreq driver based on the ACPI CPPC spec"
- depends on ACPI_PROCESSOR
- select ACPI_CPPC_LIB
- help
- This adds a CPUFreq driver which uses CPPC methods
- as described in the ACPIv5.1 spec. CPPC stands for
- Collaborative Processor Performance Controls. It
- is based on an abstract continuous scale of CPU
- performance values which allows the remote power
- processor to flexibly optimize for power and
- performance. CPPC relies on power management firmware
- support for its operation.
-
- If in doubt, say N.
-
-config ACPI_CPPC_CPUFREQ_FIE
- bool "Frequency Invariance support for CPPC cpufreq driver"
- depends on ACPI_CPPC_CPUFREQ && GENERIC_ARCH_TOPOLOGY
- default y
- help
- This extends frequency invariance support in the CPPC cpufreq driver,
- by using CPPC delivered and reference performance counters.
-
- If in doubt, say N.
-
config ARM_ALLWINNER_SUN50I_CPUFREQ_NVMEM
tristate "Allwinner nvmem based SUN50I CPUFreq driver"
depends on ARCH_SUNXI
