158 lines
3.5 KiB
C
158 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Implement CPPC FFH helper routines for RISC-V.
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*
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* Copyright (C) 2024 Ventana Micro Systems Inc.
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*/
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#include <acpi/cppc_acpi.h>
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#include <asm/csr.h>
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#include <asm/sbi.h>
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#define SBI_EXT_CPPC 0x43505043
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/* CPPC interfaces defined in SBI spec */
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#define SBI_CPPC_PROBE 0x0
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#define SBI_CPPC_READ 0x1
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#define SBI_CPPC_READ_HI 0x2
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#define SBI_CPPC_WRITE 0x3
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/* RISC-V FFH definitions from RISC-V FFH spec */
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#define FFH_CPPC_TYPE(r) (((r) & GENMASK_ULL(63, 60)) >> 60)
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#define FFH_CPPC_SBI_REG(r) ((r) & GENMASK(31, 0))
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#define FFH_CPPC_CSR_NUM(r) ((r) & GENMASK(11, 0))
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#define FFH_CPPC_SBI 0x1
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#define FFH_CPPC_CSR 0x2
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struct sbi_cppc_data {
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u64 val;
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u32 reg;
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struct sbiret ret;
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};
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static bool cppc_ext_present;
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static int __init sbi_cppc_init(void)
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{
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if (sbi_spec_version >= sbi_mk_version(2, 0) &&
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sbi_probe_extension(SBI_EXT_CPPC) > 0) {
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pr_info("SBI CPPC extension detected\n");
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cppc_ext_present = true;
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} else {
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pr_info("SBI CPPC extension NOT detected!!\n");
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cppc_ext_present = false;
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}
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return 0;
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}
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device_initcall(sbi_cppc_init);
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static void sbi_cppc_read(void *read_data)
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{
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struct sbi_cppc_data *data = (struct sbi_cppc_data *)read_data;
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data->ret = sbi_ecall(SBI_EXT_CPPC, SBI_CPPC_READ,
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data->reg, 0, 0, 0, 0, 0);
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}
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static void sbi_cppc_write(void *write_data)
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{
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struct sbi_cppc_data *data = (struct sbi_cppc_data *)write_data;
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data->ret = sbi_ecall(SBI_EXT_CPPC, SBI_CPPC_WRITE,
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data->reg, data->val, 0, 0, 0, 0);
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}
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static void cppc_ffh_csr_read(void *read_data)
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{
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struct sbi_cppc_data *data = (struct sbi_cppc_data *)read_data;
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switch (data->reg) {
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/* Support only TIME CSR for now */
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case CSR_TIME:
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data->ret.value = csr_read(CSR_TIME);
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data->ret.error = 0;
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break;
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default:
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data->ret.error = -EINVAL;
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break;
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}
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}
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static void cppc_ffh_csr_write(void *write_data)
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{
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struct sbi_cppc_data *data = (struct sbi_cppc_data *)write_data;
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data->ret.error = -EINVAL;
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}
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/*
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* Refer to drivers/acpi/cppc_acpi.c for the description of the functions
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* below.
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*/
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bool cpc_ffh_supported(void)
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{
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return true;
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}
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int cpc_read_ffh(int cpu, struct cpc_reg *reg, u64 *val)
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{
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struct sbi_cppc_data data;
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if (WARN_ON_ONCE(irqs_disabled()))
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return -EPERM;
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if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_SBI) {
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if (!cppc_ext_present)
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return -EINVAL;
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data.reg = FFH_CPPC_SBI_REG(reg->address);
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smp_call_function_single(cpu, sbi_cppc_read, &data, 1);
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*val = data.ret.value;
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return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
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} else if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_CSR) {
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data.reg = FFH_CPPC_CSR_NUM(reg->address);
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smp_call_function_single(cpu, cppc_ffh_csr_read, &data, 1);
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*val = data.ret.value;
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return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
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}
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return -EINVAL;
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}
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int cpc_write_ffh(int cpu, struct cpc_reg *reg, u64 val)
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{
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struct sbi_cppc_data data;
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if (WARN_ON_ONCE(irqs_disabled()))
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return -EPERM;
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if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_SBI) {
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if (!cppc_ext_present)
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return -EINVAL;
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data.reg = FFH_CPPC_SBI_REG(reg->address);
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data.val = val;
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smp_call_function_single(cpu, sbi_cppc_write, &data, 1);
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return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
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} else if (FFH_CPPC_TYPE(reg->address) == FFH_CPPC_CSR) {
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data.reg = FFH_CPPC_CSR_NUM(reg->address);
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data.val = val;
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smp_call_function_single(cpu, cppc_ffh_csr_write, &data, 1);
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return (data.ret.error) ? sbi_err_map_linux_errno(data.ret.error) : 0;
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}
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return -EINVAL;
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}
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