mirror of
https://github.com/riscv-software-src/opensbi
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33caae8069
Implement SBI CPPC extension. This extension is only available when OpenSBI platform provides a CPPC device to generic library. Signed-off-by: Sunil V L <sunilvl@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Reviewed-by: Anup Patel <anup@brainfault.org>
111 lines
2.2 KiB
C
111 lines
2.2 KiB
C
/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2023 Ventana Micro Systems Inc.
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*
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*/
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#include <sbi/sbi_error.h>
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#include <sbi/sbi_cppc.h>
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static const struct sbi_cppc_device *cppc_dev = NULL;
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const struct sbi_cppc_device *sbi_cppc_get_device(void)
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{
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return cppc_dev;
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}
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void sbi_cppc_set_device(const struct sbi_cppc_device *dev)
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{
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if (!dev || cppc_dev)
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return;
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cppc_dev = dev;
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}
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static bool sbi_cppc_is_reserved(unsigned long reg)
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{
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if ((reg > SBI_CPPC_ACPI_LAST && reg < SBI_CPPC_TRANSITION_LATENCY) ||
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reg > SBI_CPPC_NON_ACPI_LAST)
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return true;
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return false;
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}
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static bool sbi_cppc_readable(unsigned long reg)
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{
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/* there are no write-only cppc registers currently */
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return true;
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}
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static bool sbi_cppc_writable(unsigned long reg)
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{
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switch (reg) {
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case SBI_CPPC_HIGHEST_PERF:
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case SBI_CPPC_NOMINAL_PERF:
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case SBI_CPPC_LOW_NON_LINEAR_PERF:
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case SBI_CPPC_LOWEST_PERF:
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case SBI_CPPC_GUARANTEED_PERF:
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case SBI_CPPC_CTR_WRAP_TIME:
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case SBI_CPPC_REFERENCE_CTR:
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case SBI_CPPC_DELIVERED_CTR:
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case SBI_CPPC_REFERENCE_PERF:
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case SBI_CPPC_LOWEST_FREQ:
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case SBI_CPPC_NOMINAL_FREQ:
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case SBI_CPPC_TRANSITION_LATENCY:
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return false;
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}
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return true;
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}
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int sbi_cppc_probe(unsigned long reg)
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{
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if (!cppc_dev || !cppc_dev->cppc_probe)
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return SBI_EFAIL;
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/* Check whether register is reserved */
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if (sbi_cppc_is_reserved(reg))
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return SBI_ERR_INVALID_PARAM;
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return cppc_dev->cppc_probe(reg);
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}
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int sbi_cppc_read(unsigned long reg, uint64_t *val)
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{
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int ret;
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if (!cppc_dev || !cppc_dev->cppc_read)
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return SBI_EFAIL;
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/* Check whether register is implemented */
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ret = sbi_cppc_probe(reg);
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if (ret <= 0)
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return SBI_ERR_NOT_SUPPORTED;
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/* Check whether the register is write-only */
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if (!sbi_cppc_readable(reg))
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return SBI_ERR_DENIED;
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return cppc_dev->cppc_read(reg, val);
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}
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int sbi_cppc_write(unsigned long reg, uint64_t val)
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{
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int ret;
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if (!cppc_dev || !cppc_dev->cppc_write)
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return SBI_EFAIL;
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/* Check whether register is implemented */
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ret = sbi_cppc_probe(reg);
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if (ret <= 0)
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return SBI_ERR_NOT_SUPPORTED;
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/* Check whether the register is read-only */
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if (!sbi_cppc_writable(reg))
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return SBI_ERR_DENIED;
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return cppc_dev->cppc_write(reg, val);
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}
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