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/*
* SPDX-License-Identifier: BSD-2-Clause
*
* Copyright (c) 2023 Ventana Micro Systems Inc.
*
*/
#include <sbi/sbi_error.h>
#include <sbi/sbi_cppc.h>
static const struct sbi_cppc_device *cppc_dev = NULL;
const struct sbi_cppc_device *sbi_cppc_get_device(void)
{
return cppc_dev;
}
void sbi_cppc_set_device(const struct sbi_cppc_device *dev)
{
if (!dev || cppc_dev)
return;
cppc_dev = dev;
}
static bool sbi_cppc_is_reserved(unsigned long reg)
{
if ((reg > SBI_CPPC_ACPI_LAST && reg < SBI_CPPC_TRANSITION_LATENCY) ||
reg > SBI_CPPC_NON_ACPI_LAST)
return true;
return false;
}
static bool sbi_cppc_readable(unsigned long reg)
{
/* there are no write-only cppc registers currently */
return true;
}
static bool sbi_cppc_writable(unsigned long reg)
{
switch (reg) {
case SBI_CPPC_HIGHEST_PERF:
case SBI_CPPC_NOMINAL_PERF:
case SBI_CPPC_LOW_NON_LINEAR_PERF:
case SBI_CPPC_LOWEST_PERF:
case SBI_CPPC_GUARANTEED_PERF:
case SBI_CPPC_CTR_WRAP_TIME:
case SBI_CPPC_REFERENCE_CTR:
case SBI_CPPC_DELIVERED_CTR:
case SBI_CPPC_REFERENCE_PERF:
case SBI_CPPC_LOWEST_FREQ:
case SBI_CPPC_NOMINAL_FREQ:
case SBI_CPPC_TRANSITION_LATENCY:
return false;
}
return true;
}
int sbi_cppc_probe(unsigned long reg)
{
if (!cppc_dev || !cppc_dev->cppc_probe)
return SBI_EFAIL;
/* Check whether register is reserved */
if (sbi_cppc_is_reserved(reg))
return SBI_ERR_INVALID_PARAM;
return cppc_dev->cppc_probe(reg);
}
int sbi_cppc_read(unsigned long reg, uint64_t *val)
{
int ret;
if (!cppc_dev || !cppc_dev->cppc_read)
return SBI_EFAIL;
/* Check whether register is implemented */
ret = sbi_cppc_probe(reg);
if (ret <= 0)
return SBI_ERR_NOT_SUPPORTED;
/* Check whether the register is write-only */
if (!sbi_cppc_readable(reg))
return SBI_ERR_DENIED;
return cppc_dev->cppc_read(reg, val);
}
int sbi_cppc_write(unsigned long reg, uint64_t val)
{
int ret;
if (!cppc_dev || !cppc_dev->cppc_write)
return SBI_EFAIL;
/* Check whether register is implemented */
ret = sbi_cppc_probe(reg);
if (ret <= 0)
return SBI_ERR_NOT_SUPPORTED;
/* Check whether the register is read-only */
if (!sbi_cppc_writable(reg))
return SBI_ERR_DENIED;
return cppc_dev->cppc_write(reg, val);
}
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