// SPDX-License-Identifier: GPL-2.0
/*
* Allwinner CPUFreq nvmem based driver
*
* The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
* provide the OPP framework with required information.
*
* Copyright (C) 2019 Yangtao Li <[email protected]>
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/arm-smccc.h>
#include <linux/cpu.h>
#include <linux/module.h>
#include <linux/nvmem-consumer.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/slab.h>
#define NVMEM_MASK 0x7
#define NVMEM_SHIFT 5
static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
struct sunxi_cpufreq_data {
u32 (*efuse_xlate)(u32 speedbin);
};
static u32 sun50i_h6_efuse_xlate(u32 speedbin)
{
u32 efuse_value;
efuse_value = (speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
/*
* We treat unexpected efuse values as if the SoC was from
* the slowest bin. Expected efuse values are 1-3, slowest
* to fastest.
*/
if (efuse_value >= 1 && efuse_value <= 3)
return efuse_value - 1;
else
return 0;
}
static int get_soc_id_revision(void)
{
#ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
return arm_smccc_get_soc_id_revision();
#else
return SMCCC_RET_NOT_SUPPORTED;
#endif
}
/*
* Judging by the OPP tables in the vendor BSP, the quality order of the
* returned speedbin index is 4 -> 0/2 -> 3 -> 1, from worst to best.
* 0 and 2 seem identical from the OPP tables' point of view.
*/
static u32 sun50i_h616_efuse_xlate(u32 speedbin)
{
int ver_bits = get_soc_id_revision();
u32 value = 0;
switch (speedbin & 0xffff) {
case 0x2000:
value = 0;
break;
case 0x2400:
case 0x7400:
case 0x2c00:
case 0x7c00:
if (ver_bits != SMCCC_RET_NOT_SUPPORTED && ver_bits <= 1) {
/* ic version A/B */
value = 1;
} else {
/* ic version C and later version */
value = 2;
}
break;
case 0x5000:
case 0x5400:
case 0x6000:
value = 3;
break;
case 0x5c00:
value = 4;
break;
case 0x5d00:
value = 0;
break;
case 0x6c00:
value = 5;
break;
default:
pr_warn("sun50i-cpufreq-nvmem: unknown speed bin 0x%x, using default bin 0\n",
speedbin & 0xffff);
value = 0;
break;
}
return value;
}
static struct sunxi_cpufreq_data sun50i_h6_cpufreq_data = {
.efuse_xlate = sun50i_h6_efuse_xlate,
};
static struct sunxi_cpufreq_data sun50i_h616_cpufreq_data = {
.efuse_xlate = sun50i_h616_efuse_xlate,
};
static const struct of_device_id cpu_opp_match_list[] = {
{ .compatible = "allwinner,sun50i-h6-operating-points",
.data = &sun50i_h6_cpufreq_data,
},
{ .compatible = "allwinner,sun50i-h616-operating-points",
.data = &sun50i_h616_cpufreq_data,
},
{}
};
/**
* dt_has_supported_hw() - Check if any OPPs use opp-supported-hw
*
* If we ask the cpufreq framework to use the opp-supported-hw feature, it
* will ignore every OPP node without that DT property. If none of the OPPs
* have it, the driver will fail probing, due to the lack of OPPs.
*
* Returns true if we have at least one OPP with the opp-supported-hw property.
*/
static bool dt_has_supported_hw(void)
{
bool has_opp_supported_hw = false;
struct device *cpu_dev;
cpu_dev = get_cpu_device(0);
if (!cpu_dev)
return false;
struct device_node *np __free(device_node) =
dev_pm_opp_of_get_opp_desc_node(cpu_dev);
if (!np)
return false;
for_each_child_of_node_scoped(np, opp) {
if (of_find_property(opp, "opp-supported-hw", NULL)) {
has_opp_supported_hw = true;
break;
}
}
return has_opp_supported_hw;
}
/**
* sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
*
* Returns non-negative speed bin index on success, a negative error
* value otherwise.
*/
static int sun50i_cpufreq_get_efuse(void)
{
const struct sunxi_cpufreq_data *opp_data;
struct nvmem_cell *speedbin_nvmem;
const struct of_device_id *match;
struct device *cpu_dev;
u32 *speedbin;
int ret;
cpu_dev = get_cpu_device(0);
if (!cpu_dev)
return -ENODEV;
struct device_node *np __free(device_node) =
dev_pm_opp_of_get_opp_desc_node(cpu_dev);
if (!np)
return -ENOENT;
match = of_match_node(cpu_opp_match_list, np);
if (!match)
return -ENOENT;
opp_data = match->data;
speedbin_nvmem = of_nvmem_cell_get(np, NULL);
if (IS_ERR(speedbin_nvmem))
return dev_err_probe(cpu_dev, PTR_ERR(speedbin_nvmem),
"Could not get nvmem cell\n");
speedbin = nvmem_cell_read(speedbin_nvmem, NULL);
nvmem_cell_put(speedbin_nvmem);
if (IS_ERR(speedbin))
return PTR_ERR(speedbin);
ret = opp_data->efuse_xlate(*speedbin);
kfree(speedbin);
return ret;
};
static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
{
int *opp_tokens;
char name[] = "speedXXXXXXXXXXX"; /* Integers can take 11 chars max */
unsigned int cpu, supported_hw;
struct dev_pm_opp_config config = {};
int speed;
int ret;
opp_tokens = kcalloc(num_possible_cpus(), sizeof(*opp_tokens),
GFP_KERNEL);
if (!opp_tokens)
return -ENOMEM;
speed = sun50i_cpufreq_get_efuse();
if (speed < 0) {
kfree(opp_tokens);
return speed;
}
/*
* We need at least one OPP with the "opp-supported-hw" property,
* or else the upper layers will ignore every OPP and will bail out.
*/
if (dt_has_supported_hw()) {
supported_hw = 1U << speed;
config.supported_hw = &supported_hw;
config.supported_hw_count = 1;
}
snprintf(name, sizeof(name), "speed%d", speed);
config.prop_name = name;
for_each_possible_cpu(cpu) {
struct device *cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
ret = -ENODEV;
goto free_opp;
}
ret = dev_pm_opp_set_config(cpu_dev, &config);
if (ret < 0)
goto free_opp;
opp_tokens[cpu] = ret;
}
cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
NULL, 0);
if (!IS_ERR(cpufreq_dt_pdev)) {
platform_set_drvdata(pdev, opp_tokens);
return 0;
}
ret = PTR_ERR(cpufreq_dt_pdev);
pr_err("Failed to register platform device\n");
free_opp:
for_each_possible_cpu(cpu)
dev_pm_opp_clear_config(opp_tokens[cpu]);
kfree(opp_tokens);
return ret;
}
static void sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
{
int *opp_tokens = platform_get_drvdata(pdev);
unsigned int cpu;
platform_device_unregister(cpufreq_dt_pdev);
for_each_possible_cpu(cpu)
dev_pm_opp_clear_config(opp_tokens[cpu]);
kfree(opp_tokens);
}
static struct platform_driver sun50i_cpufreq_driver = {
.probe = sun50i_cpufreq_nvmem_probe,
.remove_new = sun50i_cpufreq_nvmem_remove,
.driver = {
.name = "sun50i-cpufreq-nvmem",
},
};
static const struct of_device_id sun50i_cpufreq_match_list[] = {
{ .compatible = "allwinner,sun50i-h6" },
{ .compatible = "allwinner,sun50i-h616" },
{ .compatible = "allwinner,sun50i-h618" },
{ .compatible = "allwinner,sun50i-h700" },
{}
};
MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list);
static const struct of_device_id *sun50i_cpufreq_match_node(void)
{
struct device_node *np __free(device_node) = of_find_node_by_path("/");
return of_match_node(sun50i_cpufreq_match_list, np);
}
/*
* Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
* all the real activity is done in the probe, which may be defered as well.
* The init here is only registering the driver and the platform device.
*/
static int __init sun50i_cpufreq_init(void)
{
const struct of_device_id *match;
int ret;
match = sun50i_cpufreq_match_node();
if (!match)
return -ENODEV;
ret = platform_driver_register(&sun50i_cpufreq_driver);
if (unlikely(ret < 0))
return ret;
sun50i_cpufreq_pdev =
platform_device_register_simple("sun50i-cpufreq-nvmem",
-1, NULL, 0);
ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
if (ret == 0)
return 0;
platform_driver_unregister(&sun50i_cpufreq_driver);
return ret;
}
module_init(sun50i_cpufreq_init);
static void __exit sun50i_cpufreq_exit(void)
{
platform_device_unregister(sun50i_cpufreq_pdev);
platform_driver_unregister(&sun50i_cpufreq_driver);
}
module_exit(sun50i_cpufreq_exit);
MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
MODULE_LICENSE("GPL v2");
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