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cpufreq: Add sun50i nvmem based CPU scaling driver
For some SoCs, the CPU frequency subset and voltage value of each OPP varies based on the silicon variant in use. The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to provide the OPP framework with required information. Signed-off-by: Yangtao Li <tiny.windzz@gmail.com> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
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// 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 <tiny.windzz@gmail.com> | ||
*/ | ||
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | ||
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#include <linux/module.h> | ||
#include <linux/nvmem-consumer.h> | ||
#include <linux/of_device.h> | ||
#include <linux/platform_device.h> | ||
#include <linux/pm_opp.h> | ||
#include <linux/slab.h> | ||
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#define MAX_NAME_LEN 7 | ||
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#define NVMEM_MASK 0x7 | ||
#define NVMEM_SHIFT 5 | ||
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static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev; | ||
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/** | ||
* sun50i_cpufreq_get_efuse() - Parse and return efuse value present on SoC | ||
* @versions: Set to the value parsed from efuse | ||
* | ||
* Returns 0 if success. | ||
*/ | ||
static int sun50i_cpufreq_get_efuse(u32 *versions) | ||
{ | ||
struct nvmem_cell *speedbin_nvmem; | ||
struct device_node *np; | ||
struct device *cpu_dev; | ||
u32 *speedbin, efuse_value; | ||
size_t len; | ||
int ret; | ||
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cpu_dev = get_cpu_device(0); | ||
if (!cpu_dev) | ||
return -ENODEV; | ||
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np = dev_pm_opp_of_get_opp_desc_node(cpu_dev); | ||
if (!np) | ||
return -ENOENT; | ||
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ret = of_device_is_compatible(np, | ||
"allwinner,sun50i-h6-operating-points"); | ||
if (!ret) { | ||
of_node_put(np); | ||
return -ENOENT; | ||
} | ||
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speedbin_nvmem = of_nvmem_cell_get(np, NULL); | ||
of_node_put(np); | ||
if (IS_ERR(speedbin_nvmem)) { | ||
if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER) | ||
pr_err("Could not get nvmem cell: %ld\n", | ||
PTR_ERR(speedbin_nvmem)); | ||
return PTR_ERR(speedbin_nvmem); | ||
} | ||
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speedbin = nvmem_cell_read(speedbin_nvmem, &len); | ||
nvmem_cell_put(speedbin_nvmem); | ||
if (IS_ERR(speedbin)) | ||
return PTR_ERR(speedbin); | ||
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efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK; | ||
switch (efuse_value) { | ||
case 0b0001: | ||
*versions = 1; | ||
break; | ||
case 0b0011: | ||
*versions = 2; | ||
break; | ||
default: | ||
/* | ||
* For other situations, we treat it as bin0. | ||
* This vf table can be run for any good cpu. | ||
*/ | ||
*versions = 0; | ||
break; | ||
} | ||
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kfree(speedbin); | ||
return 0; | ||
}; | ||
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static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev) | ||
{ | ||
struct opp_table **opp_tables; | ||
char name[MAX_NAME_LEN]; | ||
unsigned int cpu; | ||
u32 speed = 0; | ||
int ret; | ||
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opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables), | ||
GFP_KERNEL); | ||
if (!opp_tables) | ||
return -ENOMEM; | ||
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ret = sun50i_cpufreq_get_efuse(&speed); | ||
if (ret) | ||
return ret; | ||
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snprintf(name, MAX_NAME_LEN, "speed%d", speed); | ||
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for_each_possible_cpu(cpu) { | ||
struct device *cpu_dev = get_cpu_device(cpu); | ||
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if (!cpu_dev) { | ||
ret = -ENODEV; | ||
goto free_opp; | ||
} | ||
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opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name); | ||
if (IS_ERR(opp_tables[cpu])) { | ||
ret = PTR_ERR(opp_tables[cpu]); | ||
pr_err("Failed to set prop name\n"); | ||
goto free_opp; | ||
} | ||
} | ||
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cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1, | ||
NULL, 0); | ||
if (!IS_ERR(cpufreq_dt_pdev)) { | ||
platform_set_drvdata(pdev, opp_tables); | ||
return 0; | ||
} | ||
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ret = PTR_ERR(cpufreq_dt_pdev); | ||
pr_err("Failed to register platform device\n"); | ||
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free_opp: | ||
for_each_possible_cpu(cpu) { | ||
if (IS_ERR_OR_NULL(opp_tables[cpu])) | ||
break; | ||
dev_pm_opp_put_prop_name(opp_tables[cpu]); | ||
} | ||
kfree(opp_tables); | ||
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return ret; | ||
} | ||
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static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev) | ||
{ | ||
struct opp_table **opp_tables = platform_get_drvdata(pdev); | ||
unsigned int cpu; | ||
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platform_device_unregister(cpufreq_dt_pdev); | ||
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for_each_possible_cpu(cpu) | ||
dev_pm_opp_put_prop_name(opp_tables[cpu]); | ||
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kfree(opp_tables); | ||
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return 0; | ||
} | ||
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static struct platform_driver sun50i_cpufreq_driver = { | ||
.probe = sun50i_cpufreq_nvmem_probe, | ||
.remove = sun50i_cpufreq_nvmem_remove, | ||
.driver = { | ||
.name = "sun50i-cpufreq-nvmem", | ||
}, | ||
}; | ||
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static const struct of_device_id sun50i_cpufreq_match_list[] = { | ||
{ .compatible = "allwinner,sun50i-h6" }, | ||
{} | ||
}; | ||
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static const struct of_device_id *sun50i_cpufreq_match_node(void) | ||
{ | ||
const struct of_device_id *match; | ||
struct device_node *np; | ||
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np = of_find_node_by_path("/"); | ||
match = of_match_node(sun50i_cpufreq_match_list, np); | ||
of_node_put(np); | ||
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return match; | ||
} | ||
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/* | ||
* 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; | ||
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match = sun50i_cpufreq_match_node(); | ||
if (!match) | ||
return -ENODEV; | ||
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ret = platform_driver_register(&sun50i_cpufreq_driver); | ||
if (unlikely(ret < 0)) | ||
return ret; | ||
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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; | ||
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platform_driver_unregister(&sun50i_cpufreq_driver); | ||
return ret; | ||
} | ||
module_init(sun50i_cpufreq_init); | ||
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static void __exit sun50i_cpufreq_exit(void) | ||
{ | ||
platform_device_unregister(sun50i_cpufreq_pdev); | ||
platform_driver_unregister(&sun50i_cpufreq_driver); | ||
} | ||
module_exit(sun50i_cpufreq_exit); | ||
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MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver"); | ||
MODULE_LICENSE("GPL v2"); |