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![Ondrej Jirman](/assets/img/avatar_default.png)
I have observed failures to boot on Orange Pi 3, because this driver
determined that my SoC is from the normal bin, but my SoC only works
reliably with the OPP values for the slowest bin.
By querying H6 owners, it was found that e-fuse values found in the wild
are in the range of 1-3, value of 7 was not reported, yet. From this and
from unused defines in BSP code, it can be assumed that meaning of efuse
values on H6 actually is:
- 1 = slowest bin
- 2 = normal bin
- 3 = fastest bin
Vendor code actually treats 0 and 2 as invalid efuse values, but later
treats all invalid values as a normal bin. This looks like a mistake in
bin detection code, that was plastered over by a hack in cpufreq code,
so let's not repeat it here. It probably only works because there are no
SoCs in the wild with efuse value of 0, and fast bin SoCs are made to
use normal bin OPP tables, which is also safe.
Let's play it safe and interpret 0 as the slowest bin, but fix detection
of other bins to match this research. More research will be done before
actual OPP tables are merged.
Fixes: f328584f7b
("cpufreq: Add sun50i nvmem based CPU scaling driver")
Acked-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Ondrej Jirman <megous@megous.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
221 lines
5 KiB
C
221 lines
5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Allwinner CPUFreq nvmem based driver
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*
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* The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
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* provide the OPP framework with required information.
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*
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* Copyright (C) 2019 Yangtao Li <tiny.windzz@gmail.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/nvmem-consumer.h>
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#include <linux/of_device.h>
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#include <linux/platform_device.h>
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#include <linux/pm_opp.h>
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#include <linux/slab.h>
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#define MAX_NAME_LEN 7
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#define NVMEM_MASK 0x7
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#define NVMEM_SHIFT 5
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static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
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/**
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* sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
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* @versions: Set to the value parsed from efuse
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*
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* Returns 0 if success.
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*/
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static int sun50i_cpufreq_get_efuse(u32 *versions)
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{
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struct nvmem_cell *speedbin_nvmem;
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struct device_node *np;
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struct device *cpu_dev;
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u32 *speedbin, efuse_value;
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size_t len;
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int ret;
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cpu_dev = get_cpu_device(0);
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if (!cpu_dev)
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return -ENODEV;
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np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
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if (!np)
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return -ENOENT;
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ret = of_device_is_compatible(np,
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"allwinner,sun50i-h6-operating-points");
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if (!ret) {
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of_node_put(np);
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return -ENOENT;
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}
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speedbin_nvmem = of_nvmem_cell_get(np, NULL);
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of_node_put(np);
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if (IS_ERR(speedbin_nvmem)) {
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if (PTR_ERR(speedbin_nvmem) != -EPROBE_DEFER)
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pr_err("Could not get nvmem cell: %ld\n",
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PTR_ERR(speedbin_nvmem));
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return PTR_ERR(speedbin_nvmem);
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}
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speedbin = nvmem_cell_read(speedbin_nvmem, &len);
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nvmem_cell_put(speedbin_nvmem);
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if (IS_ERR(speedbin))
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return PTR_ERR(speedbin);
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efuse_value = (*speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
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/*
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* We treat unexpected efuse values as if the SoC was from
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* the slowest bin. Expected efuse values are 1-3, slowest
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* to fastest.
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*/
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if (efuse_value >= 1 && efuse_value <= 3)
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*versions = efuse_value - 1;
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else
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*versions = 0;
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kfree(speedbin);
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return 0;
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};
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static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
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{
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struct opp_table **opp_tables;
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char name[MAX_NAME_LEN];
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unsigned int cpu;
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u32 speed = 0;
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int ret;
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opp_tables = kcalloc(num_possible_cpus(), sizeof(*opp_tables),
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GFP_KERNEL);
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if (!opp_tables)
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return -ENOMEM;
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ret = sun50i_cpufreq_get_efuse(&speed);
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if (ret)
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return ret;
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snprintf(name, MAX_NAME_LEN, "speed%d", speed);
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for_each_possible_cpu(cpu) {
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struct device *cpu_dev = get_cpu_device(cpu);
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if (!cpu_dev) {
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ret = -ENODEV;
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goto free_opp;
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}
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opp_tables[cpu] = dev_pm_opp_set_prop_name(cpu_dev, name);
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if (IS_ERR(opp_tables[cpu])) {
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ret = PTR_ERR(opp_tables[cpu]);
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pr_err("Failed to set prop name\n");
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goto free_opp;
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}
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}
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cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
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NULL, 0);
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if (!IS_ERR(cpufreq_dt_pdev)) {
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platform_set_drvdata(pdev, opp_tables);
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return 0;
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}
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ret = PTR_ERR(cpufreq_dt_pdev);
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pr_err("Failed to register platform device\n");
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free_opp:
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for_each_possible_cpu(cpu) {
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if (IS_ERR_OR_NULL(opp_tables[cpu]))
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break;
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dev_pm_opp_put_prop_name(opp_tables[cpu]);
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}
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kfree(opp_tables);
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return ret;
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}
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static int sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
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{
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struct opp_table **opp_tables = platform_get_drvdata(pdev);
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unsigned int cpu;
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platform_device_unregister(cpufreq_dt_pdev);
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for_each_possible_cpu(cpu)
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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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}
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static struct platform_driver sun50i_cpufreq_driver = {
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.probe = sun50i_cpufreq_nvmem_probe,
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.remove = sun50i_cpufreq_nvmem_remove,
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.driver = {
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.name = "sun50i-cpufreq-nvmem",
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},
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};
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static const struct of_device_id sun50i_cpufreq_match_list[] = {
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{ .compatible = "allwinner,sun50i-h6" },
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{}
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};
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static const struct of_device_id *sun50i_cpufreq_match_node(void)
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{
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const struct of_device_id *match;
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struct device_node *np;
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np = of_find_node_by_path("/");
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match = of_match_node(sun50i_cpufreq_match_list, np);
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of_node_put(np);
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return match;
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}
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/*
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* Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
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* all the real activity is done in the probe, which may be defered as well.
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* The init here is only registering the driver and the platform device.
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*/
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static int __init sun50i_cpufreq_init(void)
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{
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const struct of_device_id *match;
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int ret;
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match = sun50i_cpufreq_match_node();
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if (!match)
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return -ENODEV;
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ret = platform_driver_register(&sun50i_cpufreq_driver);
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if (unlikely(ret < 0))
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return ret;
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sun50i_cpufreq_pdev =
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platform_device_register_simple("sun50i-cpufreq-nvmem",
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-1, NULL, 0);
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ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
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if (ret == 0)
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return 0;
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platform_driver_unregister(&sun50i_cpufreq_driver);
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return ret;
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}
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module_init(sun50i_cpufreq_init);
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static void __exit sun50i_cpufreq_exit(void)
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{
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platform_device_unregister(sun50i_cpufreq_pdev);
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platform_driver_unregister(&sun50i_cpufreq_driver);
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}
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module_exit(sun50i_cpufreq_exit);
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MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
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MODULE_LICENSE("GPL v2");
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