1 // SPDX-License-Identifier: GPL-2.0
3 * Allwinner CPUFreq nvmem based driver
5 * The sun50i-cpufreq-nvmem driver reads the efuse value from the SoC to
6 * provide the OPP framework with required information.
11 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
13 #include <linux/arm-smccc.h>
14 #include <linux/cpu.h>
15 #include <linux/module.h>
16 #include <linux/nvmem-consumer.h>
18 #include <linux/platform_device.h>
19 #include <linux/pm_opp.h>
20 #include <linux/slab.h>
22 #define NVMEM_MASK 0x7
25 static struct platform_device *cpufreq_dt_pdev, *sun50i_cpufreq_pdev;
27 struct sunxi_cpufreq_data {
28 u32 (*efuse_xlate)(u32 speedbin);
31 static u32 sun50i_h6_efuse_xlate(u32 speedbin)
35 efuse_value = (speedbin >> NVMEM_SHIFT) & NVMEM_MASK;
38 * We treat unexpected efuse values as if the SoC was from
39 * the slowest bin. Expected efuse values are 1-3, slowest
42 if (efuse_value >= 1 && efuse_value <= 3)
43 return efuse_value - 1;
48 static int get_soc_id_revision(void)
50 #ifdef CONFIG_HAVE_ARM_SMCCC_DISCOVERY
51 return arm_smccc_get_soc_id_revision();
53 return SMCCC_RET_NOT_SUPPORTED;
58 * Judging by the OPP tables in the vendor BSP, the quality order of the
59 * returned speedbin index is 4 -> 0/2 -> 3 -> 1, from worst to best.
60 * 0 and 2 seem identical from the OPP tables' point of view.
62 static u32 sun50i_h616_efuse_xlate(u32 speedbin)
64 int ver_bits = get_soc_id_revision();
67 switch (speedbin & 0xffff) {
75 if (ver_bits != SMCCC_RET_NOT_SUPPORTED && ver_bits <= 1) {
79 /* ic version C and later version */
98 pr_warn("sun50i-cpufreq-nvmem: unknown speed bin 0x%x, using default bin 0\n",
107 static struct sunxi_cpufreq_data sun50i_h6_cpufreq_data = {
108 .efuse_xlate = sun50i_h6_efuse_xlate,
111 static struct sunxi_cpufreq_data sun50i_h616_cpufreq_data = {
112 .efuse_xlate = sun50i_h616_efuse_xlate,
115 static const struct of_device_id cpu_opp_match_list[] = {
116 { .compatible = "allwinner,sun50i-h6-operating-points",
117 .data = &sun50i_h6_cpufreq_data,
119 { .compatible = "allwinner,sun50i-h616-operating-points",
120 .data = &sun50i_h616_cpufreq_data,
126 * dt_has_supported_hw() - Check if any OPPs use opp-supported-hw
128 * If we ask the cpufreq framework to use the opp-supported-hw feature, it
129 * will ignore every OPP node without that DT property. If none of the OPPs
130 * have it, the driver will fail probing, due to the lack of OPPs.
132 * Returns true if we have at least one OPP with the opp-supported-hw property.
134 static bool dt_has_supported_hw(void)
136 bool has_opp_supported_hw = false;
137 struct device *cpu_dev;
139 cpu_dev = get_cpu_device(0);
143 struct device_node *np __free(device_node) =
144 dev_pm_opp_of_get_opp_desc_node(cpu_dev);
148 for_each_child_of_node_scoped(np, opp) {
149 if (of_find_property(opp, "opp-supported-hw", NULL)) {
150 has_opp_supported_hw = true;
155 return has_opp_supported_hw;
159 * sun50i_cpufreq_get_efuse() - Determine speed grade from efuse value
161 * Returns non-negative speed bin index on success, a negative error
164 static int sun50i_cpufreq_get_efuse(void)
166 const struct sunxi_cpufreq_data *opp_data;
167 struct nvmem_cell *speedbin_nvmem;
168 const struct of_device_id *match;
169 struct device *cpu_dev;
173 cpu_dev = get_cpu_device(0);
177 struct device_node *np __free(device_node) =
178 dev_pm_opp_of_get_opp_desc_node(cpu_dev);
182 match = of_match_node(cpu_opp_match_list, np);
186 opp_data = match->data;
188 speedbin_nvmem = of_nvmem_cell_get(np, NULL);
189 if (IS_ERR(speedbin_nvmem))
190 return dev_err_probe(cpu_dev, PTR_ERR(speedbin_nvmem),
191 "Could not get nvmem cell\n");
193 speedbin = nvmem_cell_read(speedbin_nvmem, NULL);
194 nvmem_cell_put(speedbin_nvmem);
195 if (IS_ERR(speedbin))
196 return PTR_ERR(speedbin);
198 ret = opp_data->efuse_xlate(*speedbin);
205 static int sun50i_cpufreq_nvmem_probe(struct platform_device *pdev)
208 char name[] = "speedXXXXXXXXXXX"; /* Integers can take 11 chars max */
209 unsigned int cpu, supported_hw;
210 struct dev_pm_opp_config config = {};
214 opp_tokens = kcalloc(num_possible_cpus(), sizeof(*opp_tokens),
219 speed = sun50i_cpufreq_get_efuse();
226 * We need at least one OPP with the "opp-supported-hw" property,
227 * or else the upper layers will ignore every OPP and will bail out.
229 if (dt_has_supported_hw()) {
230 supported_hw = 1U << speed;
231 config.supported_hw = &supported_hw;
232 config.supported_hw_count = 1;
235 snprintf(name, sizeof(name), "speed%d", speed);
236 config.prop_name = name;
238 for_each_possible_cpu(cpu) {
239 struct device *cpu_dev = get_cpu_device(cpu);
246 ret = dev_pm_opp_set_config(cpu_dev, &config);
250 opp_tokens[cpu] = ret;
253 cpufreq_dt_pdev = platform_device_register_simple("cpufreq-dt", -1,
255 if (!IS_ERR(cpufreq_dt_pdev)) {
256 platform_set_drvdata(pdev, opp_tokens);
260 ret = PTR_ERR(cpufreq_dt_pdev);
261 pr_err("Failed to register platform device\n");
264 for_each_possible_cpu(cpu)
265 dev_pm_opp_clear_config(opp_tokens[cpu]);
271 static void sun50i_cpufreq_nvmem_remove(struct platform_device *pdev)
273 int *opp_tokens = platform_get_drvdata(pdev);
276 platform_device_unregister(cpufreq_dt_pdev);
278 for_each_possible_cpu(cpu)
279 dev_pm_opp_clear_config(opp_tokens[cpu]);
284 static struct platform_driver sun50i_cpufreq_driver = {
285 .probe = sun50i_cpufreq_nvmem_probe,
286 .remove_new = sun50i_cpufreq_nvmem_remove,
288 .name = "sun50i-cpufreq-nvmem",
292 static const struct of_device_id sun50i_cpufreq_match_list[] = {
293 { .compatible = "allwinner,sun50i-h6" },
294 { .compatible = "allwinner,sun50i-h616" },
295 { .compatible = "allwinner,sun50i-h618" },
296 { .compatible = "allwinner,sun50i-h700" },
299 MODULE_DEVICE_TABLE(of, sun50i_cpufreq_match_list);
301 static const struct of_device_id *sun50i_cpufreq_match_node(void)
303 struct device_node *np __free(device_node) = of_find_node_by_path("/");
305 return of_match_node(sun50i_cpufreq_match_list, np);
309 * Since the driver depends on nvmem drivers, which may return EPROBE_DEFER,
310 * all the real activity is done in the probe, which may be defered as well.
311 * The init here is only registering the driver and the platform device.
313 static int __init sun50i_cpufreq_init(void)
315 const struct of_device_id *match;
318 match = sun50i_cpufreq_match_node();
322 ret = platform_driver_register(&sun50i_cpufreq_driver);
323 if (unlikely(ret < 0))
326 sun50i_cpufreq_pdev =
327 platform_device_register_simple("sun50i-cpufreq-nvmem",
329 ret = PTR_ERR_OR_ZERO(sun50i_cpufreq_pdev);
333 platform_driver_unregister(&sun50i_cpufreq_driver);
336 module_init(sun50i_cpufreq_init);
338 static void __exit sun50i_cpufreq_exit(void)
340 platform_device_unregister(sun50i_cpufreq_pdev);
341 platform_driver_unregister(&sun50i_cpufreq_driver);
343 module_exit(sun50i_cpufreq_exit);
345 MODULE_DESCRIPTION("Sun50i-h6 cpufreq driver");
346 MODULE_LICENSE("GPL v2");