142099322SDeepak Sikri /* 242099322SDeepak Sikri * drivers/cpufreq/spear-cpufreq.c 342099322SDeepak Sikri * 442099322SDeepak Sikri * CPU Frequency Scaling for SPEAr platform 542099322SDeepak Sikri * 642099322SDeepak Sikri * Copyright (C) 2012 ST Microelectronics 742099322SDeepak Sikri * Deepak Sikri <deepak.sikri@st.com> 842099322SDeepak Sikri * 942099322SDeepak Sikri * This file is licensed under the terms of the GNU General Public 1042099322SDeepak Sikri * License version 2. This program is licensed "as is" without any 1142099322SDeepak Sikri * warranty of any kind, whether express or implied. 1242099322SDeepak Sikri */ 1342099322SDeepak Sikri 1442099322SDeepak Sikri #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 1542099322SDeepak Sikri 1642099322SDeepak Sikri #include <linux/clk.h> 1742099322SDeepak Sikri #include <linux/cpufreq.h> 1842099322SDeepak Sikri #include <linux/err.h> 1942099322SDeepak Sikri #include <linux/init.h> 2042099322SDeepak Sikri #include <linux/module.h> 21c0e46948SSudeep KarkadaNagesha #include <linux/of_device.h> 2242099322SDeepak Sikri #include <linux/slab.h> 2342099322SDeepak Sikri #include <linux/types.h> 2442099322SDeepak Sikri 2542099322SDeepak Sikri /* SPEAr CPUFreq driver data structure */ 2642099322SDeepak Sikri static struct { 2742099322SDeepak Sikri struct clk *clk; 2842099322SDeepak Sikri unsigned int transition_latency; 2942099322SDeepak Sikri struct cpufreq_frequency_table *freq_tbl; 3042099322SDeepak Sikri u32 cnt; 3142099322SDeepak Sikri } spear_cpufreq; 3242099322SDeepak Sikri 3342099322SDeepak Sikri static unsigned int spear_cpufreq_get(unsigned int cpu) 3442099322SDeepak Sikri { 3542099322SDeepak Sikri return clk_get_rate(spear_cpufreq.clk) / 1000; 3642099322SDeepak Sikri } 3742099322SDeepak Sikri 3842099322SDeepak Sikri static struct clk *spear1340_cpu_get_possible_parent(unsigned long newfreq) 3942099322SDeepak Sikri { 4042099322SDeepak Sikri struct clk *sys_pclk; 4142099322SDeepak Sikri int pclk; 4242099322SDeepak Sikri /* 4342099322SDeepak Sikri * In SPEAr1340, cpu clk's parent sys clk can take input from 4442099322SDeepak Sikri * following sources 4542099322SDeepak Sikri */ 4642099322SDeepak Sikri const char *sys_clk_src[] = { 4742099322SDeepak Sikri "sys_syn_clk", 4842099322SDeepak Sikri "pll1_clk", 4942099322SDeepak Sikri "pll2_clk", 5042099322SDeepak Sikri "pll3_clk", 5142099322SDeepak Sikri }; 5242099322SDeepak Sikri 5342099322SDeepak Sikri /* 5442099322SDeepak Sikri * As sys clk can have multiple source with their own range 5542099322SDeepak Sikri * limitation so we choose possible sources accordingly 5642099322SDeepak Sikri */ 5742099322SDeepak Sikri if (newfreq <= 300000000) 5842099322SDeepak Sikri pclk = 0; /* src is sys_syn_clk */ 5942099322SDeepak Sikri else if (newfreq > 300000000 && newfreq <= 500000000) 6042099322SDeepak Sikri pclk = 3; /* src is pll3_clk */ 6142099322SDeepak Sikri else if (newfreq == 600000000) 6242099322SDeepak Sikri pclk = 1; /* src is pll1_clk */ 6342099322SDeepak Sikri else 6442099322SDeepak Sikri return ERR_PTR(-EINVAL); 6542099322SDeepak Sikri 6642099322SDeepak Sikri /* Get parent to sys clock */ 6742099322SDeepak Sikri sys_pclk = clk_get(NULL, sys_clk_src[pclk]); 6842099322SDeepak Sikri if (IS_ERR(sys_pclk)) 6942099322SDeepak Sikri pr_err("Failed to get %s clock\n", sys_clk_src[pclk]); 7042099322SDeepak Sikri 7142099322SDeepak Sikri return sys_pclk; 7242099322SDeepak Sikri } 7342099322SDeepak Sikri 7442099322SDeepak Sikri /* 7542099322SDeepak Sikri * In SPEAr1340, we cannot use newfreq directly because we need to actually 7642099322SDeepak Sikri * access a source clock (clk) which might not be ancestor of cpu at present. 7742099322SDeepak Sikri * Hence in SPEAr1340 we would operate on source clock directly before switching 7842099322SDeepak Sikri * cpu clock to it. 7942099322SDeepak Sikri */ 8042099322SDeepak Sikri static int spear1340_set_cpu_rate(struct clk *sys_pclk, unsigned long newfreq) 8142099322SDeepak Sikri { 8242099322SDeepak Sikri struct clk *sys_clk; 8342099322SDeepak Sikri int ret = 0; 8442099322SDeepak Sikri 8542099322SDeepak Sikri sys_clk = clk_get_parent(spear_cpufreq.clk); 8642099322SDeepak Sikri if (IS_ERR(sys_clk)) { 8742099322SDeepak Sikri pr_err("failed to get cpu's parent (sys) clock\n"); 8842099322SDeepak Sikri return PTR_ERR(sys_clk); 8942099322SDeepak Sikri } 9042099322SDeepak Sikri 9142099322SDeepak Sikri /* Set the rate of the source clock before changing the parent */ 9242099322SDeepak Sikri ret = clk_set_rate(sys_pclk, newfreq); 9342099322SDeepak Sikri if (ret) { 9442099322SDeepak Sikri pr_err("Failed to set sys clk rate to %lu\n", newfreq); 9542099322SDeepak Sikri return ret; 9642099322SDeepak Sikri } 9742099322SDeepak Sikri 9842099322SDeepak Sikri ret = clk_set_parent(sys_clk, sys_pclk); 9942099322SDeepak Sikri if (ret) { 10042099322SDeepak Sikri pr_err("Failed to set sys clk parent\n"); 10142099322SDeepak Sikri return ret; 10242099322SDeepak Sikri } 10342099322SDeepak Sikri 10442099322SDeepak Sikri return 0; 10542099322SDeepak Sikri } 10642099322SDeepak Sikri 10742099322SDeepak Sikri static int spear_cpufreq_target(struct cpufreq_policy *policy, 10842099322SDeepak Sikri unsigned int target_freq, unsigned int relation) 10942099322SDeepak Sikri { 11042099322SDeepak Sikri struct cpufreq_freqs freqs; 11142099322SDeepak Sikri unsigned long newfreq; 11242099322SDeepak Sikri struct clk *srcclk; 11342099322SDeepak Sikri int index, ret, mult = 1; 11442099322SDeepak Sikri 11542099322SDeepak Sikri if (cpufreq_frequency_table_target(policy, spear_cpufreq.freq_tbl, 11642099322SDeepak Sikri target_freq, relation, &index)) 11742099322SDeepak Sikri return -EINVAL; 11842099322SDeepak Sikri 11942099322SDeepak Sikri freqs.old = spear_cpufreq_get(0); 12042099322SDeepak Sikri 12142099322SDeepak Sikri newfreq = spear_cpufreq.freq_tbl[index].frequency * 1000; 12242099322SDeepak Sikri if (of_machine_is_compatible("st,spear1340")) { 12342099322SDeepak Sikri /* 12442099322SDeepak Sikri * SPEAr1340 is special in the sense that due to the possibility 12542099322SDeepak Sikri * of multiple clock sources for cpu clk's parent we can have 12642099322SDeepak Sikri * different clock source for different frequency of cpu clk. 12742099322SDeepak Sikri * Hence we need to choose one from amongst these possible clock 12842099322SDeepak Sikri * sources. 12942099322SDeepak Sikri */ 13042099322SDeepak Sikri srcclk = spear1340_cpu_get_possible_parent(newfreq); 13142099322SDeepak Sikri if (IS_ERR(srcclk)) { 13242099322SDeepak Sikri pr_err("Failed to get src clk\n"); 13342099322SDeepak Sikri return PTR_ERR(srcclk); 13442099322SDeepak Sikri } 13542099322SDeepak Sikri 13642099322SDeepak Sikri /* SPEAr1340: src clk is always 2 * intended cpu clk */ 13742099322SDeepak Sikri mult = 2; 13842099322SDeepak Sikri } else { 13942099322SDeepak Sikri /* 14042099322SDeepak Sikri * src clock to be altered is ancestor of cpu clock. Hence we 14142099322SDeepak Sikri * can directly work on cpu clk 14242099322SDeepak Sikri */ 14342099322SDeepak Sikri srcclk = spear_cpufreq.clk; 14442099322SDeepak Sikri } 14542099322SDeepak Sikri 14642099322SDeepak Sikri newfreq = clk_round_rate(srcclk, newfreq * mult); 14742099322SDeepak Sikri if (newfreq < 0) { 14842099322SDeepak Sikri pr_err("clk_round_rate failed for cpu src clock\n"); 14942099322SDeepak Sikri return newfreq; 15042099322SDeepak Sikri } 15142099322SDeepak Sikri 15242099322SDeepak Sikri freqs.new = newfreq / 1000; 15342099322SDeepak Sikri freqs.new /= mult; 1546f35a65fSViresh Kumar 155b43a7ffbSViresh Kumar cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); 15642099322SDeepak Sikri 15742099322SDeepak Sikri if (mult == 2) 15842099322SDeepak Sikri ret = spear1340_set_cpu_rate(srcclk, newfreq); 15942099322SDeepak Sikri else 16042099322SDeepak Sikri ret = clk_set_rate(spear_cpufreq.clk, newfreq); 16142099322SDeepak Sikri 16242099322SDeepak Sikri /* Get current rate after clk_set_rate, in case of failure */ 16342099322SDeepak Sikri if (ret) { 16442099322SDeepak Sikri pr_err("CPU Freq: cpu clk_set_rate failed: %d\n", ret); 16542099322SDeepak Sikri freqs.new = clk_get_rate(spear_cpufreq.clk) / 1000; 16642099322SDeepak Sikri } 16742099322SDeepak Sikri 168b43a7ffbSViresh Kumar cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); 16942099322SDeepak Sikri return ret; 17042099322SDeepak Sikri } 17142099322SDeepak Sikri 17242099322SDeepak Sikri static int spear_cpufreq_init(struct cpufreq_policy *policy) 17342099322SDeepak Sikri { 17442099322SDeepak Sikri int ret; 17542099322SDeepak Sikri 1764a1fe2bfSViresh Kumar ret = cpufreq_table_validate_and_show(policy, spear_cpufreq.freq_tbl); 17742099322SDeepak Sikri if (ret) { 1784a1fe2bfSViresh Kumar pr_err("cpufreq_table_validate_and_show() failed"); 17942099322SDeepak Sikri return ret; 18042099322SDeepak Sikri } 18142099322SDeepak Sikri 18242099322SDeepak Sikri policy->cpuinfo.transition_latency = spear_cpufreq.transition_latency; 18342099322SDeepak Sikri policy->cur = spear_cpufreq_get(0); 18442099322SDeepak Sikri 1854c738d00SViresh Kumar cpumask_setall(policy->cpus); 18642099322SDeepak Sikri 18742099322SDeepak Sikri return 0; 18842099322SDeepak Sikri } 18942099322SDeepak Sikri 19042099322SDeepak Sikri static struct cpufreq_driver spear_cpufreq_driver = { 19142099322SDeepak Sikri .name = "cpufreq-spear", 19242099322SDeepak Sikri .flags = CPUFREQ_STICKY, 193e2132fa6SViresh Kumar .verify = cpufreq_generic_frequency_table_verify, 19442099322SDeepak Sikri .target = spear_cpufreq_target, 19542099322SDeepak Sikri .get = spear_cpufreq_get, 19642099322SDeepak Sikri .init = spear_cpufreq_init, 197e2132fa6SViresh Kumar .exit = cpufreq_generic_exit, 198e2132fa6SViresh Kumar .attr = cpufreq_generic_attr, 19942099322SDeepak Sikri }; 20042099322SDeepak Sikri 20142099322SDeepak Sikri static int spear_cpufreq_driver_init(void) 20242099322SDeepak Sikri { 20342099322SDeepak Sikri struct device_node *np; 20442099322SDeepak Sikri const struct property *prop; 20542099322SDeepak Sikri struct cpufreq_frequency_table *freq_tbl; 20642099322SDeepak Sikri const __be32 *val; 20742099322SDeepak Sikri int cnt, i, ret; 20842099322SDeepak Sikri 209c0e46948SSudeep KarkadaNagesha np = of_cpu_device_node_get(0); 21042099322SDeepak Sikri if (!np) { 21142099322SDeepak Sikri pr_err("No cpu node found"); 21242099322SDeepak Sikri return -ENODEV; 21342099322SDeepak Sikri } 21442099322SDeepak Sikri 21542099322SDeepak Sikri if (of_property_read_u32(np, "clock-latency", 21642099322SDeepak Sikri &spear_cpufreq.transition_latency)) 21742099322SDeepak Sikri spear_cpufreq.transition_latency = CPUFREQ_ETERNAL; 21842099322SDeepak Sikri 21942099322SDeepak Sikri prop = of_find_property(np, "cpufreq_tbl", NULL); 22042099322SDeepak Sikri if (!prop || !prop->value) { 22142099322SDeepak Sikri pr_err("Invalid cpufreq_tbl"); 22242099322SDeepak Sikri ret = -ENODEV; 22342099322SDeepak Sikri goto out_put_node; 22442099322SDeepak Sikri } 22542099322SDeepak Sikri 22642099322SDeepak Sikri cnt = prop->length / sizeof(u32); 22742099322SDeepak Sikri val = prop->value; 22842099322SDeepak Sikri 22942099322SDeepak Sikri freq_tbl = kmalloc(sizeof(*freq_tbl) * (cnt + 1), GFP_KERNEL); 23042099322SDeepak Sikri if (!freq_tbl) { 23142099322SDeepak Sikri ret = -ENOMEM; 23242099322SDeepak Sikri goto out_put_node; 23342099322SDeepak Sikri } 23442099322SDeepak Sikri 23542099322SDeepak Sikri for (i = 0; i < cnt; i++) { 23650701588SViresh Kumar freq_tbl[i].driver_data = i; 23742099322SDeepak Sikri freq_tbl[i].frequency = be32_to_cpup(val++); 23842099322SDeepak Sikri } 23942099322SDeepak Sikri 24050701588SViresh Kumar freq_tbl[i].driver_data = i; 24142099322SDeepak Sikri freq_tbl[i].frequency = CPUFREQ_TABLE_END; 24242099322SDeepak Sikri 24342099322SDeepak Sikri spear_cpufreq.freq_tbl = freq_tbl; 24442099322SDeepak Sikri 24542099322SDeepak Sikri of_node_put(np); 24642099322SDeepak Sikri 24742099322SDeepak Sikri spear_cpufreq.clk = clk_get(NULL, "cpu_clk"); 24842099322SDeepak Sikri if (IS_ERR(spear_cpufreq.clk)) { 24942099322SDeepak Sikri pr_err("Unable to get CPU clock\n"); 25042099322SDeepak Sikri ret = PTR_ERR(spear_cpufreq.clk); 25142099322SDeepak Sikri goto out_put_mem; 25242099322SDeepak Sikri } 25342099322SDeepak Sikri 25442099322SDeepak Sikri ret = cpufreq_register_driver(&spear_cpufreq_driver); 25542099322SDeepak Sikri if (!ret) 25642099322SDeepak Sikri return 0; 25742099322SDeepak Sikri 25842099322SDeepak Sikri pr_err("failed register driver: %d\n", ret); 25942099322SDeepak Sikri clk_put(spear_cpufreq.clk); 26042099322SDeepak Sikri 26142099322SDeepak Sikri out_put_mem: 26242099322SDeepak Sikri kfree(freq_tbl); 26342099322SDeepak Sikri return ret; 26442099322SDeepak Sikri 26542099322SDeepak Sikri out_put_node: 26642099322SDeepak Sikri of_node_put(np); 26742099322SDeepak Sikri return ret; 26842099322SDeepak Sikri } 26942099322SDeepak Sikri late_initcall(spear_cpufreq_driver_init); 27042099322SDeepak Sikri 27142099322SDeepak Sikri MODULE_AUTHOR("Deepak Sikri <deepak.sikri@st.com>"); 27242099322SDeepak Sikri MODULE_DESCRIPTION("SPEAr CPUFreq driver"); 27342099322SDeepak Sikri MODULE_LICENSE("GPL"); 274