--- /dev/null
+/*
+ * Blackfin core clock scaling
+ *
+ * Copyright 2008-2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/clk.h>
+#include <linux/cpufreq.h>
+#include <linux/fs.h>
+#include <linux/delay.h>
+#include <asm/blackfin.h>
+#include <asm/time.h>
+#include <asm/dpmc.h>
+
+
+/* this is the table of CCLK frequencies, in Hz */
+/* .driver_data is the entry in the auxiliary dpm_state_table[] */
+static struct cpufreq_frequency_table bfin_freq_table[] = {
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .driver_data = 0,
+ },
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .driver_data = 1,
+ },
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .driver_data = 2,
+ },
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .driver_data = 0,
+ },
+};
+
+static struct bfin_dpm_state {
+ unsigned int csel; /* system clock divider */
+ unsigned int tscale; /* change the divider on the core timer interrupt */
+} dpm_state_table[3];
+
+#if defined(CONFIG_CYCLES_CLOCKSOURCE)
+/*
+ * normalized to maximum frequency offset for CYCLES,
+ * used in time-ts cycles clock source, but could be used
+ * somewhere also.
+ */
+unsigned long long __bfin_cycles_off;
+unsigned int __bfin_cycles_mod;
+#endif
+
+/**************************************************************************/
+static void __init bfin_init_tables(unsigned long cclk, unsigned long sclk)
+{
+
+ unsigned long csel, min_cclk;
+ int index;
+
+ /* Anomaly 273 seems to still exist on non-BF54x w/dcache turned on */
+#if ANOMALY_05000273 || ANOMALY_05000274 || \
+ (!(defined(CONFIG_BF54x) || defined(CONFIG_BF60x)) \
+ && defined(CONFIG_BFIN_EXTMEM_DCACHEABLE))
+ min_cclk = sclk * 2;
+#else
+ min_cclk = sclk;
+#endif
+
+#ifndef CONFIG_BF60x
+ csel = ((bfin_read_PLL_DIV() & CSEL) >> 4);
+#else
+ csel = bfin_read32(CGU0_DIV) & 0x1F;
+#endif
+
+ for (index = 0; (cclk >> index) >= min_cclk && csel <= 3 && index < 3; index++, csel++) {
+ bfin_freq_table[index].frequency = cclk >> index;
+#ifndef CONFIG_BF60x
+ dpm_state_table[index].csel = csel << 4; /* Shift now into PLL_DIV bitpos */
+#else
+ dpm_state_table[index].csel = csel;
+#endif
+ dpm_state_table[index].tscale = (TIME_SCALE >> index) - 1;
+
+ pr_debug("cpufreq: freq:%d csel:0x%x tscale:%d\n",
+ bfin_freq_table[index].frequency,
+ dpm_state_table[index].csel,
+ dpm_state_table[index].tscale);
+ }
+ return;
+}
+
+static void bfin_adjust_core_timer(void *info)
+{
+ unsigned int tscale;
+ unsigned int index = *(unsigned int *)info;
+
+ /* we have to adjust the core timer, because it is using cclk */
+ tscale = dpm_state_table[index].tscale;
+ bfin_write_TSCALE(tscale);
+ return;
+}
+
+static unsigned int bfin_getfreq_khz(unsigned int cpu)
+{
+ /* Both CoreA/B have the same core clock */
+ return get_cclk() / 1000;
+}
+
+#ifdef CONFIG_BF60x
+unsigned long cpu_set_cclk(int cpu, unsigned long new)
+{
+ struct clk *clk;
+ int ret;
+
+ clk = clk_get(NULL, "CCLK");
+ if (IS_ERR(clk))
+ return -ENODEV;
+
+ ret = clk_set_rate(clk, new);
+ clk_put(clk);
+ return ret;
+}
+#endif
+
+static int bfin_target(struct cpufreq_policy *policy, unsigned int index)
+{
+#ifndef CONFIG_BF60x
+ unsigned int plldiv;
+#endif
+ static unsigned long lpj_ref;
+ static unsigned int lpj_ref_freq;
+ unsigned int old_freq, new_freq;
+ int ret = 0;
+
+#if defined(CONFIG_CYCLES_CLOCKSOURCE)
+ cycles_t cycles;
+#endif
+
+ old_freq = bfin_getfreq_khz(0);
+ new_freq = bfin_freq_table[index].frequency;
+
+#ifndef CONFIG_BF60x
+ plldiv = (bfin_read_PLL_DIV() & SSEL) | dpm_state_table[index].csel;
+ bfin_write_PLL_DIV(plldiv);
+#else
+ ret = cpu_set_cclk(policy->cpu, new_freq * 1000);
+ if (ret != 0) {
+ WARN_ONCE(ret, "cpufreq set freq failed %d\n", ret);
+ return ret;
+ }
+#endif
+ on_each_cpu(bfin_adjust_core_timer, &index, 1);
+#if defined(CONFIG_CYCLES_CLOCKSOURCE)
+ cycles = get_cycles();
+ SSYNC();
+ cycles += 10; /* ~10 cycles we lose after get_cycles() */
+ __bfin_cycles_off += (cycles << __bfin_cycles_mod) - (cycles << index);
+ __bfin_cycles_mod = index;
+#endif
+ if (!lpj_ref_freq) {
+ lpj_ref = loops_per_jiffy;
+ lpj_ref_freq = old_freq;
+ }
+ if (new_freq != old_freq) {
+ loops_per_jiffy = cpufreq_scale(lpj_ref,
+ lpj_ref_freq, new_freq);
+ }
+
+ return ret;
+}
+
+static int __bfin_cpu_init(struct cpufreq_policy *policy)
+{
+
+ unsigned long cclk, sclk;
+
+ cclk = get_cclk() / 1000;
+ sclk = get_sclk() / 1000;
+
+ if (policy->cpu == CPUFREQ_CPU)
+ bfin_init_tables(cclk, sclk);
+
+ policy->cpuinfo.transition_latency = 50000; /* 50us assumed */
+
+ return cpufreq_table_validate_and_show(policy, bfin_freq_table);
+}
+
+static struct cpufreq_driver bfin_driver = {
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = bfin_target,
+ .get = bfin_getfreq_khz,
+ .init = __bfin_cpu_init,
+ .name = "bfin cpufreq",
+ .attr = cpufreq_generic_attr,
+};
+
+static int __init bfin_cpu_init(void)
+{
+ return cpufreq_register_driver(&bfin_driver);
+}
+
+static void __exit bfin_cpu_exit(void)
+{
+ cpufreq_unregister_driver(&bfin_driver);
+}
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("cpufreq driver for Blackfin");
+MODULE_LICENSE("GPL");
+
+module_init(bfin_cpu_init);
+module_exit(bfin_cpu_exit);
Code Review / kvmfornfv.git / blobdiff