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authorAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
committerAnton Arapov <anton@redhat.com>2012-04-16 10:05:28 +0200
commitb4b6116a13633898cf868f2f103c96a90c4c20f8 (patch)
tree93d1b7e2cfcdf473d8d4ff3ad141fa864f8491f6 /arch/blackfin/mach-common/cpufreq.c
parentedd4be777c953e5faafc80d091d3084b4343f5d3 (diff)
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fedora kernel: d9aad82f3319f3cfd1aebc01234254ef0c37ad84v3.3.2-1
Signed-off-by: Anton Arapov <anton@redhat.com>
Diffstat (limited to 'arch/blackfin/mach-common/cpufreq.c')
-rw-r--r--arch/blackfin/mach-common/cpufreq.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/arch/blackfin/mach-common/cpufreq.c b/arch/blackfin/mach-common/cpufreq.c
new file mode 100644
index 00000000000..2e6eefd812f
--- /dev/null
+++ b/arch/blackfin/mach-common/cpufreq.c
@@ -0,0 +1,220 @@
+/*
+ * 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/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 */
+/* .index is the entry in the auxiliary dpm_state_table[] */
+static struct cpufreq_frequency_table bfin_freq_table[] = {
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .index = 0,
+ },
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .index = 1,
+ },
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .index = 2,
+ },
+ {
+ .frequency = CPUFREQ_TABLE_END,
+ .index = 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_BFIN_EXTMEM_DCACHEABLE))
+ min_cclk = sclk * 2;
+#else
+ min_cclk = sclk;
+#endif
+ csel = ((bfin_read_PLL_DIV() & CSEL) >> 4);
+
+ for (index = 0; (cclk >> index) >= min_cclk && csel <= 3; index++, csel++) {
+ bfin_freq_table[index].frequency = cclk >> index;
+ dpm_state_table[index].csel = csel << 4; /* Shift now into PLL_DIV bitpos */
+ dpm_state_table[index].tscale = (TIME_SCALE / (1 << csel)) - 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;
+}
+
+static int bfin_target(struct cpufreq_policy *poli,
+ unsigned int target_freq, unsigned int relation)
+{
+ unsigned int index, plldiv, cpu;
+ unsigned long flags, cclk_hz;
+ struct cpufreq_freqs freqs;
+ static unsigned long lpj_ref;
+ static unsigned int lpj_ref_freq;
+
+#if defined(CONFIG_CYCLES_CLOCKSOURCE)
+ cycles_t cycles;
+#endif
+
+ for_each_online_cpu(cpu) {
+ struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
+
+ if (!policy)
+ continue;
+
+ if (cpufreq_frequency_table_target(policy, bfin_freq_table,
+ target_freq, relation, &index))
+ return -EINVAL;
+
+ cclk_hz = bfin_freq_table[index].frequency;
+
+ freqs.old = bfin_getfreq_khz(0);
+ freqs.new = cclk_hz;
+ freqs.cpu = cpu;
+
+ pr_debug("cpufreq: changing cclk to %lu; target = %u, oldfreq = %u\n",
+ cclk_hz, target_freq, freqs.old);
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+ if (cpu == CPUFREQ_CPU) {
+ flags = hard_local_irq_save();
+ plldiv = (bfin_read_PLL_DIV() & SSEL) |
+ dpm_state_table[index].csel;
+ bfin_write_PLL_DIV(plldiv);
+ 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 = freqs.old;
+ }
+ if (freqs.new != freqs.old) {
+ loops_per_jiffy = cpufreq_scale(lpj_ref,
+ lpj_ref_freq, freqs.new);
+ }
+ hard_local_irq_restore(flags);
+ }
+ /* TODO: just test case for cycles clock source, remove later */
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+ }
+
+ pr_debug("cpufreq: done\n");
+ return 0;
+}
+
+static int bfin_verify_speed(struct cpufreq_policy *policy)
+{
+ return cpufreq_frequency_table_verify(policy, bfin_freq_table);
+}
+
+static int __init __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 */
+
+ policy->cur = cclk;
+ cpufreq_frequency_table_get_attr(bfin_freq_table, policy->cpu);
+ return cpufreq_frequency_table_cpuinfo(policy, bfin_freq_table);
+}
+
+static struct freq_attr *bfin_freq_attr[] = {
+ &cpufreq_freq_attr_scaling_available_freqs,
+ NULL,
+};
+
+static struct cpufreq_driver bfin_driver = {
+ .verify = bfin_verify_speed,
+ .target = bfin_target,
+ .get = bfin_getfreq_khz,
+ .init = __bfin_cpu_init,
+ .name = "bfin cpufreq",
+ .owner = THIS_MODULE,
+ .attr = bfin_freq_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);