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 00000000..2e6eefd8
--- /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);