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path: root/drivers/cpufreq/cris-artpec3-cpufreq.c
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Diffstat (limited to 'drivers/cpufreq/cris-artpec3-cpufreq.c')
-rw-r--r--drivers/cpufreq/cris-artpec3-cpufreq.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/drivers/cpufreq/cris-artpec3-cpufreq.c b/drivers/cpufreq/cris-artpec3-cpufreq.c
new file mode 100644
index 000000000..601b88c49
--- /dev/null
+++ b/drivers/cpufreq/cris-artpec3-cpufreq.c
@@ -0,0 +1,92 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/cpufreq.h>
+#include <hwregs/reg_map.h>
+#include <hwregs/reg_rdwr.h>
+#include <hwregs/clkgen_defs.h>
+#include <hwregs/ddr2_defs.h>
+
+static int
+cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
+ void *data);
+
+static struct notifier_block cris_sdram_freq_notifier_block = {
+ .notifier_call = cris_sdram_freq_notifier
+};
+
+static struct cpufreq_frequency_table cris_freq_table[] = {
+ {0, 0x01, 6000},
+ {0, 0x02, 200000},
+ {0, 0, CPUFREQ_TABLE_END},
+};
+
+static unsigned int cris_freq_get_cpu_frequency(unsigned int cpu)
+{
+ reg_clkgen_rw_clk_ctrl clk_ctrl;
+ clk_ctrl = REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
+ return clk_ctrl.pll ? 200000 : 6000;
+}
+
+static int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
+{
+ reg_clkgen_rw_clk_ctrl clk_ctrl;
+ clk_ctrl = REG_RD(clkgen, regi_clkgen, rw_clk_ctrl);
+
+ local_irq_disable();
+
+ /* Even though we may be SMP they will share the same clock
+ * so all settings are made on CPU0. */
+ if (cris_freq_table[state].frequency == 200000)
+ clk_ctrl.pll = 1;
+ else
+ clk_ctrl.pll = 0;
+ REG_WR(clkgen, regi_clkgen, rw_clk_ctrl, clk_ctrl);
+
+ local_irq_enable();
+
+ return 0;
+}
+
+static int cris_freq_cpu_init(struct cpufreq_policy *policy)
+{
+ return cpufreq_generic_init(policy, cris_freq_table, 1000000);
+}
+
+static struct cpufreq_driver cris_freq_driver = {
+ .get = cris_freq_get_cpu_frequency,
+ .verify = cpufreq_generic_frequency_table_verify,
+ .target_index = cris_freq_target,
+ .init = cris_freq_cpu_init,
+ .name = "cris_freq",
+ .attr = cpufreq_generic_attr,
+};
+
+static int __init cris_freq_init(void)
+{
+ int ret;
+ ret = cpufreq_register_driver(&cris_freq_driver);
+ cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ return ret;
+}
+
+static int
+cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
+ void *data)
+{
+ int i;
+ struct cpufreq_freqs *freqs = data;
+ if (val == CPUFREQ_PRECHANGE) {
+ reg_ddr2_rw_cfg cfg =
+ REG_RD(ddr2, regi_ddr2_ctrl, rw_cfg);
+ cfg.ref_interval = (freqs->new == 200000 ? 1560 : 46);
+
+ if (freqs->new == 200000)
+ for (i = 0; i < 50000; i++);
+ REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
+ }
+ return 0;
+}
+
+
+module_init(cris_freq_init);