[PATCH 18/21] ARM: tegra: cpufreq: Adjust memory frequency with cpu frequency

Colin Cross
2011-02-13T09:44:08Z

arch/arm/mach-tegra/cpu-tegra.c | 21 +++++++++++++++++++++
1 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-tegra/cpu-tegra.c b/arch/arm/mach-tegra/cpu-tegra.c
index f02ba60..0e1016a 100644
--- a/arch/arm/mach-tegra/cpu-tegra.c
+++ b/arch/arm/mach-tegra/cpu-tegra.c
@@ -51,6 +51,7 @@ static struct cpufreq_frequency_table freq_table[] = {
#define NUM_CPUS 2

static struct clk *cpu_clk;
+static struct clk *emc_clk;

static unsigned long target_cpu_speed[NUM_CPUS];
static DEFINE_MUTEX(tegra_cpu_lock);
@@ -83,6 +84,17 @@ static int tegra_update_cpu_speed(unsigned long rate)
if (freqs.old == freqs.new)
return ret;

+ /*
+ * Vote on memory bus frequency based on cpu frequency
+ * This sets the minimum frequency, display or avp may request higher
+ */
+ if (rate >= 816000)
+ clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
+ else if (rate >= 456000)
+ clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
+ else
+ clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */
+
for_each_online_cpu(freqs.cpu)
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

@@ -173,6 +185,13 @@ static int tegra_cpu_init(struct cpufreq_policy *policy)
if (IS_ERR(cpu_clk))
return PTR_ERR(cpu_clk);

+ emc_clk = clk_get_sys("cpu", "emc");
+ if (IS_ERR(emc_clk)) {
+ clk_put(cpu_clk);
+ return PTR_ERR(emc_clk);
+ }
+
+ clk_enable(emc_clk);
clk_enable(cpu_clk);

cpufreq_frequency_table_cpuinfo(policy, freq_table);
@@ -195,6 +214,8 @@ static int tegra_cpu_init(struct cpufreq_policy *policy)
static int tegra_cpu_exit(struct cpufreq_policy *policy)
{
cpufreq_frequency_table_cpuinfo(policy, freq_table);
+ clk_disable(emc_clk);
+ clk_put(emc_clk);
clk_put(cpu_clk);
return 0;
}
--
1.7.3.1