ARM: tegra: cpufreq: Adjust memory frequency with cpu frequency

Change-Id: I08c64f64a12bcb11e7c0e466fa77fe971e4b2cba
Signed-off-by: Colin Cross <ccross@android.com>

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 1be794d015cf..d8c103e8964c 100644
--- a/arch/arm/mach-tegra/cpu-tegra.c
+++ b/arch/arm/mach-tegra/cpu-tegra.c
@@ -59,6 +59,7 @@ static struct cpufreq_frequency_table freq_table[] = {
 #define NUM_CPUS	2
 
 static struct clk *cpu_clk;
+static struct clk *emc_clk;
 
 static struct workqueue_struct *workqueue;
 
@@ -115,6 +116,17 @@ 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);
 
@@ -336,6 +348,13 @@ 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);
+
 	cpufreq_frequency_table_cpuinfo(policy, freq_table);
 	cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
 	policy->cur = tegra_getspeed(policy->cpu);
@@ -358,6 +377,8 @@ 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;
 }