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

Adjusts the minimum memory frequency when the cpu frequency
changes.  The values are currently hardcoded to a reasonable
default.  If memory frequency scaling is not enabled this
patch will have no effect.

Acked-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Colin Cross <ccross@android.com>
This commit is contained in:
Colin Cross 2010-11-22 18:54:36 -08:00
parent 6d2968284f
commit 7a28128412
1 changed files with 21 additions and 0 deletions
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21
arch/arm/mach-tegra/cpu-tegra.c
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@ -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;
}