From 7a281284125fe8704ea16fd1ca243971b7c0a105 Mon Sep 17 00:00:00 2001 From: Colin Cross Date: Mon, 22 Nov 2010 18:54:36 -0800 Subject: [PATCH] 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 Signed-off-by: Colin Cross --- arch/arm/mach-tegra/cpu-tegra.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/arch/arm/mach-tegra/cpu-tegra.c b/arch/arm/mach-tegra/cpu-tegra.c index f02ba603ceb7..0e1016a827ac 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; } -- 2.39.2