aboutsummaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorSekhar Nori <nsekhar@ti.com>2009-09-22 21:14:01 +0530
committerKevin Hilman <khilman@deeprootsystems.com>2009-11-25 10:21:29 -0800
commit683b1e1f0e6f7b2690c0ce76751ba8f26f0235c6 (patch)
tree2b8c1c9cc6067ee1dfca8d9bd9af188f6dd22193 /arch
parent6601b8030de3e9c29930684eeac15302a59f991a (diff)
davinci: DA850/OMAP-L138: add frequency scaling support
Adds basic frequency scaling support for DA850/OMAP-L138. Currently, frequency scaling only on PLL0 is supported. No scaling of PLL1 as yet. Peripherals like MMC/SD which have a clock input synchronous with ARM clock will not work well since the clock will change behind their backs. Support for notification to such devices to adjust themselves to the new frequency will be added in later patches. Current defconfigs keep CPUFreq disabled so it will not affect normal operation. The OPP defintions assume clock input of 24MHz to the SoC. This is inline with hardcoding of input frequency in the <soc>.c files. At some point this will need to move into board dependent code as new boards appear with a different reference clock. Tested on OMAP-L138 EVM with ondemand governer and a shell script to vary processor load. Signed-off-by: Sekhar Nori <nsekhar@ti.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/mach-davinci/da850.c153
-rw-r--r--arch/arm/mach-davinci/include/mach/da8xx.h2
2 files changed, 155 insertions, 0 deletions
diff --git a/arch/arm/mach-davinci/da850.c b/arch/arm/mach-davinci/da850.c
index a62863c5745..49dcc71168c 100644
--- a/arch/arm/mach-davinci/da850.c
+++ b/arch/arm/mach-davinci/da850.c
@@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
+#include <linux/cpufreq.h>
#include <asm/mach/map.h>
@@ -26,6 +27,7 @@
#include <mach/common.h>
#include <mach/time.h>
#include <mach/da8xx.h>
+#include <mach/cpufreq.h>
#include "clock.h"
#include "mux.h"
@@ -40,6 +42,11 @@
#define DA850_REF_FREQ 24000000
#define CFGCHIP3_ASYNC3_CLKSRC BIT(4)
+#define CFGCHIP0_PLL_MASTER_LOCK BIT(4)
+
+static int da850_set_armrate(struct clk *clk, unsigned long rate);
+static int da850_round_armrate(struct clk *clk, unsigned long rate);
+static int da850_set_pll0rate(struct clk *clk, unsigned long armrate);
static struct pll_data pll0_data = {
.num = 1,
@@ -57,6 +64,7 @@ static struct clk pll0_clk = {
.parent = &ref_clk,
.pll_data = &pll0_data,
.flags = CLK_PLL,
+ .set_rate = da850_set_pll0rate,
};
static struct clk pll0_aux_clk = {
@@ -283,6 +291,8 @@ static struct clk arm_clk = {
.parent = &pll0_sysclk6,
.lpsc = DA8XX_LPSC0_ARM,
.flags = ALWAYS_ENABLED,
+ .set_rate = da850_set_armrate,
+ .round_rate = da850_round_armrate,
};
static struct clk rmii_clk = {
@@ -820,6 +830,149 @@ static void da850_set_async3_src(int pllnum)
__raw_writel(v, DA8XX_SYSCFG_VIRT(DA8XX_CFGCHIP3_REG));
}
+#ifdef CONFIG_CPU_FREQ
+/*
+ * Notes:
+ * According to the TRM, minimum PLLM results in maximum power savings.
+ * The OPP definitions below should keep the PLLM as low as possible.
+ *
+ * The output of the PLLM must be between 400 to 600 MHz.
+ * This rules out prediv of anything but divide-by-one for 24Mhz OSC input.
+ */
+struct da850_opp {
+ unsigned int freq; /* in KHz */
+ unsigned int prediv;
+ unsigned int mult;
+ unsigned int postdiv;
+};
+
+static const struct da850_opp da850_opp_300 = {
+ .freq = 300000,
+ .prediv = 1,
+ .mult = 25,
+ .postdiv = 2,
+};
+
+static const struct da850_opp da850_opp_200 = {
+ .freq = 200000,
+ .prediv = 1,
+ .mult = 25,
+ .postdiv = 3,
+};
+
+static const struct da850_opp da850_opp_96 = {
+ .freq = 96000,
+ .prediv = 1,
+ .mult = 20,
+ .postdiv = 5,
+};
+
+#define OPP(freq) \
+ { \
+ .index = (unsigned int) &da850_opp_##freq, \
+ .frequency = freq * 1000, \
+ }
+
+static struct cpufreq_frequency_table da850_freq_table[] = {
+ OPP(300),
+ OPP(200),
+ OPP(96),
+ {
+ .index = 0,
+ .frequency = CPUFREQ_TABLE_END,
+ },
+};
+
+static struct davinci_cpufreq_config cpufreq_info = {
+ .freq_table = &da850_freq_table[0],
+};
+
+static struct platform_device da850_cpufreq_device = {
+ .name = "cpufreq-davinci",
+ .dev = {
+ .platform_data = &cpufreq_info,
+ },
+};
+
+int __init da850_register_cpufreq(void)
+{
+ return platform_device_register(&da850_cpufreq_device);
+}
+
+static int da850_round_armrate(struct clk *clk, unsigned long rate)
+{
+ int i, ret = 0, diff;
+ unsigned int best = (unsigned int) -1;
+
+ rate /= 1000; /* convert to kHz */
+
+ for (i = 0; da850_freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
+ diff = da850_freq_table[i].frequency - rate;
+ if (diff < 0)
+ diff = -diff;
+
+ if (diff < best) {
+ best = diff;
+ ret = da850_freq_table[i].frequency;
+ }
+ }
+
+ return ret * 1000;
+}
+
+static int da850_set_armrate(struct clk *clk, unsigned long index)
+{
+ struct clk *pllclk = &pll0_clk;
+
+ return clk_set_rate(pllclk, index);
+}
+
+static int da850_set_pll0rate(struct clk *clk, unsigned long index)
+{
+ unsigned int prediv, mult, postdiv;
+ struct da850_opp *opp;
+ struct pll_data *pll = clk->pll_data;
+ unsigned int v;
+ int ret;
+
+ opp = (struct da850_opp *) da850_freq_table[index].index;
+ prediv = opp->prediv;
+ mult = opp->mult;
+ postdiv = opp->postdiv;
+
+ /* Unlock writing to PLL registers */
+ v = __raw_readl(DA8XX_SYSCFG_VIRT(DA8XX_CFGCHIP0_REG));
+ v &= ~CFGCHIP0_PLL_MASTER_LOCK;
+ __raw_writel(v, DA8XX_SYSCFG_VIRT(DA8XX_CFGCHIP0_REG));
+
+ ret = davinci_set_pllrate(pll, prediv, mult, postdiv);
+ if (WARN_ON(ret))
+ return ret;
+
+ return 0;
+}
+#else
+int __init da850_register_cpufreq(void)
+{
+ return 0;
+}
+
+static int da850_set_armrate(struct clk *clk, unsigned long rate)
+{
+ return -EINVAL;
+}
+
+static int da850_set_pll0rate(struct clk *clk, unsigned long armrate)
+{
+ return -EINVAL;
+}
+
+static int da850_round_armrate(struct clk *clk, unsigned long rate)
+{
+ return clk->rate;
+}
+#endif
+
static struct davinci_soc_info davinci_soc_info_da850 = {
.io_desc = da850_io_desc,
.io_desc_num = ARRAY_SIZE(da850_io_desc),
diff --git a/arch/arm/mach-davinci/include/mach/da8xx.h b/arch/arm/mach-davinci/include/mach/da8xx.h
index 3b7527324bf..401bf93fd32 100644
--- a/arch/arm/mach-davinci/include/mach/da8xx.h
+++ b/arch/arm/mach-davinci/include/mach/da8xx.h
@@ -37,6 +37,7 @@ extern void __iomem *da8xx_syscfg_base;
#define DA8XX_SYSCFG_BASE (IO_PHYS + 0x14000)
#define DA8XX_SYSCFG_VIRT(x) (da8xx_syscfg_base + (x))
#define DA8XX_JTAG_ID_REG 0x18
+#define DA8XX_CFGCHIP0_REG 0x17c
#define DA8XX_CFGCHIP2_REG 0x184
#define DA8XX_CFGCHIP3_REG 0x188
@@ -85,6 +86,7 @@ int da8xx_register_lcdc(struct da8xx_lcdc_platform_data *pdata);
int da8xx_register_mmcsd0(struct davinci_mmc_config *config);
void __init da8xx_register_mcasp(int id, struct snd_platform_data *pdata);
int da8xx_register_rtc(void);
+int da850_register_cpufreq(void);
extern struct platform_device da8xx_serial_device;
extern struct emac_platform_data da8xx_emac_pdata;