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ARM: OMAP: implement CPUfreq frequency table based on PRCM table

PATCH/RFC 2 Kevin Hilman 2 participants 2 messages Nov 1, 2007 – Nov 15, 2007

Subsystems (4)
Arm (32-bit) Arm sub-architectures OMAP2+ support OMAP clock framework support
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Kevin Hilman

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#0 lore raw

[Tony, the cpu-omap code now passes in a table pointer which gets set
to the one filled out in the clock code. Is this what you meant? ]

This patch adds a CPUfreq frequency-table implementation for OMAP2 by walking the PRCM rate-table for available entries and adding them to a CPUfreq table.

CPUfreq can then be used to manage switching between all the available entries in the PRCM rate table. Either use the CPUfreq sysfs interface directly, (see Section 3 of Documentation/cpu-freq/user-guide.txt) or use the cpufrequtils package:
http://www.kernel.org/pub/linux/utils/kernel/cpufreq/cpufrequtils.html

Signed-off-by Kevin Hilman <[email protected]>
---
 arch/arm/mach-omap2/clock24xx.c |   34 ++++++++++++++++++++++++++
 arch/arm/plat-omap/cpu-omap.c   |   52 ++++++++++++++++++++++++++++++++++++++--
 2 files changed, 84 insertions(+), 2 deletions(-)
arch/arm/mach-omap2/clock24xx.c +34 -0
Index: dev/arch/arm/mach-omap2/clock24xx.c
===================================================================
@@ -26,6 +26,7 @@
 #include <linux/clk.h>
 
 #include <linux/io.h>
+#include <linux/cpufreq.h>
 
 #include <asm/arch/clock.h>
 #include <asm/arch/sram.h>

@@ -461,6 +462,39 @@ static int __init omap2_clk_arch_init(vo
 }
 arch_initcall(omap2_clk_arch_init);
 
+#ifdef CONFIG_CPU_FREQ
+/*
+ * Walk PRCM rate table and fillout cpufreq freq_table
+ */
+static struct cpufreq_frequency_table freq_table[ARRAY_SIZE(rate_table)];
+
+void omap2_cpufreq_init_table(struct cpufreq_frequency_table **table)
+{
+	struct prcm_config *prcm;
+	int i = 0;
+
+	for (prcm = rate_table; prcm->mpu_speed; prcm++) {
+		if (!(prcm->flags & cpu_mask))
+			continue;
+		if (prcm->xtal_speed != sys_ck.rate)
+			continue;
+
+		/* don't put bypass rates in table */
+		if (prcm->dpll_speed == prcm->xtal_speed)
+			continue;
+
+		freq_table[i].index = i;
+		freq_table[i].frequency = prcm->mpu_speed / 1000;
+		i++;
+	}
+
+	freq_table[i].index = i;
+	freq_table[i].frequency = CPUFREQ_TABLE_END;
+
+	*table = &freq_table[0];
+}
+#endif
+
 int __init omap2_clk_init(void)
 {
 	struct prcm_config *prcm;
arch/arm/plat-omap/cpu-omap.c +50 -2

111 lines not on this page · raw message

--

maintainer
#1 lore raw

Hi,

Quoted 2 lines · Kevin Hilman

[Tony, the cpu-omap code now passes in a table pointer which gets set
to the one filled out in the clock code. Is this what you meant? ]

Yeh, looks good. Just one more thing below.

Quoted 9 lines

This patch adds a CPUfreq frequency-table implementation for OMAP2 by walking the PRCM rate-table for available entries and adding them to a CPUfreq table.

CPUfreq can then be used to manage switching between all the available entries in the PRCM rate table. Either use the CPUfreq sysfs interface directly, (see Section 3 of Documentation/cpu-freq/user-guide.txt) or use the cpufrequtils package:
http://www.kernel.org/pub/linux/utils/kernel/cpufreq/cpufrequtils.html

<snip>

Quoted 6 lines

Index: dev/arch/arm/plat-omap/cpu-omap.c
===================================================================

arch/arm/plat-omap/cpu-omap.c +0 -0
@@ -30,6 +30,11 @@
 #ifdef CONFIG_ARCH_OMAP1

arch/arm/plat-omap/cpu-omap.c line 40

Quoted 10 lines
arch/arm/plat-omap/cpu-omap.c +5 -0
 #define MPU_CLK		"mpu"
 #else
+
+#define USE_FREQ_TABLE
+void omap2_cpufreq_init_table(struct cpufreq_frequency_table **table);
+static struct cpufreq_frequency_table *freq_table;
+
 #define MPU_CLK		"virt_prcm_set"
 #endif

How about calling omap2_cpufreq_init_table clk_init_cpufreq_table instead? Then export it and define it in clock.h for omap? It should be possible to have cpufreq as a module.

Regards,

Tony