ARM: S3C2410: CPUFREQ: Add core support.

Add core support for frequency scaling on the S3C2410 SoC.

Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

6 files changed, 241 insertions, 0 deletions

diff --git a/arch/arm/mach-s3c2410/Kconfig b/arch/arm/mach-s3c2410/Kconfig
index 41bb65d5b91f..a7f70e18ccb4 100644
--- a/arch/arm/mach-s3c2410/Kconfig
+++ b/arch/arm/mach-s3c2410/Kconfig
@@ -12,6 +12,7 @@ config CPU_S3C2410
         select S3C2410_GPIO
         select CPU_LLSERIAL_S3C2410
         select S3C2410_PM if PM
+        select S3C2410_CPUFREQ if CPU_FREQ_S3C24XX
         help
           Support for S3C2410 and S3C2410A family from the S3C24XX line
           of Samsung Mobile CPUs.
@@ -45,6 +46,15 @@ config MACH_BAST_IDE
           Internal node for machines with an BAST style IDE
           interface
 
+# cpu frequency scaling support
+
+config S3C2410_CPUFREQ
+        bool
+        depends on CPU_FREQ_S3C24XX && CPU_S3C2410
+        select S3C2410_CPUFREQ_UTILS
+        help
+          CPU Frequency scaling support for S3C2410
+
 menu "S3C2410 Machines"
 
 config ARCH_SMDK2410
@@ -79,6 +89,7 @@ config MACH_N30
 config ARCH_BAST
         bool "Simtec Electronics BAST (EB2410ITX)"
         select CPU_S3C2410
+        select S3C2410_IOTIMING if S3C2410_CPUFREQ
         select PM_SIMTEC if PM
         select SIMTEC_NOR
         select MACH_BAST_IDE
diff --git a/arch/arm/mach-s3c2410/Makefile b/arch/arm/mach-s3c2410/Makefile
index fca02f82711c..cc25eb0eb2cd 100644
--- a/arch/arm/mach-s3c2410/Makefile
+++ b/arch/arm/mach-s3c2410/Makefile
@@ -15,6 +15,7 @@ obj-$(CONFIG_CPU_S3C2410_DMA)	+= dma.o
 obj-$(CONFIG_CPU_S3C2410_DMA)   += dma.o
 obj-$(CONFIG_S3C2410_PM)        += pm.o sleep.o
 obj-$(CONFIG_S3C2410_GPIO)      += gpio.o
+obj-$(CONFIG_S3C2410_CPUFREQ)   += cpu-freq.o
 
 # Machine support
 
diff --git a/arch/arm/mach-s3c2410/cpu-freq.c b/arch/arm/mach-s3c2410/cpu-freq.c
new file mode 100644
index 000000000000..f2cbdbab0df6
--- /dev/null
+++ b/arch/arm/mach-s3c2410/cpu-freq.c
@@ -0,0 +1,157 @@
+/* linux/arch/arm/mach-s3c2410/cpu-freq.c
+ *
+ * Copyright (c) 2006,2008 Simtec Electronics
+ *      http://armlinux.simtec.co.uk/
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2410 CPU Frequency scaling
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/cpufreq.h>
+#include <linux/sysdev.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include <mach/regs-clock.h>
+
+#include <plat/cpu.h>
+#include <plat/clock.h>
+#include <plat/cpu-freq-core.h>
+
+/* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */
+
+static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
+{
+        u32 clkdiv = 0;
+
+        if (cfg->divs.h_divisor == 2)
+                clkdiv |= S3C2410_CLKDIVN_HDIVN;
+
+        if (cfg->divs.p_divisor != cfg->divs.h_divisor)
+                clkdiv |= S3C2410_CLKDIVN_PDIVN;
+
+        __raw_writel(clkdiv, S3C2410_CLKDIVN);
+}
+
+static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
+{
+        unsigned long hclk, fclk, pclk;
+        unsigned int hdiv, pdiv;
+        unsigned long hclk_max;
+
+        fclk = cfg->freq.fclk;
+        hclk_max = cfg->max.hclk;
+
+        cfg->freq.armclk = fclk;
+
+        s3c_freq_dbg("%s: fclk is %lu, max hclk %lu\n",
+                      __func__, fclk, hclk_max);
+
+        hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
+        hclk = fclk / hdiv;
+
+        if (hclk > cfg->max.hclk) {
+                s3c_freq_dbg("%s: hclk too big\n", __func__);
+                return -EINVAL;
+        }
+
+        pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
+        pclk = hclk / pdiv;
+
+        if (pclk > cfg->max.pclk) {
+                s3c_freq_dbg("%s: pclk too big\n", __func__);
+                return -EINVAL;
+        }
+
+        pdiv *= hdiv;
+
+        /* record the result */
+        cfg->divs.p_divisor = pdiv;
+        cfg->divs.h_divisor = hdiv;
+
+        return 0      ;
+}
+
+static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
+        .max            = {
+                .fclk   = 200000000,
+                .hclk   = 100000000,
+                .pclk   =  50000000,
+        },
+
+        /* transition latency is about 5ms worst-case, so
+         * set 10ms to be sure */
+        .latency        = 10000000,
+
+        .locktime_m     = 150,
+        .locktime_u     = 150,
+        .locktime_bits  = 12,
+
+        .need_pll       = 1,
+
+        .name           = "s3c2410",
+        .calc_iotiming  = s3c2410_iotiming_calc,
+        .set_iotiming   = s3c2410_iotiming_set,
+        .get_iotiming   = s3c2410_iotiming_get,
+        .resume_clocks  = s3c2410_setup_clocks,
+
+        .set_fvco       = s3c2410_set_fvco,
+        .set_refresh    = s3c2410_cpufreq_setrefresh,
+        .set_divs       = s3c2410_cpufreq_setdivs,
+        .calc_divs      = s3c2410_cpufreq_calcdivs,
+};
+
+static int s3c2410_cpufreq_add(struct sys_device *sysdev)
+{
+        return s3c_cpufreq_register(&s3c2410_cpufreq_info);
+}
+
+static struct sysdev_driver s3c2410_cpufreq_driver = {
+        .add            = s3c2410_cpufreq_add,
+};
+
+static int __init s3c2410_cpufreq_init(void)
+{
+        return sysdev_driver_register(&s3c2410_sysclass,
+                                      &s3c2410_cpufreq_driver);
+}
+
+arch_initcall(s3c2410_cpufreq_init);
+
+static int s3c2410a_cpufreq_add(struct sys_device *sysdev)
+{
+        /* alter the maximum freq settings for S3C2410A. If a board knows
+         * it only has a maximum of 200, then it should register its own
+         * limits. */
+
+        s3c2410_cpufreq_info.max.fclk = 266000000;
+        s3c2410_cpufreq_info.max.hclk = 133000000;
+        s3c2410_cpufreq_info.max.pclk =  66500000;
+        s3c2410_cpufreq_info.name = "s3c2410a";
+
+        return s3c2410_cpufreq_add(sysdev);
+}
+
+static struct sysdev_driver s3c2410a_cpufreq_driver = {
+        .add            = s3c2410a_cpufreq_add,
+};
+
+static int __init s3c2410a_cpufreq_init(void)
+{
+        return sysdev_driver_register(&s3c2410a_sysclass,
+                                      &s3c2410a_cpufreq_driver);
+}
+
+arch_initcall(s3c2410a_cpufreq_init);
diff --git a/arch/arm/plat-s3c24xx/Kconfig b/arch/arm/plat-s3c24xx/Kconfig
index d82d30c2f059..a547c79ed6ce 100644
--- a/arch/arm/plat-s3c24xx/Kconfig
+++ b/arch/arm/plat-s3c24xx/Kconfig
@@ -116,6 +116,13 @@ config S3C2410_IOTIMING
           Internal node to select io timing code that is common to the s3c2410
           and s3c2440/s3c2442 cpu frequency support.
 
+config S3C2410_CPUFREQ_UTILS
+        bool
+        depends on CPU_FREQ_S3C24XX
+        help
+          Internal node to select timing code that is common to the s3c2410
+          and s3c2440/s3c244 cpu frequency support.
+
 config MACH_SMDK
         bool
         help
diff --git a/arch/arm/plat-s3c24xx/Makefile b/arch/arm/plat-s3c24xx/Makefile
index 6f9afd13ab4f..b28fe9cb0e5e 100644
--- a/arch/arm/plat-s3c24xx/Makefile
+++ b/arch/arm/plat-s3c24xx/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_S3C2410_CLOCK)	+= s3c2410-clock.o
 obj-$(CONFIG_S3C2410_DMA)       += dma.o
 obj-$(CONFIG_S3C24XX_ADC)       += adc.o
 obj-$(CONFIG_S3C2410_IOTIMING)  += s3c2410-iotiming.o
+obj-$(CONFIG_S3C2410_CPUFREQ_UTILS) += s3c2410-cpufreq-utils.o
 
 # device specific setup and/or initialisation
 obj-$(CONFIG_ARCH_S3C2410)      += setup-i2c.o
diff --git a/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c b/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
new file mode 100644
index 000000000000..43ea80190d87
--- /dev/null
+++ b/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
@@ -0,0 +1,64 @@
+/* linux/arch/arm/plat-s3c24xx/s3c2410-cpufreq-utils.c
+ *
+ * Copyright (c) 2009 Simtec Electronics
+ *      http://armlinux.simtec.co.uk/
+ *      Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C24XX CPU Frequency scaling - utils for S3C2410/S3C2440/S3C2442
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+*/
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/cpufreq.h>
+#include <linux/io.h>
+
+#include <mach/map.h>
+#include <mach/regs-mem.h>
+#include <mach/regs-clock.h>
+
+#include <plat/cpu-freq-core.h>
+
+/**
+ * s3c2410_cpufreq_setrefresh - set SDRAM refresh value
+ * @cfg: The frequency configuration
+ *
+ * Set the SDRAM refresh value appropriately for the configured
+ * frequency.
+ */
+void s3c2410_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
+{
+        struct s3c_cpufreq_board *board = cfg->board;
+        unsigned long refresh;
+        unsigned long refval;
+
+        /* Reduce both the refresh time (in ns) and the frequency (in MHz)
+         * down to ensure that we do not overflow 32 bit numbers.
+         *
+         * This should work for HCLK up to 133MHz and refresh period up
+         * to 30usec.
+         */
+
+        refresh = (cfg->freq.hclk / 100) * (board->refresh / 10);
+        refresh = DIV_ROUND_UP(refresh, (1000 * 1000)); /* apply scale  */
+        refresh = (1 << 11) + 1 - refresh;
+
+        s3c_freq_dbg("%s: refresh value %lu\n", __func__, refresh);
+
+        refval = __raw_readl(S3C2410_REFRESH);
+        refval &= ~((1 << 12) - 1);
+        refval |= refresh;
+        __raw_writel(refval, S3C2410_REFRESH);
+}
+
+/**
+ * s3c2410_set_fvco - set the PLL value
+ * @cfg: The frequency configuration
+ */
+void s3c2410_set_fvco(struct s3c_cpufreq_config *cfg)
+{
+        __raw_writel(cfg->pll.index, S3C2410_MPLLCON);
+}