--- /dev/null
+/* linux/arch/arm/plat-s3c24xx/s3c2440-cpufreq.c
+ *
+ * Copyright (c) 2006,2008,2009 Simtec Electronics
+ * http://armlinux.simtec.co.uk/
+ * Ben Dooks <ben@simtec.co.uk>
+ * Vincent Sanders <vince@simtec.co.uk>
+ *
+ * S3C2440/S3C2442 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/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+
+#include <mach/hardware.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include <mach/regs-clock.h>
+
+#include <plat/cpu.h>
+#include <plat/cpu-freq-core.h>
+#include <plat/clock.h>
+
+static struct clk *xtal;
+static struct clk *fclk;
+static struct clk *hclk;
+static struct clk *armclk;
+
+/* HDIV: 1, 2, 3, 4, 6, 8 */
+
+static inline int within_khz(unsigned long a, unsigned long b)
+{
+ long diff = a - b;
+
+ return (diff >= -1000 && diff <= 1000);
+}
+
+/**
+ * s3c2440_cpufreq_calcdivs - calculate divider settings
+ * @cfg: The cpu frequency settings.
+ *
+ * Calcualte the divider values for the given frequency settings
+ * specified in @cfg. The values are stored in @cfg for later use
+ * by the relevant set routine if the request settings can be reached.
+ */
+int s3c2440_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
+{
+ unsigned int hdiv, pdiv;
+ unsigned long hclk, fclk, armclk;
+ unsigned long hclk_max;
+
+ fclk = cfg->freq.fclk;
+ armclk = cfg->freq.armclk;
+ hclk_max = cfg->max.hclk;
+
+ s3c_freq_dbg("%s: fclk is %lu, armclk %lu, max hclk %lu\n",
+ __func__, fclk, armclk, hclk_max);
+
+ if (armclk > fclk) {
+ printk(KERN_WARNING "%s: armclk > fclk\n", __func__);
+ armclk = fclk;
+ }
+
+ /* if we are in DVS, we need HCLK to be <= ARMCLK */
+ if (armclk < fclk && armclk < hclk_max)
+ hclk_max = armclk;
+
+ for (hdiv = 1; hdiv < 9; hdiv++) {
+ if (hdiv == 5 || hdiv == 7)
+ hdiv++;
+
+ hclk = (fclk / hdiv);
+ if (hclk <= hclk_max || within_khz(hclk, hclk_max))
+ break;
+ }
+
+ s3c_freq_dbg("%s: hclk %lu, div %d\n", __func__, hclk, hdiv);
+
+ if (hdiv > 8)
+ goto invalid;
+
+ pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
+
+ if ((hclk / pdiv) > cfg->max.pclk)
+ pdiv++;
+
+ s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv);
+
+ if (pdiv > 2)
+ goto invalid;
+
+ pdiv *= hdiv;
+
+ /* calculate a valid armclk */
+
+ if (armclk < hclk)
+ armclk = hclk;
+
+ /* if we're running armclk lower than fclk, this really means
+ * that the system should go into dvs mode, which means that
+ * armclk is connected to hclk. */
+ if (armclk < fclk) {
+ cfg->divs.dvs = 1;
+ armclk = hclk;
+ } else
+ cfg->divs.dvs = 0;
+
+ cfg->freq.armclk = armclk;
+
+ /* store the result, and then return */
+
+ cfg->divs.h_divisor = hdiv;
+ cfg->divs.p_divisor = pdiv;
+
+ return 0;
+
+ invalid:
+ return -EINVAL;
+}
+
+#define CAMDIVN_HCLK_HALF (S3C2440_CAMDIVN_HCLK3_HALF | \
+ S3C2440_CAMDIVN_HCLK4_HALF)
+
+/**
+ * s3c2440_cpufreq_setdivs - set the cpu frequency divider settings
+ * @cfg: The cpu frequency settings.
+ *
+ * Set the divisors from the settings in @cfg, which where generated
+ * during the calculation phase by s3c2440_cpufreq_calcdivs().
+ */
+static void s3c2440_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
+{
+ unsigned long clkdiv, camdiv;
+
+ s3c_freq_dbg("%s: divsiors: h=%d, p=%d\n", __func__,
+ cfg->divs.h_divisor, cfg->divs.p_divisor);
+
+ clkdiv = __raw_readl(S3C2410_CLKDIVN);
+ camdiv = __raw_readl(S3C2440_CAMDIVN);
+
+ clkdiv &= ~(S3C2440_CLKDIVN_HDIVN_MASK | S3C2440_CLKDIVN_PDIVN);
+ camdiv &= ~CAMDIVN_HCLK_HALF;
+
+ switch (cfg->divs.h_divisor) {
+ case 1:
+ clkdiv |= S3C2440_CLKDIVN_HDIVN_1;
+ break;
+
+ case 2:
+ clkdiv |= S3C2440_CLKDIVN_HDIVN_2;
+ break;
+
+ case 6:
+ camdiv |= S3C2440_CAMDIVN_HCLK3_HALF;
+ case 3:
+ clkdiv |= S3C2440_CLKDIVN_HDIVN_3_6;
+ break;
+
+ case 8:
+ camdiv |= S3C2440_CAMDIVN_HCLK4_HALF;
+ case 4:
+ clkdiv |= S3C2440_CLKDIVN_HDIVN_4_8;
+ break;
+
+ default:
+ BUG(); /* we don't expect to get here. */
+ }
+
+ if (cfg->divs.p_divisor != cfg->divs.h_divisor)
+ clkdiv |= S3C2440_CLKDIVN_PDIVN;
+
+ /* todo - set pclk. */
+
+ /* Write the divisors first with hclk intentionally halved so that
+ * when we write clkdiv we will under-frequency instead of over. We
+ * then make a short delay and remove the hclk halving if necessary.
+ */
+
+ __raw_writel(camdiv | CAMDIVN_HCLK_HALF, S3C2440_CAMDIVN);
+ __raw_writel(clkdiv, S3C2410_CLKDIVN);
+
+ ndelay(20);
+ __raw_writel(camdiv, S3C2440_CAMDIVN);
+
+ clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk);
+}
+
+static int run_freq_for(unsigned long max_hclk, unsigned long fclk,
+ int *divs,
+ struct cpufreq_frequency_table *table,
+ size_t table_size)
+{
+ unsigned long freq;
+ int index = 0;
+ int div;
+
+ for (div = *divs; div > 0; div = *divs++) {
+ freq = fclk / div;
+
+ if (freq > max_hclk && div != 1)
+ continue;
+
+ freq /= 1000; /* table is in kHz */
+ index = s3c_cpufreq_addfreq(table, index, table_size, freq);
+ if (index < 0)
+ break;
+ }
+
+ return index;
+}
+
+static int hclk_divs[] = { 1, 2, 3, 4, 6, 8, -1 };
+
+static int s3c2440_cpufreq_calctable(struct s3c_cpufreq_config *cfg,
+ struct cpufreq_frequency_table *table,
+ size_t table_size)
+{
+ int ret;
+
+ WARN_ON(cfg->info == NULL);
+ WARN_ON(cfg->board == NULL);
+
+ ret = run_freq_for(cfg->info->max.hclk,
+ cfg->info->max.fclk,
+ hclk_divs,
+ table, table_size);
+
+ s3c_freq_dbg("%s: returning %d\n", __func__, ret);
+
+ return ret;
+}
+
+struct s3c_cpufreq_info s3c2440_cpufreq_info = {
+ .max = {
+ .fclk = 400000000,
+ .hclk = 133333333,
+ .pclk = 66666666,
+ },
+
+ .locktime_m = 300,
+ .locktime_u = 300,
+ .locktime_bits = 16,
+
+ .name = "s3c244x",
+ .calc_iotiming = s3c2410_iotiming_calc,
+ .set_iotiming = s3c2410_iotiming_set,
+ .get_iotiming = s3c2410_iotiming_get,
+ .set_fvco = s3c2410_set_fvco,
+
+ .set_refresh = s3c2410_cpufreq_setrefresh,
+ .set_divs = s3c2440_cpufreq_setdivs,
+ .calc_divs = s3c2440_cpufreq_calcdivs,
+ .calc_freqtable = s3c2440_cpufreq_calctable,
+
+ .resume_clocks = s3c244x_setup_clocks,
+};
+
+static int s3c2440_cpufreq_add(struct sys_device *sysdev)
+{
+ xtal = s3c_cpufreq_clk_get(NULL, "xtal");
+ hclk = s3c_cpufreq_clk_get(NULL, "hclk");
+ fclk = s3c_cpufreq_clk_get(NULL, "fclk");
+ armclk = s3c_cpufreq_clk_get(NULL, "armclk");
+
+ if (IS_ERR(xtal) || IS_ERR(hclk) || IS_ERR(fclk) || IS_ERR(armclk)) {
+ printk(KERN_ERR "%s: failed to get clocks\n", __func__);
+ return -ENOENT;
+ }
+
+ return s3c_cpufreq_register(&s3c2440_cpufreq_info);
+}
+
+static struct sysdev_driver s3c2440_cpufreq_driver = {
+ .add = s3c2440_cpufreq_add,
+};
+
+static int s3c2440_cpufreq_init(void)
+{
+ return sysdev_driver_register(&s3c2440_sysclass,
+ &s3c2440_cpufreq_driver);
+}
+
+/* arch_initcall adds the clocks we need, so use subsys_initcall. */
+subsys_initcall(s3c2440_cpufreq_init);
+
+static struct sysdev_driver s3c2442_cpufreq_driver = {
+ .add = s3c2440_cpufreq_add,
+};
+
+static int s3c2442_cpufreq_init(void)
+{
+ return sysdev_driver_register(&s3c2442_sysclass,
+ &s3c2442_cpufreq_driver);
+}
+
+subsys_initcall(s3c2442_cpufreq_init);
git.openpandora.org / pandora-kernel.git / commitdiff