--- /dev/null
+/* linux/arch/arm/mach-s3c2412/cpu-freq.c
+ *
+ * Copyright 2008 Simtec Electronics
+ * http://armlinux.simtec.co.uk/
+ * Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2412 CPU Frequency scalling
+ *
+ * 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 <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#include <mach/regs-clock.h>
+#include <mach/regs-s3c2412-mem.h>
+
+#include <plat/cpu.h>
+#include <plat/clock.h>
+#include <plat/cpu-freq-core.h>
+
+/* our clock resources. */
+static struct clk *xtal;
+static struct clk *fclk;
+static struct clk *hclk;
+static struct clk *armclk;
+
+/* HDIV: 1, 2, 3, 4, 6, 8 */
+
+static int s3c2412_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
+{
+ unsigned int hdiv, pdiv, armdiv, dvs;
+ unsigned long hclk, fclk, armclk, armdiv_clk;
+ unsigned long hclk_max;
+
+ fclk = cfg->freq.fclk;
+ armclk = cfg->freq.armclk;
+ hclk_max = cfg->max.hclk;
+
+ /* We can't run hclk above armclk as at the best we have to
+ * have armclk and hclk in dvs mode. */
+
+ if (hclk_max > armclk)
+ hclk_max = armclk;
+
+ s3c_freq_dbg("%s: fclk=%lu, armclk=%lu, hclk_max=%lu\n",
+ __func__, fclk, armclk, hclk_max);
+ s3c_freq_dbg("%s: want f=%lu, arm=%lu, h=%lu, p=%lu\n",
+ __func__, cfg->freq.fclk, cfg->freq.armclk,
+ cfg->freq.hclk, cfg->freq.pclk);
+
+ armdiv = fclk / armclk;
+
+ if (armdiv < 1)
+ armdiv = 1;
+ if (armdiv > 2)
+ armdiv = 2;
+
+ cfg->divs.arm_divisor = armdiv;
+ armdiv_clk = fclk / armdiv;
+
+ hdiv = armdiv_clk / hclk_max;
+ if (hdiv < 1)
+ hdiv = 1;
+
+ cfg->freq.hclk = hclk = armdiv_clk / hdiv;
+
+ /* set dvs depending on whether we reached armclk or not. */
+ cfg->divs.dvs = dvs = armclk < armdiv_clk;
+
+ /* update the actual armclk we achieved. */
+ cfg->freq.armclk = dvs ? hclk : armdiv_clk;
+
+ s3c_freq_dbg("%s: armclk %lu, hclk %lu, armdiv %d, hdiv %d, dvs %d\n",
+ __func__, armclk, hclk, armdiv, hdiv, cfg->divs.dvs);
+
+ if (hdiv > 4)
+ goto invalid;
+
+ pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
+
+ if ((hclk / pdiv) > cfg->max.pclk)
+ pdiv++;
+
+ cfg->freq.pclk = hclk / pdiv;
+
+ s3c_freq_dbg("%s: pdiv %d\n", __func__, pdiv);
+
+ if (pdiv > 2)
+ goto invalid;
+
+ pdiv *= hdiv;
+
+ /* store the result, and then return */
+
+ cfg->divs.h_divisor = hdiv * armdiv;
+ cfg->divs.p_divisor = pdiv * armdiv;
+
+ return 0;
+
+ invalid:
+ return -EINVAL;
+}
+
+static void s3c2412_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
+{
+ unsigned long clkdiv;
+ unsigned long olddiv;
+
+ olddiv = clkdiv = __raw_readl(S3C2410_CLKDIVN);
+
+ /* clear off current clock info */
+
+ clkdiv &= ~S3C2412_CLKDIVN_ARMDIVN;
+ clkdiv &= ~S3C2412_CLKDIVN_HDIVN_MASK;
+ clkdiv &= ~S3C2412_CLKDIVN_PDIVN;
+
+ if (cfg->divs.arm_divisor == 2)
+ clkdiv |= S3C2412_CLKDIVN_ARMDIVN;
+
+ clkdiv |= ((cfg->divs.h_divisor / cfg->divs.arm_divisor) - 1);
+
+ if (cfg->divs.p_divisor != cfg->divs.h_divisor)
+ clkdiv |= S3C2412_CLKDIVN_PDIVN;
+
+ s3c_freq_dbg("%s: div %08lx => %08lx\n", __func__, olddiv, clkdiv);
+ __raw_writel(clkdiv, S3C2410_CLKDIVN);
+
+ clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk);
+}
+
+static void s3c2412_cpufreq_setrefresh(struct s3c_cpufreq_config *cfg)
+{
+ struct s3c_cpufreq_board *board = cfg->board;
+ unsigned long refresh;
+
+ s3c_freq_dbg("%s: refresh %u ns, hclk %lu\n", __func__,
+ board->refresh, cfg->freq.hclk);
+
+ /* Reduce both the refresh time (in ns) and the frequency (in MHz)
+ * by 10 each 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 = (board->refresh / 10);
+ refresh *= (cfg->freq.hclk / 100);
+ refresh /= (1 * 1000 * 1000); /* 10^6 */
+
+ s3c_freq_dbg("%s: setting refresh 0x%08lx\n", __func__, refresh);
+ __raw_writel(refresh, S3C2412_REFRESH);
+}
+
+/* set the default cpu frequency information, based on an 200MHz part
+ * as we have no other way of detecting the speed rating in software.
+ */
+
+static struct s3c_cpufreq_info s3c2412_cpufreq_info = {
+ .max = {
+ .fclk = 200000000,
+ .hclk = 100000000,
+ .pclk = 50000000,
+ },
+
+ .latency = 5000000, /* 5ms */
+
+ .locktime_m = 150,
+ .locktime_u = 150,
+ .locktime_bits = 16,
+
+ .name = "s3c2412",
+ .set_refresh = s3c2412_cpufreq_setrefresh,
+ .set_divs = s3c2412_cpufreq_setdivs,
+ .calc_divs = s3c2412_cpufreq_calcdivs,
+
+ .resume_clocks = s3c2412_setup_clocks,
+};
+
+static int s3c2412_cpufreq_add(struct sys_device *sysdev)
+{
+ unsigned long fclk_rate;
+
+ hclk = clk_get(NULL, "hclk");
+ if (IS_ERR(hclk)) {
+ printk(KERN_ERR "%s: cannot find hclk clock\n", __func__);
+ return -ENOENT;
+ }
+
+ fclk = clk_get(NULL, "fclk");
+ if (IS_ERR(fclk)) {
+ printk(KERN_ERR "%s: cannot find fclk clock\n", __func__);
+ goto err_fclk;
+ }
+
+ fclk_rate = clk_get_rate(fclk);
+ if (fclk_rate > 200000000) {
+ printk(KERN_INFO
+ "%s: fclk %ld MHz, assuming 266MHz capable part\n",
+ __func__, fclk_rate / 1000000);
+ s3c2412_cpufreq_info.max.fclk = 266000000;
+ s3c2412_cpufreq_info.max.hclk = 133000000;
+ s3c2412_cpufreq_info.max.pclk = 66000000;
+ }
+
+ armclk = clk_get(NULL, "armclk");
+ if (IS_ERR(armclk)) {
+ printk(KERN_ERR "%s: cannot find arm clock\n", __func__);
+ goto err_armclk;
+ }
+
+ xtal = clk_get(NULL, "xtal");
+ if (IS_ERR(xtal)) {
+ printk(KERN_ERR "%s: cannot find xtal clock\n", __func__);
+ goto err_xtal;
+ }
+
+ return s3c_cpufreq_register(&s3c2412_cpufreq_info);
+
+err_xtal:
+ clk_put(armclk);
+err_armclk:
+ clk_put(fclk);
+err_fclk:
+ clk_put(hclk);
+
+ return -ENOENT;
+}
+
+static struct sysdev_driver s3c2412_cpufreq_driver = {
+ .add = s3c2412_cpufreq_add,
+};
+
+static int s3c2412_cpufreq_init(void)
+{
+ return sysdev_driver_register(&s3c2412_sysclass,
+ &s3c2412_cpufreq_driver);
+}
+
+arch_initcall(s3c2412_cpufreq_init);
projects / linux-2.6-block.git / commitdiff