1 files changed, 240 insertions, 0 deletions
diff --git a/drivers/cpufreq/s3c2412-cpufreq.c b/drivers/cpufreq/s3c2412-cpufreq.c
new file mode 100644
index 000000000..5945945ea
--- /dev/null
+++ b/drivers/cpufreq/s3c2412-cpufreq.c
@@ -0,0 +1,240 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright 2008 Simtec Electronics
+ *	http://armlinux.simtec.co.uk/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * S3C2412 CPU Frequency scalling
+*/
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/cpufreq.h>
+#include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/soc/samsung/s3c-cpufreq-core.h>
+#include <linux/soc/samsung/s3c-pm.h>
+
+#include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+
+#define S3C2412_CLKDIVN_PDIVN		(1<<2)
+#define S3C2412_CLKDIVN_HDIVN_MASK	(3<<0)
+#define S3C2412_CLKDIVN_ARMDIVN		(1<<3)
+#define S3C2412_CLKDIVN_DVSEN		(1<<4)
+#define S3C2412_CLKDIVN_HALFHCLK	(1<<5)
+#define S3C2412_CLKDIVN_USB48DIV	(1<<6)
+#define S3C2412_CLKDIVN_UARTDIV_MASK	(15<<8)
+#define S3C2412_CLKDIVN_UARTDIV_SHIFT	(8)
+#define S3C2412_CLKDIVN_I2SDIV_MASK	(15<<12)
+#define S3C2412_CLKDIVN_I2SDIV_SHIFT	(12)
+#define S3C2412_CLKDIVN_CAMDIV_MASK	(15<<16)
+#define S3C2412_CLKDIVN_CAMDIV_SHIFT	(16)
+
+/* 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 = s3c24xx_read_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);
+	s3c24xx_write_clkdivn(clkdiv);
+
+	clk_set_parent(armclk, cfg->divs.dvs ? hclk : fclk);
+}
+
+/* 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,
+
+	.calc_iotiming	= s3c2412_iotiming_calc,
+	.set_iotiming	= s3c2412_iotiming_set,
+	.get_iotiming	= s3c2412_iotiming_get,
+
+	.debug_io_show  = s3c_cpufreq_debugfs_call(s3c2412_iotiming_debugfs),
+};
+
+static int s3c2412_cpufreq_add(struct device *dev,
+			       struct subsys_interface *sif)
+{
+	unsigned long fclk_rate;
+
+	hclk = clk_get(NULL, "hclk");
+	if (IS_ERR(hclk)) {
+		pr_err("cannot find hclk clock\n");
+		return -ENOENT;
+	}
+
+	fclk = clk_get(NULL, "fclk");
+	if (IS_ERR(fclk)) {
+		pr_err("cannot find fclk clock\n");
+		goto err_fclk;
+	}
+
+	fclk_rate = clk_get_rate(fclk);
+	if (fclk_rate > 200000000) {
+		pr_info("fclk %ld MHz, assuming 266MHz capable part\n",
+			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)) {
+		pr_err("cannot find arm clock\n");
+		goto err_armclk;
+	}
+
+	xtal = clk_get(NULL, "xtal");
+	if (IS_ERR(xtal)) {
+		pr_err("cannot find xtal clock\n");
+		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 subsys_interface s3c2412_cpufreq_interface = {
+	.name		= "s3c2412_cpufreq",
+	.subsys		= &s3c2412_subsys,
+	.add_dev	= s3c2412_cpufreq_add,
+};
+
+static int s3c2412_cpufreq_init(void)
+{
+	return subsys_interface_register(&s3c2412_cpufreq_interface);
+}
+arch_initcall(s3c2412_cpufreq_init);