This patch adds a new 's3c2410' command which currently supports 's3c2410 speed
{set,get,list} and thus allows dynamic change of the CPU clock.

Signed-off-by: Harald Welte <laforge@openmoko.org>

Index: u-boot/cpu/arm920t/s3c24x0/Makefile
===================================================================
--- u-boot.orig/cpu/arm920t/s3c24x0/Makefile
+++ u-boot/cpu/arm920t/s3c24x0/Makefile
@@ -26,7 +26,8 @@
 LIB	= $(obj)lib$(SOC).a
 
 COBJS	= i2c.o interrupts.o serial.o speed.o \
-	  usb.o usb_ohci.o nand_read.o nand.o
+	  usb.o usb_ohci.o nand_read.o nand.o \
+	  cmd_s3c24xx.o
 
 SRCS	:= $(SOBJS:.o=.S) $(COBJS:.o=.c)
 OBJS	:= $(addprefix $(obj),$(SOBJS) $(COBJS))
Index: u-boot/cpu/arm920t/s3c24x0/cmd_s3c24xx.c
===================================================================
--- /dev/null
+++ u-boot/cpu/arm920t/s3c24x0/cmd_s3c24xx.c
@@ -0,0 +1,157 @@
+/*
+ * (C) Copyright 2006 by OpenMoko, Inc.
+ * Author: Harald Welte <laforge@openmoko.org>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Boot support
+ */
+#include <common.h>
+#include <command.h>
+#include <net.h>		/* for print_IPaddr */
+#include <s3c2410.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#if defined(CONFIG_CMD_BDI)
+
+#define ARRAY_SIZE(x)           (sizeof(x) / sizeof((x)[0]))
+#define MHZ	1000000
+
+static void print_cpu_speed(void)
+{
+	printf("FCLK = %u MHz, HCLK = %u MHz, PCLK = %u MHz, UCLK = %u MHz\n",
+		get_FCLK()/MHZ, get_HCLK()/MHZ, get_PCLK()/MHZ, get_UCLK()/MHZ);
+}
+
+struct s3c24x0_pll_speed {
+	u_int16_t	mhz;
+	u_int32_t	mpllcon;
+	u_int32_t	clkdivn;
+};
+
+#define CLKDIVN_1_1_1	0x00
+#define CLKDIVN_1_2_2	0x02
+#define CLKDIVN_1_2_4	0x03
+#define CLKDIVN_1_4_4	0x04
+
+#if defined(CONFIG_S3C2410)
+static const u_int32_t upllcon = ((0x78 << 12) + (0x2 << 4) + 0x3);
+static const struct s3c24x0_pll_speed pll_configs[] = {
+	{
+		.mhz = 50,
+		.mpllcon = ((0x5c << 12) + (0x4 << 4) + 0x2),
+		.clkdivn = CLKDIVN_1_1_1,
+	},
+	{
+		.mhz = 101,
+		.mpllcon = ((0x7f << 12) + (0x2 << 4) + 0x2),
+		.clkdivn = CLKDIVN_1_2_2,
+	},
+	{
+		.mhz = 202,
+		.mpllcon = ((0x90 << 12) + (0x7 << 4) + 0x0),
+		.clkdivn = CLKDIVN_1_2_4,
+	},
+	{
+		.mhz = 266,
+		.mpllcon = ((0x7d << 12) + (0x1 << 4) + 0x1),
+		.clkdivn = CLKDIVN_1_2_4,
+	},
+};
+#else
+#error "please define valid pll configurations for your cpu type"
+#endif
+
+static void list_cpu_speeds(void)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(pll_configs); i++)
+		printf("%u MHz\n", pll_configs[i].mhz);
+}
+
+static int reconfig_mpll(u_int16_t mhz)
+{
+	S3C24X0_CLOCK_POWER * const clk_power = S3C24X0_GetBase_CLOCK_POWER();
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pll_configs); i++) {
+		if (pll_configs[i].mhz == mhz) {
+			/* to reduce PLL lock time, adjust the LOCKTIME register */
+			clk_power->LOCKTIME = 0xFFFFFF;
+
+			/* configure MPLL */
+			clk_power->MPLLCON = pll_configs[i].mpllcon;
+			clk_power->UPLLCON = upllcon;
+			clk_power->CLKDIVN = pll_configs[i].clkdivn;
+
+			/* If we changed the speed, we need to re-configure
+			 * the serial baud rate generator */
+			serial_setbrg();
+			return 0;
+		}
+	}
+	return -1;
+}
+
+int do_s3c24xx ( cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
+{
+	if (!strcmp(argv[1], "speed")) {
+		if (argc < 2)
+			goto out_help;
+		if (!strcmp(argv[2], "get"))
+			print_cpu_speed();
+		else if (!strcmp(argv[2], "list"))
+			list_cpu_speeds();
+		else if (!strcmp(argv[2], "set")) {
+			unsigned long mhz;
+			if (argc < 3)
+				goto out_help;
+
+			mhz = simple_strtoul(argv[3], NULL, 10);
+
+			if (reconfig_mpll(mhz) < 0)
+				printf("error, speed %uMHz unknown\n", mhz);
+			else
+				print_cpu_speed();
+		} else
+			goto out_help;
+	} else {
+out_help:
+		printf("Usage:\n%s\n", cmdtp->usage);
+		return 1;
+	}
+
+	return 0;
+}
+
+/* -------------------------------------------------------------------- */
+
+
+U_BOOT_CMD(
+	s3c24xx,	4,	1,	do_s3c24xx,
+	"s3c24xx - SoC  specific commands\n",
+	"speed get - display current PLL speed config\n"
+	"s3c24xx speed list - display supporte PLL speed configs\n"
+	"s3c24xx speed set - set PLL speed\n"
+);
+
+#endif
