change name from clock.c to system_clock.c

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@746 bbd45198-f89e-11dd-88c7-29a3b14d5316

libcpu/arm/s3c24x0/system_clock.c

+/*
+ * File      : clock.c
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006, RT-Thread Development Team
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://openlab.rt-thread.com/license/LICENSE
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2008-04-25     Yi.qiu       first version
+ */
+
+#include <rtthread.h>
+#include "s3c24x0.h"
+
+#define CONFIG_SYS_CLK_FREQ	12000000	// Fin = 12.00MHz
+
+#if CONFIG_SYS_CLK_FREQ == 12000000
+	/* MPLL=2*12*100/6=400MHz	*/
+	#define 	MPL_MIDV	92		/* m=MPL_MDIV+8=100 */
+	#define 	MPL_PDIV	4		/* p=MPL_PDIV+2=6	*/
+	#define 	MPL_SDIV	0		/* s=MPL_SDIV=0 */
+	/* UPLL=12*64/8=96MHz */	
+	#define 	UPL_MDIV	56		/* m=UPL_MDIV+8=64 */		
+	#define 	UPL_PDIV	2		/* p=UPL_PDIV+2=4	*/
+	#define 	UPL_SDIV	1		/* s=UPL_SDIV=1 */
+	/* System clock divider FCLK:HCLK:PCLK=1:4:8 */
+	#define 	DIVN_UPLL		0x1 	/* UCLK = UPLL clock / 2 */
+	#define 	HDIVN			0x2 	/* HCLK = FCLK / 4 */
+	#define 	PDIVN			0x1 	/* PCLK = HCLK / 2 */
+#endif
+
+rt_uint32_t PCLK;
+rt_uint32_t FCLK;
+rt_uint32_t HCLK;
+rt_uint32_t UCLK;
+
+void rt_hw_get_clock(void)
+{
+	rt_uint32_t val;
+	rt_uint8_t m, p, s;
+
+	val = MPLLCON;
+	m = (val>>12)&0xff;
+	p = (val>>4)&0x3f;
+	s = val&3;
+
+	FCLK = ((m+8)*(CONFIG_SYS_CLK_FREQ/100)*2)/((p+2)*(1<<s))*100;
+
+	val = CLKDIVN;
+	m = (val>>1)&3;
+	p = val&1;
+
+	switch (m) {
+	case 0:
+		HCLK = FCLK;
+		break;
+	case 1:
+		HCLK = FCLK>>1;
+		break;
+	case 2:
+		if(s&2)
+			HCLK = FCLK>>3;
+		else
+			HCLK = FCLK>>2;
+		break;
+	case 3:
+		if(s&1)
+			HCLK = FCLK/6;
+		else
+			HCLK = FCLK/3;
+		break;
+}
+
+	if(p)
+		PCLK = HCLK>>1;
+	else
+		PCLK = HCLK;
+}
+
+void rt_hw_set_mpll_clock(rt_uint8_t sdiv, rt_uint8_t pdiv, rt_uint8_t mdiv)
+{
+	MPLLCON = sdiv | (pdiv<<4) | (mdiv<<12);
+}
+
+void rt_hw_set_upll_clock(rt_uint8_t sdiv, rt_uint8_t pdiv, rt_uint8_t mdiv)
+{
+	UPLLCON = (mdiv<<12) | (pdiv<<4) | sdiv;
+}
+
+void rt_hw_set_divider(rt_uint8_t hdivn, rt_uint8_t pdivn)
+{
+	CLKDIVN = (hdivn<<1) | pdivn;
+}
+
+/**
+ * @brief System Clock Configuration
+ */
+void rt_hw_clock_init(void)
+{
+	LOCKTIME = 0xFFFFFFFF;
+	rt_hw_set_divider(HDIVN, PDIVN);
+	rt_hw_set_upll_clock(UPL_SDIV, UPL_PDIV, UPL_MDIV);
+	rt_hw_set_mpll_clock(MPL_SDIV, MPL_PDIV, MPL_MIDV);
+}
+