GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/arch/arm/cpu/arm1136/mx31/timer.c

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2007
+ * Sascha Hauer, Pengutronix
+ */
+
+#include <common.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/io.h>
+
+#define TIMER_BASE 0x53f90000 /* General purpose timer 1 */
+
+/* General purpose timers registers */
+#define GPTCR	__REG(TIMER_BASE)		/* Control register	*/
+#define GPTPR	__REG(TIMER_BASE + 0x4)		/* Prescaler register	*/
+#define GPTSR	__REG(TIMER_BASE + 0x8)		/* Status register	*/
+#define GPTCNT	__REG(TIMER_BASE + 0x24)	/* Counter register	*/
+
+/* General purpose timers bitfields */
+#define GPTCR_SWR		(1 << 15)	/* Software reset	*/
+#define GPTCR_FRR		(1 << 9)	/* Freerun / restart	*/
+#define GPTCR_CLKSOURCE_32	(4 << 6)	/* Clock source		*/
+#define GPTCR_TEN		1		/* Timer enable		*/
+
+/* The 32768Hz 32-bit timer overruns in 131072 seconds */
+int timer_init(void)
+{
+	int i;
+
+	/* setup GP Timer 1 */
+	GPTCR = GPTCR_SWR;
+	for (i = 0; i < 100; i++)
+		GPTCR = 0; /* We have no udelay by now */
+	GPTPR = 0; /* 32Khz */
+	/* Freerun Mode, PERCLK1 input */
+	GPTCR |= GPTCR_CLKSOURCE_32 | GPTCR_TEN;
+
+	return 0;
+}
+
+unsigned long timer_read_counter(void)
+{
+	return GPTCNT;
+}