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

2026-09-06 03:52:57 +08:00
commit b1928b41c0
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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Freescale i.MX28 timer driver
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * Based on code from LTIB:
+ * (C) Copyright 2009-2010 Freescale Semiconductor, Inc.
+ */
+
+#include <common.h>
+#include <time.h>
+#include <asm/io.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/sys_proto.h>
+
+/* Maximum fixed count */
+#if defined(CONFIG_MX23)
+#define TIMER_LOAD_VAL 0xffff
+#elif defined(CONFIG_MX28)
+#define TIMER_LOAD_VAL 0xffffffff
+#endif
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define timestamp (gd->arch.tbl)
+#define lastdec (gd->arch.lastinc)
+
+/*
+ * This driver uses 1kHz clock source.
+ */
+#define	MXS_INCREMENTER_HZ		1000
+
+static inline unsigned long tick_to_time(unsigned long tick)
+{
+	return tick / (MXS_INCREMENTER_HZ / CONFIG_SYS_HZ);
+}
+
+static inline unsigned long time_to_tick(unsigned long time)
+{
+	return time * (MXS_INCREMENTER_HZ / CONFIG_SYS_HZ);
+}
+
+/* Calculate how many ticks happen in "us" microseconds */
+static inline unsigned long us_to_tick(unsigned long us)
+{
+	return (us * MXS_INCREMENTER_HZ) / 1000000;
+}
+
+int timer_init(void)
+{
+	struct mxs_timrot_regs *timrot_regs =
+		(struct mxs_timrot_regs *)MXS_TIMROT_BASE;
+
+	/* Reset Timers and Rotary Encoder module */
+	mxs_reset_block(&timrot_regs->hw_timrot_rotctrl_reg);
+
+	/* Set fixed_count to 0 */
+#if defined(CONFIG_MX23)
+	writel(0, &timrot_regs->hw_timrot_timcount0);
+#elif defined(CONFIG_MX28)
+	writel(0, &timrot_regs->hw_timrot_fixed_count0);
+#endif
+
+	/* Set UPDATE bit and 1Khz frequency */
+	writel(TIMROT_TIMCTRLn_UPDATE | TIMROT_TIMCTRLn_RELOAD |
+		TIMROT_TIMCTRLn_SELECT_1KHZ_XTAL,
+		&timrot_regs->hw_timrot_timctrl0);
+
+	/* Set fixed_count to maximal value */
+#if defined(CONFIG_MX23)
+	writel(TIMER_LOAD_VAL - 1, &timrot_regs->hw_timrot_timcount0);
+#elif defined(CONFIG_MX28)
+	writel(TIMER_LOAD_VAL, &timrot_regs->hw_timrot_fixed_count0);
+#endif
+
+	return 0;
+}
+
+unsigned long long get_ticks(void)
+{
+	struct mxs_timrot_regs *timrot_regs =
+		(struct mxs_timrot_regs *)MXS_TIMROT_BASE;
+	uint32_t now;
+
+	/* Current tick value */
+#if defined(CONFIG_MX23)
+	/* Upper bits are the valid ones. */
+	now = readl(&timrot_regs->hw_timrot_timcount0) >>
+		TIMROT_RUNNING_COUNTn_RUNNING_COUNT_OFFSET;
+#elif defined(CONFIG_MX28)
+	now = readl(&timrot_regs->hw_timrot_running_count0);
+#else
+#error "Don't know how to read timrot_regs"
+#endif
+
+	if (lastdec >= now) {
+		/*
+		 * normal mode (non roll)
+		 * move stamp forward with absolut diff ticks
+		 */
+		timestamp += (lastdec - now);
+	} else {
+		/* we have rollover of decrementer */
+		timestamp += (TIMER_LOAD_VAL - now) + lastdec;
+
+	}
+	lastdec = now;
+
+	return timestamp;
+}
+
+ulong get_timer(ulong base)
+{
+	return tick_to_time(get_ticks()) - base;
+}
+
+/* We use the HW_DIGCTL_MICROSECONDS register for sub-millisecond timer. */
+#define	MXS_HW_DIGCTL_MICROSECONDS	0x8001c0c0
+
+void __udelay(unsigned long usec)
+{
+	uint32_t old, new, incr;
+	uint32_t counter = 0;
+
+	old = readl(MXS_HW_DIGCTL_MICROSECONDS);
+
+	while (counter < usec) {
+		new = readl(MXS_HW_DIGCTL_MICROSECONDS);
+
+		/* Check if the timer wrapped. */
+		if (new < old) {
+			incr = 0xffffffff - old;
+			incr += new;
+		} else {
+			incr = new - old;
+		}
+
+		/*
+		 * Check if we are close to the maximum time and the counter
+		 * would wrap if incremented. If that's the case, break out
+		 * from the loop as the requested delay time passed.
+		 */
+		if (counter + incr < counter)
+			break;
+
+		counter += incr;
+		old = new;
+	}
+}
+
+ulong get_tbclk(void)
+{
+	return MXS_INCREMENTER_HZ;
+}