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

source/bootloader/u-boot-2020.01/arch/arm/mach-zynq/timer.c

@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2017 Weidmüller Interface GmbH & Co. KG
+ * Stefan Herbrechtsmeier <stefan.herbrechtsmeier@weidmueller.com>
+ *
+ * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2011-2017 Xilinx, Inc. All rights reserved.
+ *
+ * (C) Copyright 2008
+ * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
+ *
+ * (C) Copyright 2004
+ * Philippe Robin, ARM Ltd. <philippe.robin@arm.com>
+ *
+ * (C) Copyright 2002-2004
+ * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
+ *
+ * (C) Copyright 2003
+ * Texas Instruments <www.ti.com>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Marius Groeger <mgroeger@sysgo.de>
+ *
+ * (C) Copyright 2002
+ * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
+ * Alex Zuepke <azu@sysgo.de>
+ */
+
+#include <clk.h>
+#include <common.h>
+#include <div64.h>
+#include <dm.h>
+#include <asm/io.h>
+#include <asm/arch/hardware.h>
+#include <asm/arch/clk.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct scu_timer {
+	u32 load; /* Timer Load Register */
+	u32 counter; /* Timer Counter Register */
+	u32 control; /* Timer Control Register */
+};
+
+static struct scu_timer *timer_base =
+			      (struct scu_timer *)ZYNQ_SCUTIMER_BASEADDR;
+
+#define SCUTIMER_CONTROL_PRESCALER_MASK	0x0000FF00 /* Prescaler */
+#define SCUTIMER_CONTROL_PRESCALER_SHIFT	8
+#define SCUTIMER_CONTROL_AUTO_RELOAD_MASK	0x00000002 /* Auto-reload */
+#define SCUTIMER_CONTROL_ENABLE_MASK		0x00000001 /* Timer enable */
+
+#define TIMER_LOAD_VAL 0xFFFFFFFF
+#define TIMER_PRESCALE 255
+
+int timer_init(void)
+{
+	const u32 emask = SCUTIMER_CONTROL_AUTO_RELOAD_MASK |
+			(TIMER_PRESCALE << SCUTIMER_CONTROL_PRESCALER_SHIFT) |
+			SCUTIMER_CONTROL_ENABLE_MASK;
+
+	struct udevice *dev;
+	struct clk clk;
+	int ret;
+
+	ret = uclass_get_device_by_driver(UCLASS_CLK,
+		DM_GET_DRIVER(zynq_clk), &dev);
+	if (ret)
+		return ret;
+
+	clk.id = cpu_6or4x_clk;
+	ret = clk_request(dev, &clk);
+	if (ret < 0)
+		return ret;
+
+	gd->cpu_clk = clk_get_rate(&clk);
+
+	clk_free(&clk);
+
+	gd->arch.timer_rate_hz = (gd->cpu_clk / 2) / (TIMER_PRESCALE + 1);
+
+	/* Load the timer counter register */
+	writel(0xFFFFFFFF, &timer_base->load);
+
+	/*
+	 * Start the A9Timer device
+	 * Enable Auto reload mode, Clear prescaler control bits
+	 * Set prescaler value, Enable the decrementer
+	 */
+	clrsetbits_le32(&timer_base->control, SCUTIMER_CONTROL_PRESCALER_MASK,
+								emask);
+
+	/* Reset time */
+	gd->arch.lastinc = readl(&timer_base->counter) /
+				(gd->arch.timer_rate_hz / CONFIG_SYS_HZ);
+	gd->arch.tbl = 0;
+
+	return 0;
+}
+
+/*
+ * This function is derived from PowerPC code (timebase clock frequency).
+ * On ARM it returns the number of timer ticks per second.
+ */
+ulong get_tbclk(void)
+{
+	return gd->arch.timer_rate_hz;
+}