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

source/bootloader/u-boot-2020.01/drivers/timer/riscv_timer.c

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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ *
+ * RISC-V privileged architecture defined generic timer driver
+ *
+ * This driver relies on RISC-V platform codes to provide the essential API
+ * riscv_get_time() which is supposed to return the timer counter as defined
+ * by the RISC-V privileged architecture spec.
+ *
+ * This driver can be used in both M-mode and S-mode U-Boot.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
+#include <asm/io.h>
+
+/**
+ * riscv_get_time() - get the timer counter
+ *
+ * Platform codes should provide this API in order to make this driver function.
+ *
+ * @time:	the 64-bit timer count  as defined by the RISC-V privileged
+ *		architecture spec.
+ * @return:	0 on success, -ve on error.
+ */
+extern int riscv_get_time(u64 *time);
+
+static int riscv_timer_get_count(struct udevice *dev, u64 *count)
+{
+	return riscv_get_time(count);
+}
+
+static int riscv_timer_probe(struct udevice *dev)
+{
+	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+
+	/* clock frequency was passed from the cpu driver as driver data */
+	uc_priv->clock_rate = dev->driver_data;
+
+	return 0;
+}
+
+static const struct timer_ops riscv_timer_ops = {
+	.get_count = riscv_timer_get_count,
+};
+
+U_BOOT_DRIVER(riscv_timer) = {
+	.name = "riscv_timer",
+	.id = UCLASS_TIMER,
+	.probe = riscv_timer_probe,
+	.ops = &riscv_timer_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};