riscv: Move Andes PLMT driver to drivers/timer

This is a regular timer driver, and should live with the other timer
drivers.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Rick Chen <rick@andestech.com>

drivers/timer/Kconfig

@@ -53,6 +53,13 @@ config ALTERA_TIMER
 	  Select this to enable a timer for Altera devices. Please find
 	  details on the "Embedded Peripherals IP User Guide" of Altera.
 
+config ANDES_PLMT
+	bool
+	depends on RISCV_MMODE || SPL_RISCV_MMODE
+	help
+	  The Andes PLMT block holds memory-mapped mtime register
+	  associated with timer tick.
+
 config ARC_TIMER
 	bool "ARC timer support"
 	depends on TIMER && ARC && CLK

drivers/timer/Makefile

@@ -5,6 +5,7 @@
 obj-y += timer-uclass.o
 obj-$(CONFIG_AG101P_TIMER) += ag101p_timer.o
 obj-$(CONFIG_ALTERA_TIMER)	+= altera_timer.o
+obj-$(CONFIG_ANDES_PLMT) += andes_plmt_timer.o
 obj-$(CONFIG_ARC_TIMER)	+= arc_timer.o
 obj-$(CONFIG_AST_TIMER)	+= ast_timer.o
 obj-$(CONFIG_ATCPIT100_TIMER) += atcpit100_timer.o

drivers/timer/andes_plmt_timer.c

@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019, Rick Chen <rick@andestech.com>
+ * Copyright (C) 2020, Sean Anderson <seanga2@gmail.com>
+ *
+ * U-Boot syscon driver for Andes's Platform Level Machine Timer (PLMT).
+ * The PLMT block holds memory-mapped mtime register
+ * associated with timer tick.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <timer.h>
+#include <asm/io.h>
+#include <linux/err.h>
+
+/* mtime register */
+#define MTIME_REG(base)			((ulong)(base))
+
+static u64 andes_plmt_get_count(struct udevice *dev)
+{
+	return readq((void __iomem *)MTIME_REG(dev->priv));
+}
+
+static const struct timer_ops andes_plmt_ops = {
+	.get_count = andes_plmt_get_count,
+};
+
+static int andes_plmt_probe(struct udevice *dev)
+{
+	dev->priv = dev_read_addr_ptr(dev);
+	if (!dev->priv)
+		return -EINVAL;
+
+	return timer_timebase_fallback(dev);
+}
+
+static const struct udevice_id andes_plmt_ids[] = {
+	{ .compatible = "riscv,plmt0" },
+	{ }
+};
+
+U_BOOT_DRIVER(andes_plmt) = {
+	.name		= "andes_plmt",
+	.id		= UCLASS_TIMER,
+	.of_match	= andes_plmt_ids,
+	.ops		= &andes_plmt_ops,
+	.probe		= andes_plmt_probe,
+	.flags		= DM_FLAG_PRE_RELOC,
+};