serial: Add serial_mvebu_a3700 for Armada 3700 SoC

The Armada 3700's UART is a simple serial port. It has a 32 bytes
Tx FIFO and a 64 bytes Rx FIFO integrated. This patch adds support
for this UART including the DEBUG UART functions for very early
debug output.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Nadav Haklai <nadavh@marvell.com>
Cc: Kostya Porotchkin <kostap@marvell.com>
Cc: Wilson Ding <dingwei@marvell.com>
Cc: Victor Gu <xigu@marvell.com>
Cc: Hua Jing <jinghua@marvell.com>
Cc: Terry Zhou <bjzhou@marvell.com>
Cc: Hanna Hawa <hannah@marvell.com>
Cc: Haim Boot <hayim@marvell.com>

1 files changed, 175 insertions, 0 deletions

diff --git a/drivers/serial/serial_mvebu_a3700.c b/drivers/serial/serial_mvebu_a3700.c
new file mode 100644
index 0000000..192e79a
--- /dev/null
+++ b/drivers/serial/serial_mvebu_a3700.c
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2016 Stefan Roese <sr@denx.de>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <serial.h>
+#include <asm/io.h>
+
+struct mvebu_platdata {
+	void __iomem *base;
+};
+
+/*
+ * Register offset
+ */
+#define UART_RX_REG		0x00
+#define UART_TX_REG		0x04
+#define UART_CTRL_REG		0x08
+#define UART_STATUS_REG		0x0c
+#define UART_BAUD_REG		0x10
+#define UART_POSSR_REG		0x14
+
+#define UART_STATUS_RX_RDY	0x10
+#define UART_STATUS_TXFIFO_FULL	0x800
+
+#define UART_CTRL_RXFIFO_RESET	0x4000
+#define UART_CTRL_TXFIFO_RESET	0x8000
+
+#define CONFIG_UART_BASE_CLOCK	25804800
+
+static int mvebu_serial_putc(struct udevice *dev, const char ch)
+{
+	struct mvebu_platdata *plat = dev_get_platdata(dev);
+	void __iomem *base = plat->base;
+
+	while (readl(base + UART_STATUS_REG) & UART_STATUS_TXFIFO_FULL)
+		;
+
+	writel(ch, base + UART_TX_REG);
+
+	return 0;
+}
+
+static int mvebu_serial_getc(struct udevice *dev)
+{
+	struct mvebu_platdata *plat = dev_get_platdata(dev);
+	void __iomem *base = plat->base;
+
+	while (!(readl(base + UART_STATUS_REG) & UART_STATUS_RX_RDY))
+		;
+
+	return readl(base + UART_RX_REG) & 0xff;
+}
+
+static int mvebu_serial_pending(struct udevice *dev, bool input)
+{
+	struct mvebu_platdata *plat = dev_get_platdata(dev);
+	void __iomem *base = plat->base;
+
+	if (readl(base + UART_STATUS_REG) & UART_STATUS_RX_RDY)
+		return 1;
+
+	return 0;
+}
+
+static int mvebu_serial_setbrg(struct udevice *dev, int baudrate)
+{
+	struct mvebu_platdata *plat = dev_get_platdata(dev);
+	void __iomem *base = plat->base;
+
+	/*
+	 * Calculate divider
+	 * baudrate = clock / 16 / divider
+	 */
+	writel(CONFIG_UART_BASE_CLOCK / baudrate / 16, base + UART_BAUD_REG);
+
+	/*
+	 * Set Programmable Oversampling Stack to 0,
+	 * UART defaults to 16x scheme
+	 */
+	writel(0, base + UART_POSSR_REG);
+
+	return 0;
+}
+
+static int mvebu_serial_probe(struct udevice *dev)
+{
+	struct mvebu_platdata *plat = dev_get_platdata(dev);
+	void __iomem *base = plat->base;
+
+	/* reset FIFOs */
+	writel(UART_CTRL_RXFIFO_RESET | UART_CTRL_TXFIFO_RESET,
+	       base + UART_CTRL_REG);
+
+	/* No Parity, 1 Stop */
+	writel(0, base + UART_CTRL_REG);
+
+	return 0;
+}
+
+static int mvebu_serial_ofdata_to_platdata(struct udevice *dev)
+{
+	struct mvebu_platdata *plat = dev_get_platdata(dev);
+
+	plat->base = dev_get_addr_ptr(dev);
+
+	return 0;
+}
+
+static const struct dm_serial_ops mvebu_serial_ops = {
+	.putc = mvebu_serial_putc,
+	.pending = mvebu_serial_pending,
+	.getc = mvebu_serial_getc,
+	.setbrg = mvebu_serial_setbrg,
+};
+
+static const struct udevice_id mvebu_serial_ids[] = {
+	{ .compatible = "marvell,armada-3700-uart" },
+	{ }
+};
+
+U_BOOT_DRIVER(serial_mvebu) = {
+	.name	= "serial_mvebu",
+	.id	= UCLASS_SERIAL,
+	.of_match = mvebu_serial_ids,
+	.ofdata_to_platdata = mvebu_serial_ofdata_to_platdata,
+	.platdata_auto_alloc_size = sizeof(struct mvebu_platdata),
+	.probe	= mvebu_serial_probe,
+	.ops	= &mvebu_serial_ops,
+	.flags	= DM_FLAG_PRE_RELOC,
+};
+
+#ifdef CONFIG_DEBUG_MVEBU_A3700_UART
+
+#include <debug_uart.h>
+
+static inline void _debug_uart_init(void)
+{
+	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+	/* reset FIFOs */
+	writel(UART_CTRL_RXFIFO_RESET | UART_CTRL_TXFIFO_RESET,
+	       base + UART_CTRL_REG);
+
+	/* No Parity, 1 Stop */
+	writel(0, base + UART_CTRL_REG);
+
+	/*
+	 * Calculate divider
+	 * baudrate = clock / 16 / divider
+	 */
+	writel(CONFIG_UART_BASE_CLOCK / 115200 / 16, base + UART_BAUD_REG);
+
+	/*
+	 * Set Programmable Oversampling Stack to 0,
+	 * UART defaults to 16x scheme
+	 */
+	writel(0, base + UART_POSSR_REG);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+	void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE;
+
+	while (readl(base + UART_STATUS_REG) & UART_STATUS_TXFIFO_FULL)
+		;
+
+	writel(ch, base + UART_TX_REG);
+}
+
+DEBUG_UART_FUNCS
+#endif