serial: add LPC32X0 high-speed UART devices support

This change adds an implementation of high-speed UART found on NXP
LPC32X0 SoCs. Such UARTs are enumerated as UART1, UART2 and UART7.

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Acked-by: Marek Vasut <marek.vasut@gmail.com>

arch/arm/include/asm/arch-lpc32xx/uart.h

@@ -22,6 +22,66 @@
 
 #include <asm/types.h>
 
+/* 14-clock UART Registers */
+struct hsuart_regs {
+	union {
+		u32 rx;		/* Receiver FIFO		*/
+		u32 tx;		/* Transmitter FIFO		*/
+	};
+	u32 level;		/* FIFO Level Register		*/
+	u32 iir;		/* Interrupt ID Register	*/
+	u32 ctrl;		/* Control Register		*/
+	u32 rate;		/* Rate Control Register	*/
+};
+
+/* 14-clock UART Receiver FIFO Register bits */
+#define HSUART_RX_BREAK			(1 << 10)
+#define HSUART_RX_ERROR			(1 << 9)
+#define HSUART_RX_EMPTY			(1 << 8)
+#define HSUART_RX_DATA			(0xff << 0)
+
+/* 14-clock UART Level Register bits */
+#define HSUART_LEVEL_TX			(0xff << 8)
+#define HSUART_LEVEL_RX			(0xff << 0)
+
+/* 14-clock UART Interrupt Identification Register bits */
+#define HSUART_IIR_TX_INT_SET		(1 << 6)
+#define HSUART_IIR_RX_OE		(1 << 5)
+#define HSUART_IIR_BRK			(1 << 4)
+#define HSUART_IIR_FE			(1 << 3)
+#define HSUART_IIR_RX_TIMEOUT		(1 << 2)
+#define HSUART_IIR_RX_TRIG		(1 << 1)
+#define HSUART_IIR_TX			(1 << 0)
+
+/* 14-clock UART Control Register bits */
+#define HSUART_CTRL_HRTS_INV		(1 << 21)
+#define HSUART_CTRL_HRTS_TRIG_48	(0x3 << 19)
+#define HSUART_CTRL_HRTS_TRIG_32	(0x2 << 19)
+#define HSUART_CTRL_HRTS_TRIG_16	(0x1 << 19)
+#define HSUART_CTRL_HRTS_TRIG_8		(0x0 << 19)
+#define HSUART_CTRL_HRTS_EN		(1 << 18)
+#define HSUART_CTRL_TMO_16		(0x3 << 16)
+#define HSUART_CTRL_TMO_8		(0x2 << 16)
+#define HSUART_CTRL_TMO_4		(0x1 << 16)
+#define HSUART_CTRL_TMO_DISABLED	(0x0 << 16)
+#define HSUART_CTRL_HCTS_INV		(1 << 15)
+#define HSUART_CTRL_HCTS_EN		(1 << 14)
+#define HSUART_CTRL_HSU_OFFSET(n)	((n) << 9)
+#define HSUART_CTRL_HSU_BREAK		(1 << 8)
+#define HSUART_CTRL_HSU_ERR_INT_EN	(1 << 7)
+#define HSUART_CTRL_HSU_RX_INT_EN	(1 << 6)
+#define HSUART_CTRL_HSU_TX_INT_EN	(1 << 5)
+#define HSUART_CTRL_HSU_RX_TRIG_48	(0x5 << 2)
+#define HSUART_CTRL_HSU_RX_TRIG_32	(0x4 << 2)
+#define HSUART_CTRL_HSU_RX_TRIG_16	(0x3 << 2)
+#define HSUART_CTRL_HSU_RX_TRIG_8	(0x2 << 2)
+#define HSUART_CTRL_HSU_RX_TRIG_4	(0x1 << 2)
+#define HSUART_CTRL_HSU_RX_TRIG_1	(0x0 << 2)
+#define HSUART_CTRL_HSU_TX_TRIG_16	(0x3 << 0)
+#define HSUART_CTRL_HSU_TX_TRIG_8	(0x2 << 0)
+#define HSUART_CTRL_HSU_TX_TRIG_4	(0x1 << 0)
+#define HSUART_CTRL_HSU_TX_TRIG_0	(0x0 << 0)
+
 /* UART Control Registers */
 struct uart_ctrl_regs {
 	u32 ctrl;		/* Control Register		*/

drivers/serial/Makefile

@@ -29,6 +29,7 @@ COBJS-$(CONFIG_ALTERA_UART) += altera_uart.o
 COBJS-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
 COBJS-$(CONFIG_ARM_DCC) += arm_dcc.o
 COBJS-$(CONFIG_ATMEL_USART) += atmel_usart.o
+COBJS-$(CONFIG_LPC32XX_HSUART) += lpc32xx_hsuart.o
 COBJS-$(CONFIG_MCFUART) += mcfuart.o
 COBJS-$(CONFIG_NS9750_UART) += ns9750_serial.o
 COBJS-$(CONFIG_OPENCORES_YANU) += opencores_yanu.o

drivers/serial/lpc32xx_hsuart.c

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2011 Vladimir Zapolskiy <vz@mleia.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
+ * MA 02110-1301, USA.
+ */
+
+#include <common.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/clk.h>
+#include <asm/arch/uart.h>
+#include <asm/io.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static struct hsuart_regs *hsuart = (struct hsuart_regs *)HS_UART_BASE;
+
+static void lpc32xx_hsuart_set_baudrate(void)
+{
+	u32 div;
+
+	/* UART rate = PERIPH_CLK / ((HSU_RATE + 1) x 14) */
+	div = (get_serial_clock() / 14 + gd->baudrate / 2) / gd->baudrate - 1;
+	if (div > 255)
+		div = 255;
+
+	writel(div, &hsuart->rate);
+}
+
+static int lpc32xx_hsuart_getc(void)
+{
+	while (!(readl(&hsuart->level) & HSUART_LEVEL_RX))
+		/* NOP */;
+
+	return readl(&hsuart->rx) & HSUART_RX_DATA;
+}
+
+static void lpc32xx_hsuart_putc(const char c)
+{
+	writel(c, &hsuart->tx);
+
+	/* Wait for character to be sent */
+	while (readl(&hsuart->level) & HSUART_LEVEL_TX)
+		/* NOP */;
+}
+
+static int lpc32xx_hsuart_tstc(void)
+{
+	if (readl(&hsuart->level) & HSUART_LEVEL_RX)
+		return 1;
+
+	return 0;
+}
+
+static void lpc32xx_hsuart_init(void)
+{
+	lpc32xx_hsuart_set_baudrate();
+
+	/* Disable hardware RTS and CTS flow control, set up RX and TX FIFO */
+	writel(HSUART_CTRL_TMO_16 | HSUART_CTRL_HSU_OFFSET(20) |
+	       HSUART_CTRL_HSU_RX_TRIG_32 | HSUART_CTRL_HSU_TX_TRIG_0,
+	       &hsuart->ctrl);
+}
+
+void serial_setbrg(void)
+{
+	return lpc32xx_hsuart_set_baudrate();
+}
+
+void serial_putc(const char c)
+{
+	lpc32xx_hsuart_putc(c);
+
+	/* If \n, also do \r */
+	if (c == '\n')
+		lpc32xx_hsuart_putc('\r');
+}
+
+int serial_getc(void)
+{
+	return lpc32xx_hsuart_getc();
+}
+
+void serial_puts(const char *s)
+{
+	while (*s)
+		serial_putc(*s++);
+}
+
+int serial_tstc(void)
+{
+	return lpc32xx_hsuart_tstc();
+}
+
+int serial_init(void)
+{
+	lpc32xx_hsuart_init();
+
+	return 0;
+}