[U-Boot] [PATCH v3 5/6] arm: mvf600: Add uart support for Vybrid MVF600

[Alison Wang]

This patch adds lpuart support for Vybrid MVF600 platform.

Signed-off-by: TsiChung Liew <tsicliew at gmail.com>
Signed-off-by: Alison Wang <b18965 at freescale.com>
---
Changes in v3:
- Move the structure definition to imx-regs.h

Changes in v2:
- Define C structures and access C structures to set/read registers
- Change the names to reuse this driver on other platforms

 drivers/serial/Makefile        |   1 +
 drivers/serial/serial_lpuart.c | 132 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 drivers/serial/serial_lpuart.c

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index fbc4e97..bb6559b 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -52,6 +52,7 @@ COBJS-$(CONFIG_XILINX_UARTLITE) += serial_xuartlite.o
 COBJS-$(CONFIG_SANDBOX_SERIAL) += sandbox.o
 COBJS-$(CONFIG_SCIF_CONSOLE) += serial_sh.o
 COBJS-$(CONFIG_ZYNQ_SERIAL) += serial_zynq.o
+COBJS-$(CONFIG_FSL_LPUART) += serial_lpuart.o
 
 ifndef CONFIG_SPL_BUILD
 COBJS-$(CONFIG_USB_TTY) += usbtty.o
diff --git a/drivers/serial/serial_lpuart.c b/drivers/serial/serial_lpuart.c
new file mode 100644
index 0000000..51d5666
--- /dev/null
+++ b/drivers/serial/serial_lpuart.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <common.h>
+#include <watchdog.h>
+#include <asm/io.h>
+#include <serial.h>
+#include <linux/compiler.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/clock.h>
+
+#define US1_TDRE        (1 << 7)
+#define US1_RDRF        (1 << 5)
+#define UC2_TE          (1 << 3)
+#define UC2_RE          (1 << 2)
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct lpuart_fsl *base = (struct lpuart_fsl *)LPUART_BASE;
+
+static void lpuart_serial_setbrg(void)
+{
+	u32 clk = mxc_get_clock(MXC_UART_CLK);
+	u16 sbr;
+
+	if (!gd->baudrate)
+		gd->baudrate = CONFIG_BAUDRATE;
+
+	sbr = (u16)(clk / (16 * gd->baudrate));
+	/* place adjustment later - n/32 BRFA */
+
+	__raw_writeb(sbr >> 8, &base->ubdh);
+	__raw_writeb(sbr & 0xff, &base->ubdl);
+}
+
+static int lpuart_serial_getc(void)
+{
+	u8 status;
+
+	while (!(__raw_readb(&base->us1) & US1_RDRF))
+		WATCHDOG_RESET();
+
+	status = __raw_readb(&base->us1);
+	status |= US1_RDRF;
+	__raw_writeb(status, &base->us1);
+
+	return __raw_readb(&base->ud);
+}
+
+static void lpuart_serial_putc(const char c)
+{
+	if (c == '\n')
+		serial_putc('\r');
+
+	while (!(__raw_readb(&base->us1) & US1_TDRE))
+		WATCHDOG_RESET();
+
+	__raw_writeb(c, &base->ud);
+}
+
+/*
+ * Test whether a character is in the RX buffer
+ */
+static int lpuart_serial_tstc(void)
+{
+	if (__raw_readb(&base->urcfifo) == 0)
+		return 0;
+
+	return 1;
+}
+
+/*
+ * Initialise the serial port with the given baudrate. The settings
+ * are always 8 data bits, no parity, 1 stop bit, no start bits.
+ */
+static int lpuart_serial_init(void)
+{
+	u8 ctrl;
+
+	ctrl = __raw_readb(&base->uc2);
+	ctrl &= ~UC2_RE;
+	ctrl &= ~UC2_TE;
+	__raw_writeb(ctrl, &base->uc2);
+
+	__raw_writeb(0, &base->umodem);
+	__raw_writeb(0, &base->uc1);
+
+	/* provide data bits, parity, stop bit, etc */
+
+	serial_setbrg();
+
+	__raw_writeb(UC2_RE | UC2_TE, &base->uc2);
+
+	return 0;
+}
+
+static struct serial_device lpuart_serial_drv = {
+	.name = "lpuart_serial",
+	.start = lpuart_serial_init,
+	.stop = NULL,
+	.setbrg = lpuart_serial_setbrg,
+	.putc = lpuart_serial_putc,
+	.puts = default_serial_puts,
+	.getc = lpuart_serial_getc,
+	.tstc = lpuart_serial_tstc,
+};
+
+void lpuart_serial_initialize(void)
+{
+	serial_register(&lpuart_serial_drv);
+}
+
+__weak struct serial_device *default_serial_console(void)
+{
+	return &lpuart_serial_drv;
+}
-- 
1.8.0