arm: add Debug Communications Channel serial driver support

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

drivers/serial/Kconfig

@@ -1,5 +1,9 @@
 menu "serial drivers                "
 
+config DRIVER_SERIAL_ARM_DCC
+	depends on ARM
+	bool "ARM Debug Communications Channel (DCC) serial driver"
+
 config DRIVER_SERIAL_IMX
 	depends on ARCH_IMX
 	default y

drivers/serial/Makefile

@@ -5,6 +5,7 @@
 # serial_pl010.o
 # serial_pl011.o
 # serial_xuartlite.o
+obj-$(CONFIG_DRIVER_SERIAL_ARM_DCC)		+= arm_dcc.o
 obj-$(CONFIG_DRIVER_SERIAL_IMX)			+= serial_imx.o
 obj-$(CONFIG_DRIVER_SERIAL_ATMEL)		+= atmel.o
 obj-$(CONFIG_DRIVER_SERIAL_NETX)		+= serial_netx.o

drivers/serial/arm_dcc.c

@@ -0,0 +1,169 @@
+/*
+ * Copyright (C) 2004-2007 ARM Limited.
+ * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * 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
+ *
+ * As a special exception, if other files instantiate templates or use macros
+ * or inline functions from this file, or you compile this file and link it
+ * with other works to produce a work based on this file, this file does not
+ * by itself cause the resulting work to be covered by the GNU General Public
+ * License. However the source code for this file must still be made available
+ * in accordance with section (3) of the GNU General Public License.
+
+ * This exception does not invalidate any other reasons why a work based on
+ * this file might be covered by the GNU General Public License.
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+
+#if defined(CONFIG_CPU_V6)
+/*
+ * ARMV6
+ */
+#define DCC_RBIT	(1 << 30)
+#define DCC_WBIT	(1 << 29)
+
+#define write_dcc(x)	\
+		__asm__ volatile ("mcr p14, 0, %0, c0, c5, 0\n" : : "r" (x))
+
+#define read_dcc(x)	\
+		__asm__ volatile ("mrc p14, 0, %0, c0, c5, 0\n" : "=r" (x))
+
+#define status_dcc(x)	\
+		__asm__ volatile ("mrc p14, 0, %0, c0, c1, 0\n" : "=r" (x))
+
+#elif defined(CONFIG_CPU_XSCALE)
+/*
+ * XSCALE
+ */
+#define DCC_RBIT	(1 << 31)
+#define DCC_WBIT	(1 << 28)
+
+#define write_dcc(x)	\
+		__asm__ volatile ("mcr p14, 0, %0, c8, c0, 0\n" : : "r" (x))
+
+#define read_dcc(x)	\
+		__asm__ volatile ("mrc p14, 0, %0, c9, c0, 0\n" : "=r" (x))
+
+#define status_dcc(x)	\
+		__asm__ volatile ("mrc p14, 0, %0, c14, c0, 0\n" : "=r" (x))
+
+#else
+#define DCC_RBIT	(1 << 0)
+#define DCC_WBIT	(1 << 1)
+
+#define write_dcc(x)	\
+		__asm__ volatile ("mcr p14, 0, %0, c1, c0, 0\n" : : "r" (x))
+
+#define read_dcc(x)	\
+		__asm__ volatile ("mrc p14, 0, %0, c1, c0, 0\n" : "=r" (x))
+
+#define status_dcc(x)	\
+		__asm__ volatile ("mrc p14, 0, %0, c0, c0, 0\n" : "=r" (x))
+
+#endif
+
+#define can_read_dcc(x)	do {	\
+		status_dcc(x);	\
+		x &= DCC_RBIT;	\
+		} while (0);
+
+#define can_write_dcc(x) do {	\
+		status_dcc(x);	\
+		x &= DCC_WBIT;	\
+		x = (x == 0);	\
+		} while (0);
+
+#define TIMEOUT_COUNT 0x4000000
+
+static int arm_dcc_getc(struct console_device *cdev)
+{
+	int c;
+	register unsigned int reg;
+
+	do {
+		can_read_dcc(reg);
+	} while (!reg);
+	read_dcc(c);
+
+	return c;
+}
+
+static void arm_dcc_putc(struct console_device *cdev, char c)
+{
+	register unsigned int reg;
+	unsigned int timeout_count = TIMEOUT_COUNT;
+
+	while (--timeout_count) {
+		can_write_dcc(reg);
+		if (reg)
+			break;
+	}
+	if (timeout_count == 0)
+		return;
+	else
+		write_dcc(c);
+}
+
+static int arm_dcc_tstc(struct console_device *cdev)
+{
+	register unsigned int reg;
+
+	can_read_dcc(reg);
+
+	return reg;
+}
+
+static struct console_device arm_dcc_dev;
+
+static int arm_dcc_probe(struct device_d *dev)
+{
+	struct console_device *cdev;
+
+	cdev = &arm_dcc_dev;
+	dev->type_data = cdev;
+	cdev->dev = dev;
+	cdev->f_caps = CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR;
+	cdev->tstc = arm_dcc_tstc;
+	cdev->putc = arm_dcc_putc;
+	cdev->getc = arm_dcc_getc;
+
+	/* Enable UART */
+
+	console_register(cdev);
+
+	return 0;
+}
+
+static struct driver_d arm_dcc_driver = {
+	.name	= "arm_dcc",
+	.probe	= arm_dcc_probe,
+};
+
+static struct device_d arm_dcc_device = {
+	.name	= "arm_dcc",
+	.size	= 4096,
+};
+
+static int arm_dcc_init(void)
+{
+	register_device(&arm_dcc_device);
+	register_driver(&arm_dcc_driver);
+	return 0;
+}
+
+console_initcall(arm_dcc_init);