--- /dev/null
+/*
+ * Copyright (C) 2011 Freescale Semiconductor, Inc. All Rights Reserved.
+ *
+ * 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.
+ */
+
+/*!
+ * @file drivers/serial/mxc_uart_early.c
+ *
+ * @brief Driver for the Freescale Semiconductor MXC serial ports based on
+ * drivers/char/8250_early.c,
+ * Copyright 2004 Hewlett-Packard Development Company,
+ * L.P.by Bjorn Helgaasby.
+ *
+ * Early serial console for MXC UARTS.
+ *
+ * This is for use before the serial driver has initialized, in
+ * particular, before the UARTs have been discovered and named.
+ * Instead of specifying the console device as, e.g., "ttymxc0",
+ * we locate the device directly by its MMIO or I/O port address.
+ *
+ * The user can specify the device directly, e.g.,
+ * console=mxcuart,0x43f90000,115200n8
+ * or platform code can call early_uart_console_init() to set
+ * the early UART device.
+ *
+ * After the normal serial driver starts, we try to locate the
+ * matching ttymxc device and start a console there.
+ */
+
+/*
+ * Include Files
+ */
+
+#include <linux/tty.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/console.h>
+#include <linux/serial_core.h>
+#include <linux/serial_reg.h>
+#include <linux/clk.h>
+#include <mach/mxc_uart.h>
+
+struct mxc_early_uart_device {
+ struct uart_port port;
+ char options[16]; /* e.g., 115200n8 */
+ unsigned int baud;
+ struct clk *clk;
+};
+static struct mxc_early_uart_device mxc_early_device __initdata;
+
+/*
+ * Write out a character once the UART is ready
+ */
+static void __init mxcuart_console_write_char(struct uart_port *port, int ch)
+{
+ unsigned int status;
+
+ do {
+ status = readl(port->membase + MXC_UARTUSR2);
+ } while ((status & MXC_UARTUSR2_TXFE) == 0);
+ writel(ch, port->membase + MXC_UARTUTXD);
+}
+
+/*!
+ * This function is called to write the console messages through the UART port.
+ *
+ * @param co the console structure
+ * @param s the log message to be written to the UART
+ * @param count length of the message
+ */
+void __init early_mxcuart_console_write(struct console *co, const char *s,
+ u_int count)
+{
+ struct uart_port *port = &mxc_early_device.port;
+ unsigned int status, oldcr1, oldcr2, oldcr3, cr2, cr3;
+
+ /*
+ * First save the control registers and then disable the interrupts
+ */
+ oldcr1 = readl(port->membase + MXC_UARTUCR1);
+ oldcr2 = readl(port->membase + MXC_UARTUCR2);
+ oldcr3 = readl(port->membase + MXC_UARTUCR3);
+ cr2 =
+ oldcr2 & ~(MXC_UARTUCR2_ATEN | MXC_UARTUCR2_RTSEN |
+ MXC_UARTUCR2_ESCI);
+ cr3 =
+ oldcr3 & ~(MXC_UARTUCR3_DCD | MXC_UARTUCR3_RI |
+ MXC_UARTUCR3_DTRDEN);
+ writel(MXC_UARTUCR1_UARTEN, port->membase + MXC_UARTUCR1);
+ writel(cr2, port->membase + MXC_UARTUCR2);
+ writel(cr3, port->membase + MXC_UARTUCR3);
+
+ /* Transmit string */
+ uart_console_write(port, s, count, mxcuart_console_write_char);
+
+ /*
+ * Finally, wait for the transmitter to become empty
+ */
+ do {
+ status = readl(port->membase + MXC_UARTUSR2);
+ } while (!(status & MXC_UARTUSR2_TXDC));
+
+ /*
+ * Restore the control registers
+ */
+ writel(oldcr1, port->membase + MXC_UARTUCR1);
+ writel(oldcr2, port->membase + MXC_UARTUCR2);
+ writel(oldcr3, port->membase + MXC_UARTUCR3);
+}
+
+static unsigned int __init probe_baud(struct uart_port *port)
+{
+ /* FIXME Return Default Baud Rate */
+ return 115200;
+}
+
+static int __init mxc_early_uart_setup(struct console *console, char *options)
+{
+ struct mxc_early_uart_device *device = &mxc_early_device;
+ struct uart_port *port = &device->port;
+ int length;
+
+ if (device->port.membase || device->port.iobase)
+ return -ENODEV;
+
+ /* Enable Early MXC UART Clock */
+ clk_enable(device->clk);
+
+ port->uartclk = 5600000;
+ port->iotype = UPIO_MEM;
+ port->membase = ioremap(port->mapbase, SZ_4K);
+
+ if (options) {
+ device->baud = simple_strtoul(options, NULL, 0);
+ length = min(strlen(options), sizeof(device->options));
+ strncpy(device->options, options, length);
+ } else {
+ device->baud = probe_baud(port);
+ snprintf(device->options, sizeof(device->options), "%u",
+ device->baud);
+ }
+ printk(KERN_INFO
+ "MXC_Early serial console at MMIO 0x%x (options '%s')\n",
+ port->mapbase, device->options);
+ return 0;
+}
+
+static struct console mxc_early_uart_console __initdata = {
+ .name = "ttymxc",
+ .write = early_mxcuart_console_write,
+ .setup = mxc_early_uart_setup,
+ .flags = CON_PRINTBUFFER | CON_BOOT,
+ .index = -1,
+};
+
+int __init mxc_early_serial_console_init(unsigned long base, struct clk *clk)
+{
+ mxc_early_device.clk = clk;
+ mxc_early_device.port.mapbase = base;
+
+ register_console(&mxc_early_uart_console);
+ return 0;
+}
+
+int __init mxc_early_uart_console_disable(void)
+{
+ struct mxc_early_uart_device *device = &mxc_early_device;
+ struct uart_port *port = &device->port;
+
+ if (mxc_early_uart_console.index >= 0) {
+ iounmap(port->membase);
+ clk_disable(device->clk);
+ clk_put(device->clk);
+ }
+ return 0;
+}
+late_initcall(mxc_early_uart_console_disable);
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