Initial import

1 files changed, 217 insertions, 0 deletions

diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
new file mode 100644
index 000000000..6dc471e30
--- /dev/null
+++ b/drivers/tty/serial/earlycon.c
@@ -0,0 +1,217 @@
+/*
+ * Copyright (C) 2014 Linaro Ltd.
+ * Author: Rob Herring <robh@kernel.org>
+ *
+ * Based on 8250 earlycon:
+ * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
+ *	Bjorn Helgaas <bjorn.helgaas@hp.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.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/console.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/serial_core.h>
+#include <linux/sizes.h>
+#include <linux/mod_devicetable.h>
+
+#ifdef CONFIG_FIX_EARLYCON_MEM
+#include <asm/fixmap.h>
+#endif
+
+#include <asm/serial.h>
+
+static struct console early_con = {
+	.name =		"uart", /* 8250 console switch requires this name */
+	.flags =	CON_PRINTBUFFER | CON_BOOT,
+	.index =	-1,
+};
+
+static struct earlycon_device early_console_dev = {
+	.con = &early_con,
+};
+
+extern struct earlycon_id __earlycon_table[];
+static const struct earlycon_id __earlycon_table_sentinel
+	__used __section(__earlycon_table_end);
+
+static const struct of_device_id __earlycon_of_table_sentinel
+	__used __section(__earlycon_of_table_end);
+
+static void __iomem * __init earlycon_map(unsigned long paddr, size_t size)
+{
+	void __iomem *base;
+#ifdef CONFIG_FIX_EARLYCON_MEM
+	set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr & PAGE_MASK);
+	base = (void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
+	base += paddr & ~PAGE_MASK;
+#else
+	base = ioremap(paddr, size);
+#endif
+	if (!base)
+		pr_err("%s: Couldn't map 0x%llx\n", __func__,
+		       (unsigned long long)paddr);
+
+	return base;
+}
+
+static int __init parse_options(struct earlycon_device *device, char *options)
+{
+	struct uart_port *port = &device->port;
+	int length;
+	unsigned long addr;
+
+	if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
+		return -EINVAL;
+
+	switch (port->iotype) {
+	case UPIO_MEM32:
+		port->regshift = 2;	/* fall-through */
+	case UPIO_MEM:
+		port->mapbase = addr;
+		break;
+	case UPIO_PORT:
+		port->iobase = addr;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (options) {
+		device->baud = simple_strtoul(options, NULL, 0);
+		length = min(strcspn(options, " ") + 1,
+			     (size_t)(sizeof(device->options)));
+		strlcpy(device->options, options, length);
+	}
+
+	if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM32)
+		pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n",
+			(port->iotype == UPIO_MEM32) ? "32" : "",
+			(unsigned long long)port->mapbase,
+			device->options);
+	else
+		pr_info("Early serial console at I/O port 0x%lx (options '%s')\n",
+			port->iobase,
+			device->options);
+
+	return 0;
+}
+
+static int __init register_earlycon(char *buf, const struct earlycon_id *match)
+{
+	int err;
+	struct uart_port *port = &early_console_dev.port;
+
+	/* On parsing error, pass the options buf to the setup function */
+	if (buf && !parse_options(&early_console_dev, buf))
+		buf = NULL;
+
+	port->uartclk = BASE_BAUD * 16;
+	if (port->mapbase)
+		port->membase = earlycon_map(port->mapbase, 64);
+
+	early_console_dev.con->data = &early_console_dev;
+	err = match->setup(&early_console_dev, buf);
+	if (err < 0)
+		return err;
+	if (!early_console_dev.con->write)
+		return -ENODEV;
+
+	register_console(early_console_dev.con);
+	return 0;
+}
+
+/**
+ *	setup_earlycon - match and register earlycon console
+ *	@buf:	earlycon param string
+ *
+ *	Registers the earlycon console matching the earlycon specified
+ *	in the param string @buf. Acceptable param strings are of the form
+ *	   <name>,io|mmio|mmio32,<addr>,<options>
+ *	   <name>,0x<addr>,<options>
+ *	   <name>,<options>
+ *	   <name>
+ *
+ *	Only for the third form does the earlycon setup() method receive the
+ *	<options> string in the 'options' parameter; all other forms set
+ *	the parameter to NULL.
+ *
+ *	Returns 0 if an attempt to register the earlycon was made,
+ *	otherwise negative error code
+ */
+int __init setup_earlycon(char *buf)
+{
+	const struct earlycon_id *match;
+
+	if (!buf || !buf[0])
+		return -EINVAL;
+
+	if (early_con.flags & CON_ENABLED)
+		return -EALREADY;
+
+	for (match = __earlycon_table; match->name[0]; match++) {
+		size_t len = strlen(match->name);
+
+		if (strncmp(buf, match->name, len))
+			continue;
+
+		if (buf[len]) {
+			if (buf[len] != ',')
+				continue;
+			buf += len + 1;
+		} else
+			buf = NULL;
+
+		return register_earlycon(buf, match);
+	}
+
+	return -ENOENT;
+}
+
+/* early_param wrapper for setup_earlycon() */
+static int __init param_setup_earlycon(char *buf)
+{
+	int err;
+
+	/*
+	 * Just 'earlycon' is a valid param for devicetree earlycons;
+	 * don't generate a warning from parse_early_params() in that case
+	 */
+	if (!buf || !buf[0])
+		return 0;
+
+	err = setup_earlycon(buf);
+	if (err == -ENOENT || err == -EALREADY)
+		return 0;
+	return err;
+}
+early_param("earlycon", param_setup_earlycon);
+
+int __init of_setup_earlycon(unsigned long addr,
+			     int (*setup)(struct earlycon_device *, const char *))
+{
+	int err;
+	struct uart_port *port = &early_console_dev.port;
+
+	port->iotype = UPIO_MEM;
+	port->mapbase = addr;
+	port->uartclk = BASE_BAUD * 16;
+	port->membase = earlycon_map(addr, SZ_4K);
+
+	early_console_dev.con->data = &early_console_dev;
+	err = setup(&early_console_dev, NULL);
+	if (err < 0)
+		return err;
+	if (!early_console_dev.con->write)
+		return -ENODEV;
+
+
+	register_console(early_console_dev.con);
+	return 0;
+}