[PATCH v2 3/7] tty/serial: convert 8250 to generic earlycon

[Rob Herring <robherring2@gmail.com>]

From: Rob Herring <robh@kernel.org>

With the generic earlycon infrastructure in place, convert the 8250
early console to use it.

Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
---
 drivers/tty/serial/8250/8250_early.c | 138 ++++-------------------------------
 drivers/tty/serial/8250/Kconfig      |   1 +
 2 files changed, 16 insertions(+), 123 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_early.c b/drivers/tty/serial/8250/8250_early.c
index c100d63..e83c9db 100644
--- a/drivers/tty/serial/8250/8250_early.c
+++ b/drivers/tty/serial/8250/8250_early.c
@@ -35,18 +35,8 @@
 #include <linux/serial_8250.h>
 #include <asm/io.h>
 #include <asm/serial.h>
-#ifdef CONFIG_FIX_EARLYCON_MEM
-#include <asm/pgtable.h>
-#include <asm/fixmap.h>
-#endif
 
-struct early_serial8250_device {
-	struct uart_port port;
-	char options[16];		/* e.g., 115200n8 */
-	unsigned int baud;
-};
-
-static struct early_serial8250_device early_device;
+static struct earlycon_device *early_device;
 
 unsigned int __weak __init serial8250_early_in(struct uart_port *port, int offset)
 {
@@ -100,7 +90,7 @@ static void __init serial_putc(struct uart_port *port, int c)
 static void __init early_serial8250_write(struct console *console,
 					const char *s, unsigned int count)
 {
-	struct uart_port *port = &early_device.port;
+	struct uart_port *port = &early_device->port;
 	unsigned int ier;
 
 	/* Save the IER and disable interrupts */
@@ -129,7 +119,7 @@ static unsigned int __init probe_baud(struct uart_port *port)
 	return (port->uartclk / 16) / quot;
 }
 
-static void __init init_port(struct early_serial8250_device *device)
+static void __init init_port(struct earlycon_device *device)
 {
 	struct uart_port *port = &device->port;
 	unsigned int divisor;
@@ -148,128 +138,32 @@ static void __init init_port(struct early_serial8250_device *device)
 	serial8250_early_out(port, UART_LCR, c & ~UART_LCR_DLAB);
 }
 
-static int __init parse_options(struct early_serial8250_device *device,
-								char *options)
-{
-	struct uart_port *port = &device->port;
-	int mmio, mmio32, length;
-
-	if (!options)
-		return -ENODEV;
-
-	port->uartclk = BASE_BAUD * 16;
-
-	mmio = !strncmp(options, "mmio,", 5);
-	mmio32 = !strncmp(options, "mmio32,", 7);
-	if (mmio || mmio32) {
-		port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32);
-		port->mapbase = simple_strtoul(options + (mmio ? 5 : 7),
-					       &options, 0);
-		if (mmio32)
-			port->regshift = 2;
-#ifdef CONFIG_FIX_EARLYCON_MEM
-		set_fixmap_nocache(FIX_EARLYCON_MEM_BASE,
-					port->mapbase & PAGE_MASK);
-		port->membase =
-			(void __iomem *)__fix_to_virt(FIX_EARLYCON_MEM_BASE);
-		port->membase += port->mapbase & ~PAGE_MASK;
-#else
-		port->membase = ioremap_nocache(port->mapbase, 64);
-		if (!port->membase) {
-			printk(KERN_ERR "%s: Couldn't ioremap 0x%llx\n",
-				__func__,
-			       (unsigned long long) port->mapbase);
-			return -ENOMEM;
-		}
-#endif
-	} else if (!strncmp(options, "io,", 3)) {
-		port->iotype = UPIO_PORT;
-		port->iobase = simple_strtoul(options + 3, &options, 0);
-		mmio = 0;
-	} else
-		return -EINVAL;
-
-	options = strchr(options, ',');
-	if (options) {
-		options++;
-		device->baud = simple_strtoul(options, NULL, 0);
-		length = min(strcspn(options, " ") + 1,
-			     (size_t)(sizeof(device->options)));
-		strlcpy(device->options, options, length);
-	} else {
-		device->baud = probe_baud(port);
-		snprintf(device->options, sizeof(device->options), "%u",
-			device->baud);
-	}
-
-	if (mmio || mmio32)
-		printk(KERN_INFO
-		       "Early serial console at MMIO%s 0x%llx (options '%s')\n",
-			mmio32 ? "32" : "",
-			(unsigned long long)port->mapbase,
-			device->options);
-	else
-		printk(KERN_INFO
-		      "Early serial console at I/O port 0x%lx (options '%s')\n",
-			port->iobase,
-			device->options);
-
-	return 0;
-}
-
-static struct console early_serial8250_console __initdata = {
-	.name	= "uart",
-	.write	= early_serial8250_write,
-	.flags	= CON_PRINTBUFFER | CON_BOOT,
-	.index	= -1,
-};
-
-static int __init early_serial8250_setup(char *options)
+static int __init early_serial8250_setup(struct earlycon_device *device,
+					 const char *options)
 {
-	struct early_serial8250_device *device = &early_device;
-	int err;
-
-	if (device->port.membase || device->port.iobase)
+	if (!(device->port.membase || device->port.iobase))
 		return 0;
 
-	err = parse_options(device, options);
-	if (err < 0)
-		return err;
+	if (!device->baud)
+		device->baud = probe_baud(&device->port);
 
 	init_port(device);
-	return 0;
-}
-
-int __init setup_early_serial8250_console(char *cmdline)
-{
-	char *options;
-	int err;
-
-	options = strstr(cmdline, "uart8250,");
-	if (!options) {
-		options = strstr(cmdline, "uart,");
-		if (!options)
-			return 0;
-	}
-
-	options = strchr(cmdline, ',') + 1;
-	err = early_serial8250_setup(options);
-	if (err < 0)
-		return err;
-
-	register_console(&early_serial8250_console);
 
+	early_device = device;
+	device->con->write = early_serial8250_write;
 	return 0;
 }
+EARLYCON_DECLARE(uart8250, early_serial8250_setup);
+EARLYCON_DECLARE(uart, early_serial8250_setup);
 
 int serial8250_find_port_for_earlycon(void)
 {
-	struct early_serial8250_device *device = &early_device;
-	struct uart_port *port = &device->port;
+	struct earlycon_device *device = early_device;
+	struct uart_port *port = device ? &device->port : NULL;
 	int line;
 	int ret;
 
-	if (!device->port.membase && !device->port.iobase)
+	if (!port || (!port->membase && !port->iobase))
 		return -ENODEV;
 
 	line = serial8250_find_port(port);
@@ -284,5 +178,3 @@ int serial8250_find_port_for_earlycon(void)
 
 	return ret;
 }
-
-early_param("earlycon", setup_early_serial8250_console);
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index 91f1d83..349ee59 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -61,6 +61,7 @@ config SERIAL_8250_CONSOLE
 	bool "Console on 8250/16550 and compatible serial port"
 	depends on SERIAL_8250=y
 	select SERIAL_CORE_CONSOLE
+	select SERIAL_EARLYCON
 	---help---
 	  If you say Y here, it will be possible to use a serial port as the
 	  system console (the system console is the device which receives all
-- 
1.9.1