[PATCH v2 -next 01/13] serial: earlycon: Refactor parse_options into serial core

From: Peter Hurley
Date: Sun Mar 01 2015 - 11:10:12 EST


Prepare to support console-defined matching; refactor the command
line parameter string processing from parse_options() into a
new core function, uart_parse_earlycon(), which decodes command line
parameters of the form:
earlycon=<name>,io|mmio|mmio32,<addr>,<options>
console=<name>,io|mmio|mmio32,<addr>,<options>
earlycon=<name>,0x<addr>,<options>
console=<name>,0x<addr>,<options>

Signed-off-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/earlycon.c | 39 ++++++++++++----------------------
drivers/tty/serial/serial_core.c | 46 ++++++++++++++++++++++++++++++++++++++++
include/linux/serial_core.h | 2 ++
3 files changed, 61 insertions(+), 26 deletions(-)

diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index 64fe25a..58d6bcd 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -54,44 +54,31 @@ static void __iomem * __init earlycon_map(unsigned long paddr, size_t size)
return base;
}

-static int __init parse_options(struct earlycon_device *device,
- char *options)
+static int __init parse_options(struct earlycon_device *device, char *options)
{
struct uart_port *port = &device->port;
- int mmio, mmio32, length;
+ int length;
unsigned long addr;

- if (!options)
- return -ENODEV;
+ if (uart_parse_earlycon(options, &port->iotype, &addr, &options))
+ return -EINVAL;

- mmio = !strncmp(options, "mmio,", 5);
- mmio32 = !strncmp(options, "mmio32,", 7);
- if (mmio || mmio32) {
- port->iotype = (mmio ? UPIO_MEM : UPIO_MEM32);
- options += mmio ? 5 : 7;
- addr = simple_strtoul(options, NULL, 0);
+ switch (port->iotype) {
+ case UPIO_MEM32:
+ port->regshift = 2; /* fall-through */
+ case UPIO_MEM:
port->mapbase = addr;
- if (mmio32)
- port->regshift = 2;
- } else if (!strncmp(options, "io,", 3)) {
- port->iotype = UPIO_PORT;
- options += 3;
- addr = simple_strtoul(options, NULL, 0);
+ break;
+ case UPIO_PORT:
port->iobase = addr;
- mmio = 0;
- } else if (!strncmp(options, "0x", 2)) {
- port->iotype = UPIO_MEM;
- addr = simple_strtoul(options, NULL, 0);
- port->mapbase = addr;
- } else {
+ break;
+ default:
return -EINVAL;
}

port->uartclk = BASE_BAUD * 16;

- options = strchr(options, ',');
if (options) {
- options++;
device->baud = simple_strtoul(options, NULL, 0);
length = min(strcspn(options, " ") + 1,
(size_t)(sizeof(device->options)));
@@ -100,7 +87,7 @@ static int __init parse_options(struct earlycon_device *device,

if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM32)
pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n",
- mmio32 ? "32" : "",
+ (port->iotype == UPIO_MEM32) ? "32" : "",
(unsigned long long)port->mapbase,
device->options);
else
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 6a1055a..3f823c26 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1810,6 +1810,52 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co)
}

/**
+ * uart_parse_earlycon - Parse earlycon options
+ * @p: ptr to 2nd field (ie., just beyond '<name>,')
+ * @iotype: ptr for decoded iotype (out)
+ * @addr: ptr for decoded mapbase/iobase (out)
+ * @options: ptr for <options> field; NULL if not present (out)
+ *
+ * Decodes earlycon kernel command line parameters of the form
+ * earlycon=<name>,io|mmio|mmio32,<addr>,<options>
+ * console=<name>,io|mmio|mmio32,<addr>,<options>
+ *
+ * The optional form
+ * earlycon=<name>,0x<addr>,<options>
+ * console=<name>,0x<addr>,<options>
+ * is also accepted; the returned @iotype will be UPIO_MEM.
+ *
+ * Returns 0 on success or -EINVAL on failure
+ */
+int uart_parse_earlycon(char *p, unsigned char *iotype, unsigned long *addr,
+ char **options)
+{
+ if (strncmp(p, "mmio,", 5) == 0) {
+ *iotype = UPIO_MEM;
+ p += 5;
+ } else if (strncmp(p, "mmio32,", 7) == 0) {
+ *iotype = UPIO_MEM32;
+ p += 7;
+ } else if (strncmp(p, "io,", 3) == 0) {
+ *iotype = UPIO_PORT;
+ p += 3;
+ } else if (strncmp(p, "0x", 2) == 0) {
+ *iotype = UPIO_MEM;
+ } else {
+ return -EINVAL;
+ }
+
+ *addr = simple_strtoul(p, NULL, 0);
+ p = strchr(p, ',');
+ if (p)
+ p++;
+
+ *options = p;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(uart_parse_earlycon);
+
+/**
* uart_parse_options - Parse serial port baud/parity/bits/flow control.
* @options: pointer to option string
* @baud: pointer to an 'int' variable for the baud rate.
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index baf3e1d..cc5c506 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -354,6 +354,8 @@ early_param("earlycon", name ## _setup_earlycon);

struct uart_port *uart_get_console(struct uart_port *ports, int nr,
struct console *c);
+int uart_parse_earlycon(char *p, unsigned char *iotype, unsigned long *addr,
+ char **options);
void uart_parse_options(char *options, int *baud, int *parity, int *bits,
int *flow);
int uart_set_options(struct uart_port *port, struct console *co, int baud,
--
2.3.0

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