powerpc/boot: Parse chosen/cmdline-timeout parameter

On some platforms a 5 second timeout during boot might be quite long, so
make it configurable. Run the loop at least once to let the user stop
the boot by holding a key pressed. If the timeout is set to 0, don't
wait for input, which can be used as a workaround if the boot hangs on
random data coming in on the serial port.

Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net>
[mpe: Changelog wording & whitespace]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

3 files changed, 17 insertions, 6 deletions

diff --git a/arch/powerpc/boot/main.c b/arch/powerpc/boot/main.c
index d367a0aece2a..d80161b633f4 100644
--- a/arch/powerpc/boot/main.c
+++ b/arch/powerpc/boot/main.c
@@ -144,13 +144,24 @@ static char cmdline[BOOT_COMMAND_LINE_SIZE]
 
 static void prep_cmdline(void *chosen)
 {
+        unsigned int getline_timeout = 5000;
+        int v;
+        int n;
+
+        /* Wait-for-input time */
+        n = getprop(chosen, "linux,cmdline-timeout", &v, sizeof(v));
+        if (n == sizeof(v))
+                getline_timeout = v;
+
         if (cmdline[0] == '\0')
                 getprop(chosen, "bootargs", cmdline, BOOT_COMMAND_LINE_SIZE-1);
 
         printf("\n\rLinux/PowerPC load: %s", cmdline);
+
         /* If possible, edit the command line */
-        if (console_ops.edit_cmdline)
-                console_ops.edit_cmdline(cmdline, BOOT_COMMAND_LINE_SIZE);
+        if (console_ops.edit_cmdline && getline_timeout)
+                console_ops.edit_cmdline(cmdline, BOOT_COMMAND_LINE_SIZE, getline_timeout);
+
         printf("\n\r");
 
         /* Put the command line back into the devtree for the kernel */
diff --git a/arch/powerpc/boot/ops.h b/arch/powerpc/boot/ops.h
index 8aad3c55aeda..5e75e1c5518e 100644
--- a/arch/powerpc/boot/ops.h
+++ b/arch/powerpc/boot/ops.h
@@ -58,7 +58,7 @@ extern struct dt_ops dt_ops;
 struct console_ops {
         int     (*open)(void);
         void    (*write)(const char *buf, int len);
-        void    (*edit_cmdline)(char *buf, int len);
+        void    (*edit_cmdline)(char *buf, int len, unsigned int getline_timeout);
         void    (*close)(void);
         void    *data;
 };
diff --git a/arch/powerpc/boot/serial.c b/arch/powerpc/boot/serial.c
index f2156f07571f..167ee9433de6 100644
--- a/arch/powerpc/boot/serial.c
+++ b/arch/powerpc/boot/serial.c
@@ -33,7 +33,7 @@ static void serial_write(const char *buf, int len)
                 scdp->putc(*buf++);
 }
 
-static void serial_edit_cmdline(char *buf, int len)
+static void serial_edit_cmdline(char *buf, int len, unsigned int timeout)
 {
         int timer = 0, count;
         char ch, *cp;
@@ -44,7 +44,7 @@ static void serial_edit_cmdline(char *buf, int len)
         cp = &buf[count];
         count++;
 
-        while (timer++ < 5*1000) {
+        do {
                 if (scdp->tstc()) {
                         while (((ch = scdp->getc()) != '\n') && (ch != '\r')) {
                                 /* Test for backspace/delete */
@@ -70,7 +70,7 @@ static void serial_edit_cmdline(char *buf, int len)
                         break;  /* Exit 'timer' loop */
                 }
                 udelay(1000);  /* 1 msec */
-        }
+        } while (timer++ < timeout);
         *cp = 0;
 }