mmc: make number of mmcblk minors configurable

The old limit of number of minor numbers per mmcblk device was hardcoded
at 8.  This isn't enough for some of the more elaborate partitioning
schemes, for example those used by Chrome OS.

Since there might be a bunch of systems out there with static /dev
contents that relies on the old numbering scheme, let's make it a
build-time option with the default set to the previous 8.

Also provide a boot/modprobe-time parameter to override the config
default: mmcblk.perdev_minors.

Signed-off-by: Olof Johansson <olof@lixom.net>
Cc: Mandeep Baines <msb@chromium.org>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/drivers/mmc/card/Kconfig b/drivers/mmc/card/Kconfig
index 3f2a912..57e4416 100644
--- a/drivers/mmc/card/Kconfig
+++ b/drivers/mmc/card/Kconfig
@@ -14,6 +14,23 @@ config MMC_BLOCK
 	  mount the filesystem. Almost everyone wishing MMC support
 	  should say Y or M here.
 
+config MMC_BLOCK_MINORS
+	int "Number of minors per block device"
+	range 4 256
+	default 8
+	help
+	  Number of minors per block device. One is needed for every
+	  partition on the disk (plus one for the whole disk).
+
+	  Number of total MMC minors available is 256, so your number
+	  of supported block devices will be limited to 256 divided
+	  by this number.
+
+	  Default is 8 to be backwards compatible with previous
+	  hardwired device numbering.
+
+	  If unsure, say 8 here.
+
 config MMC_BLOCK_BOUNCE
 	bool "Use bounce buffer for simple hosts"
 	depends on MMC_BLOCK