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, 6 insertions, 0 deletions

diff --git a/Documentation/devices.txt b/Documentation/devices.txt
index c58abf1ccc71..170cc1e7e135 100644
--- a/Documentation/devices.txt
+++ b/Documentation/devices.txt
@@ -2520,6 +2520,12 @@ Your cooperation is appreciated.
                   8 = /dev/mmcblk1      Second SD/MMC card
                     ...
 
+                The start of next SD/MMC card can be configured with
+                CONFIG_MMC_BLOCK_MINORS, or overridden at boot/modprobe
+                time using the mmcblk.perdev_minors option. That would
+                bump the offset between each card to be the configured
+                value instead of the default 8.
+
 179 char        CCube DVXChip-based PCI products
                   0 = /dev/dvxirq0      First DVX device
                   1 = /dev/dvxirq1      Second DVX device