[PATCH v2 0/4] Patches to allow consistent mmc / mmcblk numbering w/ device tree

Douglas Anderson
2016-04-29T17:32:15Z

This series picks patches from various different places to produce what
I consider the best solution to getting consistent mmc and mmcblk
ordering.

Why consistent ordering and why not just use UUIDs? IMHO consistent
ordering solves a few different problems:

1. For poor, feeble-minded humans like me, have sane numbering for
devices helps a lot. When grepping through dmesg it's terribly handy
if a given SDMMC device has a consistent number. I know that I can
do "dmesg | grep mmc0" or "dmesg | grep mmcblk0" to find info about
the eMMC. I know that I can do "dmesg | grep mmc1" to find info
about the SD card slot. I don't want it to matter which one probed
first, I don't want it to matter if I'm working on a variant of the
hardware that has the SD card slot disabled, and I don't want to care
what my boot device was. Worrying about what device number I got
increases my cognitive load.

2. There are cases where it's not trivially easy during development to
use the UUID. Specifically I work a lot with coreboot / depthcharge
as a BIOS. When configured properly, that BIOS has a nice feature to
allow you to fetch the kernel and kernel command line from TFTP by
pressing Ctrl-N. In this particular case the BIOS doesn't actually
know which disk I'd like for my root filesystem, so it's not so easy
for it to put the right UUID into the command line. For this
purpose, knowing that "mmcblk0" will always refer to eMMC is handy.

Changes in v2:
- Rebased atop mmc-next
- Stat dynamic allocation after fixed allocation; thanks Wolfram!
- rk3288 patch new for v2

Douglas Anderson (1):
ARM: dts: rockchip: Add mmc aliases for rk3288 platform

Jaehoon Chung (1):
Documentation: mmc: Document mmc aliases

Stefan Agner (2):
mmc: read mmc alias from device tree
mmc: use SD/MMC host ID for block device name ID

Documentation/devicetree/bindings/mmc/mmc.txt | 11 +++++++++++
arch/arm/boot/dts/rk3288.dtsi | 4 ++++
drivers/mmc/card/block.c | 2 +-
drivers/mmc/core/host.c | 17 ++++++++++++++++-
4 files changed, 32 insertions(+), 2 deletions(-)

--
2.8.0.rc3.226.g39d4020

--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html