Commit graph

9 commits

Author SHA1 Message Date
Pierre Ossman
4101c16a91 mmc: refactor bus operations
Move bus operations to its own file for the sake of clarity. Also
delegate sysfs attributes to bus handlers in preparation for other
more exotic types.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-07-09 21:27:56 +02:00
Pierre Ossman
c3bff2ec10 mmc: get back read-only switch function
Somehow the code to read the read-only switch of SD cards got lost
in the reorganisation.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-06-13 19:11:20 +02:00
Pierre Ossman
3373c0ae6a mmc: don't call switch on old cards
Make sure we don't call the switch function on cards too old to
support it. They should just ignore it, but some have been reported
to lock up instead.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-06-07 09:25:58 +02:00
Pierre Ossman
71651297a4 mmc: fix broken if clause
Fix a broken if clause which was causing SD cards to go into
4-bit mode even if the host did not support it.

(Reported by David Brownell and Marc Pignat)

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-06-07 09:25:54 +02:00
Pierre Ossman
bd76631261 mmc: remove old card states
Remove card states that no longer make any sense.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 16:11:57 +02:00
Pierre Ossman
6abaa0c9fe mmc: support unsafe resume of cards
Since many have the system root on MMC/SD we must allow some foot
shooting when it comes to resume.

We cannot detect if a card is removed and reinserted during suspend,
so the safe approach would be to assume it was, avoiding potential
filesystem corruption. This will of course not work if you cannot
release the card before suspend.

This commit adds a compile time option that makes the MMC layer
assume the card wasn't touched if it is redetected upon resume.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 16:00:02 +02:00
Pierre Ossman
1addfcdbe4 mmc: break apart switch function
Break apart the SD switch function into one that reads the capabilities
and one that acts on them.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 14:46:08 +02:00
Philip Langdale
55556da012 MMC: Fix handling of low-voltage cards
Fix handling of low voltage MMC cards.

The latest MMC and SD specs both agree that support for
low-voltage operations is indicated by bit 7 in the OCR.
The MMC spec states that the low voltage range is
1.65-1.95V while the SD spec leaves the actual voltage
range undefined - meaning that there is still no such
thing as a low voltage SD card.

However, an old Sandisk spec implied that bits 7.0
represented voltages below 2.0V in 1V or 0.5V increments,
and the code was accordingly written with that expectation.

This confusion meant that host drivers attempting to support
the typical low voltage (1.8V) would set the wrong bits in
the host OCR mask (usually bits 5 and/or 6) resulting in the
the low voltage mode never being used.

This change corrects the low voltage range and adds sanity
checks on the reserved bits (0-6) and for SD cards that
claim to support low-voltage operations.

Signed-off-by: Philip Langdale <philipl@overt.org>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 14:14:50 +02:00
Pierre Ossman
7ea239d9e6 mmc: add bus handler
Delegate protocol handling to "bus handlers". This allows the core to
just handle the task of arbitrating the bus. Initialisation and
pampering of cards is now done by the different bus handlers.

This design also allows MMC and SD (and later SDIO) to be more cleanly
separated, allowing easier maintenance.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
2007-05-01 13:41:06 +02:00