It is sometimes necessary to give up on trying to claim the host lock,
especially if that happens in a thread that has to be stopped.
While at it, fix the description for mmc_claim_host() which was wrong.
Signed-off-by: Nicolas Pitre <npitre@mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
The problem is that the sdio_bus must be registered before any SDIO
drivers are registered against it otherwise the kernel sulks. Because
the sdio_bus registration happens through module_init (equivalent to
device_initcall), then any SDIO
drivers linked before the SDIO core code in the kernel will be initialized
first.
Upcoming SDIO function drivers are likely to be located outside the
drivers/mmc directory as it is common practice to group drivers according
to their function rather than the bus they use. SDIO drivers are therefore
likely to appear at random location in the kernel link.
To make sure the sdio_bus is always initialized before any SDIO drivers,
let's move the MMC init to the subsys_initcall level.
Signed-off-by: Nicolas Pitre <npitre@mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Add a more clean separation between global, common CIS information
and the function specific one as we need the common information in
places where no specific function is specified.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
This way those tuples that the core cares about are consumed by the core
code, and tuples that only function drivers might make sense of are
available to drivers.
Signed-off-by: Nicolas Pitre <npitre@mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Like many other buses, the devices (functions) on the SDIO bus
must be enabled before they can be used. Add functions that allow
drivers to do so.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
The write parameter in mmc_set_data_timeout() is redundant as the
data structure contains information about the direction of the
transfer.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
This patch makes the following needlessly global functions static:
- sd_ops.c: mmc_app_cmd()
- core.c: __mmc_release_bus()
- core.c: mmc_start_request()
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Make sure that the debugging output in the core is complete.
This should allow us to clean up all the extra debug output
that each and every other host driver seems to contain.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Let the user know that the kernel actually detected the card
by printing some basic information in dmesg.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
When the card has been added to the device model, it might be bound
to a card driver. Therefore, we have to release the host lock when
trying to remove it as we otherwise might deadlock with the driver.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
In the normal case, the host lock can be claimed directly.
When it cannot, the caller will sleep. Make sure we don't
have any latent bugs by always calling might_sleep().
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
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>
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>
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>
As mmc_detect_change() can be called from irq context, using
claim (which can sleep) is inherently unsafe. Use the host
spinlock instead, which also is faster.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
Change Kconfig objects from "menu, config" into "menuconfig" so
that the user can disable the whole feature without having to
enter the menu first.
Signed-off-by: Jan Engelhardt <jengelh@gmx.de>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
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>
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>
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>
Move protocol operations and definitions into their own files
in an effort to separate protocol handling and bus
arbitration more clearly.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
