The MMC_CAP2_HC_ERASE_SZ is used only by a few mmc host drivers. Its intent
is to enable eMMC's high-capacity erase size, as to improve the behaviour
of the erase operations.

We should strive to avoid software configuration options that aren't
necessary, but instead deploy common behaviours. For these reasons, let's
remove the capability bit for MMC_CAP2_HC_ERASE_SZ and make it the default
behaviour.

Note that this change doesn't affect eMMCs supporting trim/discard, because
these commands operates on sectors and takes precedence over erase
commands.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Tested-by: NShawn Lin <shawn.lin@rock-chips.com>

The mmc_queue_req is a per-request state container the MMC core uses
to carry bounce buffers, pointers to asynchronous requests and so on.
Currently allocated as a static array of objects, then as a request
comes in, a mmc_queue_req is assigned to it, and used during the
lifetime of the request.

This is backwards compared to how other block layer drivers work:
they usally let the block core provide a per-request struct that get
allocated right beind the struct request, and which can be obtained
using the blk_mq_rq_to_pdu() helper. (The _mq_ infix in this function
name is misleading: it is used by both the old and the MQ block
layer.)

The per-request struct gets allocated to the size stored in the queue
variable .cmd_size initialized using the .init_rq_fn() and
cleaned up using .exit_rq_fn().

The block layer code makes the MMC core rely on this mechanism to
allocate the per-request mmc_queue_req state container.

Doing this make a lot of complicated queue handling go away. We only
need to keep the .qnct that keeps count of how many request are
currently being processed by the MMC layer. The MQ block layer will
replace also this once we transition to it.

Doing this refactoring is necessary to move the ioctl() operations
into custom block layer requests tagged with REQ_OP_DRV_[IN|OUT]
instead of the custom code using the BigMMCHostLock that we have
today: those require that per-request data be obtainable easily from
a request after creating a custom request with e.g.:

struct request *rq = blk_get_request(q, REQ_OP_DRV_IN, __GFP_RECLAIM);
struct mmc_queue_req *mq_rq = req_to_mq_rq(rq);

And this is not possible with the current construction, as the request
is not immediately assigned the per-request state container, but
instead it gets assigned when the request finally enters the MMC
queue, which is way too late for custom requests.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
[Ulf: Folded in the fix to drop a call to blk_cleanup_queue()]
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NHeiner Kallweit <hkallweit1@gmail.com>

This option is activated by all multiplatform configs and what
not so we almost always have it turned on, and the memory it
saves is negligible, even more so moving forward. The actual
bounce buffer only gets allocated only when used, the only
thing the ifdefs are saving is a little bit of code.

It is highly improper to have this as a Kconfig option that
get turned on by Kconfig, make this a pure runtime-thing and
let the host decide whether we use bounce buffers. We add a
new property "disable_bounce" to the host struct.

Notice that mmc_queue_calc_bouncesz() already disables the
bounce buffers if host->max_segs != 1, so any arch that has a
maximum number of segments higher than 1 will have bounce
buffers disabled.

The option CONFIG_MMC_BLOCK_BOUNCE is default y so the
majority of platforms in the kernel already have it on, and
it then gets turned off at runtime since most of these have
a host->max_segs > 1. The few exceptions that have
host->max_segs == 1 and still turn off the bounce buffering
are those that disable it in their defconfig.

Those are the following:

arch/arm/configs/colibri_pxa300_defconfig
arch/arm/configs/zeus_defconfig
- Uses MMC_PXA, drivers/mmc/host/pxamci.c
- Sets host->max_segs = NR_SG, which is 1
- This needs its bounce buffer deactivated so we set
  host->disable_bounce to true in the host driver

arch/arm/configs/davinci_all_defconfig
- Uses MMC_DAVINCI, drivers/mmc/host/davinci_mmc.c
- This driver sets host->max_segs to MAX_NR_SG, which is 16
- That means this driver anyways disabled bounce buffers
- No special action needed for this platform

arch/arm/configs/lpc32xx_defconfig
arch/arm/configs/nhk8815_defconfig
arch/arm/configs/u300_defconfig
- Uses MMC_ARMMMCI, drivers/mmc/host/mmci.[c|h]
- This driver by default sets host->max_segs to NR_SG,
  which is 128, unless a DMA engine is used, and in that case
  the number of segments are also > 1
- That means this driver already disables bounce buffers
- No special action needed for these platforms

arch/arm/configs/sama5_defconfig
- Uses MMC_SDHCI, MMC_SDHCI_PLTFM, MMC_SDHCI_OF_AT91, MMC_ATMELMCI
- Uses drivers/mmc/host/sdhci.c
- Normally sets host->max_segs to SDHCI_MAX_SEGS which is 128 and
  thus disables bounce buffers
- Sets host->max_segs to 1 if SDHCI_USE_SDMA is set
- SDHCI_USE_SDMA is only set by SDHCI on PCI adapers
- That means that for this platform bounce buffers are already
  disabled at runtime
- No special action needed for this platform

arch/blackfin/configs/CM-BF533_defconfig
arch/blackfin/configs/CM-BF537E_defconfig
- Uses MMC_SPI (a simple MMC card connected on SPI pins)
- Uses drivers/mmc/host/mmc_spi.c
- Sets host->max_segs to MMC_SPI_BLOCKSATONCE which is 128
- That means this platform already disables bounce buffers at
  runtime
- No special action needed for these platforms

arch/mips/configs/cavium_octeon_defconfig
- Uses MMC_CAVIUM_OCTEON, drivers/mmc/host/cavium.c
- Sets host->max_segs to 16 or 1
- Setting host->disable_bounce to be sure for the 1 case

arch/mips/configs/qi_lb60_defconfig
- Uses MMC_JZ4740, drivers/mmc/host/jz4740_mmc.c
- This sets host->max_segs to 128 so bounce buffers are
  already runtime disabled
- No action needed for this platform

It would be interesting to come up with a list of the platforms
that actually end up using bounce buffers. I have not been
able to infer such a list, but it occurs when
host->max_segs == 1 and the bounce buffering is not explicitly
disabled.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

For hosts not supporting MMC_CAP2_SDIO_IRQ_NOTHREAD but MMC_CAP_SDIO_IRQ,
the SDIO IRQs are processed from a dedicated kernel thread. For these
cases, the host calls mmc_signal_sdio_irq() from its ISR to signal a new
SDIO IRQ.

Signaling an SDIO IRQ makes the host's ->enable_sdio_irq() callback to be
invoked to temporary disable the IRQs, before the kernel thread is woken up
to process it. When processing of the IRQs are completed, they are
re-enabled by the kernel thread, again via invoking the host's
->enable_sdio_irq().

The observation from this, is that the execution path is being unnecessary
complex, as the host driver already knows that it needs to temporary
disable the IRQs before signaling a new one. Moreover, replacing the kernel
thread with a work/workqueue would not only greatly simplify the code, but
also make it more robust.

To address the above problems, let's continue to build upon the support for
MMC_CAP2_SDIO_IRQ_NOTHREAD, as it already implements SDIO IRQs to be
processed without using the clumsy kernel thread and without the ping-pong
calls of the host's ->enable_sdio_irq() callback for each processed IRQ.

Therefore, let's add new API sdio_signal_irq(), which enables hosts to
signal/process SDIO IRQs by using a work/workqueue, rather than using the
kernel thread.

Add also a new host callback ->ack_sdio_irq(), which the work invokes when
the SDIO IRQs have been processed. This informs the host about when it
shall re-enable the SDIO IRQs. Potentially, we could re-use the existing
->enable_sdio_irq() callback instead of adding a new one, however it has
turned out that it's more convenient for hosts to get this information via
a separate callback.

Hosts that wants to use this new method to signal/process SDIO IRQs, must
enable MMC_CAP2_SDIO_IRQ_NOTHREAD and implement the ->ack_sdio_irq()
callback.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NDouglas Anderson <dianders@chromium.org>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>

Some hosts controllers, like Cavium, needs to know whether the card
operates in byte- or block-address mode. Therefore export a new API,
mmc_card_is_blockaddr(), which provides this information.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NSteven J. Hill <Steven.Hill@cavium.com>
Acked-by: NDavid Daney <david.daney@cavium.com>

Normal read and write commands may not be used while the command queue is
enabled. Disable the Command Queue when mmc_test is probed and re-enable it
when it is removed.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add helper functions to enable or disable the Command Queue.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

eMMC can have multiple internal partitions that are represented as separate
disks / queues. However switching between partitions is only done when the
queue is empty. Consequently the array of mmc requests that are queued can
be shared between partitions saving memory.

Keep a pointer to the mmc request queue on the card, and use that instead
of allocating a new one for each partition.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add function for determining DMA direction to core.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Certain 64-bit systems (e.g. Amlogic Meson GX) require buffers to be
used for DMA to be 8-byte-aligned. struct sdio_func has an embedded
small DMA buffer not meeting this requirement.
When testing switching to descriptor chain mode in meson-gx driver
SDIO is broken therefore. Fix this by allocating the small DMA buffer
separately as kmalloc ensures that the returned memory area is
properly aligned for every basic data type.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Tested-by: NHelmut Klein <hgkr.klein@gmail.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Consolidate all the sdio devices' IDs into sdio_ids.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Adding dedicated flag for AUTO_BKOPS in card->ext_csd structure.
Read AUTO_BKOPS bit value from the device EXT_CSD and set to the
card->ext_csd structure.
In mmc_decode_ext_csd() add a print message in case the AUTO_BKOPS
is enabled
Signed-off-by: NUri Yanai <uri.yanai@sandisk.com>
Signed-off-by: NAlex Lemberg <alex.lemberg@sandisk.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

With the coexisting __mmc_start_request(), mmc_start_request()
and __mmc_start_req() it is a bit confusing that mmc_start_req()
actually does not start a normal request, but an asynchronous
request.

Rename it to mmc_start_areq() to make it explicit what the
function is doing, also fix the kerneldoc for this function
while we're at it.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

According the JEDEC specification an eMMC card supporting 1.8V vccq in DDR
mode should also be capable of 3.3V. However, it's been reported that some
mmc hosts supports 3.3V, but not 1.8V.

Currently the mmc core implements an error handling when the host fails to
set 1.8V for vccq, by falling back to 3.3V. Unfortunate, this seems to be
insufficient for some mmc hosts. To enable these to use eMMC DDR mode let's
invent a new mmc cap, MMC_CAP_3_3V_DDR, which tells whether they support
the eMMC 3.3V DDR mode.

In case MMC_CAP_3_3V_DDR is set, but not MMC_CAP_1_8V_DDR, let's change to
remain on the 3.3V, as it's the default voltage level for vccq, set by the
earlier power up sequence.

As this change introduces MMC_CAP_3_3V_DDR, let's take the opportunity to
do some re-formatting of the related defines in the header file.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Tested-by: NJan Glauber <jglauber@cavium.com>
Tested-by: NStefan Wahren <stefan.wahren@i2se.com>

Using extern when declaring functions in the public header, core.h, is
redundant. Let's just remove the use of it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

A significant amount of functions are available through the public mmc
host.h header file. Let's slim down this public mmc interface, as to
prevent users from abusing it, by moving some of the functions to private
mmc host.h header file.

This change concentrates on moving the functions into private mmc headers,
following changes may continue with additional clean-ups.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

A significant amount of functions and other definitions are available
through the public mmc card.h header file. Let's slim down this public mmc
interface, as to prevent users from abusing it, by moving some of the
functions/definitions to private mmc header files.

This change concentrates on moving the functions into private mmc headers,
following changes may continue with additional clean-ups.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

The struct _mmc_csd isn't being used and has been lurking around for a
while. Let's kill it.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

As the public mmc.h header already contains similar defines for other mmc
commands and arguments, let's move those for erase/trim/discard into here
as well.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

Ideally the public mmc header file, core.h, shouldn't contain interfaces
particularly intended to be used by host drivers. Instead those should
remain in the host.h header file. Therefore, let's move a couple functions
from core.h to host.h.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

A significant amount of functions are available through the public mmc
core.h header file. Let's slim down this public mmc interface, as to
prevent users from abusing it, by moving some of the functions to private
mmc header files.

This change concentrates on moving the functions into private mmc headers,
following changes may continue with additional clean-ups, as an example
some functions can be turned into static.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

This is the first step in cleaning up the public mmc header files. In this
change we makes sure each header file builds standalone, as that helps to
resolve dependencies.

While changing this, it also seems reasonable to stop including other
headers from inside a header itself which it don't depend upon.
Additionally, in some cases such dependencies are better resolved by
forward declaring the needed struct.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

There are currently no external users of the public dw_mmc header file,
except the dw_mmc driver itself. Therefore let's move the definitions from
the public dw_mmc header file into the existing private dw_mmc header file
and then remove the public one.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

There are currently no users of the clk_ctrl2_present member from the
platform data, so let's remove it.

Note, as some of the sh_mmcif variants may support clk_ctrl2, let's keep
the current code in the driver, which deals with this. For future support,
we should invent a DT binding instead, but let's leave that until it's
needed.

Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

There are currently no users of the ccs_unsupported member from the
platform data, so let's remove it.

Note, as some of the sh_mmcif variants may not support ccs, let's keep the
current code in the driver, which deals with this. For future support, we
should invent a DT binding instead, but let's leave that until it's needed.

Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

Removing the callback also enables us to remove the sh_mmcif_get_cd()
altogether, as we convert to use mmc_gpio_get_cd() to the same kind of
work.

Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>

In the eMMC 5.0 version of the spec, several EXT_CSD fields about
device lifetime are added.

 - Two types of estimated indications reflected by averaged wear out of memory
 - An indication reflected by average reserved blocks

Export the information through sysfs.
Signed-off-by: NJungseung Lee <js07.lee@samsung.com>
Reviewed-by: NJaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

BCM43455 is a more recent revision of the BCM4345. Some of the BCM43455
got a dedicated SDIO device ID which is currently not supported by
brcmfmac.
Adding the new sdio_device_id to brcmfmac is enough to get the BCM43455
supported because the chip itself is already supported (due to BCM4345
support in the driver).
Signed-off-by: NMartin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: NArend van Spriel <arend.vanspriel@broadcom.com>
Reviewed-by: NAndreas Färber <afaerber@suse.de>
Tested-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

If a tuning command times out, the card could still be processing it, which
will cause problems for recovery. The eMMC specification says that CMD12
can be used to stop CMD21, so add a function that does that.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add definitions relating to Command Queuing.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The only time the driver sleeps expecting to be woken upon the arrival of
a new request, is when the dispatch queue is empty. The only time that it
is known whether the dispatch queue is empty is after NULL is returned
from blk_fetch_request() while under the queue lock.

Recognizing those facts, simplify the synchronization between the queue
thread and the request function. A couple of flags tell the request
function what to do, and the queue lock and barriers associated with
wake-ups ensure synchronization.

The result is simpler and allows the removal of the context_info lock.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NHarjani Ritesh <riteshh@codeaurora.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

I've had it with this code now.

The packed command support is a complex hurdle in the MMC/SD block
layer, around 500+ lines of code which was introduced in 2013 in

commit ce39f9d1 ("mmc: support packed write command for eMMC4.5
devices")
commit abd9ac14 ("mmc: add packed command feature of eMMC4.5")

...and since then it has been rotting. The original author of the
code has disappeared from the community and the mail address is
bouncing.

For the code to be exercised the host must flag that it supports
packed commands, so in mmc_blk_prep_packed_list() which is called for
every single request, the following construction appears:

u8 max_packed_rw = 0;

if ((rq_data_dir(cur) == WRITE) &&
    mmc_host_packed_wr(card->host))
        max_packed_rw = card->ext_csd.max_packed_writes;

if (max_packed_rw == 0)
    goto no_packed;

This has the following logical deductions:

- Only WRITE commands can really be packed, so the solution is
  only half-done: we support packed WRITE but not packed READ.
  The packed command support has not been finalized by supporting
  reads in three years!

- mmc_host_packed_wr() is just a static inline that checks
  host->caps2 & MMC_CAP2_PACKED_WR. The problem with this is
  that NO upstream host sets this capability flag! No driver
  in the kernel is using it, and we can't test it. Packed
  command may be supported in out-of-tree code, but I doubt
  it. I doubt that the code is even working anymore due to
  other refactorings in the MMC block layer, who would
  notice if patches affecting it broke packed commands?
  No one.

- There is no Device Tree binding or code to mark a host as
  supporting packed read or write commands, just this flag
  in caps2, so for sure there are not any DT systems using
  it either.

It has other problems as well: mmc_blk_prep_packed_list() is
speculatively picking requests out of the request queue with
blk_fetch_request() making the MMC/SD stack harder to convert
to the multiqueue block layer. By this we get rid of an
obstacle.

The way I see it this is just cruft littering the MMC/SD
stack.

Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Maya Erez <qca_merez@qca.qualcomm.com>
Acked-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The void (*pre_req) callback in the struct mmc_host_ops vtable
is passing an argument "is_first_req" indicating whether this is
the first request or not.

None of the in-kernel users use this parameter: instead, since
they all just do variants of dma_map* they use the DMA cookie
to indicate whether a pre* callback has already been done for
a request when they decide how to handle it.

Delete the parameter from the callback and all users, as it is
just pointless cruft.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

This patch removed the meaningless value. Instead, use the cookie's enum
values for executing correctly.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Tested-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

This is in preparation for restoring saved tuning parameters
when resuming the TMIO driver.
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>
Acked-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

There were several instances of code using the
enum mmc_blk_status by arbitrarily converting it to an int and
throwing it around to different functions. This makes the code
hard to understand to may give rise to strange errors.

Especially the function prototype mmc_start_req() had to be
modified to take a pointer to an enum mmc_blk_status and the
function pointer .err_check() inside struct mmc_async_req
needed to return an enum mmc_blk_status.

In every case: instead of assigning the block layer error code
to an int, use the enum, also change the signature of all
functions actually passing this enum to use the enum.

To make it possible to use the enum everywhere applicable, move
it to <linux/mmc/core.h> so that all code actually using it can
also see it.

An interesting case was encountered in the MMC test code which
did not return a enum mmc_blk_status at all in the .err_check
function supposed to check whether asynchronous requests worked
or not: instead it returned a normal -ERROR or even the test
frameworks internal error codes.

The test code would also pass on enum mmc_blk_status codes as
error codes inside the test code instead of converting them
to the local RESULT_* codes.

I have tried to fix all instances properly and run some tests
on the result.

Cc: Chunyan Zhang <zhang.chunyan@linaro.org>
Cc: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add new helper API mmc_can_gpio_cd for slot-gpio to make
host drivers know whether it supports gpio card detect.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The core uses it for polling. Give drivers a proper define handle this
case like for other response types.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>