This wraps single ioctl() commands into block requests using
the custom block layer request types REQ_OP_DRV_IN and
REQ_OP_DRV_OUT.

By doing this we are loosening the grip on the big host lock,
since two calls to mmc_get_card()/mmc_put_card() are removed.

We are storing the ioctl() in/out argument as a pointer in
the per-request struct mmc_blk_request container. Since we
now let the block layer allocate this data, blk_get_request()
will allocate it for us and we can immediately dereference
it and use it to pass the argument into the block layer.

We refactor the if/else/if/else ladder in mmc_blk_issue_rq()
as part of the job, keeping some extra attention to the
case when a NULL req is passed into this function and
making that pipeline flush more explicit.

Tested on the ux500 with the userspace:
mmc extcsd read /dev/mmcblk3
resulting in a successful EXTCSD info dump back to the
console.

This commit fixes a starvation issue in the MMC/SD stack
that can be easily provoked in the following way by
issueing the following commands in sequence:

> dd if=/dev/mmcblk3 of=/dev/null bs=1M &
> mmc extcs read /dev/mmcblk3

Before this patch, the extcsd read command would hang
(starve) while waiting for the dd command to finish since
the block layer was holding the card/host lock.

After this patch, the extcsd ioctl() command is nicely
interpersed with the rest of the block commands and we
can issue a bunch of ioctl()s from userspace while there
is some busy block IO going on without any problems.

Conversely userspace ioctl()s can no longer starve
the block layer by holding the card/host lock.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NAvri Altman <Avri.Altman@sandisk.com>

The variable is_rpmb is clearly a bool and even assigned true
and false, yet declared as an int.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

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>

Factor out data preparation into a separate function mmc_blk_data_prep()
which can be re-used for 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>

mmc_apply_rel_rw() will be used by Software Command Queuing also. In that
case the command argument is not the block address so change
mmc_apply_rel_rw() to get block address from the request.
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>

RPMB does not allow Command Queue commands. Disable and re-enable the
Command Queue when switching.

Note that the driver only switches partitions when the queue is empty.
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>

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>

Change from viewing the requests in progress as 'current' and 'previous',
to viewing them as a queue. The current request is allocated to the first
free slot. The presence of incomplete requests is determined from the
count (mq->qcnt) of entries in the queue. Non-read-write requests (i.e.
discards and flushes) are not added to the queue at all and require no
special handling. Also no special handling is needed for the
MMC_BLK_NEW_REQUEST case.

As well as allowing an arbitrarily sized queue, the queue thread function
is significantly simpler.
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>

A subsequent patch will remove 'mq->mqrq_cur'. Prepare for that by
assigning it to a local variable.
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>

Fix compilation warning:

drivers/mmc/core/block.c:1563:24: warning: variable ‘mq_rq’ set but not
used [-Wunused-but-set-variable]  struct mmc_queue_req *mq_rq;
Signed-off-by: NTomas Winkler <tomas.winkler@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Commit 4e1f7800 ("mmc: block: break out mmc_blk_rw_cmd_abort()")
assumed the request had not completed, but in one case it had. Fix that.

Fixes: 4e1f7800 ("mmc: block: break out mmc_blk_rw_cmd_abort()")
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>

Commit 15520111 ("mmc: core: Further fix thread wake-up") allowed a
queue to release the host with is_waiting_last_req set to true. A queue
waiting to claim the host will not reset it, which can result in the
queue getting stuck in a loop.

Fixes: 15520111 ("mmc: core: Further fix thread wake-up")
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

That makes all the quirks table look more consistent.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

It's not appreciated to place quirks everywhere, let's
put them together just like what we do for USB, PCI etc.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Rename quirks.c to quirks.h, and include it for
individual C files which need it.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The return value from blk_end_request() is a bool but is
treated like an int. This is generally safe, but the variable
also has the opaque name "ret" and gets returned from the
helper function mmc_blk_cmd_err().

- Switch the variable to a bool, applies everywhere.

- Return a bool from mmc_blk_cmd_err() and rename the function
  mmc_blk_rw_cmd_err() to indicate through the namespace that
  this is a helper for mmc_blk_issue_rw_rq().

- Rename the variable from "ret" to "req_pending" inside the
  while() loop inside mmc_blk_issue_rq_rq(), which finally
  makes it very clear what this while loop is waiting for.

- Augment the argument "ret" to mmc_blk_rq_cmd_err() to
  old_req_pending so it becomes evident that this is an
  older state, and it is returned only if we fail to get
  the number of written blocks from an SD card in the
  function mmc_sd_num_wr_blocks().

- Augment the while() loop in mmc_blk_rq_cmd_abort(): it
  is evident now that we know this is a bool variable,
  that the function is just spinning waiting for
  blk_end_request() to return false.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

mmc_sd_num_wr_blocks() has an interesting construction that
saves one return argument by casting (u32)-1 as error code
if something goes wrong.

This is however a bit confusing when the normal kernel
pattern is to return an int error code on success.

So instead pass a variable "blocks" that the function can
fill in with the number of successfully transferred blocks
and return an integer as error code.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
[Ulf: Changed a return code to -EIO, reported by Dan Carpenter and fixed
by Linus Walleij]

Instead of masking and setting two bits in the "flags" field
for the mmc_queue, just use two bools named "suspended" and
"new_request".

The masking and setting would likely have race conditions
anyways, it is better to use a simple member like this.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The mmc_active member of struct mmc_queue_req has a very
confusing name: this is certainly not always "active", it is
the asynchronous request associated by the mmc_queue_req
but it is not guaranteed to be "active" in any sense, such
as being running on the host.

Simply rename this member to "areq".
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The mmc_blk_rw_start_new() was named after the label inside
mmc_blk_issue_rw_rq() but is really a confusing name for this
function: what it does is to try to restart the latest issued
command on the host and card of the current MMC queue.

So rename it mmc_blk_rw_try_restart() that reflects what it
is doing and at this point also refactore the function to
treat the removed card as an exception and just exit if this
happens and run on in the function if that is not happening.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
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>

In the function mmc_blk_issue_rw_rq() the new request coming in
from the block layer is called "rqc" and the old request that
was potentially just returned back from the asynchronous
mechanism is called "req".

This is really confusing when trying to analyze and understand
the code, it becomes a perceptual nightmare to me. Maybe others
have better parserheads but it is not working for me.

Rename "rqc" to "new_req" and "req" to "old_req" to reflect what
is semantically going on into the syntax.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The goto statements sprinkled over the mmc_blk_issue_rw_rq()
function has grown over the years and makes the code pretty hard
to read.

Inline the calls such that:

goto cmd_abort; ->
mmc_blk_rw_cmd_abort(card, req);
mmc_blk_rw_start_new(mq, card, rqc);
return;

goto start_new_req; ->
mmc_blk_rw_start_new(mq, card, rqc);
return;

After this it is more clear how we exit the do {} while
loop in this function, and it gets possible to split the
code apart.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

ida code in block.c can be significantly simplified by switching to
the ida_simple_ functions.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The mmc_blk_issue_rq() function is called in exactly one place
in queue.c and there the return value is ignored. So the
functions called from that function that also meticulously
return 0/1 do so for no good reason.

Error reporting on the asynchronous requests are done upward to
the block layer when the requests are eventually completed or
fail, which may happen during the flow of the mmc_blk_issue_*
functions directly (for "special commands") or later, when an
asynchronous read/write request is completed.

The issuing functions do not give rise to errors on their own,
and there is nothing to return back to the caller in queue.c.
Drop all return values and make the function return void.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Recycling the same variable in an x=x+1 fashion may seem
clever here but it makes the code terse and hard to follow
for humans. Introduce a new_areq and old_areq variable so
we see what is going on.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Setting rqc to NULL followed by a goto to cmd_abort is just a way
to do unconditional abort without starting any new command.
Inline the calls to mmc_blk_rw_cmd_abort() and return immediately
in those cases.

Add some comments to the code flow so it is clear that this is
where the asynchronous requests come back in and the result of
them gets handled.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The code in mmc_blk_issue_rq_rq() aborts a command if the request
is not properly aligned on large sectors. As part of the path
jumping out, it assigns the local variable mq_rq reflecting
a MMC queue request to the current MMC queue request, which is
confusing since the variable is not used after this jump.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

As a step toward breaking apart the very complex function
mmc_blk_issue_rw_rq() we break out the code to start a new
request.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

As a first step toward breaking apart the very complex function
mmc_blk_issue_rw_rq() we break out the command abort code.
This code assumes "ret" is != 0 and then repeatedly hammers
blk_end_request() until the request to the block layer to end
the request succeeds.
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

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>

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>

In the MMC subsystem, we see such initializers that only clears the
first member explicitly.

For example,

  struct mmc_request mrq = {NULL};

sets the first member (.sbc) to NULL explicitly.  However, this is
an unstable form because we may insert a non-pointer member at the
top of the struct mmc_request in the future. (if we do so, the
compiler will spit warnings.)

So, using a designated initializer is preferred coding style.  The
expression above is equivalent to:

  struct mmc_request mrq = { .sbc = NULL };

Of course, this does not express our intention.  We want to fill
all struct members with zeros.  Please note struct members are
implicitly zero-cleared unless otherwise specified in the initializer.

After all, the most reasonable (and stable) form is:

  struct mmc_request mrq = {};

Do likewise for mmc_command, mmc_data as well.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

With gcc-4.1.2:

    mmc/core/block.c: In function ‘mmc_blk_issue_discard_rq’:
    mmc/core/block.c:1150: warning: ‘arg’ may be used uninitialized in this function
    mmc/core/block.c:1150: warning: ‘nr’ may be used uninitialized in this function
    mmc/core/block.c:1150: warning: ‘from’ may be used uninitialized in this function

While this is a false positive, it can be avoided easily by jumping over
the checks for "err" that are always false.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

This was entirely automated, using the script by Al:

  PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
  sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
        $(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)

to do the replacement at the end of the merge window.
Requested-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Once upon a time it made sense to keep the mmc block device driver and its
related code, in its own directory called card. Over time, more an more
functions/structures have become shared through generic mmc header files,
between the core and the card directory. In other words, the relationship
between them has become closer.

By sharing functions/structures via generic header files, it becomes easy
for outside users to abuse them. In a way to avoid that from happen, let's
move the files from card directory into the core directory, as it enables
us to move definitions of functions/structures into mmc core specific
header files.

Note, this is only the first step in providing a cleaner mmc interface for
outside users. Following changes will do the actual cleanup, as that is not
part of this change.
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NLinus Walleij <linus.walleij@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>

The 4K native sector check does not allow for the 'do' loop nor the
variables used after the 'cmd_abort' label.

'brq' and 'req' get reassigned in the 'do' loop, so the check must not
assume what their values are. After the 'cmd_abort' label, 'mq_rq' and
'req' are used, but 'rqc' must be NULL otherwise it can be started again.
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>