mmc: core: use sysfs_emit() instead of sprintf()

sprintf() (still used in the MMC core for the sysfs output) is vulnerable
to the buffer overflow. Use the new-fangled sysfs_emit() instead.

Found b

mmc: core: use sysfs_emit() instead of sprintf()

sprintf() (still used in the MMC core for the sysfs output) is vulnerable
to the buffer overflow. Use the new-fangled sysfs_emit() instead.

Found by Linux Verification Center (linuxtesting.org) with the SVACE static
analysis tool.

Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/717729b2-d65b-c72e-9fac-471d28d00b5a@omp.ru
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: change __mmc_poll_for_busy() parameter type

This patch changes the __mmc_poll_for_busy() first parameter type
from 'struct mmc_card*' to 'struct mmc_host*'.
Because the function refers on

mmc: core: change __mmc_poll_for_busy() parameter type

This patch changes the __mmc_poll_for_busy() first parameter type
from 'struct mmc_card*' to 'struct mmc_host*'.
Because the function refers only 'struct mmc_host' to get hostname.

Signed-off-by: Huijin Park <huijin.park@samsung.com>
Link: https://lore.kernel.org/r/20211104063231.2115-2-huijin.park@samsung.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Add host specific tuning support for eMMC HS400 mode

This adds a ->execute_hs400_tuning() host callback to enable optional
support for host specific tuning for eMMC HS400 mode. Additional

mmc: core: Add host specific tuning support for eMMC HS400 mode

This adds a ->execute_hs400_tuning() host callback to enable optional
support for host specific tuning for eMMC HS400 mode. Additionally, share
mmc_get_ext_csd() through the public host headerfile, to allow it to be
used by the host drivers, which is needed to support the HS400 tuning.

Signed-off-by: Wenbin Mei <wenbin.mei@mediatek.com>
Link: https://lore.kernel.org/r/20210917124803.22871-3-wenbin.mei@mediatek.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Set HS clock speed before sending HS CMD13

commit 4bc31edebde51fcf8ad0794763b8679a7ecb5ec0 upstream.

Way back in commit 4f25580fb84d ("mmc: core: changes frequency to
hs_max_dtr when sel

mmc: core: Set HS clock speed before sending HS CMD13

commit 4bc31edebde51fcf8ad0794763b8679a7ecb5ec0 upstream.

Way back in commit 4f25580fb84d ("mmc: core: changes frequency to
hs_max_dtr when selecting hs400es"), Rockchip engineers noticed that
some eMMC don't respond to SEND_STATUS commands very reliably if they're
still running at a low initial frequency. As mentioned in that commit,
JESD84-B51 P49 suggests a sequence in which the host:
1. sets HS_TIMING
2. bumps the clock ("<= 52 MHz")
3. sends further commands

It doesn't exactly require that we don't use a lower-than-52MHz
frequency, but in practice, these eMMC don't like it.

The aforementioned commit tried to get that right for HS400ES, although
it's unclear whether this ever truly worked as committed into mainline,
as other changes/refactoring adjusted the sequence in conflicting ways:

08573eaf1a70 ("mmc: mmc: do not use CMD13 to get status after speed mode
switch")

53e60650f74e ("mmc: core: Allow CMD13 polling when switching to HS mode
for mmc")

In any case, today we do step 3 before step 2. Let's fix that, and also
apply the same logic to HS200/400, where this eMMC has problems too.

Resolves errors like this seen when booting some RK3399 Gru/Scarlet
systems:

[ 2.058881] mmc1: CQHCI version 5.10
[ 2.097545] mmc1: SDHCI controller on fe330000.mmc [fe330000.mmc] using ADMA
[ 2.209804] mmc1: mmc_select_hs400es failed, error -84
[ 2.215597] mmc1: error -84 whilst initialising MMC card
[ 2.417514] mmc1: mmc_select_hs400es failed, error -110
[ 2.423373] mmc1: error -110 whilst initialising MMC card
[ 2.605052] mmc1: mmc_select_hs400es failed, error -110
[ 2.617944] mmc1: error -110 whilst initialising MMC card
[ 2.835884] mmc1: mmc_select_hs400es failed, error -110
[ 2.841751] mmc1: error -110 whilst initialising MMC card

Ealier versions of this patch bumped to 200MHz/HS200 speeds too early,
which caused issues on, e.g., qcom-msm8974-fairphone-fp2. (Thanks for
the report Luca!) After a second look, it appears that aligns with
JESD84 / page 45 / table 28, so we need to keep to lower (HS / 52 MHz)
rates first.

Fixes: 08573eaf1a70 ("mmc: mmc: do not use CMD13 to get status after speed mode switch")
Fixes: 53e60650f74e ("mmc: core: Allow CMD13 polling when switching to HS mode for mmc")
Fixes: 4f25580fb84d ("mmc: core: changes frequency to hs_max_dtr when selecting hs400es")
Cc: Shawn Lin <shawn.lin@rock-chips.com>
Link: https://lore.kernel.org/linux-mmc/11962455.O9o76ZdvQC@g550jk/
Reported-by: Luca Weiss <luca@z3ntu.xyz>
Signed-off-by: Brian Norris <briannorris@chromium.org>
Tested-by: Luca Weiss <luca@z3ntu.xyz>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220422100824.v4.1.I484f4ee35609f78b932bd50feed639c29e64997e@changeid
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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mmc: block: Support alternative_gpt_sector() operation

Support generic alternative_gpt_sector() block device operation.
It calculates location of GPT entry for eMMC of NVIDIA Tegra Android
devices.

mmc: block: Support alternative_gpt_sector() operation

Support generic alternative_gpt_sector() block device operation.
It calculates location of GPT entry for eMMC of NVIDIA Tegra Android
devices. Add new MMC_CAP2_ALT_GPT_TEGRA flag that enables scanning of
alternative GPT sector and add raw_boot_mult field to mmc_ext_csd
which allows to get size of the boot partitions that is needed for
the calculation.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20210820004536.15791-4-digetx@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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mmc: core: Move eMMC cache flushing to a new bus_ops callback

To prepare to add internal cache management for SD cards, let's start by
moving the eMMC specific code into a new ->flush_cache() bus_op

mmc: core: Move eMMC cache flushing to a new bus_ops callback

To prepare to add internal cache management for SD cards, let's start by
moving the eMMC specific code into a new ->flush_cache() bus_ops callback.

In this way, it becomes straight forward to add the SD specific parts,
as subsequent changes are about to show.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210506145829.198823-2-ulf.hansson@linaro.org

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mmc: core: Enable eMMC sleep commands to use HW busy polling

After the eMMC sleep command (CMD5) has been sent, the card start signals
busy on the DAT0 line, which can be monitored to understand whe

mmc: core: Enable eMMC sleep commands to use HW busy polling

After the eMMC sleep command (CMD5) has been sent, the card start signals
busy on the DAT0 line, which can be monitored to understand when it's
allowed to proceed to power off the VCC regulator.

When MMC_CAP_WAIT_WHILE_BUSY isn't supported by the host the DAT0 line
isn't being monitored for busy completion, but instead we are waiting a
fixed period of time. The time corresponds to the sleep timeout that is
specified in the EXT_CSD register of the eMMC card. This is many cases
suboptimal, as the timeout corresponds to the worst case scenario.

To improve the situation add support for HW busy polling through the
->card_busy() host ops, when the host supports this.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Acked-by: Avri Altman <avri.altman@wdc.com>
Link: https://lore.kernel.org/r/20210504161222.101536-6-ulf.hansson@linaro.org

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mmc: core: Drop open coding when preparing commands with busy signaling

Similar code for validating the host->max_busy_timeout towards the current
command's busy timeout, exists in mmc_do_erase(), m

mmc: core: Drop open coding when preparing commands with busy signaling

Similar code for validating the host->max_busy_timeout towards the current
command's busy timeout, exists in mmc_do_erase(), mmc_sleep() and
__mmc_switch(). Let's move the common code into a helper function.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Acked-by: Avri Altman <avri.altman@wdc.com>
Link: https://lore.kernel.org/r/20210504161222.101536-2-ulf.hansson@linaro.org

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mmc: block: Issue a cache flush only when it's enabled

In command queueing mode, the cache isn't flushed via the mmc_flush_cache()
function, but instead by issuing a CMDQ_TASK_MGMT (CMD48) with a
FL

mmc: block: Issue a cache flush only when it's enabled

In command queueing mode, the cache isn't flushed via the mmc_flush_cache()
function, but instead by issuing a CMDQ_TASK_MGMT (CMD48) with a
FLUSH_CACHE opcode. In this path, we need to check if cache has been
enabled, before deciding to flush the cache, along the lines of what's
being done in mmc_flush_cache().

To fix this problem, let's add a new bus ops callback ->cache_enabled() and
implement it for the mmc bus type. In this way, the mmc block device driver
can call it to know whether cache flushing should be done.

Fixes: 1e8e55b67030 (mmc: block: Add CQE support)
Cc: stable@vger.kernel.org
Reported-by: Brendan Peter <bpeter@lytx.com>
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Tested-by: Brendan Peter <bpeter@lytx.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20210425060207.2591-2-avri.altman@wdc.com
Link: https://lore.kernel.org/r/20210425060207.2591-3-avri.altman@wdc.com
[Ulf: Squashed the two patches and made some minor updates]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Add a retries parameter to __mmc_switch function

Add command retries parameter to __mmc_switch(), let caller
pass retries according to the caller's condition.

Signed-off-by: Bean Huo <be

mmc: core: Add a retries parameter to __mmc_switch function

Add command retries parameter to __mmc_switch(), let caller
pass retries according to the caller's condition.

Signed-off-by: Bean Huo <beanhuo@micron.com>
Link: https://lore.kernel.org/r/20210414212236.346813-2-huobean@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Fix partition switch time for eMMC

Avoid the following warning by always defining partition switch time:

[ 3.209874] mmc1: unspecified timeout for CMD6 - use generic
[ 3.222780]

mmc: core: Fix partition switch time for eMMC

Avoid the following warning by always defining partition switch time:

[ 3.209874] mmc1: unspecified timeout for CMD6 - use generic
[ 3.222780] ------------[ cut here ]------------
[ 3.233363] WARNING: CPU: 1 PID: 111 at drivers/mmc/core/mmc_ops.c:575 __mmc_switch+0x200/0x204

Reported-by: Paul Fertser <fercerpav@gmail.com>
Fixes: 1c447116d017 ("mmc: mmc: Fix partition switch timeout for some eMMCs")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/168bbfd6-0c5b-5ace-ab41-402e7937c46e@intel.com
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: remove redundant card null check to mmc_can_sleep()

Note that only _mmc_suspend() will call mmc_can_sleep(). And card is
checked before in mmc_can_poweroff_notify().

Signed-off-by: Yue H

mmc: core: remove redundant card null check to mmc_can_sleep()

Note that only _mmc_suspend() will call mmc_can_sleep(). And card is
checked before in mmc_can_poweroff_notify().

Signed-off-by: Yue Hu <huyue2@yulong.com>
Link: https://lore.kernel.org/r/20210115034506.646-1-zbestahu@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: remove needless err = 0 in mmc_init_card()

Since they will always being in successful path to return 0 directly,
no need to set err = 0.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Link: h

mmc: core: remove needless err = 0 in mmc_init_card()

Since they will always being in successful path to return 0 directly,
no need to set err = 0.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Link: https://lore.kernel.org/r/20210113113431.522-1-zbestahu@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: block: Issue a cache flush only when it's enabled

commit 97fce126e279690105ee15be652b465fd96f9997 upstream.

In command queueing mode, the cache isn't flushed via the mmc_flush_cache()
function

mmc: block: Issue a cache flush only when it's enabled

commit 97fce126e279690105ee15be652b465fd96f9997 upstream.

In command queueing mode, the cache isn't flushed via the mmc_flush_cache()
function, but instead by issuing a CMDQ_TASK_MGMT (CMD48) with a
FLUSH_CACHE opcode. In this path, we need to check if cache has been
enabled, before deciding to flush the cache, along the lines of what's
being done in mmc_flush_cache().

To fix this problem, let's add a new bus ops callback ->cache_enabled() and
implement it for the mmc bus type. In this way, the mmc block device driver
can call it to know whether cache flushing should be done.

Fixes: 1e8e55b67030 (mmc: block: Add CQE support)
Cc: stable@vger.kernel.org
Reported-by: Brendan Peter <bpeter@lytx.com>
Signed-off-by: Avri Altman <avri.altman@wdc.com>
Tested-by: Brendan Peter <bpeter@lytx.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20210425060207.2591-2-avri.altman@wdc.com
Link: https://lore.kernel.org/r/20210425060207.2591-3-avri.altman@wdc.com
[Ulf: Squashed the two patches and made some minor updates]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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mmc: core: Fix partition switch time for eMMC

commit 66fbacccbab91e6e55d9c8f1fc0910a8eb6c81f7 upstream.

Avoid the following warning by always defining partition switch time:

[ 3.209874] mmc1:

mmc: core: Fix partition switch time for eMMC

commit 66fbacccbab91e6e55d9c8f1fc0910a8eb6c81f7 upstream.

Avoid the following warning by always defining partition switch time:

[ 3.209874] mmc1: unspecified timeout for CMD6 - use generic
[ 3.222780] ------------[ cut here ]------------
[ 3.233363] WARNING: CPU: 1 PID: 111 at drivers/mmc/core/mmc_ops.c:575 __mmc_switch+0x200/0x204

Reported-by: Paul Fertser <fercerpav@gmail.com>
Fixes: 1c447116d017 ("mmc: mmc: Fix partition switch timeout for some eMMCs")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/168bbfd6-0c5b-5ace-ab41-402e7937c46e@intel.com
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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mmc: core: clear 'doing_init_tune' also after failures

Reorganize the code, so that the flag is always cleared independently of
a good or bad case.

Fixes: 97a7d87e96b0 ("mmc: core: add a 'doing_ini

mmc: core: clear 'doing_init_tune' also after failures

Reorganize the code, so that the flag is always cleared independently of
a good or bad case.

Fixes: 97a7d87e96b0 ("mmc: core: add a 'doing_init_tune' flag and a 'mmc_doing_tune' helper")
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20200914112845.21855-1-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: simplify an expression

We already have 'host' as a variable, so use it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.u

mmc: core: simplify an expression

We already have 'host' as a variable, so use it.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20200901150250.26236-5-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: add a 'doing_init_tune' flag and a 'mmc_doing_tune' helper

Our driver needs to know when tuning is in progress. 'doing_retune' only
covers re-tuning, not the initial tuning. Add another f

mmc: core: add a 'doing_init_tune' flag and a 'mmc_doing_tune' helper

Our driver needs to know when tuning is in progress. 'doing_retune' only
covers re-tuning, not the initial tuning. Add another flag to detect the
initial tuning state and add a helper which tells us if any kind of
tuning is going on. Only implemented for MMC currently because that's
where we need it. SD can be added later if it becomes necessary.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20200901150250.26236-3-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: when downgrading HS400, callback into drivers earlier

The driver specific downgrade function makes more sense if we run it
before we set the timing to something lower, not after. Otherwis

mmc: core: when downgrading HS400, callback into drivers earlier

The driver specific downgrade function makes more sense if we run it
before we set the timing to something lower, not after. Otherwise some
non-HS400 communication has already happened.

No need to convert users. There is only one currently which needs this
change in a following patch.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/20200901150250.26236-2-wsa+renesas@sang-engineering.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Add MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND

The commit 5a36d6bcdf23 ("mmc: core: Add DT-bindings for
MMC_CAP2_FULL_PWR_CYCLE") added the "full-pwr-cycle" property which
is possible to perform

mmc: core: Add MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND

The commit 5a36d6bcdf23 ("mmc: core: Add DT-bindings for
MMC_CAP2_FULL_PWR_CYCLE") added the "full-pwr-cycle" property which
is possible to perform a full power cycle of the card at any time.

However, some environment (like r8a77951-salvator-xs) is possible
to perform a full power cycle of the card in suspend via firmware
(PSCI on arm-trusted-firmware). So, in worst case, since we are
not doing a graceful shutdown of the eMMC device (just cut VCCQ
while the eMMC is "sleeping") in suspend, it could lead to internal
data corruptions. So, add MMC_CAP2_FULL_PWR_CYCLE_IN_SUSPEND
to do a graceful shutdown which issues Power Off notification
before entering system suspend.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Link: https://lore.kernel.org/r/1594123122-13156-3-git-send-email-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: expose info about enhanced rpmb support

Following eMMC JEDEC JESD84-B51 standard, an enhanced form of
rpmb is supported. What this enhanced mode supports is in addition
to be able to writ

mmc: core: expose info about enhanced rpmb support

Following eMMC JEDEC JESD84-B51 standard, an enhanced form of
rpmb is supported. What this enhanced mode supports is in addition
to be able to write one rpmb or two rpmb frames at a time,
32 frames can be written at a time.

Expose this information present in ext csd field so that the
user space application that wants to make use of this can do so.

Signed-off-by: Krishna Konda <kkonda@codeaurora.org>
Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
Link: https://lore.kernel.org/r/1588341189-4371-1-git-send-email-vbadigan@codeaurora.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Drop redundant in-parameter to __mmc_switch()

The use_busy_signal in-parameter is set true by all callers of
__mmc_switch(), hence it's redundant so drop it.

Signed-off-by: Ulf Hansson <

mmc: core: Drop redundant in-parameter to __mmc_switch()

The use_busy_signal in-parameter is set true by all callers of
__mmc_switch(), hence it's redundant so drop it.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Tested-by: Ludovic Barre <ludovic.barre@st.com>
Reviewed-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200204085449.32585-5-ulf.hansson@linaro.org

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mmc: core: Extend mmc_switch_status() to rid of __mmc_switch_status()

To simplify code, let's extend mmc_switch_status() to cope with needs
addressed in __mmc_switch_status(). Then move all users to

mmc: core: Extend mmc_switch_status() to rid of __mmc_switch_status()

To simplify code, let's extend mmc_switch_status() to cope with needs
addressed in __mmc_switch_status(). Then move all users to the updated
mmc_switch_status() API and drop __mmc_switch_status() altogether.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Baolin Wang <baolin.wang7@gmail.com>
Tested-by: Ludovic Barre <ludovic.barre@st.com>
Reviewed-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200204085449.32585-4-ulf.hansson@linaro.org

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mmc: Add MMC host software queue support

Now the MMC read/write stack will always wait for previous request is
completed by mmc_blk_rw_wait(), before sending a new request to hardware,
or queue a wo

mmc: Add MMC host software queue support

Now the MMC read/write stack will always wait for previous request is
completed by mmc_blk_rw_wait(), before sending a new request to hardware,
or queue a work to complete request, that will bring context switching
overhead and spend some extra time to poll the card for busy completion
for I/O writes via sending CMD13, especially for high I/O per second
rates, to affect the IO performance.

Thus this patch introduces MMC software queue interface based on the
hardware command queue engine's interfaces, which is similar with the
hardware command queue engine's idea, that can remove the context
switching. Moreover we set the default queue depth as 64 for software
queue, which allows more requests to be prepared, merged and inserted
into IO scheduler to improve performance, but we only allow 2 requests
in flight, that is enough to let the irq handler always trigger the
next request without a context switch, as well as avoiding a long latency.

Moreover the host controller should support HW busy detection for I/O
operations when enabling the host software queue. That means, the host
controller must not complete a data transfer request, until after the
card stops signals busy.

From the fio testing data in cover letter, we can see the software
queue can improve some performance with 4K block size, increasing
about 16% for random read, increasing about 90% for random write,
though no obvious improvement for sequential read and write.

Moreover we can expand the software queue interface to support MMC
packed request or packed command in future.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Link: https://lore.kernel.org/r/4409c1586a9b3ed20d57ad2faf6c262fc3ccb6e2.1581478568.git.baolin.wang7@gmail.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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mmc: core: Respect MMC_CAP_NEED_RSP_BUSY for eMMC sleep command

The busy timeout for the CMD5 to put the eMMC into sleep state, is specific
to the card. Potentially the timeout may exceed the host->

mmc: core: Respect MMC_CAP_NEED_RSP_BUSY for eMMC sleep command

The busy timeout for the CMD5 to put the eMMC into sleep state, is specific
to the card. Potentially the timeout may exceed the host->max_busy_timeout.
If that becomes the case, mmc_sleep() converts from using an R1B response
to an R1 response, as to prevent the host from doing HW busy detection.

However, it has turned out that some hosts requires an R1B response no
matter what, so let's respect that via checking MMC_CAP_NEED_RSP_BUSY. Note
that, if the R1B gets enforced, the host becomes fully responsible of
managing the needed busy timeout, in one way or the other.

Suggested-by: Sowjanya Komatineni <skomatineni@nvidia.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200311092036.16084-1-ulf.hansson@linaro.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

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