Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

This issue was detected by using the Coccinelle software.
Signed-off-by: NMarkus Elfring <elfring@users.sourceforge.net>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Following up the device tree fixed in commits e78c6371 ("ARM: dts:
rockchip: Fix DWMMC clocks") and ca9eee95 ("arm64: dts: rockchip:
Fix DWMMC clocks", 2018-02-15), avoid confusion by using the correct
property name in the debug output if clocks are not found.
Signed-off-by: NJohn Keeping <john@metanate.com>
Reviewed-by: NRobin Murphy <robin.murphy@arm.com>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Variable err would be firstly initialized by the return value of
mmc_sd_switch().
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Since we could move card->host->caps & MMC_CAP_4_BIT_DATA
ahead of mmc_sdio_init_uhs_card, in mmc_host_uhs(). So there
we could save this bit to check that. Also, if the process of
sdio_enable_4bit_bus goes wrong, we should bails out early.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Per SD specification physical layer v4.0, section 3.9.4, it
says "UHS-I supports only 4-bit mode. Host shall select 4-bit
mode by ACMD6. However mmc_sd_init_uhs_card() still go ahead
to initialize the cards anyway, whether card or host won't
support 4-bit mode.

  This breaks the platforms which could support UHS-I mode but on
some certain boards only support 1-bit mode with a UHS-I card inserted,
as all the tuning process is broken due to this. Alternatively, we
should check the return value from mmc_set_bus_width() to see if host
could finish the request to switch the bus width on its side. But that
needs more thing to do than this patch that just bails out early to try
high speed mode if 4-bit mode isn't available for whatever reason. And
this patch could also fix the same problem for sdio since R4_18V_PRESENT
won't be set for ocr when mmc_sdio_init_card() finds mmc_host_uhs()
is false.

  Note that this patch doesn't keep the checking of card->scr.sda_spec3
and comparing card->scr.bus_widths with SD_SCR_BUS_WIDTH_4 within
mmc_sd_init_uhs_card() since if the sd cards response with SD_ROCR_S18A,
it definitely supports UHS-I mode, which implicitly means these checkings
are always true.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

'num-slots' property had already deprecated.
Remove the 'nom-slots' property that is kept to maintain the compatibility.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

'clock-freq-min-max' property had already deprecated.
Remove the 'clock-freq-min-max' property that is kept to maintain
the compatibility.
Signed-off-by: NJaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Just applying the existing logic and adding its own characteristics into
the space pointed by an extra entry of struct of_device_id to have support
of MT7622 SoC.
Signed-off-by: NChaotian Jing <chaotian.jing@mediatek.com>
Signed-off-by: NSean Wang <sean.wang@mediatek.com>
Tested-by: NJumin Li <jumin.li@mediatek.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Commit 03dbaa04 ("mmc: slot-gpio: Add support to enable irq wake on
cd_irq") enabled wakeup at initialization. However, users also want to
control it from sysfs power/wakeup attribute. That means the driver needs
to check the PM flags before enabling it in the suspend callback. Add
support for that in sdhci-pci, which is the only driver presently using the
MMC_CAP_CD_WAKE flag, and remove the enabling in mmc_gpiod_request_cd_irq()
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Commit 03dbaa04 ("mmc: slot-gpio: Add support to enable irq wake on
cd_irq") enabled wakeup at initialization. However drivers may wish to
enable and disable based on different criteria. Add a helper function
mmc_gpio_set_cd_wake() to make it easy for drivers to do that.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Do not enable wakeup for SDIO card interrupt unless the SDIO function
driver has requested it which is indicated by mmc_card_wake_sdio_irq().
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Do not unnecessarily enable card detect wakeup in the cases that the card
is not removable or a GPIO is used for card detect.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Now that tuning no longer leaves the Buffer Read Enable bit set (refer
intel_execute_tuning()), glk_cqe_enable() is no longer needed. Get rid of
it.
Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Not sure why it was there in the first place, but it's
obviously useless check, so let's remove it.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

cur_slot and num_slots has been removed from struct dw_mci in 42f989c0.
Unfortunately, inline documentation was not updated so far.

Fix @lock field documentation in Locking section.
Move @mrq field of struct dw_mci_slot mention closer to it
description, so no one could miss this slightest detail.

Couple of code style fixes as a bonus.
Signed-off-by: NAlexey Roslyakov <alexey.roslyakov@gmail.com>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Acked-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Clang reports a compile warning:
drivers/mmc/host/dw_mmc.c:2124:5: warning: Value stored to 'prev_state'
is never read

By checking the code, prev_state and state assignment for
STATE_SENDING_CMD is indeed never used after jumping to unlock tag.
So remove it.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Acked-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Use the newly added macro to simply to the code.
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

...instead of open coding file operations followed by custom ->open()
callbacks per each attribute.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: NAvri Altman <avri.altman@wdc.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

TMIO_MASK_CMD is properly enabled in tmio_mmc_start_command().

We have no reason to set it up in tmio_mmc_host_probe().  (If we
really wanted to set it in the probe, we would have to do likewise
when resuming.)

Even worse, the following code is extremely confusing:

  _host->sdcard_irq_mask &= ~irq_mask;

The logic is opposite between "->sdcard_irq_mask" and "irq_mask".
The intention is not clear at a glance.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-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>

Currently, force_pio is cleared when the driver exits.  Then, it
resulted in clearing it in multiple places since MMC drivers in
general have multiple exit points.

 tmio_mmc_reset_work - bails out on timeout
 tmio_process_mrq - error out when it cannot send a command
 tmio_mmc_finish_request - successful exit

This is error-prone since we may miss to cover all bail-out points.

To simplify the code, the data structure should be initialized just
before used since we have a single entrance.  force_pio is only used
for data transfer, so tmio_mmc_start_data() will be a suitable place
to clear this flag.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-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>

As far as I tested the IP on UniPhier SoCs, TMIO_STAT_{RXRDY,TXRQ}
are asserted for DMA mode as well as for PIO.  I need to disable the
those IRQs in dma_ops->start hook, otherwise the DMA transfer fails
with the following error message:
  PIO IRQ in DMA mode!

Renesas chips are the same cases since I see their dma_ops->start
hooks explicitly clear TMIO_STAT_{RXRDY,TXRQ} (with nice comment!).

If we do this sanity check in TMIO MMC core, RXRDY/TXRQ handling
should be entirely moved to the core.  tmio_mmc_cmd_irq() will
be a suitable place to disable them.

The probe function sets TMIO_MASK_{READOP,WRITEOP} but this is odd.

    /* Unmask the IRQs we want to know about */
    if (!_host->chan_rx)
            irq_mask |= TMIO_MASK_READOP;
    if (!_host->chan_tx)
            irq_mask |= TMIO_MASK_WRITEOP;

At this point, _host->{chan_rx,chan_tx} are _always_ NULL because
tmio_mmc_request_dma() is called after this code.  Consequently,
TMIO_MASK_{READOP,WRITEOP} are set here whether DMA is used or not.
Remove this pointless code.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

The TMIO mmc cannot detect the card insertion in native_hotplug mode
if the driver is probed without a card inserted.

The reason is obvious; all IRQs are disabled by tmio_mmc_host_probe(),
as follows:

  tmio_mmc_disable_mmc_irqs(_host, TMIO_MASK_ALL);

The card event IRQs are first enabled by tmio_mmc_start_command() as
follows:

  if (!host->native_hotplug)
          irq_mask &= ~(TMIO_STAT_CARD_REMOVE | TMIO_STAT_CARD_INSERT);
  tmio_mmc_enable_mmc_irqs(host, irq_mask);

If the driver is probed without a card, tmio_mmc_start_command() is
never called in the first place.  So, the card is never detected.

The card event IRQs must be enabled in probe/resume functions.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

A card detect GPIO is set up only for platforms with "cd-gpios"
DT property or TMIO_MMC_USE_GPIO_CD flag.  However, the driver
core always uses mmc_gpio_get_cd, which just fails with -ENOSYS
if ctx->cd_gpio is unset.

The bit 5 of the status register provides the current signal level
of the CD line.  Allow to use it if the GPIO is unused.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

The commit 9d9491a7 ("mmc: dw_mmc: Fix the DTO timeout calculation")
and commit 4c2357f5 ("mmc: dw_mmc: Fix the CTO timeout calculation")
made changes, which cause multiply overflow for 32-bit systems. The broken
timeout calculations leads to unexpected ETIMEDOUT errors and causes
stacktrace splat (such as below) during normal data exchange with SD-card.

| Running :  4M-check-reassembly-tcp-cmykw2-rotatew2.out -v0 -w1
| -  Info: Finished target initialization.
| mmcblk0: error -110 transferring data, sector 320544, nr 2048, cmd
| response 0x900, card status 0x0

DIV_ROUND_UP_ULL helps to escape usage of __udivdi3() from libgcc and so
code gets compiled on all 32-bit platforms as opposed to usage of
DIV_ROUND_UP when we may only compile stuff on a very few arches.

Lets cast this multiply to u64 type to prevent the overflow.

Fixes: 9d9491a7 ("mmc: dw_mmc: Fix the DTO timeout calculation")
Fixes: 4c2357f5 ("mmc: dw_mmc: Fix the CTO timeout calculation")
Tested-by: NVineet Gupta <Vineet.Gupta1@synopsys.com>
Reported-by: Vineet Gupta <Vineet.Gupta1@synopsys.com> # ARC STAR 9001306872 HSDK, sdio: board crashes when copying big files
Signed-off-by: NEvgeniy Didin <Evgeniy.Didin@synopsys.com>
Cc: <stable@vger.kernel.org> # 4.14
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NDouglas Anderson <dianders@chromium.org>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: NJisheng Zhang <Jisheng.Zhang@synaptics.com>
Acked-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

This property is equivalent to "disable-wp" defined in
Documentation/devicetree/bindings/mmc/mmc.txt

The TMIO MMC core calls mmc_of_parse(), and it sets
MMC_CAP2_NO_WRITE_PROTECT if "disable-wp" property is present.

We do not need a vendor-specific property to do the same thing.

Let's remove the description from the dt-binding to prevent new boards
from using it.

I am keeping the driver code for existing DT files, but added
comments that this is deprecated.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NRob Herring <robh@kernel.org>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

The use of this flag has been replaced with MMC_CAP2_NO_WRITE_PROTECT.
No platform defines this flag any more.  Remove.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: NLee Jones <lee.jones@linaro.org>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

TMIO_MMC_WRPROTECT_DISABLE is equivalent to MMC_CAP2_NO_WRITE_PROTECT.

Only the difference is the TMIO_... makes tmio_mmc_get_ro() return 0
(i.e. it does not affect mmc_gpio_get_ro() at all), while MMC_CAP2_...
returns 0 before calling ->get_ro() hook (i.e. it affects both IP own
logic and GPIO detection).

The TMIO MMC drivers do not set-up gpio_ro by themselves.  Only the
possibility, if any, would be DT specifies "wp-gpios" property, and
gpio_ro is set by mmc_gpiod_request_ro() called from mmc_of_parse().
However, it does not make sense to specify "wp-gpios" property and
"toshiba,mmc-wrprotect-disable" at the same time.

I checked under arch/arm/boot/dts/ and arch/arm64/boot/dts/renesas/,
and I did not see any Renesas boards with "wp-gpios".  So, this
conversion should be safe.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

TMIO_MMC_WRPROTECT_DISABLE is equivalent to MMC_CAP2_NO_WRITE_PROTECT.

The flag is propagated as follows:
       renesas_sdhi_of_data::capabilities2
    -> tmio_mmc_data::capabilities2
    -> mmc_host::caps2

Only the difference is the TMIO_... makes tmio_mmc_get_ro() return 0
(i.e. it does not affect mmc_gpio_get_ro() at all), while MMC_CAP2_...
returns 0 before calling ->get_ro() hook (i.e. it affects both IP own
logic and GPIO detection).

The TMIO MMC drivers do not set-up gpio_ro by themselves.  Only the
possibility, if any, would be DT specifies "wp-gpios" property, and
gpio_ro is set by mmc_gpiod_request_ro() called from mmc_of_parse().
However, it does not make sense to specify "wp-gpios" property and
TMIO_MMC_WRPROTECT_DISABLE at the same time.

I checked under arch/arm/boot/dts/ and arch/arm64/boot/dts/renesas/,
and I did not see any Renesas boards with "wp-gpios".  So, this
conversion should be safe.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Tested-by: NWolfram Sang <wsa+renesas@sang-engineering.com>

According to the BCM2835 datasheet there are no preset value registers.
This wasn't an issue before, because we didn't propagate 1.8V support.
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

If the max_discard value is zero, the conditional branch that checks the
trim capabilities will never update this value with max_trim.

Change the condition statement to also check the max_discard value in order
to avoid an unnecessary call to mmc_do_calc_max_discard.
Signed-off-by: NSergio Valverde <vlvrdv@gmail.com>
Reviewed-by: NShawn Lin <shawn.lin@rock-chip.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The TODO section from 2010 is obsolete. We have DMA and PM meanwhile and
we always want to handle errors better, if possible. Also DRIVER_VERSION
is not used anymore these days.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add SDHCI_QUIRK2_PRESET_VALUE_BROKEN quirk as setting preset values loads
incorrect CLKD values (for UHS modes).

Remove SDHCI_QUIRK2_NO_1_8_V quirk as sdhci-omap now supports UHS modes.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

The data manual of J6/J6 Eco recommends to set different IODELAY values
depending on the mode in which the MMC/SD is enumerated in order to
ensure IO timings are met.

Add support to set the IODELAY values depending on the various MMC
modes using the pinctrl APIs.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Errata i802 in AM572x Sitara Processors Silicon Revision 2.0, 1.1
(SPRZ429K July 2014–Revised March 2017 [1]) mentions
DCRC error interrupts (MMCHS_STAT[21] DCRC=0x1) can occur
during the tuning procedure and it has to be disabled during the
tuning procedure Implement workaround for Errata i802 here..

[1] -> http://www.ti.com/lit/er/sprz429k/sprz429k.pdfSigned-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

MMC tuning procedure is required to support SD card
UHS1-SDR104 mode and EMMC HS200 mode.

SDR104/HS200 DLL Tuning Procedure for AM572x platform is mentioned
in Figure 25-51. SDR104/HS200 DLL Tuning Procedure of
AM572x Sitara Processors Silicon Revision 2.0, 1.1 TRM
(SPRUHZ6I - October 2014–Revised April 2017 [1]).

The tuning function sdhci_omap_execute_tuning() will only be
called by the MMC/SD core if the corresponding speed modes
are supported by the OMAP silicon which is set in the mmc
host "caps" field.

[1] -> http://www.ti.com/lit/ug/spruhz6i/spruhz6i.pdfSigned-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

UHS-1 DDR50 and MMC DDR52 mode require DDR bit to be
set in the configuration register (MMCHS_CON). Add
sdhci-omap specific set_uhs_signaling ops to set
this bit. Also while setting the UHSMS bit, clock should be
disabled.
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Add card_busy host ops in sdhci_omap to check card busy status.

The voltage switching sequence for AM572x platform is mentioned
in Figure 25-48. eMMC/SD/SDIO Power Switching Procedure of
AM572x Sitara Processors Silicon Revision 2.0, 1.1 TRM
(SPRUHZ6I - October 2014–Revised April 2017 [1]).

In the voltage switching sequence, CLKEXTFREE bit in MMCHS_CON
should also be set after switching to 1.8v which is also taken
care in the card_busy ops.

[1] -> http://www.ti.com/lit/ug/spruhz6i/spruhz6i.pdfSigned-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

Updating 'power_mode' in sdhci_omap_init_74_clocks results in
'power_mode' never updated to MMC_POWER_OFF during card
removal. This results in initialization sequence not sent to the
card during re-insertion.
Fix it here by adding sdhci_omap_set_power_mode to update power_mode.
This function can also be used later to perform operations that
are specific to a power mode (e.g, disable tuning during power off).
Signed-off-by: NKishon Vijay Abraham I <kishon@ti.com>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>

As the block layer, since the conversion to blkmq, claims the host using a
context, a following nested call to mmc_claim_host(), which isn't using a
context, may hang.

Calling mmc_interrupt_hpi() and mmc_read_bkops_status() via the mmc block
layer, may suffer from this problem, as these functions are calling
mmc_claim|release_host().

Let's fix the problem by removing the calls to mmc_claim|release_host()
from the above mentioned functions and instead make the callers responsible
of claiming/releasing the host. As a matter of fact, the existing callers
already deals with it.

Fixes: 81196976 ("mmc: block: Add blk-mq support")
Reported-by: NDmitry Osipenko <digetx@gmail.com>
Suggested-by: NAdrian Hunter <adrian.hunter@intel.com>
Tested-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Acked-by: NAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: NShawn Lin <shawn.lin@rock-chips.com>

cat /sys/kernel/debug/mmc0/regs will hang up the system since
it's in runtime suspended state, so the genpd and biu_clk is
off. This patch fixes this problem by calling pm_runtime_get_sync
to wake it up before reading the registers.

Fixes: e9ed8835 ("mmc: dw_mmc: add runtime PM callback")
Cc: <stable@vger.kernel.org>
Signed-off-by: NShawn Lin <shawn.lin@rock-chips.com>
Reviewed-by: NJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>