linux-stable.git/drivers/mmc, branch linux-4.5.y Linux kernel stable tree mmc: sdhci-pci: Remove MMC_CAP_BUS_WIDTH_TEST for Intel controllers 2016-06-01T19:16:59+00:00 Adrian Hunter adrian.hunter@intel.com 2016-05-20T07:33:47+00:00 4f0699a50407a96a31f67050dda11debb52650ee commit 822969369482166050c5b2f7013501505e025c39 upstream. The CMD19/CMD14 bus width test has been found to be unreliable in some cases. It is not essential, so simply remove it. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 822969369482166050c5b2f7013501505e025c39 upstream.

The CMD19/CMD14 bus width test has been found to be unreliable in
some cases.  It is not essential, so simply remove it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: longer timeout for long read time quirk 2016-06-01T19:16:59+00:00 Matt Gumbel matthew.k.gumbel@intel.com 2016-05-20T07:33:46+00:00 67bfab0a4c0ea829d51d7cb20db7da7be04caa42 commit 32ecd320db39bcb007679ed42f283740641b81ea upstream. 008GE0 Toshiba mmc in some Intel Baytrail tablets responds to MMC_SEND_EXT_CSD in 450-600ms. This patch will... () Increase the long read time quirk timeout from 300ms to 600ms. Original author of that quirk says 300ms was only a guess and that the number may need to be raised in the future. () Add this specific MMC to the quirk Signed-off-by: Matt Gumbel <matthew.k.gumbel@intel.com> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 32ecd320db39bcb007679ed42f283740641b81ea upstream.

008GE0 Toshiba mmc in some Intel Baytrail tablets responds to
MMC_SEND_EXT_CSD in 450-600ms.

This patch will...

() Increase the long read time quirk timeout from 300ms to 600ms. Original
   author of that quirk says 300ms was only a guess and that the number
   may need to be raised in the future.

() Add this specific MMC to the quirk

Signed-off-by: Matt Gumbel <matthew.k.gumbel@intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: sdhci-acpi: Remove MMC_CAP_BUS_WIDTH_TEST for Intel controllers 2016-06-01T19:16:59+00:00 Adrian Hunter adrian.hunter@intel.com 2016-05-20T07:33:48+00:00 96b9a9728452e7c551951903b40f1ba5b128445c commit 265984b36ce82fec67957d452dd2b22e010611e4 upstream. The CMD19/CMD14 bus width test has been found to be unreliable in some cases. It is not essential, so simply remove it. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 265984b36ce82fec67957d452dd2b22e010611e4 upstream.

The CMD19/CMD14 bus width test has been found to be unreliable in
some cases.  It is not essential, so simply remove it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: sdhci-acpi: Ensure connected devices are powered when probing 2016-06-01T19:16:59+00:00 Adrian Hunter adrian.hunter@intel.com 2016-05-19T13:25:42+00:00 36bb9f187f9c24294ff13e7e25fdb24ae82cfbd8 commit e5bbf30733f930a1d17b4ccf19eac88e30a39cc7 upstream. Some devices connected to the SDHCI controller may have separate enabling lines that are controlled through GPIO. These devices need to be powered on and enabled before probing. This is to ensure all devices connected can be seen by the controller. Note, for "stable" this patch depends on the following change: commit 78a898d0e395 ("ACPI / PM: Export acpi_device_fix_up_power()") Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reported-and-tested-by: Laszlo Fiat <laszlo.fiat@gmail.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Reported-by: Laszlo Fiat <laszlo.fiat@gmail.com> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=112571 Link: http://lkml.kernel.org/r/CA+7w51inLtQSr656bJvOjGG9oQWKYPXH+xxDPJKbeJ=CcrkS9Q@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit e5bbf30733f930a1d17b4ccf19eac88e30a39cc7 upstream.

Some devices connected to the SDHCI controller may have separate enabling
lines that are controlled through GPIO. These devices need to be powered
on and enabled before probing. This is to ensure all devices connected can
be seen by the controller.

Note, for "stable" this patch depends on the following change:
commit 78a898d0e395 ("ACPI / PM: Export acpi_device_fix_up_power()")

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reported-and-tested-by: Laszlo Fiat <laszlo.fiat@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reported-by: Laszlo Fiat <laszlo.fiat@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=112571
Link: http://lkml.kernel.org/r/CA+7w51inLtQSr656bJvOjGG9oQWKYPXH+xxDPJKbeJ=CcrkS9Q@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: mmc: Fix partition switch timeout for some eMMCs 2016-06-01T19:16:58+00:00 Adrian Hunter adrian.hunter@intel.com 2016-05-05T05:12:28+00:00 88295eda162d8ff85c52e06d75875c67dd94f530 commit 1c447116d017a98c90f8f71c8c5a611e0aa42178 upstream. Some eMMCs set the partition switch timeout too low. Now typically eMMCs are considered a critical component (e.g. because they store the root file system) and consequently are expected to be reliable. Thus we can neglect the use case where eMMCs can't switch reliably and we might want a lower timeout to facilitate speedy recovery. Although we could employ a quirk for the cards that are affected (if we could identify them all), as described above, there is little benefit to having a low timeout, so instead simply set a minimum timeout. The minimum is set to 300ms somewhat arbitrarily - the examples that have been seen had a timeout of 10ms but were sometimes taking 60-70ms. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1c447116d017a98c90f8f71c8c5a611e0aa42178 upstream.

Some eMMCs set the partition switch timeout too low.

Now typically eMMCs are considered a critical component (e.g. because
they store the root file system) and consequently are expected to be
reliable.  Thus we can neglect the use case where eMMCs can't switch
reliably and we might want a lower timeout to facilitate speedy
recovery.

Although we could employ a quirk for the cards that are affected (if
we could identify them all), as described above, there is little
benefit to having a low timeout, so instead simply set a minimum
timeout.

The minimum is set to 300ms somewhat arbitrarily - the examples that
have been seen had a timeout of 10ms but were sometimes taking 60-70ms.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: sdhci-acpi: Reduce Baytrail eMMC/SD/SDIO hangs 2016-05-04T21:49:07+00:00 Adrian Hunter adrian.hunter@intel.com 2016-04-15T11:06:57+00:00 2068f4681b73b91c62b089bdea352c6853ea752b commit 6e1c7d6103fe7031035cec321307c6356809adf4 upstream. Baytrail eMMC/SD/SDIO host controllers have been known to hang. A change to a hardware setting has been found to reduce the occurrence of such hangs. This patch ensures the correct setting. This patch applies cleanly to v4.4+. It could go to earlier kernels also, so I will send backports to the stable list in due course. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 6e1c7d6103fe7031035cec321307c6356809adf4 upstream.

Baytrail eMMC/SD/SDIO host controllers have been known to
hang.  A change to a hardware setting has been found to
reduce the occurrence of such hangs.  This patch ensures
the correct setting.

This patch applies cleanly to v4.4+.  It could go to
earlier kernels also, so I will send backports to the
stable list in due course.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: block: Use the mmc host device index as the mmcblk device index 2016-05-04T21:48:57+00:00 Ulf Hansson ulf.hansson@linaro.org 2016-04-06T14:12:08+00:00 58821da858919f93f85c7e6823b49d439722a9e9 commit 9aaf3437aa72ed5370bf32c99580a3fa2c330e3d upstream. Commit 520bd7a8b415 ("mmc: core: Optimize boot time by detecting cards simultaneously") causes regressions for some platforms. These platforms relies on fixed mmcblk device indexes, instead of deploying the defacto standard with UUID/PARTUUID. In other words their rootfs needs to be available at hardcoded paths, like /dev/mmcblk0p2. Such guarantees have never been made by the kernel, but clearly the above commit changes the behaviour. More precisely, because of that the order changes of how cards becomes detected, so do their corresponding mmcblk device indexes. As the above commit significantly improves boot time for some platforms (magnitude of seconds), let's avoid reverting this change but instead restore the behaviour of how mmcblk device indexes becomes picked. By using the same index for the mmcblk device as for the corresponding mmc host device, the probe order of mmc host devices decides the index we get for the mmcblk device. For those platforms that suffers from a regression, one could expect that this updated behaviour should be sufficient to meet their expectations of "fixed" mmcblk device indexes. Another side effect from this change, is that the same index is used for the mmc host device, the mmcblk device and the mmc block queue. That should clarify their relationship. Reported-by: Peter Hurley <peter@hurleysoftware.com> Reported-by: Laszlo Fiat <laszlo.fiat@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Fixes: 520bd7a8b415 ("mmc: core: Optimize boot time by detecting cards simultaneously") Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9aaf3437aa72ed5370bf32c99580a3fa2c330e3d upstream.

Commit 520bd7a8b415 ("mmc: core: Optimize boot time by detecting cards
simultaneously") causes regressions for some platforms.

These platforms relies on fixed mmcblk device indexes, instead of
deploying the defacto standard with UUID/PARTUUID. In other words their
rootfs needs to be available at hardcoded paths, like /dev/mmcblk0p2.

Such guarantees have never been made by the kernel, but clearly the above
commit changes the behaviour. More precisely, because of that the order
changes of how cards becomes detected, so do their corresponding mmcblk
device indexes.

As the above commit significantly improves boot time for some platforms
(magnitude of seconds), let's avoid reverting this change but instead
restore the behaviour of how mmcblk device indexes becomes picked.

By using the same index for the mmcblk device as for the corresponding mmc
host device, the probe order of mmc host devices decides the index we get
for the mmcblk device.

For those platforms that suffers from a regression, one could expect that
this updated behaviour should be sufficient to meet their expectations of
"fixed" mmcblk device indexes.

Another side effect from this change, is that the same index is used for
the mmc host device, the mmcblk device and the mmc block queue. That
should clarify their relationship.

Reported-by: Peter Hurley <peter@hurleysoftware.com>
Reported-by: Laszlo Fiat <laszlo.fiat@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Fixes: 520bd7a8b415 ("mmc: core: Optimize boot time by detecting cards
simultaneously")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: sdhci-pci: Add support and PCI IDs for more Broxton host controllers 2016-04-20T06:45:26+00:00 Adrian Hunter adrian.hunter@intel.com 2016-04-04T09:40:37+00:00 9e91bf335767d83368fb0e1dbfa4342bffaa0b0f commit 01d6b2a40a0fa73c90e05b1033f181a51fec9292 upstream. Add support and PCI IDs for more Broxton host controllers Other BXT IDs were added in v4.4 so cc'ing stable. This patch is dependent on commit 163cbe31e516 ("mmc: sdhci-pci: Fix card detect race for Intel BXT/APL") but that is already in stable since v4.4.4. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 01d6b2a40a0fa73c90e05b1033f181a51fec9292 upstream.

Add support and PCI IDs for more Broxton host controllers

Other BXT IDs were added in v4.4 so cc'ing stable. This patch
is dependent on commit 163cbe31e516 ("mmc: sdhci-pci: Fix card
detect race for Intel BXT/APL") but that is already in stable
since v4.4.4.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: sdhci: Fix regression setting power on Trats2 board 2016-04-20T06:45:26+00:00 Adrian Hunter adrian.hunter@intel.com 2016-03-29T09:45:43+00:00 46d75c0b7432a53014055044fa06c0c77bf0a5b2 commit 1dceb0415aa0c6bc11dacdab47c9ef83a3604166 upstream. Several commits relating to setting power have been introducing problems by putting driver-specific rules into generic SDHCI code. Krzysztof Kozlowski reported that after commit 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD via external regulator") on Trats2 board there are warnings for invalid VDD value (2.8V): [ 3.119656] ------------[ cut here ]------------ [ 3.119666] WARNING: CPU: 3 PID: 90 at ../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0 [ 3.119669] mmc0: Invalid vdd 0x10 [ 3.119673] Modules linked in: [ 3.119679] CPU: 3 PID: 90 Comm: kworker/3:1 Tainted: G W 4.5.0-next-20160324 #23 [ 3.119681] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 3.119690] Workqueue: events_freezable mmc_rescan [ 3.119708] [<c010e0ac>] (unwind_backtrace) from [<c010ae10>] (show_stack+0x10/0x14) [ 3.119719] [<c010ae10>] (show_stack) from [<c0323260>] (dump_stack+0x88/0x9c) [ 3.119728] [<c0323260>] (dump_stack) from [<c011b754>] (__warn+0xe8/0x100) [ 3.119734] [<c011b754>] (__warn) from [<c011b7a4>] (warn_slowpath_fmt+0x38/0x48) [ 3.119740] [<c011b7a4>] (warn_slowpath_fmt) from [<c0527d28>] (sdhci_do_set_ios+0x4cc/0x5e0) [ 3.119748] [<c0527d28>] (sdhci_do_set_ios) from [<c0528018>] (sdhci_runtime_resume_host+0x60/0x114) [ 3.119758] [<c0528018>] (sdhci_runtime_resume_host) from [<c0402570>] (__rpm_callback+0x2c/0x60) [ 3.119767] [<c0402570>] (__rpm_callback) from [<c04025c4>] (rpm_callback+0x20/0x80) [ 3.119773] [<c04025c4>] (rpm_callback) from [<c04034b8>] (rpm_resume+0x36c/0x558) [ 3.119780] [<c04034b8>] (rpm_resume) from [<c04036f0>] (__pm_runtime_resume+0x4c/0x64) [ 3.119788] [<c04036f0>] (__pm_runtime_resume) from [<c0512728>] (__mmc_claim_host+0x170/0x1b0) [ 3.119795] [<c0512728>] (__mmc_claim_host) from [<c0514e2c>] (mmc_rescan+0x54/0x348) [ 3.119807] [<c0514e2c>] (mmc_rescan) from [<c0130dac>] (process_one_work+0x120/0x3f4) [ 3.119815] [<c0130dac>] (process_one_work) from [<c01310b8>] (worker_thread+0x38/0x554) [ 3.119823] [<c01310b8>] (worker_thread) from [<c01365a4>] (kthread+0xdc/0xf4) [ 3.119831] [<c01365a4>] (kthread) from [<c0107878>] (ret_from_fork+0x14/0x3c) [ 3.119834] ---[ end trace a22d652aa3276886 ]--- Fix by adding a 'set_power' callback and restoring the default behaviour prior to commit 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD via external regulator"). The desired behaviour of that commit is gotten by having sdhci-pxav3 provide its own set_power callback. Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Link: http://lkml.kernel.org/r/CAJKOXPcGDnPm-Ykh6wHqV1YxfTaov5E8iVqBoBn4OJc7BnhgEQ@mail.gmail.com Fixes: 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD...) Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Jisheng Zhang <jszhang@marvell.com> Tested-by: Jisheng Zhang <jszhang@marvell.com> Tested-by: Jaehoon Chung <jh80.chung@samsung.com> Tested-by: Anand Moon <linux.amoon@gmail.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 1dceb0415aa0c6bc11dacdab47c9ef83a3604166 upstream.

Several commits relating to setting power have been introducing
problems by putting driver-specific rules into generic SDHCI code.

Krzysztof Kozlowski reported that after commit 918f4cbd4340 ("mmc:
sdhci: restore behavior when setting VDD via external regulator")
on Trats2 board there are warnings for invalid VDD  value (2.8V):

[    3.119656] ------------[ cut here ]------------
[    3.119666] WARNING: CPU: 3 PID: 90 at
../drivers/mmc/host/sdhci.c:1234 sdhci_do_set_ios+0x4cc/0x5e0
[    3.119669] mmc0: Invalid vdd 0x10
[    3.119673] Modules linked in:
[    3.119679] CPU: 3 PID: 90 Comm: kworker/3:1 Tainted: G        W
   4.5.0-next-20160324 #23
[    3.119681] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[    3.119690] Workqueue: events_freezable mmc_rescan
[    3.119708] [<c010e0ac>] (unwind_backtrace) from [<c010ae10>]
(show_stack+0x10/0x14)
[    3.119719] [<c010ae10>] (show_stack) from [<c0323260>]
(dump_stack+0x88/0x9c)
[    3.119728] [<c0323260>] (dump_stack) from [<c011b754>] (__warn+0xe8/0x100)
[    3.119734] [<c011b754>] (__warn) from [<c011b7a4>]
(warn_slowpath_fmt+0x38/0x48)
[    3.119740] [<c011b7a4>] (warn_slowpath_fmt) from [<c0527d28>]
(sdhci_do_set_ios+0x4cc/0x5e0)
[    3.119748] [<c0527d28>] (sdhci_do_set_ios) from [<c0528018>]
(sdhci_runtime_resume_host+0x60/0x114)
[    3.119758] [<c0528018>] (sdhci_runtime_resume_host) from
[<c0402570>] (__rpm_callback+0x2c/0x60)
[    3.119767] [<c0402570>] (__rpm_callback) from [<c04025c4>]
(rpm_callback+0x20/0x80)
[    3.119773] [<c04025c4>] (rpm_callback) from [<c04034b8>]
(rpm_resume+0x36c/0x558)
[    3.119780] [<c04034b8>] (rpm_resume) from [<c04036f0>]
(__pm_runtime_resume+0x4c/0x64)
[    3.119788] [<c04036f0>] (__pm_runtime_resume) from [<c0512728>]
(__mmc_claim_host+0x170/0x1b0)
[    3.119795] [<c0512728>] (__mmc_claim_host) from [<c0514e2c>]
(mmc_rescan+0x54/0x348)
[    3.119807] [<c0514e2c>] (mmc_rescan) from [<c0130dac>]
(process_one_work+0x120/0x3f4)
[    3.119815] [<c0130dac>] (process_one_work) from [<c01310b8>]
(worker_thread+0x38/0x554)
[    3.119823] [<c01310b8>] (worker_thread) from [<c01365a4>]
(kthread+0xdc/0xf4)
[    3.119831] [<c01365a4>] (kthread) from [<c0107878>]
(ret_from_fork+0x14/0x3c)
[    3.119834] ---[ end trace a22d652aa3276886 ]---

Fix by adding a 'set_power' callback and restoring the default
behaviour prior to commit 918f4cbd4340 ("mmc: sdhci: restore
behavior when setting VDD via external regulator").  The desired
behaviour of that commit is gotten by having sdhci-pxav3 provide
its own set_power callback.

Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Link: http://lkml.kernel.org/r/CAJKOXPcGDnPm-Ykh6wHqV1YxfTaov5E8iVqBoBn4OJc7BnhgEQ@mail.gmail.com
Fixes: 918f4cbd4340 ("mmc: sdhci: restore behavior when setting VDD...)
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Jisheng Zhang <jszhang@marvell.com>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Tested-by: Jaehoon Chung <jh80.chung@samsung.com>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mmc: atmel-mci: Check pdata for NULL before dereferencing it at DMA config 2016-04-12T14:33:45+00:00 Brent Taylor motobud@gmail.com 2016-03-13T06:25:31+00:00 ae854643c178226d63c273df8bc1d42556d80540 commit 93c77d2999b09f2084b033ea6489915e0104ad9c upstream. Using an at91sam9g20ek development board with DTS configuration may trigger a kernel panic because of a NULL pointer dereference exception, while configuring DMA. Let's fix this by adding a check for pdata before dereferencing it. Signed-off-by: Brent Taylor <motobud@gmail.com> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 93c77d2999b09f2084b033ea6489915e0104ad9c upstream.

Using an at91sam9g20ek development board with DTS configuration may trigger
a kernel panic because of a NULL pointer dereference exception, while
configuring DMA. Let's fix this by adding a check for pdata before
dereferencing it.

Signed-off-by: Brent Taylor <motobud@gmail.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>