Move common alg type init to dedicated methods.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The req->iv of the skcipher_request is expected to contain the
last used IV. Update the req->iv for CTR mode.
Fixes: bd3c7b5c2a ("crypto: atmel - add Atmel AES driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
32 bit counter is not supported by neither of our AES IPs, all implement
a 16 bit block counter. Drop the 32 bit block counter logic.
Fixes: fcac83656a ("crypto: atmel-aes - fix the counter overflow in CTR mode")
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Choose label names which say what the goto does and not from where
the goto was issued. This avoids adding superfluous labels like
"err_aes_buff".
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case the probe fails, the device/driver core takes care of printing
the driver name, device name and error code. Drop superfluous error message
at probe.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The driver no longer boots in legacy mode, only via DT. This makes the
dma_request_slave_channel_compat() redundant.
If ever the filter function would be executed it will return false as the
dma_slave is not really initialized.
Switch to use dma_request_chan() which would allow legacy boot if ever
needed again by configuring dma_slave_map for the DMA driver.
At the same time skip allocating memory for dma_slave as it is not used
anymore.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In case of in-place decryption, the "lastc" buffer is used to copy
the last ciphertext block before the decryption of the message. It
is later used to update the req->iv of the skcipher_request.
"lastc" variable is not used to interact with the hardware, there
is no restriction to be of type "u32". Change the type of "lastc"
to "u8".
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Commit 7a7ffe65c8 ("crypto: skcipher - Add top-level skcipher interface")
dated 20 august 2015 introduced the new skcipher API which is supposed to
replace both blkcipher and ablkcipher. While all consumers of the API have
been converted long ago, some producers of the ablkcipher remain, forcing
us to keep the ablkcipher support routines alive, along with the matching
code to expose [a]blkciphers via the skcipher API.
So switch this driver to the skcipher API, allowing us to finally drop the
ablkcipher code in the near future.
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Tested-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As it is if CONFIG_CRYPTO_DEV_ATMEL_AUTHENC is set to m it is in
effect disabled. This patch fixes it by using IS_ENABLED instead
of ifdef.
Fixes: 89a82ef87e ("crypto: atmel-authenc - add support to...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The driver uses a couple of buffers that seem to
be __be32 or __be64 fields, but declares them as
u32. This means there are a number of warnings
from sparse due to casting to/from __beXXX.
Fix these by changing the types of the buffer
and the associated variables.
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1023:15: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1059:28: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1059:28: expected unsigned int
drivers/crypto/atmel-aes.c:1059:28: got restricted __be32 [usertype]
drivers/crypto/atmel-aes.c:1550:28: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1550:28: expected unsigned int
drivers/crypto/atmel-aes.c:1550:28: got restricted __be32 [usertype]
drivers/crypto/atmel-aes.c:1561:39: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1561:39: expected unsigned long long [usertype]
drivers/crypto/atmel-aes.c:1561:39: got restricted __be64 [usertype]
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:17: warning: cast to restricted __be32
drivers/crypto/atmel-aes.c:1599:15: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1599:15: expected unsigned int [usertype]
drivers/crypto/atmel-aes.c:1599:15: got restricted __be32 [usertype]
drivers/crypto/atmel-aes.c:1692:17: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1692:17: expected unsigned long long [usertype]
drivers/crypto/atmel-aes.c:1692:17: got restricted __be64 [usertype]
drivers/crypto/atmel-aes.c:1693:17: warning: incorrect type in assignment (different base types)
drivers/crypto/atmel-aes.c:1693:17: expected unsigned long long [usertype]
drivers/crypto/atmel-aes.c:1693:17: got restricted __be64 [usertype]
drivers/crypto/atmel-aes.c:1888:63: warning: incorrect type in initializer (different base types)
drivers/crypto/atmel-aes.c:1888:63: expected unsigned int
drivers/crypto/atmel-aes.c:1888:63: got restricted __le32 [usertype]
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
commit 394a9e0447 ("crypto: cfb - add missing 'chunksize' property")
adds a test vector where the input length is smaller than the IV length
(the second test vector). This revealed a NULL pointer dereference in
the atmel-aes driver, that is caused by passing an incorrect offset in
scatterwalk_map_and_copy() when atmel_aes_complete() is called.
Do not save the IV in req->info of ablkcipher_request (or equivalently
req->iv of skcipher_request) when req->nbytes < ivsize, because the IV
will not be further used.
While touching the code, modify the type of ivsize from int to
unsigned int, to comply with the return type of
crypto_ablkcipher_ivsize().
Fixes: 91308019ec ("crypto: atmel-aes - properly set IV after {en,de}crypt")
Cc: <stable@vger.kernel.org>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.
// <smpl>
@@
expression ret;
struct platform_device *E;
@@
ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);
if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>
While we're here, remove braces on if statements that only have one
statement (manually).
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: <linux-crypto@vger.kernel.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The Atmel AES driver uses memzero_explicit on the keys on error, but the
variable zeroed isn't the right one because of a typo. Fix this by using
the right variable.
Fixes: 89a82ef87e ("crypto: atmel-authenc - add support to authenc(hmac(shaX), Y(aes)) modes")
Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Omit extra messages for a memory allocation failure in these functions.
This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pointer members of an object with static storage duration, if not
explicitly initialized, will be initialized to a NULL pointer.
The crypto API checks if these pointers are not NULL before using them,
therefore we can safely remove these empty functions.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When using the rfc4543(gcm(aes))) mode, the registers of the hardware
engine are not empty after use. If the engine is not reset before its
next use, the following results will be invalid.
Always reset the hardware engine.
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Certain cipher modes like CTS expect the IV (req->info) of
ablkcipher_request (or equivalently req->iv of skcipher_request) to
contain the last ciphertext block when the {en,de}crypt operation is done.
Fix this issue for the Atmel AES hardware engine. The tcrypt test
case for cts(cbc(aes)) is now correctly passed.
In the case of in-place decryption, copy the ciphertext in an
intermediate buffer before decryption.
Signed-off-by: Romain Izard <romain.izard.pro@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
irq would be set to -1 and then unused, if we failed to get IORESOURCE_MEM.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch replace GCM IV size value by their constant name.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patchs allows to combine the AES and SHA hardware accelerators on
some Atmel SoCs. Doing so, AES blocks are only written to/read from the
AES hardware. Those blocks are also transferred from the AES to the SHA
accelerator internally, without additionnal accesses to the system busses.
Hence, the AES and SHA accelerators work in parallel to process all the
data blocks, instead of serializing the process by (de)crypting those
blocks first then authenticating them after like the generic
crypto/authenc.c driver does.
Of course, both the AES and SHA hardware accelerators need to be available
before we can start to process the data blocks. Hence we use their crypto
request queue to synchronize both drivers.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch fixes the value returned by atmel_aes_handle_queue(), which
could have been wrong previously when the crypto request was started
synchronously but became asynchronous during the ctx->start() call.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There is no need to have the 'struct atmel_aes_dev *aes_dd' variable
static since new value always be assigned before use it.
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the xts(aes) algorithm, which is supported from
hardware version 0x500 and above (sama5d2x).
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch fixes a compiler error when VERBOSE_DEBUG is defined. Indeed,
in atmel_aes_write(), the 3rd argument of atmel_aes_reg_name() was
missing.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Reported-by: Levent Demir <levent.demir@inria.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull crypto update from Herbert Xu:
"Here is the crypto update for 4.6:
API:
- Convert remaining crypto_hash users to shash or ahash, also convert
blkcipher/ablkcipher users to skcipher.
- Remove crypto_hash interface.
- Remove crypto_pcomp interface.
- Add crypto engine for async cipher drivers.
- Add akcipher documentation.
- Add skcipher documentation.
Algorithms:
- Rename crypto/crc32 to avoid name clash with lib/crc32.
- Fix bug in keywrap where we zero the wrong pointer.
Drivers:
- Support T5/M5, T7/M7 SPARC CPUs in n2 hwrng driver.
- Add PIC32 hwrng driver.
- Support BCM6368 in bcm63xx hwrng driver.
- Pack structs for 32-bit compat users in qat.
- Use crypto engine in omap-aes.
- Add support for sama5d2x SoCs in atmel-sha.
- Make atmel-sha available again.
- Make sahara hashing available again.
- Make ccp hashing available again.
- Make sha1-mb available again.
- Add support for multiple devices in ccp.
- Improve DMA performance in caam.
- Add hashing support to rockchip"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (116 commits)
crypto: qat - remove redundant arbiter configuration
crypto: ux500 - fix checks of error code returned by devm_ioremap_resource()
crypto: atmel - fix checks of error code returned by devm_ioremap_resource()
crypto: qat - Change the definition of icp_qat_uof_regtype
hwrng: exynos - use __maybe_unused to hide pm functions
crypto: ccp - Add abstraction for device-specific calls
crypto: ccp - CCP versioning support
crypto: ccp - Support for multiple CCPs
crypto: ccp - Remove check for x86 family and model
crypto: ccp - memset request context to zero during import
lib/mpi: use "static inline" instead of "extern inline"
lib/mpi: avoid assembler warning
hwrng: bcm63xx - fix non device tree compatibility
crypto: testmgr - allow rfc3686 aes-ctr variants in fips mode.
crypto: qat - The AE id should be less than the maximal AE number
lib/mpi: Endianness fix
crypto: rockchip - add hash support for crypto engine in rk3288
crypto: xts - fix compile errors
crypto: doc - add skcipher API documentation
crypto: doc - update AEAD AD handling
...
The change fixes potential oops while accessing iomem on invalid
address, if devm_ioremap_resource() fails due to some reason.
The devm_ioremap_resource() function returns ERR_PTR() and never
returns NULL, which makes useless a following check for NULL.
Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Fixes: b0e8b3417a ("crypto: atmel - use devm_xxx() managed function")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Move the helper function to common header for everybody to use.
changes in v2:
- move the helper to crypto/internal/aead.h
instead of crypto/aead.h
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
clk_prepare()/clk_unprepare() must not be called within atomic context.
This patch calls clk_prepare() once for all from atmel_aes_probe() and
clk_unprepare() from atmel_aes_remove().
Then calls of clk_prepare_enable()/clk_disable_unprepare() were replaced
by calls of clk_enable()/clk_disable().
Cc: stable@vger.kernel.org
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Reported-by: Matthias Mayr <matthias.mayr@student.kit.edu>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The debug function atmel_aes_reg_name was missing a break for
AES_GCMHR.
Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This feature should not be enabled in release but can be usefull for
developers who need to monitor register accesses at some specific places.
Set the AES_FLAGS_DUMP_REG flag inside dd->flags to start monitoring the
I/O accesses, clear it to stop monitoring.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds support to the GCM mode.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Increase the DMA threshold to 256: PIO accesses offer better performances
than the DMA when processing small amounts of data.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Depending on its hardware version, the AES IP provides either a 16 or a
32 bit counter. However the CTR mode expects the size of the counter to be
the same as the size of the cipher block, ie 128 bits for AES.
This patch detects and handles counter overflows.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
crypto_rfc3686_alloc() in crypto/ctr.c expects to be used with a stream
cipher (alg->cra_blocksize == 1).
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch only creates sections to regroup functions by usage.
This will help to integrate the GCM support patch later by making the
difference between shared/common and specific code. Hence current
sections are:
- Shared functions: common code which will be reused by the GCM support.
- CPU transfer: handles transfers monitored by the CPU (PIO accesses).
- DMA transfer: handles transfers monitored by the DMA controller.
- AES async block ciphers: dedicated to the already supported block ciphers
- Probe functions: used to register all crypto algorithms.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Dummy patch to fix typo and indentation.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch totally reworks data transfer.
1 - DMA
The new code now fully supports scatter-gather lists hence reducing the
number of interrupts in some cases. Also buffer alignments are better
managed to avoid useless copies.
2 - CPU
The new code allows to use PIO accesses even when transferring more than
one AES block, so futher patches could tune the DMA threshold
(ATMEL_AES_DMA_THRESHOLD).
Moreover, CPU transfers now have a chance to be processed synchronously,
hence reducing the latency by avoiding context switches when possible
(less interrupts to process, less scheduling of the 'done' task).
Indeed the 'DATA READY' bit is polled only one time in the Interrupt
Status Register before enabling then waiting for the associated interrupt.
In some condition, this single poll is enough as the data have already
been processed by the AES hardware and so are ready.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Since the 'done' task code was split into atmel_aes_cpu_complete() and
atmel_aes_dma_complete(), the AES_FLAGS_DMA flag has become useless.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
atmel_aes_dma_callback() now directly calls the 'resume' callback instead
of scheduling the done task, which in turn only calls the very same
'resume' callback.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This 'err' member was initialized to 0 but its value never changed.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch introduces a new callback 'resume' in the struct atmel_aes_dev.
This callback is run to resume/complete the processing of the crypto
request when woken up by I/O events such as AES interrupts or DMA
completion.
This callback will help implementing the GCM mode support in further
patches.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch reworks the AES_FLAGS_* to simplify the configuration of the
AES IP.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As claimed by the datasheet, writing 0 into the Control Register has no
effet. So we remove this useless register access.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Tudor Ambarus