Re: [PATCH] driver: char: bfin_crc: CRC hardware accelerator driverfor BF60x family processors.

From: Greg Kroah-Hartman
Date: Wed May 16 2012 - 10:53:35 EST


On Wed, May 16, 2012 at 01:39:41PM +0000, Arnd Bergmann wrote:
> On Wednesday 16 May 2012, Greg Kroah-Hartman wrote:
> > On Wed, May 16, 2012 at 04:26:07PM +0800, sonic.zhang@xxxxxxxxxx wrote:
> > > From: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
> > >
> > > The CRC peripheral is a hardware block used to compute the CRC of the block
> > > of data. This is based on a CRC32 engine which computes the CRC value of 32b
> > > data words presented to it. For data words of < 32b in size, it is the
> > > responsibility of the application to pack the data into 32b data units.
> > >
> > > This driver defines data strcture crc_info and 4 IOCTL interfaces for applciations.
> > > 1) CRC Memory Scan
> > > 2) CRC Memory Transfer
> > > 3) CRC Data Verify
> > > 4) CRC Data Fill
> > >
> > > Signed-off-by: Sonic Zhang <sonic.zhang@xxxxxxxxxx>
> > > ---
> > > drivers/char/Kconfig | 8 +
> > > drivers/char/Makefile | 1 +
> > > drivers/char/bfin_crc.c | 537 +++++++++++++++++++++++++++++++++++++++++++++++
> > > 3 files changed, 546 insertions(+), 0 deletions(-)
> > > create mode 100644 drivers/char/bfin_crc.c
> >
> > Why is this a char driver, and not a crypto driver, using the existing
> > crypto userspace api for things like this?
>
> Do we have a userspace crypto API these days? The last I remember every
> attempt to add one so far was abandoned before it got merged. There is
> drivers/s390/crypto/zcrypt*, which has a nonportable API, and
> then there is the in-kernel crypto layer in drivers/crypto that has
> no user interface at all.

What is CONFIG_CRYPTO_USER for then, with the matching,
crypto/crypto_user.c file?

> I agree that having another private driver for bfin_crc is not a good
> idea, but I also don't have a better one.
>
> About the driver itself, the submission seems incomplete (missing at
> least the bfin_crc.h file) and the driver has a number of shortcomings
> that we should discuss in case we decide to merge it.

I suggest at least tieing into the in-kernel crypto api first, and then
worrying about the userspace side of things, right?

thanks,

greg k-h
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/