From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: Depreciated spi_master.transfer and "prepared spi messages" for an optimized pipelined-SPI-DMA-driver Date: Wed, 6 Nov 2013 11:32:19 +0000 Message-ID: <20131106113219.GJ11602@sirena.org.uk> References: <20131030171902.GL2493@sirena.org.uk> <8D8B0BAD-0E00-4147-B4C8-FBB18F060C96@sperl.org> <20131030215716.GV2493@sirena.org.uk> <3342FD19-4438-463B-89B2-A83D3475AC22@sperl.org> <20131031001004.GW2493@sirena.org.uk> <18639D9A-630E-44F3-AA7A-ADFF5D5E8B56@sperl.org> <20131104184511.GR2493@sirena.org.uk> <5A55A832-5313-499C-A483-BF5A6649D69D@sperl.org> <20131106094854.GF11602@sirena.org.uk> <844EDAEA-3FDC-48D0-B59E-CECC0A83761E@sperl.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KCBbHYs95wY/7dOt" Cc: Linus Walleij , linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Stephen Warren To: Martin Sperl Return-path: Content-Disposition: inline In-Reply-To: <844EDAEA-3FDC-48D0-B59E-CECC0A83761E-d5rIkyn9cnPYtjvyW6yDsg@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: --KCBbHYs95wY/7dOt Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Nov 06, 2013 at 12:28:15PM +0100, Martin Sperl wrote: > >> /* generic wrapper functions for device drivers to use */ > >> static int bcm2835dma_spi_prepare_message(struct spi_device *spi, > > Like I said earlier I'm concerned about the idea of drivers calling > > these functions directly, this should all be factored out of drivers > > since there's nothing really driver specific here. > Actually it is VERY driver specific! > The thing is that you can not easily detect if the same spi_message has= =20 > been used and in some way changed without having to walk and compare the > structure to an existing checksum - and such computation would take say= =20 > 1/3rd of the time it takes to prepare the message again. I'm sorry but the above makes no sense to me. Why on earth would you need to do these checks? --KCBbHYs95wY/7dOt Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIcBAEBAgAGBQJSeijAAAoJELSic+t+oim9Bt8QAJrIh1FRBKD4cl3sn97tn0bz WwaUc8EZbt12HtiRrbkMH6bPxE1zXe8R9tt1Z6qe2KGdC4k7Z8pZCvBAoU7tWmXF G7bUaneIpaJ4ozYZTMdKZTIZ66XVw2QHkKaxXVRS+t7rJr0kxsGqbkyhCVmwtddY FTUeRRWyWKF+eM56Dd6feUVIWMIcacFfSrmBhBPcJ6Fshb1iSJ9k2DbKTFqIw+HM XJq9jCidT5Kwg/5+CcKuLyMrSPCcZiyZ8amCgdHnDSjumBFak4laxPVY2zYC0a8I 3YeCt9meyoytCvn5m89GabhxUIrZJageRNSrrq/hS8Hk37FvtdbTIw9g5r1Ll81Y LYhsqwvlag3WRu8IQDi9CLeMzjOxu3CLFodDrxb3RnxqcxlWRqCNyr/lRctOUuhL gxkZrLtuGn3b+q3wOH2EJyYmM6REKmguPQtY595GMmY66n7Ls8TbWtnBxmWnTuGs clEXdYR1Qs3jqO1FVy/XzPz/EKBydMdWMK66tHBpUTFatP9vnSMmRbSZYwNMLQ9L VgWiS9Z++1nCvfkba+m1rxFlZuiT02CaDXAOhXhZ7pWuLzVM2h1OmXg34XEMjJsK RwSTLm+LxrRfe1tCsydY0fF4q3Qm37+sqHXmI+hWzXC449jPqz9n57S65rm1BGRw f3lOh739yOois3hC+HOZ =FN30 -----END PGP SIGNATURE----- --KCBbHYs95wY/7dOt-- -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html