Path: csiph.com!aioe.org!gothmog.csi.it!bofh.it!news.nic.it!robomod From: Mark Brown Newsgroups: linux.kernel Subject: Re: [PATCH v5] spi: spi-ti-qspi: Add DMA support for QSPI mmap read Date: Tue, 16 Aug 2016 20:50:01 +0200 Message-ID: References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="bS87dHSPlkoPpvQ6" Content-Disposition: inline X-Cookie: I can't drive 55. User-Agent: Mutt/1.6.0 (2016-04-01) X-Sa-Exim-Connect-IP: 2a01:348:6:8808:fab::3 X-Sa-Exim-Mail-From: broonie@sirena.org.uk X-Sa-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-Sa-Exim-Scanned: No (on mezzanine.sirena.org.uk); Unknown failure Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 40 Organization: linux.* mail to news gateway X-Original-Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org X-Original-Date: Tue, 16 Aug 2016 19:42:53 +0100 X-Original-Message-ID: <20160816184253.GC9347@sirena.org.uk> X-Original-References: <20160809110311.13521-1-vigneshr@ti.com> <20160809113329.GA9347@sirena.org.uk> <13e676c2-7e2f-d1c5-5312-bc2e11a6b6a1@ti.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1464011 --bS87dHSPlkoPpvQ6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Aug 09, 2016 at 06:20:01PM +0530, Vignesh R wrote: >=20 >=20 > According to this thread[1], converting virtual address > pointer into scatterlist which is then DMA mapped is unsafe on systems > with certain cache architecture. Hence, I added code to handle kmap > buffers inside the driver rather than updating generic spi-core code. That's saying that things that aren't covered aren't DMAable safely at all which is a more general issue... > If its okay to update the spi_map_buf() to handle kmap buffers as above > then I can submit the patch accordingly. Yes, the whole point is that this is all in generic code so drivers don't need to worry about it. --bS87dHSPlkoPpvQ6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJXs16sAAoJECTWi3JdVIfQZiwH/RtMuJba3YSE2zXr3uWKoi/7 6AIQtUwq0nVQmTkZm53C5WNIz5AdPEcdNu6VabdUXLn9KkjT46UX92bTfvYsfo6D c8bsAvP/FEZ6hRJOxHyRxb2yqpE3qXiWtdwM1su+5UBPmNV7YJPDSRtA/V4MP97y kLwla79M056k+T+BHIT9MB9yq8oWAZTIDWXoYdkN8JKVroryLOfkPfQegGN1Gxem YQKhxKpY3zvH14h6mdC+Xjar9hoLtGQ2EnitBSpwiG+zj0Xm5ZPNJFGf79foj28Y Dn+oHlfXxSJwSsVex9WJurx3RA4VndCVqJY3w1G8kulhpFXh7NnOHhk8XVzH8ZA= =H0d3 -----END PGP SIGNATURE----- --bS87dHSPlkoPpvQ6--