Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754808AbbHOCOq (ORCPT ); Fri, 14 Aug 2015 22:14:46 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:44516 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753457AbbHOCOQ (ORCPT ); Fri, 14 Aug 2015 22:14:16 -0400 Date: Fri, 14 Aug 2015 19:33:53 +0100 From: Mark Brown To: Sagar Dharia Cc: gregkh@linuxfoundation.org, bp@suse.de, poeschel@lemonage.de, treding@nvidia.com, gong.chen@linux.intel.com, andreas.noever@gmail.com, alan@linux.intel.com, mathieu.poirier@linaro.org, daniel@ffwll.ch, oded.gabbay@amd.com, jkosina@suse.cz, sharon.dvir1@mail.huji.ac.il, joe@perches.com, davem@davemloft.net, james.hogan@imgtec.com, michael.opdenacker@free-electrons.com, daniel.thompson@linaro.org, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kheitke@audience.com, mlocke@codeaurora.org, agross@codeaurora.org, linux-arm-msm@vger.kernel.org Message-ID: <20150814183353.GA30451@sirena.org.uk> References: <1438585190-11894-1-git-send-email-sdharia@codeaurora.org> <1438585190-11894-4-git-send-email-sdharia@codeaurora.org> <20150814182525.GD10748@sirena.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="W/nzBZO5zC0uMSeA" Content-Disposition: inline In-Reply-To: <20150814182525.GD10748@sirena.org.uk> X-Cookie: This is NOT a repeat. User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: 70.98.210.100 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Re: [PATCH V3 3/6] slimbus: Add messaging APIs to slimbus framework X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: Yes (on mezzanine.sirena.org.uk) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1958 Lines: 48 --W/nzBZO5zC0uMSeA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Aug 14, 2015 at 07:25:25PM +0100, Mark Brown wrote: > On Mon, Aug 03, 2015 at 12:59:47AM -0600, Sagar Dharia wrote: > > + sema_init(&ctrl->tx_sem, (ctrl->tx.n - 1)); > This sempahore counts the number of free slots in the statically > allocated list of transfers we have allocated. It would be good to see > some discussion in the changelog as to why we've got this statically > allocated pool rather than just dynamically allocating them as needed - > I can see a performance argument there but it'd be good to have the > thinking documented. One other related thing here: we're keeping the buffers permanently coherently mapped rather than only mapping them to the device as needed. Is this the best approach? On the one hand it increases the cost to the CPU when setting things up and reading data back, on the other hand it avoids mapping operations. Since it's becoming part of the driver API with this it bears some thought, it will be a little annoying (and fiddly) to change later. --W/nzBZO5zC0uMSeA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJVzjSRAAoJECTWi3JdVIfQG0UIAIJFPwQyYVewezmN5/b19GB7 P8ZvBguplinAf9SaNKvq6zrmfmgnGrpQVYllA+F2tiKsASpiW8e3mQ1+pw3Q+7GN 7Nac+TQ+dTVp1mUjeEg/jJ108YwXQ326LQBvbW+9kav0kDExZZPQpg7Fi9GhCnif t+BK4GIG2lBVtuEP3gYCf1QwJzdKnE3kgLF4kQ1Z2xIeTh0Vs81V66DyWjGx6D8Q LQvjxRFnKvnrwpWMqkg3icq0MAiQh7KjuyUDESmdZQSTe9lGABh/FI61uvj5xuKc 4W288vpTq0LuBBXkGQrgMGcI5DP4nce6FuFVFqS88xM/yw9AlQ01sYXcA5jlrIA= =+aSu -----END PGP SIGNATURE----- --W/nzBZO5zC0uMSeA-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/