From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: [RFC] tegra_pcm DMA buffers allocation Date: Fri, 20 Apr 2012 07:58:31 +0200 Message-ID: <20120420055831.GA15470@avionic-0098.adnet.avionic-design.de> References: <1334851253.13681.49.camel@marvin> <4F90708F.8070504@wwwdotorg.org> <1334869632.13681.59.camel@marvin> <4F90858D.4010206@wwwdotorg.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="uAKRQypu60I7Lcqm" Return-path: Content-Disposition: inline In-Reply-To: <4F90858D.4010206-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Stephen Warren Cc: Andrey Smirnov , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org --uAKRQypu60I7Lcqm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable * Stephen Warren wrote: > On 04/19/2012 03:07 PM, Andrey Smirnov wrote: > > On Thu, 2012-04-19 at 16:07 -0400, Stephen Warren wrote: > ... > >> BTW, did you try running the mainline code on your board. If it's > >> derived from Harmony, it should be easy to get it going. > >=20 > > Last time we did there was no support for Tegra's NAND and display > > controllers >=20 > What do you need the NAND controllers for? I'm not 100% certain, but I > believe we plan on upstreaming NAND support into U-Boot, but not the > kernel, since we didn't see a need for it there IIRC. We use a device that is sort of a set-top box, which currently boots from an SD card. However the SD card is eventually supposed to allow users to displ= ay custom media (slide show, ...). In that case it is very stupid to keep the = OS on the same card. While U-Boot NAND support is enough to get a kernel booted, you still need the root filesystem to be loaded from NAND by the kernel. Kernel support is also pretty much a requirement for runtime updates. > (Not that we'd stop anyone else doing it) I've been trying to make the NAND controller work on Tegra 2. Unfortunately there's not much of a reference to work off except the driver that Simon Glass posted to the U-Boot mailing list and written by Jim Lin. There is al= so a driver in the NVIDIA downstream kernels but that's pretty much broken. The U-Boot driver doesn't use interrupts obviously so I've resolved to use = it as a base and add interrupt support. Unfortunately I've hit a snag and whenever I enable interrupts I see the CPU stormed by the NAND controller f= or unknown reasons (no bits in ISR, DMA control or decode status registers set= ). I'll have to investigate further. Maybe the controller isn't properly initialized yet. Thierry --uAKRQypu60I7Lcqm Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iEYEARECAAYFAk+Q+wcACgkQZ+BJyKLjJp/POgCgiRA5sLeNxIG1aiQUlAf7gJiA DtAAn3Ub86xg+LIbS/yzNbD2kk2IgJSE =sDgG -----END PGP SIGNATURE----- --uAKRQypu60I7Lcqm--