From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: ALSA Driver for ARM-Linux 2.6 Date: Mon, 16 Aug 2004 15:05:43 +0200 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: References: <411A7D75.3080701@fetron.de> <4120A964.8080402@fetron.de> Mime-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <4120A964.8080402@fetron.de> Errors-To: alsa-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Klaus Fetscher Cc: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org At Mon, 16 Aug 2004 14:32:36 +0200, Klaus Fetscher wrote: > > Hallo Takashi, > > thanks for your answer. > > >>we want to program an ALSA driver for a Codec which communicates over an > >>I2S interface with an ARM9 processor. > >>I have read several messages regarding ALSA-Drivers, Linux 2.6 and ARM > >>and know I am a little bit confused. > >> > >>Is it possible to use ALSA with ARM or need we some patches for the ARM > >>CPU ? > >> > >>I have read, that the sa11xx-uda1341 driver is not a good starting point > >>for implementing a driver. Which is a better solution ? > >> > >> > > > > > > > Does the driver under sound/arm/sa11xx-uda1341.c in the current 2.6.7 > kernel tree work with ALSA ? Well, I'm not sure about this. Someone told that it's broken. I even didn't take a deep look yet. But, as written above, it should work if the driver doesn't use mmap. > If yes, I will change this file for my requirements or do you have a > better idea ? Depends. If the board design is similar with sa11xx-uda1341, it's an easier start point. (I believe sa11xx-uda1341 driver can be more generalized, though.) > The CPU communicates with the Sound Chip over a I2S interface. Shall I > make a new subdirectory /sound/i2s or /sound/i2c/i2s for the I2S stuff > or do you recommand another directory ? Unless you need the "generic" i2s support over different architectures, you should put the stuff locally in your driver code. > > >In general, ALSA has a problem on architectures like ARM about cache > >and mmap. So far, the ALSA should work fine on ARM, too, if the > >driver doesn't use mmap. > > > >Russell King has some patches to fix this issue, which I will merge > >later on our tree. > > > > > > > If I don't use mmap in the driver (actually, sa11xx-uda1341.c don't use > this function) I don't need this patches, correct ? Yes (but again, I haven't tested ARM at all by myself). Takashi ------------------------------------------------------- SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33 Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift. http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285