From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anderson Briglia Subject: Re: [patch 5/5] [RFC] Add MMC Password Protection (lock/unlock) support V7: mmc_omap_dma.diff Date: Mon, 27 Nov 2006 09:43:12 -0400 Message-ID: <456AEB70.2000100@indt.org.br> References: <4564648B.2020005@indt.org.br> <456805F3.1020407@drzeus.cx> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <456805F3.1020407@drzeus.cx> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-omap-open-source-bounces@linux.omap.com Errors-To: linux-omap-open-source-bounces@linux.omap.com To: ext Pierre Ossman Cc: Russell King , "Linux-omap-open-source@linux.omap.com" , "Lizardo Anderson (EXT-INdT/Manaus)" , linux-kernel@vger.kernel.org List-Id: linux-omap@vger.kernel.org ext Pierre Ossman wrote: > Anderson Briglia wrote: >> OMAP platform specific patch. >> - Adjust the frame size for DMA transfers. >> >> Signed-off-by: Anderson Briglia indt.org.br> >> Signed-off-by: Carlos Eduardo Aguiar indt.org.br> >> > > This looks like a generic patch for OMAP and shouldn't be in this set. This patch is needed only for lock/unlock commands. So, it's necessary to make MMC omap works when using that feature. It's not a generic patch. But I can take off this one from the series and send after (if) the series is integrated. > >> Index: linux-omap-2.6.git/drivers/mmc/omap.c >> =================================================================== >> --- linux-omap-2.6.git.orig/drivers/mmc/omap.c 2006-11-22 >> 09:07:25.000000000 -0400 >> +++ linux-omap-2.6.git/drivers/mmc/omap.c 2006-11-22 >> 09:19:03.000000000 -0400 >> @@ -629,6 +629,14 @@ mmc_omap_prepare_dma(struct mmc_omap_hos >> >> data_addr = host->phys_base + OMAP_MMC_REG_DATA; >> frame = data->blksz; >> + >> +#ifdef CONFIG_MMC_PASSWORDS >> + /* MMC LOCK/UNLOCK: Do frame size multiple of two. This is >> + * needed for DMA transfers to work properly, once >> + * the block size depends on MMC password length. >> + */ >> + frame += frame&0x1; >> +#endif >> count = sg_dma_len(sg); >> >> if ((data->blocks == 1) && (count > (data->blksz))) >> > > Now this you're going to have to explain to me. Especially the part > where why this is specific to the lock commands. frame depends on data->blksz. When we were using data->blksz_bits everything was ok because we always had a multiple of 16 bits (2 bytes). Once a pwd can has a size not multiple of 2, the value must be rounded. According to MMC OMAP Technical Reference Manual, because of each DMA transfer is of equal size, it is necessary to have the block size of the transfer be a multiple of the DMA write access size (which is 2 bytes). I'm not a DMA expert, If I misunderstand something, please, correct me. Best Regards, Anderson Briglia