Shilimkar, Santosh <santosh.shilimkar@xxxxxx> wrote: >> -----Original Message----- >> From: svenkatr@xxxxxxxxx [mailto:svenkatr@xxxxxxxxx] On Behalf Of Venkatraman S >> Sent: Wednesday, May 05, 2010 9:56 PM >> To: Shilimkar, Santosh >> Cc: linux-omap@xxxxxxxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; >> Chikkature Rajashekar, Madhusudhan; Adrian Hunter; Tony Lindgren >> Subject: Re: [PATCH v8 1/2] sDMA: descriptor autoloading feature >> >> On Wed, May 5, 2010 at 5:31 PM, Shilimkar, Santosh >> <santosh.shilimkar@xxxxxx> wrote: >> > >> > >> >> -----Original Message----- >> >> From: svenkatr@xxxxxxxxx [mailto:svenkatr@xxxxxxxxx] On Behalf Of Venkatraman S >> >> Sent: Wednesday, May 05, 2010 5:20 PM >> >> To: Shilimkar, Santosh >> >> Cc: linux-omap@xxxxxxxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; >> >> Chikkature Rajashekar, Madhusudhan; Adrian Hunter; Tony Lindgren >> >> Subject: Re: [PATCH v8 1/2] sDMA: descriptor autoloading feature >> >> >> >> [Long sections have been trimmed to the context of the discussion] >> >> On Wed, May 5, 2010 at 3:02 PM, Shilimkar, Santosh >> >> <santosh.shilimkar@xxxxxx> wrote: >> >> >> -----Original Message----- >> >> >> +static int dma_sglist_set_phy_params(struct omap_dma_sglist_node *sghead, >> >> >> + dma_addr_t phyaddr, int nelem) >> >> >> +{ >> >> >> + struct omap_dma_sglist_node *sgcurr, *sgprev; >> >> >> + dma_addr_t elem_paddr = phyaddr; >> >> >> + >> >> >> + for (sgprev = sghead; >> >> >> + sgprev < sghead + nelem; >> >> >> + sgprev++) { >> >> >> + >> >> >> + sgcurr = sgprev + 1; >> >> >> + sgprev->next = sgcurr; >> >> >> + elem_paddr += (int)sizeof(*sgcurr); >> >> >> + sgprev->next_desc_add_ptr = elem_paddr; >> >> >> + >> >> >> + switch (sgcurr->desc_type) { >> >> >> + case OMAP_DMA_SGLIST_DESCRIPTOR_TYPE1: >> >> >> + omap_dma_list_set_ntype(sgprev, 1); >> >> >> + break; >> >> >> + >> >> >> + case OMAP_DMA_SGLIST_DESCRIPTOR_TYPE2a: >> >> >> + /* intentional no break */ >> >> >> + case OMAP_DMA_SGLIST_DESCRIPTOR_TYPE2b: >> >> >> + omap_dma_list_set_ntype(sgprev, 2); >> >> >> + break; >> >> >> + >> >> >> + case OMAP_DMA_SGLIST_DESCRIPTOR_TYPE3a: >> >> >> + /* intentional no break */ >> >> >> + case OMAP_DMA_SGLIST_DESCRIPTOR_TYPE3b: >> >> >> + omap_dma_list_set_ntype(sgprev, 3); >> >> >> + break; >> >> >> + >> >> >> + default: >> >> >> + return -EINVAL; >> >> >> + >> >> >> + } >> >> > Are we supporting all the descriptor types. I think only type2a is >> >> > supported. In that case please add FIXME, or WARN message here. >> >> >> >> From DMA perspective, all are supported - no restrictions. Only I have >> >> not figured >> >> out how to use type 2b and type 3b descriptors. It's not the fault of >> >> DMA driver or >> >> specification :-) It's actually upto the client to select the right type. >> > OK. Then the question which I wanted to ask. >> > For TX, 2b should have been better choice than 2a isn't it? >> >> Not much of a difference (as the space allocation is common), but I >> couldn't get 2b working correctly. >> Will try that once I get some clarification from hardware team. > Add a FIXME then with description in the code so that it's not forgotten once the code > is merged. OK. I am assuming the FIXME has to be in MMC driver, not here. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
