From mboxrd@z Thu Jan 1 00:00:00 1970 From: dirac3000@gmail.com (Alvaro Moran) Date: Thu, 7 Feb 2013 11:38:43 +0100 Subject: [PATCH 1/1] DMA: PL330: allow submitting 2 requests at a time Message-ID: <1360233523-20825-1-git-send-email-dirac3000@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Due to the original driver design, only one request was processed at a time by the driver, even if the low-level part of the driver was able to handle 2 requests. With this patch we are able to create 2 microcodes per thread and to launch the second transfer on the interrupt handler of the first one, instead of having to wait for the tasklet to generate the microcode. Signed-off-by: Alvaro Moran --- drivers/dma/pl330.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c index 80680ee..7814f8e 100644 --- a/drivers/dma/pl330.c +++ b/drivers/dma/pl330.c @@ -486,6 +486,8 @@ struct pl330_thread { /* Index of the last submitted request or -1 if the DMA is stopped */ int req_running; }; +/* We handle two requests at a time */ +#define NR_MAX_REQUESTS 2 enum pl330_dmac_state { UNINIT, @@ -2276,13 +2278,18 @@ static inline void handle_cyclic_desc_list(struct list_head *list) static inline void fill_queue(struct dma_pl330_chan *pch) { struct dma_pl330_desc *desc; + int busy_reqs = 0; int ret; list_for_each_entry(desc, &pch->work_list, node) { /* If already submitted */ - if (desc->status == BUSY) - break; + if (desc->status == BUSY) { + busy_reqs++; + if (busy_reqs == NR_MAX_REQUESTS) + break; + continue; + } ret = pl330_submit_req(pch->pl330_chid, &desc->req); -- 1.7.10.4