Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752597AbbGRXEF (ORCPT ); Sat, 18 Jul 2015 19:04:05 -0400 Received: from smtp07.smtpout.orange.fr ([80.12.242.129]:57929 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751917AbbGRXEC (ORCPT ); Sat, 18 Jul 2015 19:04:02 -0400 X-ME-Helo: belgarion X-ME-Auth: amFyem1pay5yb2JlcnRAb3JhbmdlLmZy X-ME-Date: Sun, 19 Jul 2015 01:03:58 +0200 X-ME-IP: 92.136.75.161 From: Robert Jarzmik To: Guennadi Liakhovetski Cc: Mauro Carvalho Chehab , Jiri Kosina , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/4] media: pxa_camera: conversion to dmaengine References: <1436120872-24484-1-git-send-email-robert.jarzmik@free.fr> <1436120872-24484-5-git-send-email-robert.jarzmik@free.fr> <87y4iljn6y.fsf@belgarion.home> X-URL: http://belgarath.falguerolles.org/ Date: Sun, 19 Jul 2015 01:00:55 +0200 In-Reply-To: <87y4iljn6y.fsf@belgarion.home> (Robert Jarzmik's message of "Sun, 12 Jul 2015 19:33:09 +0200") Message-ID: <87a8utgjfc.fsf@belgarion.home> User-Agent: Gnus/5.130008 (Ma Gnus v0.8) Emacs/24.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7423 Lines: 260 Robert Jarzmik writes: > Guennadi Liakhovetski writes: > >>> /* init DMA for Y channel */ >> >> How about taking the loop over the sg list out of pxa_init_dma_channel() >> to avoid having to iterate it from the beginning each time? Then you would >> be able to split it into channels inside that global loop? Would that >> work? Of course you might need to rearrange functions to avoid too deep >> code nesting. > > Ok, will try that. > The more I think of it, the more it looks to me like a generic thing : take an > sglist, and an array of sizes, and split the sglist into several sglists, each > of the defined size in the array. > > Or more code-like speaking : > - sglist_split(struct scatterlist *sg_int, size_t *sizes, int nb_sizes, > struct scatterlist **sg_out) > - and sg_out is an array of nb_sizes (struct scatterlist *sg) > > So I will try that out. Maybe if that works out for pxa_camera, Jens or Russell > would accept that into lib/scatterlist.c. Ok, I made the code ... and I hate it. It's in [1], which is an incremental patch over patch 4/4. If that's what you had in mind, tell me. Cheers. -- Robert [1] The despised patch ---<8--- commit 43bbb9a4e3ac Author: Robert Jarzmik Date: Tue Jul 14 20:17:51 2015 +0200 tmp: pxa_camera: working on sg_split Signed-off-by: Robert Jarzmik diff --git a/drivers/media/platform/soc_camera/pxa_camera.c b/drivers/media/platform/soc_camera/pxa_camera.c index 26a66b9ff570..83efd284e976 100644 --- a/drivers/media/platform/soc_camera/pxa_camera.c +++ b/drivers/media/platform/soc_camera/pxa_camera.c @@ -287,64 +287,110 @@ static void free_buffer(struct videobuf_queue *vq, struct pxa_buffer *buf) &buf->vb, buf->vb.baddr, buf->vb.bsize); } -static struct scatterlist *videobuf_sg_cut(struct scatterlist *sglist, - int sglen, int offset, int size, - int *new_sg_len) + +struct sg_splitter { + struct scatterlist *in_sg0; + int nents; + off_t skip_sg0; + size_t len_last_sg; + struct scatterlist *out_sg; +}; + +static struct sg_splitter * +sg_calculate_split(struct scatterlist *in, off_t skip, + const size_t *sizes, int nb_splits, gfp_t gfp_mask) { - struct scatterlist *sg0, *sg, *sg_first = NULL; - int i, dma_len, dropped_xfer_len, dropped_remain, remain; - int nfirst = -1, nfirst_offset = 0, xfer_len; - - *new_sg_len = 0; - dropped_remain = offset; - remain = size; - for_each_sg(sglist, sg, sglen, i) { - dma_len = sg_dma_len(sg); - /* PXA27x Developer's Manual 27.4.4.1: round up to 8 bytes */ - dropped_xfer_len = roundup(min(dma_len, dropped_remain), 8); - if (dropped_remain) - dropped_remain -= dropped_xfer_len; - xfer_len = dma_len - dropped_xfer_len; - - if (nfirst < 0 && xfer_len > 0) { - sg_first = sg; - nfirst = i; - nfirst_offset = dropped_xfer_len; + int i, nents; + size_t size, len; + struct sg_splitter *splitters, *curr; + struct scatterlist *sg; + + splitters = kcalloc(nb_splits, sizeof(*splitters), gfp_mask); + if (!splitters) + return NULL; + + nents = 0; + size = *sizes; + curr = splitters; + for_each_sg(in, sg, sg_nents(in), i) { + if (skip > sg_dma_len(sg)) { + skip -= sg_dma_len(sg); + continue; + } + len = min_t(size_t, size, sg_dma_len(sg) - skip); + if (!curr->in_sg0) { + curr->in_sg0 = sg; + curr->skip_sg0 = sg_dma_len(sg) - len; } - if (xfer_len > 0) { - (*new_sg_len)++; - remain -= xfer_len; + size -= len; + nents++; + if (!size) { + curr->nents = nents; + curr->len_last_sg = len; + nents = 0; + size = *(++sizes); + + if (!--nb_splits) + break; + + if (len < curr->len_last_sg) { + (splitters + 1)->in_sg0 = sg; + (splitters + 1)->skip_sg0 = 0; + } + curr++; } - if (remain <= 0) - break; } - WARN_ON(nfirst >= sglen); - sg0 = kmalloc_array(*new_sg_len, sizeof(struct scatterlist), - GFP_KERNEL); - if (!sg0) - return NULL; + return splitters; +} - remain = size; - for_each_sg(sg_first, sg, *new_sg_len, i) { - dma_len = sg_dma_len(sg); - sg0[i] = *sg; +static int sg_split(struct scatterlist *in, const int nb_splits, + const size_t *split_sizes, struct scatterlist **out, + gfp_t gfp_mask) +{ + int i, j; + struct scatterlist *in_sg, *out_sg; + struct sg_splitter *splitters, *split; - sg0[i].offset = nfirst_offset; - nfirst_offset = 0; + splitters = sg_calculate_split(in, 0, split_sizes, nb_splits, gfp_mask); + if (!splitters) + return -ENOMEM; - xfer_len = min_t(int, remain, dma_len - sg0[i].offset); - xfer_len = roundup(xfer_len, 8); - sg_dma_len(&sg0[i]) = xfer_len; + for (i = 0; i < nb_splits; i++) { + (splitters + i)->out_sg = + kmalloc_array((splitters + i)->nents, + sizeof(struct scatterlist), gfp_mask); + if (!(splitters + i)->out_sg) + goto err; + } - remain -= xfer_len; - if (remain <= 0) { - sg_mark_end(&sg0[i]); - break; + for (i = 0; i < nb_splits; i++) { + split = splitters + i; + in_sg = split->in_sg0; + out_sg = split->out_sg; + out[i] = out_sg; + for (j = 0; j < split->nents; j++) { + out_sg[j] = *in_sg; + if (!j) { + out_sg[j].offset = split->skip_sg0; + sg_dma_len(&out_sg[j]) -= split->skip_sg0; + } else { + out_sg[j].offset = 0; + } + in_sg = sg_next(in_sg); } + sg_dma_len(out_sg + split->nents - 1) = split->len_last_sg; + sg_mark_end(out_sg + split->nents - 1); } - return sg0; + kfree(splitters); + return 0; + +err: + for (i = 0; i < nb_splits; i++) + kfree((splitters + i)->out_sg); + kfree(splitters); + return -ENOMEM; } static void pxa_camera_dma_irq(struct pxa_camera_dev *pcdev, @@ -391,14 +437,11 @@ static int pxa_init_dma_channel(struct pxa_camera_dev *pcdev, int cibr, int size, int offset) { struct dma_chan *dma_chan = pcdev->dma_chans[channel]; - struct scatterlist *sg; + struct scatterlist *sg = buf->sg[channel]; int sglen; struct dma_async_tx_descriptor *tx; - sg = videobuf_sg_cut(dma->sglist, dma->sglen, offset, size, &sglen); - if (!sg) - goto fail; - + sglen = sg_nents(sg); tx = dmaengine_prep_slave_sg(dma_chan, sg, sglen, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!tx) { @@ -421,7 +464,6 @@ static int pxa_init_dma_channel(struct pxa_camera_dev *pcdev, } buf->descs[channel] = tx; - buf->sg[channel] = sg; buf->sg_len[channel] = sglen; return 0; fail: @@ -458,6 +500,7 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq, struct pxa_buffer *buf = container_of(vb, struct pxa_buffer, vb); int ret; int size_y, size_u = 0, size_v = 0; + size_t sizes[3]; dev_dbg(dev, "%s (vb=0x%p) 0x%08lx %d\n", __func__, vb, vb->baddr, vb->bsize); @@ -513,6 +556,16 @@ static int pxa_videobuf_prepare(struct videobuf_queue *vq, size_y = size; } + sizes[0] = size_y; + sizes[1] = size_u; + sizes[2] = size_v; + ret = sg_split(dma->sglist, pcdev->channels, sizes, buf->sg, + GFP_KERNEL); + if (ret) { + dev_err(dev, "sg_split failed: %d\n", ret); + goto fail; + } + /* init DMA for Y channel */ ret = pxa_init_dma_channel(pcdev, buf, dma, 0, CIBR0, size_y, 0); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/