From c14330417ef2050f4bf38ac20e125785fea14351 Mon Sep 17 00:00:00 2001 From: Ira Snyder Date: Thu, 30 Sep 2010 11:46:45 +0000 Subject: [PATCH] fsldma: implement support for scatterlist to scatterlist copy Now that the DMAEngine API has support for scatterlist to scatterlist copy, implement support for the Freescale DMA controller. Signed-off-by: Ira W. Snyder Signed-off-by: Dan Williams --- drivers/dma/fsldma.c | 128 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 125 insertions(+), 3 deletions(-) diff --git a/drivers/dma/fsldma.c b/drivers/dma/fsldma.c index cea08bed9cf9..1ed29d10a5fa 100644 --- a/drivers/dma/fsldma.c +++ b/drivers/dma/fsldma.c @@ -38,6 +38,8 @@ #include #include "fsldma.h" +static const char msg_ld_oom[] = "No free memory for link descriptor\n"; + static void dma_init(struct fsldma_chan *chan) { /* Reset the channel */ @@ -499,7 +501,7 @@ fsl_dma_prep_interrupt(struct dma_chan *dchan, unsigned long flags) new = fsl_dma_alloc_descriptor(chan); if (!new) { - dev_err(chan->dev, "No free memory for link descriptor\n"); + dev_err(chan->dev, msg_ld_oom); return NULL; } @@ -536,8 +538,7 @@ static struct dma_async_tx_descriptor *fsl_dma_prep_memcpy( /* Allocate the link descriptor from DMA pool */ new = fsl_dma_alloc_descriptor(chan); if (!new) { - dev_err(chan->dev, - "No free memory for link descriptor\n"); + dev_err(chan->dev, msg_ld_oom); goto fail; } #ifdef FSL_DMA_LD_DEBUG @@ -583,6 +584,125 @@ fail: return NULL; } +static struct dma_async_tx_descriptor *fsl_dma_prep_sg(struct dma_chan *dchan, + struct scatterlist *dst_sg, unsigned int dst_nents, + struct scatterlist *src_sg, unsigned int src_nents, + unsigned long flags) +{ + struct fsl_desc_sw *first = NULL, *prev = NULL, *new = NULL; + struct fsldma_chan *chan = to_fsl_chan(dchan); + size_t dst_avail, src_avail; + dma_addr_t dst, src; + size_t len; + + /* basic sanity checks */ + if (dst_nents == 0 || src_nents == 0) + return NULL; + + if (dst_sg == NULL || src_sg == NULL) + return NULL; + + /* + * TODO: should we check that both scatterlists have the same + * TODO: number of bytes in total? Is that really an error? + */ + + /* get prepared for the loop */ + dst_avail = sg_dma_len(dst_sg); + src_avail = sg_dma_len(src_sg); + + /* run until we are out of scatterlist entries */ + while (true) { + + /* create the largest transaction possible */ + len = min_t(size_t, src_avail, dst_avail); + len = min_t(size_t, len, FSL_DMA_BCR_MAX_CNT); + if (len == 0) + goto fetch; + + dst = sg_dma_address(dst_sg) + sg_dma_len(dst_sg) - dst_avail; + src = sg_dma_address(src_sg) + sg_dma_len(src_sg) - src_avail; + + /* allocate and populate the descriptor */ + new = fsl_dma_alloc_descriptor(chan); + if (!new) { + dev_err(chan->dev, msg_ld_oom); + goto fail; + } +#ifdef FSL_DMA_LD_DEBUG + dev_dbg(chan->dev, "new link desc alloc %p\n", new); +#endif + + set_desc_cnt(chan, &new->hw, len); + set_desc_src(chan, &new->hw, src); + set_desc_dst(chan, &new->hw, dst); + + if (!first) + first = new; + else + set_desc_next(chan, &prev->hw, new->async_tx.phys); + + new->async_tx.cookie = 0; + async_tx_ack(&new->async_tx); + prev = new; + + /* Insert the link descriptor to the LD ring */ + list_add_tail(&new->node, &first->tx_list); + + /* update metadata */ + dst_avail -= len; + src_avail -= len; + +fetch: + /* fetch the next dst scatterlist entry */ + if (dst_avail == 0) { + + /* no more entries: we're done */ + if (dst_nents == 0) + break; + + /* fetch the next entry: if there are no more: done */ + dst_sg = sg_next(dst_sg); + if (dst_sg == NULL) + break; + + dst_nents--; + dst_avail = sg_dma_len(dst_sg); + } + + /* fetch the next src scatterlist entry */ + if (src_avail == 0) { + + /* no more entries: we're done */ + if (src_nents == 0) + break; + + /* fetch the next entry: if there are no more: done */ + src_sg = sg_next(src_sg); + if (src_sg == NULL) + break; + + src_nents--; + src_avail = sg_dma_len(src_sg); + } + } + + new->async_tx.flags = flags; /* client is in control of this ack */ + new->async_tx.cookie = -EBUSY; + + /* Set End-of-link to the last link descriptor of new list */ + set_ld_eol(chan, new); + + return &first->async_tx; + +fail: + if (!first) + return NULL; + + fsldma_free_desc_list_reverse(chan, &first->tx_list); + return NULL; +} + /** * fsl_dma_prep_slave_sg - prepare descriptors for a DMA_SLAVE transaction * @chan: DMA channel @@ -1327,11 +1447,13 @@ static int __devinit fsldma_of_probe(struct platform_device *op, dma_cap_set(DMA_MEMCPY, fdev->common.cap_mask); dma_cap_set(DMA_INTERRUPT, fdev->common.cap_mask); + dma_cap_set(DMA_SG, fdev->common.cap_mask); dma_cap_set(DMA_SLAVE, fdev->common.cap_mask); fdev->common.device_alloc_chan_resources = fsl_dma_alloc_chan_resources; fdev->common.device_free_chan_resources = fsl_dma_free_chan_resources; fdev->common.device_prep_dma_interrupt = fsl_dma_prep_interrupt; fdev->common.device_prep_dma_memcpy = fsl_dma_prep_memcpy; + fdev->common.device_prep_dma_sg = fsl_dma_prep_sg; fdev->common.device_tx_status = fsl_tx_status; fdev->common.device_issue_pending = fsl_dma_memcpy_issue_pending; fdev->common.device_prep_slave_sg = fsl_dma_prep_slave_sg;