diff options
Diffstat (limited to 'drivers/dma/at_hdmac.c')
| -rw-r--r-- | drivers/dma/at_hdmac.c | 175 |
1 files changed, 164 insertions, 11 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 1e1a4c567542..4f5b262f9a40 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -65,6 +65,21 @@ static void atc_issue_pending(struct dma_chan *chan); /*----------------------------------------------------------------------*/ +static inline unsigned int atc_get_xfer_width(dma_addr_t src, dma_addr_t dst, + size_t len) +{ + unsigned int width; + + if (!((src | dst | len) & 3)) + width = 2; + else if (!((src | dst | len) & 1)) + width = 1; + else + width = 0; + + return width; +} + static struct at_desc *atc_first_active(struct at_dma_chan *atchan) { return list_first_entry(&atchan->active_list, @@ -628,16 +643,10 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, * We can be a lot more clever here, but this should take care * of the most common optimization. */ - if (!((src | dest | len) & 3)) { - ctrla = ATC_SRC_WIDTH_WORD | ATC_DST_WIDTH_WORD; - src_width = dst_width = 2; - } else if (!((src | dest | len) & 1)) { - ctrla = ATC_SRC_WIDTH_HALFWORD | ATC_DST_WIDTH_HALFWORD; - src_width = dst_width = 1; - } else { - ctrla = ATC_SRC_WIDTH_BYTE | ATC_DST_WIDTH_BYTE; - src_width = dst_width = 0; - } + src_width = dst_width = atc_get_xfer_width(src, dest, len); + + ctrla = ATC_SRC_WIDTH(src_width) | + ATC_DST_WIDTH(dst_width); for (offset = 0; offset < len; offset += xfer_count << src_width) { xfer_count = min_t(size_t, (len - offset) >> src_width, @@ -822,6 +831,144 @@ err: } /** + * atc_prep_dma_sg - prepare memory to memory scather-gather operation + * @chan: the channel to prepare operation on + * @dst_sg: destination scatterlist + * @dst_nents: number of destination scatterlist entries + * @src_sg: source scatterlist + * @src_nents: number of source scatterlist entries + * @flags: tx descriptor status flags + */ +static struct dma_async_tx_descriptor * +atc_prep_dma_sg(struct dma_chan *chan, + struct scatterlist *dst_sg, unsigned int dst_nents, + struct scatterlist *src_sg, unsigned int src_nents, + unsigned long flags) +{ + struct at_dma_chan *atchan = to_at_dma_chan(chan); + struct at_desc *desc = NULL; + struct at_desc *first = NULL; + struct at_desc *prev = NULL; + unsigned int src_width; + unsigned int dst_width; + size_t xfer_count; + u32 ctrla; + u32 ctrlb; + size_t dst_len = 0, src_len = 0; + dma_addr_t dst = 0, src = 0; + size_t len = 0, total_len = 0; + + if (unlikely(dst_nents == 0 || src_nents == 0)) + return NULL; + + if (unlikely(dst_sg == NULL || src_sg == NULL)) + return NULL; + + ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN + | ATC_SRC_ADDR_MODE_INCR + | ATC_DST_ADDR_MODE_INCR + | ATC_FC_MEM2MEM; + + /* + * loop until there is either no more source or no more destination + * scatterlist entry + */ + while (true) { + + /* prepare the next transfer */ + if (dst_len == 0) { + + /* no more destination scatterlist entries */ + if (!dst_sg || !dst_nents) + break; + + dst = sg_dma_address(dst_sg); + dst_len = sg_dma_len(dst_sg); + + dst_sg = sg_next(dst_sg); + dst_nents--; + } + + if (src_len == 0) { + + /* no more source scatterlist entries */ + if (!src_sg || !src_nents) + break; + + src = sg_dma_address(src_sg); + src_len = sg_dma_len(src_sg); + + src_sg = sg_next(src_sg); + src_nents--; + } + + len = min_t(size_t, src_len, dst_len); + if (len == 0) + continue; + + /* take care for the alignment */ + src_width = dst_width = atc_get_xfer_width(src, dst, len); + + ctrla = ATC_SRC_WIDTH(src_width) | + ATC_DST_WIDTH(dst_width); + + /* + * The number of transfers to set up refer to the source width + * that depends on the alignment. + */ + xfer_count = len >> src_width; + if (xfer_count > ATC_BTSIZE_MAX) { + xfer_count = ATC_BTSIZE_MAX; + len = ATC_BTSIZE_MAX << src_width; + } + + /* create the transfer */ + desc = atc_desc_get(atchan); + if (!desc) + goto err_desc_get; + + desc->lli.saddr = src; + desc->lli.daddr = dst; + desc->lli.ctrla = ctrla | xfer_count; + desc->lli.ctrlb = ctrlb; + + desc->txd.cookie = 0; + desc->len = len; + + /* + * Although we only need the transfer width for the first and + * the last descriptor, its easier to set it to all descriptors. + */ + desc->tx_width = src_width; + + atc_desc_chain(&first, &prev, desc); + + /* update the lengths and addresses for the next loop cycle */ + dst_len -= len; + src_len -= len; + dst += len; + src += len; + + total_len += len; + } + + /* First descriptor of the chain embedds additional information */ + first->txd.cookie = -EBUSY; + first->total_len = total_len; + + /* set end-of-link to the last link descriptor of list*/ + set_desc_eol(desc); + + first->txd.flags = flags; /* client is in control of this ack */ + + return &first->txd; + +err_desc_get: + atc_desc_put(atchan, first); + return NULL; +} + +/** * atc_dma_cyclic_check_values * Check for too big/unaligned periods and unaligned DMA buffer */ @@ -1421,8 +1568,10 @@ static int __init at_dma_probe(struct platform_device *pdev) /* setup platform data for each SoC */ dma_cap_set(DMA_MEMCPY, at91sam9rl_config.cap_mask); + dma_cap_set(DMA_SG, at91sam9rl_config.cap_mask); dma_cap_set(DMA_MEMCPY, at91sam9g45_config.cap_mask); dma_cap_set(DMA_SLAVE, at91sam9g45_config.cap_mask); + dma_cap_set(DMA_SG, at91sam9g45_config.cap_mask); /* get DMA parameters from controller type */ plat_dat = at_dma_get_driver_data(pdev); @@ -1542,11 +1691,15 @@ static int __init at_dma_probe(struct platform_device *pdev) atdma->dma_common.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; } + if (dma_has_cap(DMA_SG, atdma->dma_common.cap_mask)) + atdma->dma_common.device_prep_dma_sg = atc_prep_dma_sg; + dma_writel(atdma, EN, AT_DMA_ENABLE); - dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n", + dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s%s), %d channels\n", dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "", dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "", + dma_has_cap(DMA_SG, atdma->dma_common.cap_mask) ? "sg-cpy " : "", plat_dat->nr_channels); dma_async_device_register(&atdma->dma_common); |