diff options
Diffstat (limited to 'drivers/dma/at_hdmac.c')
-rw-r--r-- | drivers/dma/at_hdmac.c | 359 |
1 files changed, 276 insertions, 83 deletions
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 1e1a4c567542..57b2141ddddc 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, @@ -238,93 +253,126 @@ static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first) } /* - * atc_get_current_descriptors - - * locate the descriptor which equal to physical address in DSCR - * @atchan: the channel we want to start - * @dscr_addr: physical descriptor address in DSCR + * atc_get_desc_by_cookie - get the descriptor of a cookie + * @atchan: the DMA channel + * @cookie: the cookie to get the descriptor for */ -static struct at_desc *atc_get_current_descriptors(struct at_dma_chan *atchan, - u32 dscr_addr) +static struct at_desc *atc_get_desc_by_cookie(struct at_dma_chan *atchan, + dma_cookie_t cookie) { - struct at_desc *desc, *_desc, *child, *desc_cur = NULL; + struct at_desc *desc, *_desc; - list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) { - if (desc->lli.dscr == dscr_addr) { - desc_cur = desc; - break; - } + list_for_each_entry_safe(desc, _desc, &atchan->queue, desc_node) { + if (desc->txd.cookie == cookie) + return desc; + } - list_for_each_entry(child, &desc->tx_list, desc_node) { - if (child->lli.dscr == dscr_addr) { - desc_cur = child; - break; - } - } + list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) { + if (desc->txd.cookie == cookie) + return desc; } - return desc_cur; + return NULL; +} + +/** + * atc_calc_bytes_left - calculates the number of bytes left according to the + * value read from CTRLA. + * + * @current_len: the number of bytes left before reading CTRLA + * @ctrla: the value of CTRLA + * @desc: the descriptor containing the transfer width + */ +static inline int atc_calc_bytes_left(int current_len, u32 ctrla, + struct at_desc *desc) +{ + return current_len - ((ctrla & ATC_BTSIZE_MAX) << desc->tx_width); } -/* - * atc_get_bytes_left - - * Get the number of bytes residue in dma buffer, - * @chan: the channel we want to start +/** + * atc_calc_bytes_left_from_reg - calculates the number of bytes left according + * to the current value of CTRLA. + * + * @current_len: the number of bytes left before reading CTRLA + * @atchan: the channel to read CTRLA for + * @desc: the descriptor containing the transfer width + */ +static inline int atc_calc_bytes_left_from_reg(int current_len, + struct at_dma_chan *atchan, struct at_desc *desc) +{ + u32 ctrla = channel_readl(atchan, CTRLA); + + return atc_calc_bytes_left(current_len, ctrla, desc); +} + +/** + * atc_get_bytes_left - get the number of bytes residue for a cookie + * @chan: DMA channel + * @cookie: transaction identifier to check status of */ -static int atc_get_bytes_left(struct dma_chan *chan) +static int atc_get_bytes_left(struct dma_chan *chan, dma_cookie_t cookie) { struct at_dma_chan *atchan = to_at_dma_chan(chan); - struct at_dma *atdma = to_at_dma(chan->device); - int chan_id = atchan->chan_common.chan_id; struct at_desc *desc_first = atc_first_active(atchan); - struct at_desc *desc_cur; - int ret = 0, count = 0; + struct at_desc *desc; + int ret; + u32 ctrla, dscr; /* - * Initialize necessary values in the first time. - * remain_desc record remain desc length. + * If the cookie doesn't match to the currently running transfer then + * we can return the total length of the associated DMA transfer, + * because it is still queued. */ - if (atchan->remain_desc == 0) - /* First descriptor embedds the transaction length */ - atchan->remain_desc = desc_first->len; + desc = atc_get_desc_by_cookie(atchan, cookie); + if (desc == NULL) + return -EINVAL; + else if (desc != desc_first) + return desc->total_len; - /* - * This happens when current descriptor transfer complete. - * The residual buffer size should reduce current descriptor length. - */ - if (unlikely(test_bit(ATC_IS_BTC, &atchan->status))) { - clear_bit(ATC_IS_BTC, &atchan->status); - desc_cur = atc_get_current_descriptors(atchan, - channel_readl(atchan, DSCR)); - if (!desc_cur) { - ret = -EINVAL; - goto out; - } + /* cookie matches to the currently running transfer */ + ret = desc_first->total_len; + + if (desc_first->lli.dscr) { + /* hardware linked list transfer */ + + /* + * Calculate the residue by removing the length of the child + * descriptors already transferred from the total length. + * To get the current child descriptor we can use the value of + * the channel's DSCR register and compare it against the value + * of the hardware linked list structure of each child + * descriptor. + */ + + ctrla = channel_readl(atchan, CTRLA); + rmb(); /* ensure CTRLA is read before DSCR */ + dscr = channel_readl(atchan, DSCR); - count = (desc_cur->lli.ctrla & ATC_BTSIZE_MAX) - << desc_first->tx_width; - if (atchan->remain_desc < count) { - ret = -EINVAL; - goto out; + /* for the first descriptor we can be more accurate */ + if (desc_first->lli.dscr == dscr) + return atc_calc_bytes_left(ret, ctrla, desc_first); + + ret -= desc_first->len; + list_for_each_entry(desc, &desc_first->tx_list, desc_node) { + if (desc->lli.dscr == dscr) + break; + + ret -= desc->len; } - atchan->remain_desc -= count; - ret = atchan->remain_desc; - } else { /* - * Get residual bytes when current - * descriptor transfer in progress. + * For the last descriptor in the chain we can calculate + * the remaining bytes using the channel's register. + * Note that the transfer width of the first and last + * descriptor may differ. */ - count = (channel_readl(atchan, CTRLA) & ATC_BTSIZE_MAX) - << (desc_first->tx_width); - ret = atchan->remain_desc - count; + if (!desc->lli.dscr) + ret = atc_calc_bytes_left_from_reg(ret, atchan, desc); + } else { + /* single transfer */ + ret = atc_calc_bytes_left_from_reg(ret, atchan, desc_first); } - /* - * Check fifo empty. - */ - if (!(dma_readl(atdma, CHSR) & AT_DMA_EMPT(chan_id))) - atc_issue_pending(chan); -out: return ret; } @@ -539,8 +587,6 @@ static irqreturn_t at_dma_interrupt(int irq, void *dev_id) /* Give information to tasklet */ set_bit(ATC_IS_ERROR, &atchan->status); } - if (pending & AT_DMA_BTC(i)) - set_bit(ATC_IS_BTC, &atchan->status); tasklet_schedule(&atchan->tasklet); ret = IRQ_HANDLED; } @@ -628,16 +674,10 @@ 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, @@ -653,14 +693,18 @@ atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, desc->lli.ctrlb = ctrlb; desc->txd.cookie = 0; + desc->len = xfer_count << src_width; atc_desc_chain(&first, &prev, desc); } /* First descriptor of the chain embedds additional information */ first->txd.cookie = -EBUSY; - first->len = len; + first->total_len = len; + + /* set transfer width for the calculation of the residue */ first->tx_width = src_width; + prev->tx_width = src_width; /* set end-of-link to the last link descriptor of list*/ set_desc_eol(desc); @@ -752,6 +796,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, | ATC_SRC_WIDTH(mem_width) | len >> mem_width; desc->lli.ctrlb = ctrlb; + desc->len = len; atc_desc_chain(&first, &prev, desc); total_len += len; @@ -792,6 +837,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, | ATC_DST_WIDTH(mem_width) | len >> reg_width; desc->lli.ctrlb = ctrlb; + desc->len = len; atc_desc_chain(&first, &prev, desc); total_len += len; @@ -806,8 +852,11 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, /* First descriptor of the chain embedds additional information */ first->txd.cookie = -EBUSY; - first->len = total_len; + first->total_len = total_len; + + /* set transfer width for the calculation of the residue */ first->tx_width = reg_width; + prev->tx_width = reg_width; /* first link descriptor of list is responsible of flags */ first->txd.flags = flags; /* client is in control of this ack */ @@ -822,6 +871,144 @@ 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 */ @@ -872,6 +1059,7 @@ atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc, | ATC_FC_MEM2PER | ATC_SIF(atchan->mem_if) | ATC_DIF(atchan->per_if); + desc->len = period_len; break; case DMA_DEV_TO_MEM: @@ -883,6 +1071,7 @@ atc_dma_cyclic_fill_desc(struct dma_chan *chan, struct at_desc *desc, | ATC_FC_PER2MEM | ATC_SIF(atchan->per_if) | ATC_DIF(atchan->mem_if); + desc->len = period_len; break; default: @@ -964,7 +1153,7 @@ atc_prep_dma_cyclic(struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len, /* First descriptor of the chain embedds additional information */ first->txd.cookie = -EBUSY; - first->len = buf_len; + first->total_len = buf_len; first->tx_width = reg_width; return &first->txd; @@ -1118,7 +1307,7 @@ atc_tx_status(struct dma_chan *chan, spin_lock_irqsave(&atchan->lock, flags); /* Get number of bytes left in the active transactions */ - bytes = atc_get_bytes_left(chan); + bytes = atc_get_bytes_left(chan, cookie); spin_unlock_irqrestore(&atchan->lock, flags); @@ -1214,7 +1403,6 @@ static int atc_alloc_chan_resources(struct dma_chan *chan) spin_lock_irqsave(&atchan->lock, flags); atchan->descs_allocated = i; - atchan->remain_desc = 0; list_splice(&tmp_list, &atchan->free_list); dma_cookie_init(chan); spin_unlock_irqrestore(&atchan->lock, flags); @@ -1257,7 +1445,6 @@ static void atc_free_chan_resources(struct dma_chan *chan) list_splice_init(&atchan->free_list, &list); atchan->descs_allocated = 0; atchan->status = 0; - atchan->remain_desc = 0; dev_vdbg(chan2dev(chan), "free_chan_resources: done\n"); } @@ -1421,8 +1608,10 @@ 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 +1731,15 @@ 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); |