Get word-level granularity from hardware for calculating the transfer count remaining.
Signed-off-by: Christopher Freeman <[email protected]> --- drivers/dma/tegra20-apb-dma.c | 52 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 03ad64e..cc6b2fd 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -779,15 +779,54 @@ skip_dma_stop: spin_unlock_irqrestore(&tdc->lock, flags); } +static int tegra_dma_wcount_in_bytes(struct dma_chan *dc) +{ + struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc); + struct tegra_dma_sg_req *sgreq; + unsigned long wcount = 0; + unsigned long status = 0; + int bytes = 0; + + if (list_empty(&tdc->pending_sg_req) || !tdc->busy) + return 0; + + tegra_dma_pause(tdc, true); + + /* in case of interrupt, handle it and don't read wcount reg */ + status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS); + if (status & TEGRA_APBDMA_STATUS_ISE_EOC) { + tdc_write(tdc, TEGRA_APBDMA_CHAN_STATUS, status); + dev_info(tdc2dev(tdc), "%s():handling isr\n", __func__); + tdc->isr_handler(tdc, false); + tegra_dma_resume(tdc); + return 0; + } + + if (tdc->tdma->chip_data->support_separate_wcount_reg) + wcount = tdc_read(tdc, TEGRA_APBDMA_CHAN_WORD_TRANSFER); + else + wcount = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS); + + sgreq = list_first_entry(&tdc->pending_sg_req, + typeof(*sgreq), node); + bytes = get_current_xferred_count(tdc, sgreq, wcount); + + tegra_dma_resume(tdc); + + return bytes; +} + static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, dma_cookie_t cookie, struct dma_tx_state *txstate) { struct tegra_dma_channel *tdc = to_tegra_dma_chan(dc); struct tegra_dma_desc *dma_desc; struct tegra_dma_sg_req *sg_req; + struct tegra_dma_sg_req *first_entry = NULL; enum dma_status ret; unsigned long flags; unsigned int residual; + unsigned int hw_byte_count = 0; ret = dma_cookie_status(dc, cookie, txstate); if (ret == DMA_COMPLETE) @@ -812,9 +851,22 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, list_for_each_entry(sg_req, &tdc->pending_sg_req, node) { dma_desc = sg_req->dma_desc; if (dma_desc->txd.cookie == cookie) { + hw_byte_count = tegra_dma_wcount_in_bytes(dc); + + if (!list_empty(&tdc->pending_sg_req)) + first_entry = + list_first_entry(&tdc->pending_sg_req, + typeof(*first_entry), node); + residual = dma_desc->bytes_requested - (dma_desc->bytes_transferred % dma_desc->bytes_requested); + + /* hw byte count only applies to current transaction */ + if (first_entry && + first_entry->dma_desc->txd.cookie == cookie) + residual -= hw_byte_count; + dma_set_residue(txstate, residual); ret = dma_desc->dma_status; spin_unlock_irqrestore(&tdc->lock, flags); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
