diff options
Diffstat (limited to 'drivers/dma/tegra20-apb-dma.c')
| -rw-r--r-- | drivers/dma/tegra20-apb-dma.c | 75 |
1 files changed, 68 insertions, 7 deletions
diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c index 79e9593815f1..3a45079d11ec 100644 --- a/drivers/dma/tegra20-apb-dma.c +++ b/drivers/dma/tegra20-apb-dma.c @@ -152,6 +152,7 @@ struct tegra_dma_sg_req { bool last_sg; struct list_head node; struct tegra_dma_desc *dma_desc; + unsigned int words_xferred; }; /* @@ -496,6 +497,7 @@ static void tegra_dma_configure_for_next(struct tegra_dma_channel *tdc, tdc_write(tdc, TEGRA_APBDMA_CHAN_CSR, nsg_req->ch_regs.csr | TEGRA_APBDMA_CSR_ENB); nsg_req->configured = true; + nsg_req->words_xferred = 0; tegra_dma_resume(tdc); } @@ -511,6 +513,7 @@ static void tdc_start_head_req(struct tegra_dma_channel *tdc) typeof(*sg_req), node); tegra_dma_start(tdc, sg_req); sg_req->configured = true; + sg_req->words_xferred = 0; tdc->busy = true; } @@ -638,6 +641,8 @@ static void handle_cont_sngl_cycle_dma_done(struct tegra_dma_channel *tdc, list_add_tail(&dma_desc->cb_node, &tdc->cb_desc); dma_desc->cb_count++; + sgreq->words_xferred = 0; + /* If not last req then put at end of pending list */ if (!list_is_last(&sgreq->node, &tdc->pending_sg_req)) { list_move_tail(&sgreq->node, &tdc->pending_sg_req); @@ -797,6 +802,65 @@ skip_dma_stop: return 0; } +static unsigned int tegra_dma_sg_bytes_xferred(struct tegra_dma_channel *tdc, + struct tegra_dma_sg_req *sg_req) +{ + unsigned long status, wcount = 0; + + if (!list_is_first(&sg_req->node, &tdc->pending_sg_req)) + return 0; + + if (tdc->tdma->chip_data->support_separate_wcount_reg) + wcount = tdc_read(tdc, TEGRA_APBDMA_CHAN_WORD_TRANSFER); + + status = tdc_read(tdc, TEGRA_APBDMA_CHAN_STATUS); + + if (!tdc->tdma->chip_data->support_separate_wcount_reg) + wcount = status; + + if (status & TEGRA_APBDMA_STATUS_ISE_EOC) + return sg_req->req_len; + + wcount = get_current_xferred_count(tdc, sg_req, wcount); + + if (!wcount) { + /* + * If wcount wasn't ever polled for this SG before, then + * simply assume that transfer hasn't started yet. + * + * Otherwise it's the end of the transfer. + * + * The alternative would be to poll the status register + * until EOC bit is set or wcount goes UP. That's so + * because EOC bit is getting set only after the last + * burst's completion and counter is less than the actual + * transfer size by 4 bytes. The counter value wraps around + * in a cyclic mode before EOC is set(!), so we can't easily + * distinguish start of transfer from its end. + */ + if (sg_req->words_xferred) + wcount = sg_req->req_len - 4; + + } else if (wcount < sg_req->words_xferred) { + /* + * This case will never happen for a non-cyclic transfer. + * + * For a cyclic transfer, although it is possible for the + * next transfer to have already started (resetting the word + * count), this case should still not happen because we should + * have detected that the EOC bit is set and hence the transfer + * was completed. + */ + WARN_ON_ONCE(1); + + wcount = sg_req->req_len - 4; + } else { + sg_req->words_xferred = wcount; + } + + return wcount; +} + static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, dma_cookie_t cookie, struct dma_tx_state *txstate) { @@ -806,6 +870,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, enum dma_status ret; unsigned long flags; unsigned int residual; + unsigned int bytes = 0; ret = dma_cookie_status(dc, cookie, txstate); if (ret == DMA_COMPLETE) @@ -825,6 +890,7 @@ 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) { + bytes = tegra_dma_sg_bytes_xferred(tdc, sg_req); ret = dma_desc->dma_status; goto found; } @@ -836,7 +902,7 @@ static enum dma_status tegra_dma_tx_status(struct dma_chan *dc, found: if (dma_desc && txstate) { residual = dma_desc->bytes_requested - - (dma_desc->bytes_transferred % + ((dma_desc->bytes_transferred + bytes) % dma_desc->bytes_requested); dma_set_residue(txstate, residual); } @@ -1441,12 +1507,7 @@ static int tegra_dma_probe(struct platform_device *pdev) BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) | BIT(DMA_SLAVE_BUSWIDTH_8_BYTES); tdma->dma_dev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV); - /* - * XXX The hardware appears to support - * DMA_RESIDUE_GRANULARITY_BURST-level reporting, but it's - * only used by this driver during tegra_dma_terminate_all() - */ - tdma->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT; + tdma->dma_dev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST; tdma->dma_dev.device_config = tegra_dma_slave_config; tdma->dma_dev.device_terminate_all = tegra_dma_terminate_all; tdma->dma_dev.device_tx_status = tegra_dma_tx_status; |