From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrea Merello Subject: [PATCH v6 1/7] dmaengine: xilinx_dma: commonize DMA copy size calculation Date: Tue, 20 Nov 2018 16:31:45 +0100 Message-ID: <20181120153151.18024-1-andrea.merello@gmail.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: vkoul@kernel.org, dan.j.williams@intel.com, michal.simek@xilinx.com, appana.durga.rao@xilinx.com, dmaengine@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, mark.rutland@arm.com, devicetree@vger.kernel.org, radhey.shyam.pandey@xilinx.com, Andrea Merello List-Id: devicetree@vger.kernel.org This patch removes a bit of duplicated code by introducing a new function that implements calculations for DMA copy size, and prepares for changes to the copy size calculation that will happen in following patches. Suggested-by: Vinod Koul Signed-off-by: Andrea Merello Reviewed-by: Radhey Shyam Pandey --- Changes in v4: - introduce this patch in the patch series Changes in v5: None Changes in v6: - 2/7 was basically redoing what done here. Anticipate here the introduction of a local temporary variable so that 2/7 just add stuff - add dma chan ptr argument to xilinx_calc_cma_copysize() to prepare for 2/7 - introduce max_buffer_len variable in advance, to prepare for 4/7 - reword for above changes --- drivers/dma/xilinx/xilinx_dma.c | 39 ++++++++++++++++++++++++++------- 1 file changed, 31 insertions(+), 8 deletions(-) diff --git a/drivers/dma/xilinx/xilinx_dma.c b/drivers/dma/xilinx/xilinx_dma.c index c12442312595..2c1db500284f 100644 --- a/drivers/dma/xilinx/xilinx_dma.c +++ b/drivers/dma/xilinx/xilinx_dma.c @@ -423,6 +423,7 @@ struct xilinx_dma_config { * @rxs_clk: DMA s2mm stream clock * @nr_channels: Number of channels DMA device supports * @chan_id: DMA channel identifier + * @max_buffer_len: Max buffer length */ struct xilinx_dma_device { void __iomem *regs; @@ -442,6 +443,7 @@ struct xilinx_dma_device { struct clk *rxs_clk; u32 nr_channels; u32 chan_id; + u32 max_buffer_len; }; /* Macros */ @@ -957,6 +959,25 @@ static int xilinx_dma_alloc_chan_resources(struct dma_chan *dchan) return 0; } +/** + * xilinx_dma_calc_copysize - Calculate the amount of data to copy + * @chan: Driver specific DMA channel + * @size: Total data that needs to be copied + * @done: Amount of data that has been already copied + * + * Return: Amount of data that has to be copied + */ +static int xilinx_dma_calc_copysize(struct xilinx_dma_chan *chan, + int size, int done) +{ + size_t copy; + + copy = min_t(size_t, size - done, + chan->xdev->max_buffer_len); + + return copy; +} + /** * xilinx_dma_tx_status - Get DMA transaction status * @dchan: DMA channel @@ -990,7 +1011,7 @@ static enum dma_status xilinx_dma_tx_status(struct dma_chan *dchan, list_for_each_entry(segment, &desc->segments, node) { hw = &segment->hw; residue += (hw->control - hw->status) & - XILINX_DMA_MAX_TRANS_LEN; + chan->xdev->max_buffer_len; } } spin_unlock_irqrestore(&chan->lock, flags); @@ -1250,7 +1271,7 @@ static void xilinx_cdma_start_transfer(struct xilinx_dma_chan *chan) /* Start the transfer */ dma_ctrl_write(chan, XILINX_DMA_REG_BTT, - hw->control & XILINX_DMA_MAX_TRANS_LEN); + hw->control & chan->xdev->max_buffer_len); } list_splice_tail_init(&chan->pending_list, &chan->active_list); @@ -1353,7 +1374,7 @@ static void xilinx_dma_start_transfer(struct xilinx_dma_chan *chan) /* Start the transfer */ dma_ctrl_write(chan, XILINX_DMA_REG_BTT, - hw->control & XILINX_DMA_MAX_TRANS_LEN); + hw->control & chan->xdev->max_buffer_len); } list_splice_tail_init(&chan->pending_list, &chan->active_list); @@ -1714,7 +1735,7 @@ xilinx_cdma_prep_memcpy(struct dma_chan *dchan, dma_addr_t dma_dst, struct xilinx_cdma_tx_segment *segment; struct xilinx_cdma_desc_hw *hw; - if (!len || len > XILINX_DMA_MAX_TRANS_LEN) + if (!len || len > chan->xdev->max_buffer_len) return NULL; desc = xilinx_dma_alloc_tx_descriptor(chan); @@ -1804,8 +1825,8 @@ static struct dma_async_tx_descriptor *xilinx_dma_prep_slave_sg( * Calculate the maximum number of bytes to transfer, * making sure it is less than the hw limit */ - copy = min_t(size_t, sg_dma_len(sg) - sg_used, - XILINX_DMA_MAX_TRANS_LEN); + copy = xilinx_dma_calc_copysize(chan, sg_dma_len(sg), + sg_used); hw = &segment->hw; /* Fill in the descriptor */ @@ -1909,8 +1930,8 @@ static struct dma_async_tx_descriptor *xilinx_dma_prep_dma_cyclic( * Calculate the maximum number of bytes to transfer, * making sure it is less than the hw limit */ - copy = min_t(size_t, period_len - sg_used, - XILINX_DMA_MAX_TRANS_LEN); + copy = xilinx_dma_calc_copysize(chan, period_len, + sg_used); hw = &segment->hw; xilinx_axidma_buf(chan, hw, buf_addr, sg_used, period_len * i); @@ -2624,6 +2645,8 @@ static int xilinx_dma_probe(struct platform_device *pdev) /* Retrieve the DMA engine properties from the device tree */ xdev->has_sg = of_property_read_bool(node, "xlnx,include-sg"); + xdev->max_buffer_len = XILINX_DMA_MAX_TRANS_LEN; + if (xdev->dma_config->dmatype == XDMA_TYPE_AXIDMA) xdev->mcdma = of_property_read_bool(node, "xlnx,mcdma"); -- 2.17.1