Re: [PATCH 03/18] dmaengine: st_fdma: Add STMicroelectronics FDMA engine driver support

From: Vinod Koul
Date: Tue Apr 26 2016 - 12:50:37 EST


On Thu, Apr 21, 2016 at 12:04:20PM +0100, Peter Griffin wrote:

> + if (!atomic_read(&fchan->fdev->fw_loaded)) {
> + dev_err(fchan->fdev->dev, "%s: fdma fw not loaded\n", __func__);
> + return NULL;
> + }

so who is loading the fw and setting fw_loaded, it is not set in this patch?

> + if (direction == DMA_DEV_TO_MEM) {
> + fchan->cfg.req_ctrl &= ~REQ_CTRL_WNR;
> + maxburst = fchan->scfg.src_maxburst;
> + width = fchan->scfg.src_addr_width;
> + addr = fchan->scfg.src_addr;
> + } else if (direction == DMA_MEM_TO_DEV) {
> + fchan->cfg.req_ctrl |= REQ_CTRL_WNR;
> + maxburst = fchan->scfg.dst_maxburst;
> + width = fchan->scfg.dst_addr_width;
> + addr = fchan->scfg.dst_addr;
> + } else {
> + return -EINVAL;
> + }

switch please

> +
> + fchan->cfg.req_ctrl &= ~REQ_CTRL_OPCODE_MASK;
> + if (width == DMA_SLAVE_BUSWIDTH_1_BYTE)
> + fchan->cfg.req_ctrl |= REQ_CTRL_OPCODE_LD_ST1;
> + else if (width == DMA_SLAVE_BUSWIDTH_2_BYTES)
> + fchan->cfg.req_ctrl |= REQ_CTRL_OPCODE_LD_ST2;
> + else if (width == DMA_SLAVE_BUSWIDTH_4_BYTES)
> + fchan->cfg.req_ctrl |= REQ_CTRL_OPCODE_LD_ST4;
> + else if (width == DMA_SLAVE_BUSWIDTH_8_BYTES)
> + fchan->cfg.req_ctrl |= REQ_CTRL_OPCODE_LD_ST8;
> + else
> + return -EINVAL;

here as well

> +static void fill_hw_node(struct st_fdma_hw_node *hw_node,
> + struct st_fdma_chan *fchan,
> + enum dma_transfer_direction direction)
> +{
> +
> + if (direction == DMA_MEM_TO_DEV) {
> + hw_node->control |= NODE_CTRL_SRC_INCR;
> + hw_node->control |= NODE_CTRL_DST_STATIC;
> + hw_node->daddr = fchan->cfg.dev_addr;
> + } else {
> + hw_node->control |= NODE_CTRL_SRC_STATIC;
> + hw_node->control |= NODE_CTRL_DST_INCR;
> + hw_node->saddr = fchan->cfg.dev_addr;
> + }

empty line here at other places too. The code looks very compressed and bit
harder to read overall

> + fdesc = st_fdma_alloc_desc(fchan, sg_len);
> + if (!fdesc) {
> + dev_err(fchan->fdev->dev, "no memory for desc\n");
> + return NULL;
> + }
> +
> + fdesc->iscyclic = false;
> +
> + for_each_sg(sgl, sg, sg_len, i) {
> + hw_node = fdesc->node[i].desc;
> +
> + hw_node->next = fdesc->node[(i + 1) % sg_len].pdesc;
> + hw_node->control = NODE_CTRL_REQ_MAP_DREQ(fchan->dreq_line);
> +
> + fill_hw_node(hw_node, fchan, direction);
> +
> + if (direction == DMA_MEM_TO_DEV)
> + hw_node->saddr = sg_dma_address(sg);
> + else
> + hw_node->daddr = sg_dma_address(sg);
> +
> + hw_node->nbytes = sg_dma_len(sg);
> + hw_node->generic.length = sg_dma_len(sg);
> + }
> +
> + /* interrupt at end of last node */
> + hw_node->control |= NODE_CTRL_INT_EON;
> +
> + return vchan_tx_prep(&fchan->vchan, &fdesc->vdesc, flags);

bunch of this seems similar to cyclic case, can you create common setup
routine for these, anyway cyclic is a special cases of slave_sg

> +
> + ret = dma_cookie_status(chan, cookie, txstate);
> + if (ret == DMA_COMPLETE)
> + return ret;
> +
> + if (!txstate)
> + return fchan->status;

why channel status, query is for descriptor

> +static int st_fdma_remove(struct platform_device *pdev)
> +{
> + struct st_fdma_dev *fdev = platform_get_drvdata(pdev);
> +
> + st_fdma_clk_disable(fdev);

and you irq is still enabled and tasklets can be scheduled!!

--
~Vinod