PLEASE, REMOVE MY EMAIL ADDRESS FROM ITS LIST.

["William F." <william76.sh@gmail.com>]

Em 03-06-2012 16:09, Russell King - ARM Linux escreveu:
> On Sun, Jun 03, 2012 at 08:38:09PM +0200, Roland Stigge wrote:
>> +static int lpc32xx_xmit_dma(struct mtd_info *mtd, dma_addr_t dma,
>> +			    void *mem, int len, enum dma_transfer_direction dir)
>> +{
>> +	struct nand_chip *chip = mtd->priv;
>> +	struct lpc32xx_nand_host *host = chip->priv;
>> +	struct dma_async_tx_descriptor *desc;
>> +	int flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
>> +	int res;
>> +	dma_cookie_t cookie;
>> +
>> +	host->dma_slave_config.direction = dir;
>> +	host->dma_slave_config.src_addr = dma;
>> +	host->dma_slave_config.dst_addr = dma;
>> +	host->dma_slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>> +	host->dma_slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>> +	host->dma_slave_config.src_maxburst = 4;
>> +	host->dma_slave_config.dst_maxburst = 4;
>> +	/* DMA controller does flow control: */
>> +	host->dma_slave_config.device_fc = false;
>> +	if (dmaengine_slave_config(host->dma_chan,&host->dma_slave_config)) {
>> +		dev_err(mtd->dev.parent, "Failed to setup DMA slave\n");
>> +		return -ENXIO;
>> +	}
>> +
>> +	sg_init_one(&host->sgl, mem, len);
>> +
>> +	res = dma_map_sg(host->dma_chan->device->dev,&host->sgl, 1,
>> +			 DMA_BIDIRECTIONAL);
>> +	if (res != 1) {
>> +		dev_err(mtd->dev.parent, "Failed to map sg list\n");
>> +		return -ENXIO;
>> +	}
>> +	desc = dmaengine_prep_slave_sg(host->dma_chan,&host->sgl, 1, dir,
>> +				       flags);
>> +	if (!desc) {
>> +		dev_err(mtd->dev.parent, "Failed to prepare slave sg\n");
>> +		goto out1;
>> +	}
>> +
>> +	init_completion(&host->comp);
>> +	desc->callback = lpc32xx_dma_complete_func;
>> +	desc->callback_param =&host->comp;
>> +
>> +	cookie = dmaengine_submit(desc);
>> +	if (dma_submit_error(cookie)) {
>> +		dev_err(mtd->dev.parent, "Failed to dmaengine_submit()\n");
>> +		goto out1;
>> +	}
> dmaengine_submit() is no longer allowed to fail, so you don't need this
> check here anymore.  It's been that way for a long time.
>
>> +	dma_async_issue_pending(host->dma_chan);
>> +
>> +	wait_for_completion_timeout(&host->comp, msecs_to_jiffies(1000));
> What about unmapping the buffer upon completion?
>
>> +
>> +	return 0;
>> +out1:
>> +	dma_unmap_sg(host->dma_chan->device->dev,&host->sgl, 1,
>> +		     DMA_BIDIRECTIONAL);
>> +	return -ENXIO;
>> +}
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