static int pxa_ata_probe()

in pata_pxa.c [159:296]

• 89 lines of code
• 11 McCabe index (conditional complexity)

static int pxa_ata_probe(struct platform_device *pdev)
{
	struct ata_host *host;
	struct ata_port *ap;
	struct pata_pxa_data *data;
	struct resource *cmd_res;
	struct resource *ctl_res;
	struct resource *dma_res;
	struct resource *irq_res;
	struct pata_pxa_pdata *pdata = dev_get_platdata(&pdev->dev);
	struct dma_slave_config	config;
	int ret = 0;

	/*
	 * Resource validation, three resources are needed:
	 *  - CMD port base address
	 *  - CTL port base address
	 *  - DMA port base address
	 *  - IRQ pin
	 */
	if (pdev->num_resources != 4) {
		dev_err(&pdev->dev, "invalid number of resources\n");
		return -EINVAL;
	}

	/*
	 * CMD port base address
	 */
	cmd_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (unlikely(cmd_res == NULL))
		return -EINVAL;

	/*
	 * CTL port base address
	 */
	ctl_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
	if (unlikely(ctl_res == NULL))
		return -EINVAL;

	/*
	 * DMA port base address
	 */
	dma_res = platform_get_resource(pdev, IORESOURCE_DMA, 0);
	if (unlikely(dma_res == NULL))
		return -EINVAL;

	/*
	 * IRQ pin
	 */
	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (unlikely(irq_res == NULL))
		return -EINVAL;

	/*
	 * Allocate the host
	 */
	host = ata_host_alloc(&pdev->dev, 1);
	if (!host)
		return -ENOMEM;

	ap		= host->ports[0];
	ap->ops		= &pxa_ata_port_ops;
	ap->pio_mask	= ATA_PIO4;
	ap->mwdma_mask	= ATA_MWDMA2;

	ap->ioaddr.cmd_addr	= devm_ioremap(&pdev->dev, cmd_res->start,
						resource_size(cmd_res));
	ap->ioaddr.ctl_addr	= devm_ioremap(&pdev->dev, ctl_res->start,
						resource_size(ctl_res));
	ap->ioaddr.bmdma_addr	= devm_ioremap(&pdev->dev, dma_res->start,
						resource_size(dma_res));

	/*
	 * Adjust register offsets
	 */
	ap->ioaddr.altstatus_addr = ap->ioaddr.ctl_addr;
	ap->ioaddr.data_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_DATA << pdata->reg_shift);
	ap->ioaddr.error_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_ERR << pdata->reg_shift);
	ap->ioaddr.feature_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_FEATURE << pdata->reg_shift);
	ap->ioaddr.nsect_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_NSECT << pdata->reg_shift);
	ap->ioaddr.lbal_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_LBAL << pdata->reg_shift);
	ap->ioaddr.lbam_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_LBAM << pdata->reg_shift);
	ap->ioaddr.lbah_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_LBAH << pdata->reg_shift);
	ap->ioaddr.device_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_DEVICE << pdata->reg_shift);
	ap->ioaddr.status_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_STATUS << pdata->reg_shift);
	ap->ioaddr.command_addr	= ap->ioaddr.cmd_addr +
					(ATA_REG_CMD << pdata->reg_shift);

	/*
	 * Allocate and load driver's internal data structure
	 */
	data = devm_kzalloc(&pdev->dev, sizeof(struct pata_pxa_data),
								GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	ap->private_data = data;

	memset(&config, 0, sizeof(config));
	config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	config.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
	config.src_addr = dma_res->start;
	config.dst_addr = dma_res->start;
	config.src_maxburst = 32;
	config.dst_maxburst = 32;

	/*
	 * Request the DMA channel
	 */
	data->dma_chan =
		dma_request_slave_channel(&pdev->dev, "data");
	if (!data->dma_chan)
		return -EBUSY;
	ret = dmaengine_slave_config(data->dma_chan, &config);
	if (ret < 0) {
		dev_err(&pdev->dev, "dma configuration failed: %d\n", ret);
		return ret;
	}

	/*
	 * Activate the ATA host
	 */
	ret = ata_host_activate(host, irq_res->start, ata_sff_interrupt,
				pdata->irq_flags, &pxa_ata_sht);
	if (ret)
		dma_release_channel(data->dma_chan);

	return ret;
}