static int altera_cvp_probe()

in altera-cvp.c [576:674]

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

static int altera_cvp_probe(struct pci_dev *pdev,
			    const struct pci_device_id *dev_id)
{
	struct altera_cvp_conf *conf;
	struct fpga_manager *mgr;
	int ret, offset;
	u16 cmd, val;
	u32 regval;

	/* Discover the Vendor Specific Offset for this device */
	offset = pci_find_next_ext_capability(pdev, 0, PCI_EXT_CAP_ID_VNDR);
	if (!offset) {
		dev_err(&pdev->dev, "No Vendor Specific Offset.\n");
		return -ENODEV;
	}

	/*
	 * First check if this is the expected FPGA device. PCI config
	 * space access works without enabling the PCI device, memory
	 * space access is enabled further down.
	 */
	pci_read_config_word(pdev, offset + VSE_PCIE_EXT_CAP_ID, &val);
	if (val != VSE_PCIE_EXT_CAP_ID_VAL) {
		dev_err(&pdev->dev, "Wrong EXT_CAP_ID value 0x%x\n", val);
		return -ENODEV;
	}

	pci_read_config_dword(pdev, offset + VSE_CVP_STATUS, &regval);
	if (!(regval & VSE_CVP_STATUS_CVP_EN)) {
		dev_err(&pdev->dev,
			"CVP is disabled for this device: CVP_STATUS Reg 0x%x\n",
			regval);
		return -ENODEV;
	}

	conf = devm_kzalloc(&pdev->dev, sizeof(*conf), GFP_KERNEL);
	if (!conf)
		return -ENOMEM;

	conf->vsec_offset = offset;

	/*
	 * Enable memory BAR access. We cannot use pci_enable_device() here
	 * because it will make the driver unusable with FPGA devices that
	 * have additional big IOMEM resources (e.g. 4GiB BARs) on 32-bit
	 * platform. Such BARs will not have an assigned address range and
	 * pci_enable_device() will fail, complaining about not claimed BAR,
	 * even if the concerned BAR is not needed for FPGA configuration
	 * at all. Thus, enable the device via PCI config space command.
	 */
	pci_read_config_word(pdev, PCI_COMMAND, &cmd);
	if (!(cmd & PCI_COMMAND_MEMORY)) {
		cmd |= PCI_COMMAND_MEMORY;
		pci_write_config_word(pdev, PCI_COMMAND, cmd);
	}

	ret = pci_request_region(pdev, CVP_BAR, "CVP");
	if (ret) {
		dev_err(&pdev->dev, "Requesting CVP BAR region failed\n");
		goto err_disable;
	}

	conf->pci_dev = pdev;
	conf->write_data = altera_cvp_write_data_iomem;

	if (conf->vsec_offset == V1_VSEC_OFFSET)
		conf->priv = &cvp_priv_v1;
	else
		conf->priv = &cvp_priv_v2;

	conf->map = pci_iomap(pdev, CVP_BAR, 0);
	if (!conf->map) {
		dev_warn(&pdev->dev, "Mapping CVP BAR failed\n");
		conf->write_data = altera_cvp_write_data_config;
	}

	snprintf(conf->mgr_name, sizeof(conf->mgr_name), "%s @%s",
		 ALTERA_CVP_MGR_NAME, pci_name(pdev));

	mgr = fpga_mgr_register(&pdev->dev, conf->mgr_name,
				&altera_cvp_ops, conf);
	if (IS_ERR(mgr)) {
		ret = PTR_ERR(mgr);
		goto err_unmap;
	}

	pci_set_drvdata(pdev, mgr);

	return 0;

err_unmap:
	if (conf->map)
		pci_iounmap(pdev, conf->map);
	pci_release_region(pdev, CVP_BAR);
err_disable:
	cmd &= ~PCI_COMMAND_MEMORY;
	pci_write_config_word(pdev, PCI_COMMAND, cmd);
	return ret;
}