static int find_dfls_by_vsec()

in dfl-pci.c [139:211]

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

static int find_dfls_by_vsec(struct pci_dev *pcidev, struct dfl_fpga_enum_info *info)
{
	u32 bir, offset, vndr_hdr, dfl_cnt, dfl_res;
	int dfl_res_off, i, bars, voff = 0;
	resource_size_t start, len;

	while ((voff = pci_find_next_ext_capability(pcidev, voff, PCI_EXT_CAP_ID_VNDR))) {
		vndr_hdr = 0;
		pci_read_config_dword(pcidev, voff + PCI_VNDR_HEADER, &vndr_hdr);

		if (PCI_VNDR_HEADER_ID(vndr_hdr) == PCI_VSEC_ID_INTEL_DFLS &&
		    pcidev->vendor == PCI_VENDOR_ID_INTEL)
			break;
	}

	if (!voff) {
		dev_dbg(&pcidev->dev, "%s no DFL VSEC found\n", __func__);
		return -ENODEV;
	}

	dfl_cnt = 0;
	pci_read_config_dword(pcidev, voff + PCI_VNDR_DFLS_CNT, &dfl_cnt);
	if (dfl_cnt > PCI_STD_NUM_BARS) {
		dev_err(&pcidev->dev, "%s too many DFLs %d > %d\n",
			__func__, dfl_cnt, PCI_STD_NUM_BARS);
		return -EINVAL;
	}

	dfl_res_off = voff + PCI_VNDR_DFLS_RES;
	if (dfl_res_off + (dfl_cnt * sizeof(u32)) > PCI_CFG_SPACE_EXP_SIZE) {
		dev_err(&pcidev->dev, "%s DFL VSEC too big for PCIe config space\n",
			__func__);
		return -EINVAL;
	}

	for (i = 0, bars = 0; i < dfl_cnt; i++, dfl_res_off += sizeof(u32)) {
		dfl_res = GENMASK(31, 0);
		pci_read_config_dword(pcidev, dfl_res_off, &dfl_res);

		bir = dfl_res & PCI_VNDR_DFLS_RES_BAR_MASK;
		if (bir >= PCI_STD_NUM_BARS) {
			dev_err(&pcidev->dev, "%s bad bir number %d\n",
				__func__, bir);
			return -EINVAL;
		}

		if (bars & BIT(bir)) {
			dev_err(&pcidev->dev, "%s DFL for BAR %d already specified\n",
				__func__, bir);
			return -EINVAL;
		}

		bars |= BIT(bir);

		len = pci_resource_len(pcidev, bir);
		offset = dfl_res & PCI_VNDR_DFLS_RES_OFF_MASK;
		if (offset >= len) {
			dev_err(&pcidev->dev, "%s bad offset %u >= %pa\n",
				__func__, offset, &len);
			return -EINVAL;
		}

		dev_dbg(&pcidev->dev, "%s BAR %d offset 0x%x\n", __func__, bir, offset);

		len -= offset;

		start = pci_resource_start(pcidev, bir) + offset;

		dfl_fpga_enum_info_add_dfl(info, start, len);
	}

	return 0;
}