static int bcma_extpci_read_config()

in driver_pci_host.c [84:146]

• 55 lines of code
• 14 McCabe index (conditional complexity)

static int bcma_extpci_read_config(struct bcma_drv_pci *pc, unsigned int dev,
				  unsigned int func, unsigned int off,
				  void *buf, int len)
{
	int err = -EINVAL;
	u32 addr, val;
	void __iomem *mmio = 0;

	WARN_ON(!pc->hostmode);
	if (unlikely(len != 1 && len != 2 && len != 4))
		goto out;
	if (dev == 0) {
		/* we support only two functions on device 0 */
		if (func > 1)
			goto out;

		/* accesses to config registers with offsets >= 256
		 * requires indirect access.
		 */
		if (off >= PCI_CONFIG_SPACE_SIZE) {
			addr = (func << 12);
			addr |= (off & 0x0FFC);
			val = bcma_pcie_read_config(pc, addr);
		} else {
			addr = BCMA_CORE_PCI_PCICFG0;
			addr |= (func << 8);
			addr |= (off & 0xFC);
			val = pcicore_read32(pc, addr);
		}
	} else {
		addr = bcma_get_cfgspace_addr(pc, dev, func, off);
		if (unlikely(!addr))
			goto out;
		err = -ENOMEM;
		mmio = ioremap(addr, sizeof(val));
		if (!mmio)
			goto out;

		if (mips_busprobe32(val, mmio)) {
			val = 0xFFFFFFFF;
			goto unmap;
		}
	}
	val >>= (8 * (off & 3));

	switch (len) {
	case 1:
		*((u8 *)buf) = (u8)val;
		break;
	case 2:
		*((u16 *)buf) = (u16)val;
		break;
	case 4:
		*((u32 *)buf) = (u32)val;
		break;
	}
	err = 0;
unmap:
	if (mmio)
		iounmap(mmio);
out:
	return err;
}