static int __init asr_get_base_address()

in ibmasr.c [141:244]

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

static int __init asr_get_base_address(void)
{
	unsigned char low, high;
	const char *type = "";

	asr_length = 1;

	switch (asr_type) {
	case ASMTYPE_TOPAZ:
		/* SELECT SuperIO CHIP FOR QUERYING
		   (WRITE 0x07 TO BOTH 0x2E and 0x2F) */
		outb(0x07, 0x2e);
		outb(0x07, 0x2f);

		/* SELECT AND READ THE HIGH-NIBBLE OF THE GPIO BASE ADDRESS */
		outb(0x60, 0x2e);
		high = inb(0x2f);

		/* SELECT AND READ THE LOW-NIBBLE OF THE GPIO BASE ADDRESS */
		outb(0x61, 0x2e);
		low = inb(0x2f);

		asr_base = (high << 16) | low;
		asr_read_addr = asr_write_addr =
			asr_base + TOPAZ_ASR_REG_OFFSET;
		asr_length = 5;

		break;

	case ASMTYPE_JASPER:
		type = "Jaspers ";
#if 0
		u32 r;
		/* Suggested fix */
		pdev = pci_get_bus_and_slot(0, DEVFN(0x1f, 0));
		if (pdev == NULL)
			return -ENODEV;
		pci_read_config_dword(pdev, 0x58, &r);
		asr_base = r & 0xFFFE;
		pci_dev_put(pdev);
#else
		/* FIXME: need to use pci_config_lock here,
		   but it's not exported */

/*		spin_lock_irqsave(&pci_config_lock, flags);*/

		/* Select the SuperIO chip in the PCI I/O port register */
		outl(0x8000f858, 0xcf8);

		/* BUS 0, Slot 1F, fnc 0, offset 58 */

		/*
		 * Read the base address for the SuperIO chip.
		 * Only the lower 16 bits are valid, but the address is word
		 * aligned so the last bit must be masked off.
		 */
		asr_base = inl(0xcfc) & 0xfffe;

/*		spin_unlock_irqrestore(&pci_config_lock, flags);*/
#endif
		asr_read_addr = asr_write_addr =
			asr_base + JASPER_ASR_REG_OFFSET;
		asr_toggle_mask = JASPER_ASR_TOGGLE_MASK;
		asr_disable_mask = JASPER_ASR_DISABLE_MASK;
		asr_length = JASPER_ASR_REG_OFFSET + 1;

		break;

	case ASMTYPE_PEARL:
		type = "Pearls ";
		asr_base = PEARL_BASE;
		asr_read_addr = PEARL_READ;
		asr_write_addr = PEARL_WRITE;
		asr_toggle_mask = PEARL_ASR_TOGGLE_MASK;
		asr_disable_mask = PEARL_ASR_DISABLE_MASK;
		asr_length = 4;
		break;

	case ASMTYPE_JUNIPER:
		type = "Junipers ";
		asr_base = JUNIPER_BASE_ADDRESS;
		asr_read_addr = asr_write_addr = asr_base;
		asr_toggle_mask = JUNIPER_ASR_TOGGLE_MASK;
		asr_disable_mask = JUNIPER_ASR_DISABLE_MASK;
		break;

	case ASMTYPE_SPRUCE:
		type = "Spruce's ";
		asr_base = SPRUCE_BASE_ADDRESS;
		asr_read_addr = asr_write_addr = asr_base;
		asr_toggle_mask = SPRUCE_ASR_TOGGLE_MASK;
		asr_disable_mask = SPRUCE_ASR_DISABLE_MASK;
		break;
	}

	if (!request_region(asr_base, asr_length, "ibmasr")) {
		pr_err("address %#x already in use\n", asr_base);
		return -EBUSY;
	}

	pr_info("found %sASR @ addr %#x\n", type, asr_base);

	return 0;
}