static int wdat_wdt_run_action()

in wdat_wdt.c [114:202]

• 76 lines of code
• 17 McCabe index (conditional complexity)

static int wdat_wdt_run_action(struct wdat_wdt *wdat, unsigned int action,
			       u32 param, u32 *retval)
{
	struct wdat_instruction *instr;

	if (action >= ARRAY_SIZE(wdat->instructions))
		return -EINVAL;

	if (!wdat->instructions[action])
		return -EOPNOTSUPP;

	dev_dbg(&wdat->pdev->dev, "Running action %#x\n", action);

	/* Run each instruction sequentially */
	list_for_each_entry(instr, wdat->instructions[action], node) {
		const struct acpi_wdat_entry *entry = &instr->entry;
		const struct acpi_generic_address *gas;
		u32 flags, value, mask, x, y;
		bool preserve;
		int ret;

		gas = &entry->register_region;

		preserve = entry->instruction & ACPI_WDAT_PRESERVE_REGISTER;
		flags = entry->instruction & ~ACPI_WDAT_PRESERVE_REGISTER;
		value = entry->value;
		mask = entry->mask;

		switch (flags) {
		case ACPI_WDAT_READ_VALUE:
			ret = wdat_wdt_read(wdat, instr, &x);
			if (ret)
				return ret;
			x >>= gas->bit_offset;
			x &= mask;
			if (retval)
				*retval = x == value;
			break;

		case ACPI_WDAT_READ_COUNTDOWN:
			ret = wdat_wdt_read(wdat, instr, &x);
			if (ret)
				return ret;
			x >>= gas->bit_offset;
			x &= mask;
			if (retval)
				*retval = x;
			break;

		case ACPI_WDAT_WRITE_VALUE:
			x = value & mask;
			x <<= gas->bit_offset;
			if (preserve) {
				ret = wdat_wdt_read(wdat, instr, &y);
				if (ret)
					return ret;
				y = y & ~(mask << gas->bit_offset);
				x |= y;
			}
			ret = wdat_wdt_write(wdat, instr, x);
			if (ret)
				return ret;
			break;

		case ACPI_WDAT_WRITE_COUNTDOWN:
			x = param;
			x &= mask;
			x <<= gas->bit_offset;
			if (preserve) {
				ret = wdat_wdt_read(wdat, instr, &y);
				if (ret)
					return ret;
				y = y & ~(mask << gas->bit_offset);
				x |= y;
			}
			ret = wdat_wdt_write(wdat, instr, x);
			if (ret)
				return ret;
			break;

		default:
			dev_err(&wdat->pdev->dev, "Unknown instruction: %u\n",
				flags);
			return -EINVAL;
		}
	}

	return 0;
}