ARC: IOC: panic if both IOC and ZONE_HIGHMEM enabled

{

	unsigned int ioc_base, mem_sz;

	/*

	 * As for today we don't support both IOC and ZONE_HIGHMEM enabled

	 * simultaneously. This happens because as of today IOC aperture covers

	 * only ZONE_NORMAL (low mem) and any dma transactions outside this

	 * region won't be HW coherent.

	 * If we want to use both IOC and ZONE_HIGHMEM we can use

	 * bounce_buffer to handle dma transactions to HIGHMEM.

	 * Also it is possible to modify dma_direct cache ops or increase IOC

	 * aperture size if we are planning to use HIGHMEM without PAE.

	 */

	if (IS_ENABLED(CONFIG_HIGHMEM))

		panic("IOC and HIGHMEM can't be used simultaneously");

	/* Flush + invalidate + disable L1 dcache */

	__dc_disable();