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Commit 99bd5fcc authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: PAE40: don't panic and instead turn off hw ioc 



HSDK currently panics when built for HIGHMEM/ARC_HAS_PAE40 because ioc
is enabled with default which doesn't work for the 2 non contiguous
memory nodes. So get PAE working by disabling ioc instead.

Tested with !PAE40 by forcing @ioc_enable=0 and running the glibc
testsuite over ssh

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent 79a3aaa7

arch/arc/mm/cache.c

+16 −15
Original line number Diff line number Diff line
@@ -113,10 +113,24 @@ static void read_decode_cache_bcr_arcv2(int cpu) 
	}



	READ_BCR(ARC_REG_CLUSTER_BCR, cbcr);

	if (cbcr.c)

	if (cbcr.c) {

		ioc_exists = 1;

	else



		/*

		 * 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) || is_pae40_enabled())

			ioc_enable = 0;

	} else {

		ioc_enable = 0;

	}



	/* HS 2.0 didn't have AUX_VOL */

	if (cpuinfo_arc700[cpu].core.family > 0x51) {
@@ -1158,19 +1172,6 @@ noinline void __init arc_ioc_setup(void) 
	if (!ioc_enable)

		return;



	/*

	 * 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();