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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: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta 2019-03-21 17:19:37 -07:00
parent 79a3aaa7b8
commit 99bd5fcc50
1 changed files with 16 additions and 15 deletions
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31
arch/arc/mm/cache.c
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@ -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();