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ARC: IOC: panic if both IOC and ZONE_HIGHMEM enabled 

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
hifive-unleashed-5.1
Eugeniy Paltsev 2018-07-30 19:26:35 +03:00 committed by Vineet Gupta
parent 2820a708d5
commit 2b720e99a1
1 changed files with 13 additions and 0 deletions
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13
arch/arc/mm/cache.c
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@ -1144,6 +1144,19 @@ noinline void __init arc_ioc_setup(void)
{
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();