Hi Vineet,
On Fri, 2019-03-29 at 13:45 -0700, Vineet Gupta wrote:
> HSDK currently panics when built for HIGHMEM/ARC_HAS_PAE40 because ioc
> is enabled with default which doesn't for the 2 non contiguous memory
> nodes.
>
> So get PAE working with ioc disabled instead
>
> Tested with !PAE40 by forcing @ioc_enable=0 and running the glibc
> testsuite over ssh
>
> Signed-off-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
> ---
> arch/arc/mm/cache.c | 31 ++++++++++++++++---------------
> 1 file changed, 16 insertions(+), 15 deletions(-)
>
> diff --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c
> index 4135abec3fb0..63e6e6504699 100644
> --- a/arch/arc/mm/cache.c
> +++ b/arch/arc/mm/cache.c
> @@ -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())
As for today PAE40 couldn't be enabled without HIGHMEM for ARC, so probably we can
simplify this to
----------------------------->8----------------------------------
if (IS_ENABLED(CONFIG_HIGHMEM))
ioc_enable = 0;
----------------------------->8----------------------------------
> + 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();
>
--
Eugeniy Paltsev
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