From b0146f9e29ca2e82262416aca65395c322a618f9 Mon Sep 17 00:00:00 2001
From: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Date: Tue, 16 Jan 2018 19:20:28 +0300
Subject: [PATCH] ARC: Cache: Disable IOC by default
We'd like to keep IOC HW at the same state as t is right after reset when we
start Linux kernel so there will be no re-configuration of IOC on the go.
The point is U-Boot doesn't benefit a lot from IOC as it doesn't do a
lot of DMA operations especially on multiple cores simultaneously.
At the same time re-configuration of IOC in run-time might become quite
a tricky experience because we need to make sure there're no DMA
trannsactions in flight otherwise unexpected consequencses might affect
us much later and debugging those kinds of issues will be a real
nightmare.
That said let's make our life easier a little bit.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
---
arch/arc/lib/cache.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/arc/lib/cache.c b/arch/arc/lib/cache.c
index a6bbe3ce5d..d17948dbaf 100644
--- a/arch/arc/lib/cache.c
+++ b/arch/arc/lib/cache.c
@@ -48,6 +48,9 @@ bool slc_exists __section(".data") = false;
bool ioc_exists __section(".data") = false;
bool pae_exists __section(".data") = false;
+/* To force enable IOC set ioc_enable to 'true' */
+bool ioc_enable __section(".data") = false;
+
void read_decode_mmu_bcr(void)
{
/* TODO: should we compare mmu version from BCR and from CONFIG? */
@@ -200,7 +203,7 @@ static void read_decode_cache_bcr_arcv2(void)
} cbcr;
cbcr.word = read_aux_reg(ARC_BCR_CLUSTER);
- if (cbcr.fields.c)
+ if (cbcr.fields.c && ioc_enable)
ioc_exists = true;
}
#endif
--
2.39.5