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From: John Keeping <john@metanate.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Heiko Stuebner <heiko@sntech.de>,
	iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	John Keeping <john@metanate.com>
Subject: [PATCH] iommu/rockchip: Fix "is stall active" check
Date: Tue,  5 Apr 2016 15:05:46 +0100	[thread overview]
Message-ID: <1459865146-25308-1-git-send-email-john@metanate.com> (raw)

Since commit cd6438c5f844 ("iommu/rockchip: Reconstruct to support multi
slaves") rk_iommu_is_stall_active() always returns false because the
bitwise AND operates on the boolean flag promoted to an integer and a
value that is either zero or BIT(2).

Explicitly convert the right-hand value to a boolean so that both sides
are guaranteed to be either zero or one.

rk_iommu_is_paging_enabled() does not suffer from the same problem since
RK_MMU_STATUS_PAGING_ENABLED is BIT(0), but let's apply the same change
for consistency and to make it clear that it's correct without needing
to lookup the value.

Fixes: cd6438c5f844 ("iommu/rockchip: Reconstruct to support multi slaves")
Signed-off-by: John Keeping <john@metanate.com>
---
 drivers/iommu/rockchip-iommu.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index a6f593a0a29e..5710a06c3049 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -315,8 +315,8 @@ static bool rk_iommu_is_stall_active(struct rk_iommu *iommu)
 	int i;
 
 	for (i = 0; i < iommu->num_mmu; i++)
-		active &= rk_iommu_read(iommu->bases[i], RK_MMU_STATUS) &
-					RK_MMU_STATUS_STALL_ACTIVE;
+		active &= !!(rk_iommu_read(iommu->bases[i], RK_MMU_STATUS) &
+					   RK_MMU_STATUS_STALL_ACTIVE);
 
 	return active;
 }
@@ -327,8 +327,8 @@ static bool rk_iommu_is_paging_enabled(struct rk_iommu *iommu)
 	int i;
 
 	for (i = 0; i < iommu->num_mmu; i++)
-		enable &= rk_iommu_read(iommu->bases[i], RK_MMU_STATUS) &
-					RK_MMU_STATUS_PAGING_ENABLED;
+		enable &= !!(rk_iommu_read(iommu->bases[i], RK_MMU_STATUS) &
+					   RK_MMU_STATUS_PAGING_ENABLED);
 
 	return enable;
 }
-- 
2.8.0.rc4.238.g874082a

             reply	other threads:[~2016-04-05 14:10 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-05 14:05 John Keeping [this message]
2016-04-05 17:21 ` [PATCH] iommu/rockchip: Fix "is stall active" check Heiko Stuebner
2016-04-05 17:28   ` John Keeping
2016-04-05 19:10     ` Heiko Stuebner
2016-04-06  7:45       ` Tomeu Vizoso
2016-04-07 12:50 ` Joerg Roedel

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