From: Heiko Stuebner <heiko@sntech.de>
To: John Keeping <john@metanate.com>
Cc: Joerg Roedel <joro@8bytes.org>,
iommu@lists.linux-foundation.org,
linux-arm-kernel@lists.infradead.org,
linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu/rockchip: Fix "is stall active" check
Date: Tue, 05 Apr 2016 10:21:27 -0700 [thread overview]
Message-ID: <5389576.zuTxjFsmO4@phil> (raw)
In-Reply-To: <1459865146-25308-1-git-send-email-john@metanate.com>
Am Dienstag, 5. April 2016, 15:05:46 schrieb John Keeping:
> 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>
Nice catch, thanks.
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
John, out of curiosity, how did you find that problem? Excess stall error
messages or something else?
Thanks
Heiko
> ---
> 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;
> }
next prev parent reply other threads:[~2016-04-05 17:21 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 14:05 [PATCH] iommu/rockchip: Fix "is stall active" check John Keeping
2016-04-05 17:21 ` Heiko Stuebner [this message]
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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