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From:   Peter Geis <pgwipeout@gmail.com>
Date:   Wed, 24 Nov 2021 07:44:32 -0500
Message-ID: <CAMdYzYo=6H3NaBDZ2rQnDUr89rnA0rvxWGfEbRP6sQGt7+vB3w@mail.gmail.com>
Subject: Re: [PATCH] iommu/rockchip: Fix PAGE_DESC_HI_MASKs for RK3568
To:     =?UTF-8?Q?Heiko_St=C3=BCbner?= <heiko@sntech.de>
Cc:     Joerg Roedel <joro@8bytes.org>, Will Deacon <will@kernel.org>,
        Alex Bee <knaerzche@gmail.com>,
        Benjamin Gaignard <benjamin.gaignard@collabora.com>,
        iommu <iommu@lists.linux-foundation.org>,
        arm-mail-list <linux-arm-kernel@lists.infradead.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Wed, Nov 24, 2021 at 5:36 AM Heiko St=C3=BCbner <heiko@sntech.de> wrote:
>
> Am Mittwoch, 24. November 2021, 03:13:25 CET schrieb Alex Bee:
> > With the submission of iommu driver for RK3568 a subtle bug was
> > introduced: PAGE_DESC_HI_MASK1 and PAGE_DESC_HI_MASK2 have to be
> > the other way arround - that leads to random errors, especially when
> > addresses beyond 32 bit are used.
> >
> > Fix it.
> >
> > Fixes: c55356c534aa ("iommu: rockchip: Add support for iommu v2")
> > Signed-off-by: Alex Bee <knaerzche@gmail.com>
> > ---
> >
> > I've found this bug, when testing the recent VOP2 submission, which is
> > the first perpherial which uses iommu for RK356x. I could use it on my
> > quartz64 8GB board only, when limiting the available memory to less 4GB=
.
> >
> > This patch fixes it.
> >
> >  drivers/iommu/rockchip-iommu.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-io=
mmu.c
> > index 5cb260820eda..7f23ad61c094 100644
> > --- a/drivers/iommu/rockchip-iommu.c
> > +++ b/drivers/iommu/rockchip-iommu.c
> > @@ -200,8 +200,8 @@ static inline phys_addr_t rk_dte_pt_address(u32 dte=
)
> >  #define DTE_HI_MASK2 GENMASK(7, 4)
> >  #define DTE_HI_SHIFT1        24 /* shift bit 8 to bit 32 */
> >  #define DTE_HI_SHIFT2        32 /* shift bit 4 to bit 36 */
> > -#define PAGE_DESC_HI_MASK1   GENMASK_ULL(39, 36)
> > -#define PAGE_DESC_HI_MASK2   GENMASK_ULL(35, 32)
> > +#define PAGE_DESC_HI_MASK1   GENMASK_ULL(35, 32)
> > +#define PAGE_DESC_HI_MASK2   GENMASK_ULL(39, 36)
>
> With this change the PAGE_DESC_HI_MASK* now match the other
> constants above them in what bits they access, so
>
> Reviewed-by: Heiko Stuebner <heiko@sntech.de>
>
>

Tested on the quartz64-a board with the experimental vop2 driver,
confirmed it fixed the issue.

Tested-by: Peter Geis <pgwipeout@gmail.com>

>
>
>
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