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    SubjectRe: [PATCH v5 14/20] iommu/mediatek: Add mmu1 support
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    On Wed, 2019-01-30 at 10:55 -0800, Evan Green wrote:
    > On Mon, Dec 31, 2018 at 7:59 PM Yong Wu <yong.wu@mediatek.com> wrote:
    > >
    > > Normally the M4U HW connect EMI with smi. the diagram is like below:
    > > EMI
    > > |
    > > M4U
    > > |
    > > smi-common
    > > |
    > > -----------------
    > > | | | | ...
    > > larb0 larb1 larb2 larb3
    > >
    > > Actually there are 2 mmu cells in the M4U HW, like this diagram:
    > >
    > > EMI
    > > ---------
    > > | |
    > > mmu0 mmu1 <- M4U
    > > | |
    > > ---------
    > > |
    > > smi-common
    > > |
    > > -----------------
    > > | | | | ...
    > > larb0 larb1 larb2 larb3
    > >
    > > This patch add support for mmu1. In order to get better performance,
    > > we could adjust some larbs go to mmu1 while the others still go to
    > > mmu0. This is controlled by a SMI COMMON register SMI_BUS_SEL(0x220).
    > >
    > > mt2712, mt8173 and mt8183 M4U HW all have 2 mmu cells. the default
    > > value of that register is 0 which means all the larbs go to mmu0
    > > defaultly.
    > >
    > > This is a preparing patch for adjusting SMI_BUS_SEL for mt8183.
    > >
    > > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
    > > ---
    > > drivers/iommu/mtk_iommu.c | 47 +++++++++++++++++++++++++++++------------------
    > > 1 file changed, 29 insertions(+), 18 deletions(-)
    > >
    > > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
    > > index 66e3615..7fcef19 100644
    > > --- a/drivers/iommu/mtk_iommu.c
    > > +++ b/drivers/iommu/mtk_iommu.c
    > > @@ -70,27 +70,32 @@
    > > #define F_MISS_FIFO_ERR_INT_EN BIT(6)
    > > #define F_INT_CLR_BIT BIT(12)
    > >
    > > -#define REG_MMU_INT_MAIN_CONTROL 0x124
    > > -#define F_INT_TRANSLATION_FAULT BIT(0)
    > > -#define F_INT_MAIN_MULTI_HIT_FAULT BIT(1)
    > > -#define F_INT_INVALID_PA_FAULT BIT(2)
    > > -#define F_INT_ENTRY_REPLACEMENT_FAULT BIT(3)
    > > -#define F_INT_TLB_MISS_FAULT BIT(4)
    > > -#define F_INT_MISS_TRANSACTION_FIFO_FAULT BIT(5)
    > > -#define F_INT_PRETETCH_TRANSATION_FIFO_FAULT BIT(6)
    > > +#define REG_MMU_INT_MAIN_CONTROL 0x124 /* mmu0 | mmu1 */
    >
    > The comment being on that line is kind of weird, since the comment
    > really applies to the lines below it. Maybe the comment should be on
    > its own line, or on the TRANSLATION_FAULT line.

    Sharp eye. You are right, this comment applies the lines below.
    But If I move it below, then the next line will be over 80 chars.

    How about I add a "below:" like this:
    > +#define REG_MMU_INT_MAIN_CONTROL 0x124 /* below: mmu0 |
    mmu1 */

    >
    > Other than that,
    > Reviewed-by: Evan Green <evgreen@chromium.org>


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