Messages in this thread | | | Subject | Re: [PATCH v3 09/33] iommu/mediatek: Remove for_each_m4u in tlb_sync_all | From | AngeloGioacchino Del Regno <> | Date | Mon, 10 Jan 2022 10:16:03 +0100 |
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Il 09/01/22 03:48, Yong Wu ha scritto: > On Tue, 2022-01-04 at 16:55 +0100, AngeloGioacchino Del Regno wrote: >> Il 23/09/21 13:58, Yong Wu ha scritto: >>> The tlb_sync_all is called from these three functions: >>> a) flush_iotlb_all: it will be called for each a iommu HW. >>> b) tlb_flush_range_sync: it already has for_each_m4u. >>> c) in irq: When IOMMU HW translation fault, Only need flush itself. >>> >>> Thus, No need for_each_m4u in this tlb_sync_all. Remove it. >>> >>> Signed-off-by: Yong Wu <yong.wu@mediatek.com> >>> --- >>> drivers/iommu/mtk_iommu.c | 18 +++++++----------- >>> 1 file changed, 7 insertions(+), 11 deletions(-) >>> >>> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c >>> index 6f4f6624e3ac..0b4c30baa864 100644 >>> --- a/drivers/iommu/mtk_iommu.c >>> +++ b/drivers/iommu/mtk_iommu.c >>> @@ -206,19 +206,15 @@ static struct mtk_iommu_domain >>> *to_mtk_domain(struct iommu_domain *dom) >>> >>> static void mtk_iommu_tlb_flush_all(struct mtk_iommu_data *data) >>> { >>> - struct list_head *head = data->hw_list; >>> - >>> - for_each_m4u(data, head) { >>> - if (pm_runtime_get_if_in_use(data->dev) <= 0) >>> - continue; >>> + if (pm_runtime_get_if_in_use(data->dev) <= 0) >>> + return; >>> >>> - writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0, >>> - data->base + data->plat_data- >>>> inv_sel_reg); >>> - writel_relaxed(F_ALL_INVLD, data->base + >>> REG_MMU_INVALIDATE); >>> - wmb(); /* Make sure the tlb flush all done */ >>> + writel_relaxed(F_INVLD_EN1 | F_INVLD_EN0, >>> + data->base + data->plat_data->inv_sel_reg); >>> + writel_relaxed(F_ALL_INVLD, data->base + REG_MMU_INVALIDATE); >>> + wmb(); /* Make sure the tlb flush all done */ >> >> There aren't a lot of writes here - not anymore, since you are no >> longer doing >> this for_each_m4u()... >> ...so, please change writel_relaxed() to writel() calls, allowing you >> to also >> remove the write barrier at the end (since in the non relaxed >> version, order is already ensured). > > In the "writel", the "__iowmb()" runs before "write_relaxed". Then how > to guarantee the last register was wrote into the HW. Here the flush > all don't have sync(waiting it complete) >
That's right, I'm sorry for the invalid proposal.
Though, there's something else to mention here... if writing (F_INVLD_EN1 | F_INVLD_EN0) to inv_sel_reg is *required* to happen before writing F_ALL_INVLD to REG_MMU_INVALIDATE (which I think is exactly the case here), then, in order to ensure write ordering, you should still use writel() instead of the relaxed accessor; after which, since (as you mentioned) there is no sync readback loop, you can keep that wmb() at the end.
>> >>> >>> - pm_runtime_put(data->dev); >>> - } >>> + pm_runtime_put(data->dev); >>> } >>> >>> static void mtk_iommu_tlb_flush_range_sync(unsigned long iova, >>> size_t size, >>> >
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