On 20/06/2019 15:59, Yong Wu wrote: > On Tue, 2019-06-18 at 18:06 +0200, Matthias Brugger wrote: >> >> On 10/06/2019 14:17, Yong Wu wrote: >>> This patch only rename the variable name from enable_4GB to >>> dram_is_4gb for readable. >> >> From my understanding this is true when available RAM > 4GB so I think the name >> should be something like dram_bigger_4gb otherwise it may create confusion again. > > Strictly, It is not "dram_bigger_4gb". actually if the dram size is over > 3GB (the first 1GB is the register space), the "4GB mode" will be > enabled. then how about the name "dram_enable_32bit"?(the PA 32bit will > be enabled in the 4GB mode.) Ok I think dram_is_4gb is ok then. But I'd suggest to add an explanation above the struct mtk_iommu_data to explain exactly what this means. > > There is another option, please see the last part in [1] suggested by > Evan, something like below: > ---- > data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT)); > if (!data->plat_data->has_4gb_mode) > data->enable_4GB = false; > Then mtk_iommu_map would only have: > if (data->enable_4GB) > paddr |= BIT_ULL(32); > ---- I think that's a nicer way to handle it. Regards, Matthias > > Which one do you prefer? > > [1] https://lore.kernel.org/patchwork/patch/1028421/ > >> >> Also from my point of view this patch should be done before >> "[PATCH 06/21] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB Mode" > > OK. > >> >> Regards, >> Matthias >> >>> >>> Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx> >>> Reviewed-by: Evan Green <evgreen@xxxxxxxxxxxx> >>> --- >>> drivers/iommu/mtk_iommu.c | 10 +++++----- >>> drivers/iommu/mtk_iommu.h | 2 +- >>> 2 files changed, 6 insertions(+), 6 deletions(-) >>> >>> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c >>> index 86158d8..67cab2d 100644 >>> --- a/drivers/iommu/mtk_iommu.c >>> +++ b/drivers/iommu/mtk_iommu.c >>> @@ -382,7 +382,7 @@ static int mtk_iommu_map(struct iommu_domain *domain, unsigned long iova, >>> int ret; >>> >>> /* The "4GB mode" M4U physically can not use the lower remap of Dram. */ >>> - if (data->plat_data->has_4gb_mode && data->enable_4GB) >>> + if (data->plat_data->has_4gb_mode && data->dram_is_4gb) >>> paddr |= BIT_ULL(32); >>> >>> spin_lock_irqsave(&dom->pgtlock, flags); >>> @@ -554,13 +554,13 @@ static int mtk_iommu_hw_init(const struct mtk_iommu_data *data) >>> writel_relaxed(regval, data->base + REG_MMU_INT_MAIN_CONTROL); >>> >>> if (data->plat_data->m4u_plat == M4U_MT8173) >>> - regval = (data->protect_base >> 1) | (data->enable_4GB << 31); >>> + regval = (data->protect_base >> 1) | (data->dram_is_4gb << 31); >>> else >>> regval = lower_32_bits(data->protect_base) | >>> upper_32_bits(data->protect_base); >>> writel_relaxed(regval, data->base + REG_MMU_IVRP_PADDR); >>> >>> - if (data->enable_4GB && data->plat_data->has_vld_pa_rng) { >>> + if (data->dram_is_4gb && data->plat_data->has_vld_pa_rng) { >>> /* >>> * If 4GB mode is enabled, the validate PA range is from >>> * 0x1_0000_0000 to 0x1_ffff_ffff. here record bit[32:30]. >>> @@ -611,8 +611,8 @@ static int mtk_iommu_probe(struct platform_device *pdev) >>> return -ENOMEM; >>> data->protect_base = ALIGN(virt_to_phys(protect), MTK_PROTECT_PA_ALIGN); >>> >>> - /* Whether the current dram is over 4GB */ >>> - data->enable_4GB = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT)); >>> + /* Whether the current dram is 4GB. */ >>> + data->dram_is_4gb = !!(max_pfn > (BIT_ULL(32) >> PAGE_SHIFT)); >>> >>> res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >>> data->base = devm_ioremap_resource(dev, res); >>> diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h >>> index 753266b..e8114b2 100644 >>> --- a/drivers/iommu/mtk_iommu.h >>> +++ b/drivers/iommu/mtk_iommu.h >>> @@ -65,7 +65,7 @@ struct mtk_iommu_data { >>> struct mtk_iommu_domain *m4u_dom; >>> struct iommu_group *m4u_group; >>> struct mtk_smi_iommu smi_imu; /* SMI larb iommu info */ >>> - bool enable_4GB; >>> + bool dram_is_4gb; >>> bool tlb_flush_active; >>> >>> struct iommu_device iommu; >>> > >
