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.)
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);
----
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;
> >
