Re: [PATCH v2 05/14] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB Mode

From: Yong Wu
Date: Fri Nov 02 2018 - 02:24:15 EST

On Thu, 2018-11-01 at 16:35 +0000, Robin Murphy wrote:
> On 24/09/2018 09:58, Yong Wu wrote:
> > MediaTek extend the arm v7s descriptor to support the dram over 4GB.
> >
> > In the mt2712 and mt8173, it's called "4GB mode", the physical address
> > is from 0x4000_0000 to 0x1_3fff_ffff, but from EMI point of view, it
> > is remapped to high address from 0x1_0000_0000 to 0x1_ffff_ffff, the
> > bit32 is always enabled. thus, in the M4U, we always enable the bit9
> > for all PTEs which means to enable bit32 of physical address.
> >
> > but in mt8183, M4U support the dram from 0x4000_0000 to 0x3_ffff_ffff
> > which isn't remaped. We extend the PTEs: the bit9 represent bit32 of
> > PA and the bit4 represent bit33 of PA. Meanwhile the iova still is
> > 32bits.
> >
> > In order to unify code, in the "4GB mode", we add the bit32 for the
> > physical address manually in our driver.
> >
> > Correspondingly, Adding bit32 and bit33 for the PA in the iova_to_phys
> > has to been moved into v7s.
> >
> > Signed-off-by: Yong Wu <yong.wu@xxxxxxxxxxxx>
> > ---
> > drivers/iommu/io-pgtable-arm-v7s.c | 34 +++++++++++++++++++++++++++-------
> > drivers/iommu/io-pgtable.h | 7 +++----
> > drivers/iommu/mtk_iommu.c | 16 ++++++++++------
> > drivers/iommu/mtk_iommu.h | 1 +
> > 4 files changed, 41 insertions(+), 17 deletions(-)
> >
> > diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
> > index fa3b9ec..3679a5f 100644
> > --- a/drivers/iommu/io-pgtable-arm-v7s.c
> > +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> > @@ -124,7 +124,9 @@
> > #define ARM_V7S_TEX_MASK 0x7
> > #define ARM_V7S_ATTR_TEX(val) (((val) & ARM_V7S_TEX_MASK) << ARM_V7S_TEX_SHIFT)
> >
> > -#define ARM_V7S_ATTR_MTK_4GB BIT(9) /* MTK extend it for 4GB mode */
> > +/* MediaTek extend the two bits below for over 4GB mode */
> > +#define ARM_V7S_ATTR_MTK_PA_BIT32 BIT(9)
> > +#define ARM_V7S_ATTR_MTK_PA_BIT33 BIT(4)
> >
> > /* *well, except for TEX on level 2 large pages, of course :( */
> > #define ARM_V7S_CONT_PAGE_TEX_SHIFT 6
> > @@ -183,13 +185,24 @@ static dma_addr_t __arm_v7s_dma_addr(void *pages)
> > static arm_v7s_iopte paddr_to_iopte(phys_addr_t paddr, int lvl,
> > struct arm_v7s_io_pgtable *data)
> > {
> > - return paddr & ARM_V7S_LVL_MASK(lvl);
> > + arm_v7s_iopte pte = paddr & ARM_V7S_LVL_MASK(lvl);
> > + struct io_pgtable_cfg *cfg = &data->iop.cfg;
> > +
> > + if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_4GB) {
> > + if (paddr & BIT_ULL(32))
> > + pte |= ARM_V7S_ATTR_MTK_PA_BIT32;
> > + if (paddr & BIT_ULL(33))
> > + pte |= ARM_V7S_ATTR_MTK_PA_BIT33;
> > + }
> > + return pte;
> > }
> >
> > static phys_addr_t iopte_to_paddr(arm_v7s_iopte pte, int lvl,
> > struct arm_v7s_io_pgtable *data)
> > {
> > + struct io_pgtable_cfg *cfg = &data->iop.cfg;
> > arm_v7s_iopte mask;
> > + phys_addr_t paddr;
> >
> > if (ARM_V7S_PTE_IS_TABLE(pte, lvl))
> > mask = ARM_V7S_TABLE_MASK;
> > @@ -198,7 +211,15 @@ static phys_addr_t iopte_to_paddr(arm_v7s_iopte pte, int lvl,
> > else
> > mask = ARM_V7S_LVL_MASK(lvl);
> >
> > - return pte & mask;
> > + paddr = pte & mask;
> > + if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT) &&
>
> I don't think we need this IS_ENABLED() check - we don't have one in the
> equivalent paddr_to_iopte() case above, and what it's protecting is
> clearly a no-op anyway when paddr has a 32-bit type (a GCC 7 build for
> non-LPAE arch/arm doesn't complain with the check removed).

OK.I will delete IS_ENABLED here.
Thanks.

>
> Other than that, though, the rest looks good now;
>
> Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
>
> > + cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_4GB) {
> > + if (pte & ARM_V7S_ATTR_MTK_PA_BIT32)
> > + paddr |= BIT_ULL(32);
> > + if (pte & ARM_V7S_ATTR_MTK_PA_BIT33)
> > + paddr |= BIT_ULL(33);
> > + }
> > + return paddr;
> > }
> >
> > static arm_v7s_iopte *iopte_deref(arm_v7s_iopte pte, int lvl,
> > @@ -315,9 +336,6 @@ static arm_v7s_iopte arm_v7s_prot_to_pte(int prot, int lvl,
> > if (lvl == 1 && (cfg->quirks & IO_PGTABLE_QUIRK_ARM_NS))
> > pte |= ARM_V7S_ATTR_NS_SECTION;
> >
> > - if (cfg->quirks & IO_PGTABLE_QUIRK_ARM_MTK_4GB)
> > - pte |= ARM_V7S_ATTR_MTK_4GB;
> > -
> > return pte;
> > }
> >
> > @@ -504,7 +522,9 @@ static int arm_v7s_map(struct io_pgtable_ops *ops, unsigned long iova,
> > if (!(prot & (IOMMU_READ | IOMMU_WRITE)))
> > return 0;
> >
> > - if (WARN_ON(upper_32_bits(iova) || upper_32_bits(paddr)))
> > + if (WARN_ON(upper_32_bits(iova)) ||
> > + WARN_ON(upper_32_bits(paddr) &&
> > + !(iop->cfg.quirks & IO_PGTABLE_QUIRK_ARM_MTK_4GB)))
> > return -ERANGE;
> >
> > ret = __arm_v7s_map(data, iova, paddr, size, prot, 1, data->pgd);
> > diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h
> > index 2df7909..ee7beb5 100644
> > --- a/drivers/iommu/io-pgtable.h
> > +++ b/drivers/iommu/io-pgtable.h
> > @@ -62,10 +62,9 @@ struct io_pgtable_cfg {
> > * (unmapped) entries but the hardware might do so anyway, perform
> > * TLB maintenance when mapping as well as when unmapping.
> > *
> > - * IO_PGTABLE_QUIRK_ARM_MTK_4GB: (ARM v7s format) Set bit 9 in all
> > - * PTEs, for Mediatek IOMMUs which treat it as a 33rd address bit
> > - * when the SoC is in "4GB mode" and they can only access the high
> > - * remap of DRAM (0x1_00000000 to 0x1_ffffffff).
> > + * IO_PGTABLE_QUIRK_ARM_MTK_4GB: (ARM v7s format) MediaTek IOMMUs extend
> > + * to support up to 34 bits PA where the bit32 and bit33 are
> > + * encoded in the bit9 and bit4 of the PTE respectively.
> > *
> > * IO_PGTABLE_QUIRK_NO_DMA: Guarantees that the tables will only ever
> > * be accessed by a fully cache-coherent IOMMU or CPU (e.g. for a
> > diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> > index c0e2da5..84a12ed 100644
> > --- a/drivers/iommu/mtk_iommu.c
> > +++ b/drivers/iommu/mtk_iommu.c
> > @@ -367,12 +367,18 @@ static int mtk_iommu_map(struct iommu_domain *domain, unsigned long iova,
> > phys_addr_t paddr, size_t size, int prot)
> > {
> > struct mtk_iommu_domain *dom = to_mtk_domain(domain);
> > + struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
> > unsigned long flags;
> > int ret;
> >
> > + /* The "4GB mode" M4U physically can not use the lower remap of Dram. */
> > + if (IS_ENABLED(CONFIG_PHYS_ADDR_T_64BIT) &&
> > + data->plat_data->has_4gb_mode &&
> > + data->enable_4GB)
> > + paddr |= BIT_ULL(32);
> > +
> > spin_lock_irqsave(&dom->pgtlock, flags);
> > - ret = dom->iop->map(dom->iop, iova, paddr & DMA_BIT_MASK(32),
> > - size, prot);
> > + ret = dom->iop->map(dom->iop, iova, paddr, size, prot);
> > spin_unlock_irqrestore(&dom->pgtlock, flags);
> >
> > return ret;
> > @@ -401,7 +407,6 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
> > dma_addr_t iova)
> > {
> > struct mtk_iommu_domain *dom = to_mtk_domain(domain);
> > - struct mtk_iommu_data *data = mtk_iommu_get_m4u_data();
> > unsigned long flags;
> > phys_addr_t pa;
> >
> > @@ -409,9 +414,6 @@ static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
> > pa = dom->iop->iova_to_phys(dom->iop, iova);
> > spin_unlock_irqrestore(&dom->pgtlock, flags);
> >
> > - if (data->enable_4GB)
> > - pa |= BIT_ULL(32);
> > -
> > return pa;
> > }
> >
> > @@ -735,10 +737,12 @@ static int __maybe_unused mtk_iommu_resume(struct device *dev)
> >
> > static const struct mtk_iommu_plat_data mt2712_data = {
> > .m4u_plat = M4U_MT2712,
> > + .has_4gb_mode = true,
> > };
> >
> > static const struct mtk_iommu_plat_data mt8173_data = {
> > .m4u_plat = M4U_MT8173,
> > + .has_4gb_mode = true,
> > };
> >
> > static const struct of_device_id mtk_iommu_of_ids[] = {
> > diff --git a/drivers/iommu/mtk_iommu.h b/drivers/iommu/mtk_iommu.h
> > index 333a0ef..a243047 100644
> > --- a/drivers/iommu/mtk_iommu.h
> > +++ b/drivers/iommu/mtk_iommu.h
> > @@ -43,6 +43,7 @@ enum mtk_iommu_plat {
> >
> > struct mtk_iommu_plat_data {
> > enum mtk_iommu_plat m4u_plat;
> > + bool has_4gb_mode;
> > };
> >
> > struct mtk_iommu_domain;
> >