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Date: Thu, 1 Nov 2018 16:35:06 +0000
From: Robin Murphy <Robin.Murphy@....com>
To: Yong Wu <yong.wu@...iatek.com>, Joerg Roedel <joro@...tes.org>,
Matthias Brugger <matthias.bgg@...il.com>,
Rob Herring <robh+dt@...nel.org>
CC: Tomasz Figa <tfiga@...gle.com>, Will Deacon <Will.Deacon@....com>,
Daniel Kurtz <djkurtz@...gle.com>,
"linux-mediatek@...ts.infradead.org"
<linux-mediatek@...ts.infradead.org>,
"srv_heupstream@...iatek.com" <srv_heupstream@...iatek.com>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"iommu@...ts.linux-foundation.org" <iommu@...ts.linux-foundation.org>,
"arnd@...db.de" <arnd@...db.de>,
"yingjoe.chen@...iatek.com" <yingjoe.chen@...iatek.com>,
"youlin.pei@...iatek.com" <youlin.pei@...iatek.com>,
nd <nd@....com>
Subject: Re: [PATCH v2 05/14] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB
Mode
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@...iatek.com>
> ---
> 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).
Other than that, though, the rest looks good now;
Reviewed-by: Robin Murphy <robin.murphy@....com>
> + 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;
>
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