From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH v8 07/21] iommu/io-pgtable-arm-v7s: Extend MediaTek 4GB Mode Date: Wed, 10 Jul 2019 15:36:50 +0100 Message-ID: <20190710143649.w5dplhzdpi3bxp7e@willie-the-truck> References: <1561774167-24141-1-git-send-email-yong.wu@mediatek.com> <1561774167-24141-8-git-send-email-yong.wu@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1561774167-24141-8-git-send-email-yong.wu@mediatek.com> Sender: linux-kernel-owner@vger.kernel.org To: Yong Wu Cc: Joerg Roedel , Matthias Brugger , Robin Murphy , Rob Herring , Evan Green , Tomasz Figa , Will Deacon , linux-mediatek@lists.infradead.org, srv_heupstream@mediatek.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, iommu@lists.linux-foundation.org, yingjoe.chen@mediatek.com, youlin.pei@mediatek.com, Nicolas Boichat , anan.sun@mediatek.com, Matthias Kaehlcke List-Id: devicetree@vger.kernel.org On Sat, Jun 29, 2019 at 10:09:13AM +0800, 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. What happens if bit4 is set in the pte for mt2712 or mt8173? Perhaps the io-pgtable backend should be allowing oas > 32 when IO_PGTABLE_QUIRK_ARM_MTK_4GB is set, and then enforcing that itself. > 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. > > Regarding whether the pagetable address could be over 4GB, the mt8183 > support it while the previous mt8173 don't. thus keep it as is. > > Signed-off-by: Yong Wu > Reviewed-by: Robin Murphy > Reviewed-by: Evan Green > --- > Comparing with the previous one: > 1). Add a new patch "iommu/mediatek: Fix iova_to_phys PA start for 4GB > mode" before this one. Thus rebase it. > A little difference: in the 4gb mode, we add bit32 for PA. and the PA got > from iova_to_phys always have bit32 here, thus we should adjust it to locate > the valid pa. > 2). Add this code suggested from Evan. > if (!data->plat_data->has_4gb_mode) > data->enable_4GB = false; > --- > drivers/iommu/io-pgtable-arm-v7s.c | 31 ++++++++++++++++++++++++------- > drivers/iommu/mtk_iommu.c | 29 ++++++++++++++++++----------- > drivers/iommu/mtk_iommu.h | 1 + > 3 files changed, 43 insertions(+), 18 deletions(-) > > diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c > index 94c38db..4077822 100644 > --- a/drivers/iommu/io-pgtable-arm-v7s.c > +++ b/drivers/iommu/io-pgtable-arm-v7s.c > @@ -123,7 +123,9 @@ > #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 > @@ -190,13 +192,22 @@ static dma_addr_t __arm_v7s_dma_addr(void *pages) > static arm_v7s_iopte paddr_to_iopte(phys_addr_t paddr, int lvl, > struct io_pgtable_cfg *cfg) > { > - return paddr & ARM_V7S_LVL_MASK(lvl); > + arm_v7s_iopte pte = paddr & ARM_V7S_LVL_MASK(lvl); > + > + 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 io_pgtable_cfg *cfg) > { > arm_v7s_iopte mask; > + phys_addr_t paddr; > > if (ARM_V7S_PTE_IS_TABLE(pte, lvl)) > mask = ARM_V7S_TABLE_MASK; > @@ -205,7 +216,14 @@ 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 (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; I think this relies on CONFIG_PHYS_ADDR_T_64BIT, which isn't always set on 32-bit ARM. Will