1 // SPDX-License-Identifier: GPL-2.0+ 2 /* Copyright (C) 2017-2018 Broadcom */ 3 4 /** 5 * DOC: Broadcom V3D MMU 6 * 7 * The V3D 3.x hardware (compared to VC4) now includes an MMU. It has 8 * a single level of page tables for the V3D's 4GB address space to 9 * map to AXI bus addresses, thus it could need up to 4MB of 10 * physically contiguous memory to store the PTEs. 11 * 12 * Because the 4MB of contiguous memory for page tables is precious, 13 * and switching between them is expensive, we load all BOs into the 14 * same 4GB address space. 15 * 16 * To protect clients from each other, we should use the GMP to 17 * quickly mask out (at 128kb granularity) what pages are available to 18 * each client. This is not yet implemented. 19 */ 20 21 #include "v3d_drv.h" 22 #include "v3d_regs.h" 23 24 #define V3D_MMU_PAGE_SHIFT 12 25 26 /* Note: All PTEs for the 1MB superpage must be filled with the 27 * superpage bit set. 28 */ 29 #define V3D_PTE_SUPERPAGE BIT(31) 30 #define V3D_PTE_WRITEABLE BIT(29) 31 #define V3D_PTE_VALID BIT(28) 32 33 static int v3d_mmu_flush_all(struct v3d_dev *v3d) 34 { 35 int ret; 36 37 /* Make sure that another flush isn't already running when we 38 * start this one. 39 */ 40 ret = wait_for(!(V3D_READ(V3D_MMU_CTL) & 41 V3D_MMU_CTL_TLB_CLEARING), 100); 42 if (ret) 43 dev_err(v3d->dev, "TLB clear wait idle pre-wait failed\n"); 44 45 V3D_WRITE(V3D_MMU_CTL, V3D_READ(V3D_MMU_CTL) | 46 V3D_MMU_CTL_TLB_CLEAR); 47 48 V3D_WRITE(V3D_MMUC_CONTROL, 49 V3D_MMUC_CONTROL_FLUSH | 50 V3D_MMUC_CONTROL_ENABLE); 51 52 ret = wait_for(!(V3D_READ(V3D_MMU_CTL) & 53 V3D_MMU_CTL_TLB_CLEARING), 100); 54 if (ret) { 55 dev_err(v3d->dev, "TLB clear wait idle failed\n"); 56 return ret; 57 } 58 59 ret = wait_for(!(V3D_READ(V3D_MMUC_CONTROL) & 60 V3D_MMUC_CONTROL_FLUSHING), 100); 61 if (ret) 62 dev_err(v3d->dev, "MMUC flush wait idle failed\n"); 63 64 return ret; 65 } 66 67 int v3d_mmu_set_page_table(struct v3d_dev *v3d) 68 { 69 V3D_WRITE(V3D_MMU_PT_PA_BASE, v3d->pt_paddr >> V3D_MMU_PAGE_SHIFT); 70 V3D_WRITE(V3D_MMU_CTL, 71 V3D_MMU_CTL_ENABLE | 72 V3D_MMU_CTL_PT_INVALID | 73 V3D_MMU_CTL_PT_INVALID_ABORT | 74 V3D_MMU_CTL_WRITE_VIOLATION_ABORT | 75 V3D_MMU_CTL_CAP_EXCEEDED_ABORT); 76 V3D_WRITE(V3D_MMU_ILLEGAL_ADDR, 77 (v3d->mmu_scratch_paddr >> V3D_MMU_PAGE_SHIFT) | 78 V3D_MMU_ILLEGAL_ADDR_ENABLE); 79 V3D_WRITE(V3D_MMUC_CONTROL, V3D_MMUC_CONTROL_ENABLE); 80 81 return v3d_mmu_flush_all(v3d); 82 } 83 84 void v3d_mmu_insert_ptes(struct v3d_bo *bo) 85 { 86 struct drm_gem_shmem_object *shmem_obj = &bo->base; 87 struct v3d_dev *v3d = to_v3d_dev(shmem_obj->base.dev); 88 u32 page = bo->node.start; 89 u32 page_prot = V3D_PTE_WRITEABLE | V3D_PTE_VALID; 90 unsigned int count; 91 struct scatterlist *sgl; 92 93 for_each_sg(shmem_obj->sgt->sgl, sgl, shmem_obj->sgt->nents, count) { 94 u32 page_address = sg_dma_address(sgl) >> V3D_MMU_PAGE_SHIFT; 95 u32 pte = page_prot | page_address; 96 u32 i; 97 98 BUG_ON(page_address + (sg_dma_len(sgl) >> V3D_MMU_PAGE_SHIFT) >= 99 BIT(24)); 100 101 for (i = 0; i < sg_dma_len(sgl) >> V3D_MMU_PAGE_SHIFT; i++) 102 v3d->pt[page++] = pte + i; 103 } 104 105 WARN_ON_ONCE(page - bo->node.start != 106 shmem_obj->base.size >> V3D_MMU_PAGE_SHIFT); 107 108 if (v3d_mmu_flush_all(v3d)) 109 dev_err(v3d->dev, "MMU flush timeout\n"); 110 } 111 112 void v3d_mmu_remove_ptes(struct v3d_bo *bo) 113 { 114 struct v3d_dev *v3d = to_v3d_dev(bo->base.base.dev); 115 u32 npages = bo->base.base.size >> V3D_MMU_PAGE_SHIFT; 116 u32 page; 117 118 for (page = bo->node.start; page < bo->node.start + npages; page++) 119 v3d->pt[page] = 0; 120 121 if (v3d_mmu_flush_all(v3d)) 122 dev_err(v3d->dev, "MMU flush timeout\n"); 123 } 124