drivers/gpu/drm/gma500/gem.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  psb GEM interface
   4  *
   5  * Copyright (c) 2011, Intel Corporation.
   6  *
   7  * Authors: Alan Cox
   8  *
   9  * TODO:
  10  *      -       we need to work out if the MMU is relevant (eg for
  11  *              accelerated operations on a GEM object)
  12  */
  13
  14 #include <linux/pagemap.h>
  15
  16 #include <drm/drm.h>
  17 #include <drm/drm_vma_manager.h>
  18
  19 #include "psb_drv.h"
  20
  21 static vm_fault_t psb_gem_fault(struct vm_fault *vmf);
  22
  23 static void psb_gem_free_object(struct drm_gem_object *obj)
  24 {
  25         struct gtt_range *gtt = container_of(obj, struct gtt_range, gem);
  26
  27         /* Remove the list map if one is present */
  28         drm_gem_free_mmap_offset(obj);
  29         drm_gem_object_release(obj);
  30
  31         /* This must occur last as it frees up the memory of the GEM object */
  32         psb_gtt_free_range(obj->dev, gtt);
  33 }
  34
  35 static const struct vm_operations_struct psb_gem_vm_ops = {
  36         .fault = psb_gem_fault,
  37         .open = drm_gem_vm_open,
  38         .close = drm_gem_vm_close,
  39 };
  40
  41 const struct drm_gem_object_funcs psb_gem_object_funcs = {
  42         .free = psb_gem_free_object,
  43         .vm_ops = &psb_gem_vm_ops,
  44 };
  45
  46 /**
  47  *      psb_gem_create          -       create a mappable object
  48  *      @file: the DRM file of the client
  49  *      @dev: our device
  50  *      @size: the size requested
  51  *      @handlep: returned handle (opaque number)
  52  *
  53  *      Create a GEM object, fill in the boilerplate and attach a handle to
  54  *      it so that userspace can speak about it. This does the core work
  55  *      for the various methods that do/will create GEM objects for things
  56  */
  57 int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size,
  58                    u32 *handlep, int stolen, u32 align)
  59 {
  60         struct gtt_range *r;
  61         int ret;
  62         u32 handle;
  63
  64         size = roundup(size, PAGE_SIZE);
  65
  66         /* Allocate our object - for now a direct gtt range which is not
  67            stolen memory backed */
  68         r = psb_gtt_alloc_range(dev, size, "gem", 0, PAGE_SIZE);
  69         if (r == NULL) {
  70                 dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
  71                 return -ENOSPC;
  72         }
  73         r->gem.funcs = &psb_gem_object_funcs;
  74         /* Initialize the extra goodies GEM needs to do all the hard work */
  75         if (drm_gem_object_init(dev, &r->gem, size) != 0) {
  76                 psb_gtt_free_range(dev, r);
  77                 /* GEM doesn't give an error code so use -ENOMEM */
  78                 dev_err(dev->dev, "GEM init failed for %lld\n", size);
  79                 return -ENOMEM;
  80         }
  81         /* Limit the object to 32bit mappings */
  82         mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
  83         /* Give the object a handle so we can carry it more easily */
  84         ret = drm_gem_handle_create(file, &r->gem, &handle);
  85         if (ret) {
  86                 dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
  87                                                         &r->gem, size);
  88                 drm_gem_object_release(&r->gem);
  89                 psb_gtt_free_range(dev, r);
  90                 return ret;
  91         }
  92         /* We have the initial and handle reference but need only one now */
  93         drm_gem_object_put(&r->gem);
  94         *handlep = handle;
  95         return 0;
  96 }
  97
  98 /**
  99  *      psb_gem_dumb_create     -       create a dumb buffer
 100  *      @drm_file: our client file
 101  *      @dev: our device
 102  *      @args: the requested arguments copied from userspace
 103  *
 104  *      Allocate a buffer suitable for use for a frame buffer of the
 105  *      form described by user space. Give userspace a handle by which
 106  *      to reference it.
 107  */
 108 int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
 109                         struct drm_mode_create_dumb *args)
 110 {
 111         args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
 112         args->size = args->pitch * args->height;
 113         return psb_gem_create(file, dev, args->size, &args->handle, 0,
 114                               PAGE_SIZE);
 115 }
 116
 117 /**
 118  *      psb_gem_fault           -       pagefault handler for GEM objects
 119  *      @vma: the VMA of the GEM object
 120  *      @vmf: fault detail
 121  *
 122  *      Invoked when a fault occurs on an mmap of a GEM managed area. GEM
 123  *      does most of the work for us including the actual map/unmap calls
 124  *      but we need to do the actual page work.
 125  *
 126  *      This code eventually needs to handle faulting objects in and out
 127  *      of the GTT and repacking it when we run out of space. We can put
 128  *      that off for now and for our simple uses
 129  *
 130  *      The VMA was set up by GEM. In doing so it also ensured that the
 131  *      vma->vm_private_data points to the GEM object that is backing this
 132  *      mapping.
 133  */
 134 static vm_fault_t psb_gem_fault(struct vm_fault *vmf)
 135 {
 136         struct vm_area_struct *vma = vmf->vma;
 137         struct drm_gem_object *obj;
 138         struct gtt_range *r;
 139         int err;
 140         vm_fault_t ret;
 141         unsigned long pfn;
 142         pgoff_t page_offset;
 143         struct drm_device *dev;
 144         struct drm_psb_private *dev_priv;
 145
 146         obj = vma->vm_private_data;     /* GEM object */
 147         dev = obj->dev;
 148         dev_priv = dev->dev_private;
 149
 150         r = container_of(obj, struct gtt_range, gem);   /* Get the gtt range */
 151
 152         /* Make sure we don't parallel update on a fault, nor move or remove
 153            something from beneath our feet */
 154         mutex_lock(&dev_priv->mmap_mutex);
 155
 156         /* For now the mmap pins the object and it stays pinned. As things
 157            stand that will do us no harm */
 158         if (r->mmapping == 0) {
 159                 err = psb_gtt_pin(r);
 160                 if (err < 0) {
 161                         dev_err(dev->dev, "gma500: pin failed: %d\n", err);
 162                         ret = vmf_error(err);
 163                         goto fail;
 164                 }
 165                 r->mmapping = 1;
 166         }
 167
 168         /* Page relative to the VMA start - we must calculate this ourselves
 169            because vmf->pgoff is the fake GEM offset */
 170         page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
 171
 172         /* CPU view of the page, don't go via the GART for CPU writes */
 173         if (r->stolen)
 174                 pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
 175         else
 176                 pfn = page_to_pfn(r->pages[page_offset]);
 177         ret = vmf_insert_pfn(vma, vmf->address, pfn);
 178 fail:
 179         mutex_unlock(&dev_priv->mmap_mutex);
 180
 181         return ret;
 182 }