LXR linux/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 "gem.h"
  20#include "psb_drv.h"
  21
  22static vm_fault_t psb_gem_fault(struct vm_fault *vmf);
  23
  24static void psb_gem_free_object(struct drm_gem_object *obj)
  25{
  26        struct gtt_range *gtt = container_of(obj, struct gtt_range, gem);
  27
  28        /* Remove the list map if one is present */
  29        drm_gem_free_mmap_offset(obj);
  30        drm_gem_object_release(obj);
  31
  32        /* This must occur last as it frees up the memory of the GEM object */
  33        psb_gtt_free_range(obj->dev, gtt);
  34}
  35
  36static const struct vm_operations_struct psb_gem_vm_ops = {
  37        .fault = psb_gem_fault,
  38        .open = drm_gem_vm_open,
  39        .close = drm_gem_vm_close,
  40};
  41
  42const struct drm_gem_object_funcs psb_gem_object_funcs = {
  43        .free = psb_gem_free_object,
  44        .vm_ops = &psb_gem_vm_ops,
  45};
  46
  47/**
  48 *      psb_gem_create          -       create a mappable object
  49 *      @file: the DRM file of the client
  50 *      @dev: our device
  51 *      @size: the size requested
  52 *      @handlep: returned handle (opaque number)
  53 *      @stolen: unused
  54 *      @align: unused
  55 *
  56 *      Create a GEM object, fill in the boilerplate and attach a handle to
  57 *      it so that userspace can speak about it. This does the core work
  58 *      for the various methods that do/will create GEM objects for things
  59 */
  60int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size,
  61                   u32 *handlep, int stolen, u32 align)
  62{
  63        struct gtt_range *r;
  64        int ret;
  65        u32 handle;
  66
  67        size = roundup(size, PAGE_SIZE);
  68
  69        /* Allocate our object - for now a direct gtt range which is not
  70           stolen memory backed */
  71        r = psb_gtt_alloc_range(dev, size, "gem", 0, PAGE_SIZE);
  72        if (r == NULL) {
  73                dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
  74                return -ENOSPC;
  75        }
  76        r->gem.funcs = &psb_gem_object_funcs;
  77        /* Initialize the extra goodies GEM needs to do all the hard work */
  78        if (drm_gem_object_init(dev, &r->gem, size) != 0) {
  79                psb_gtt_free_range(dev, r);
  80                /* GEM doesn't give an error code so use -ENOMEM */
  81                dev_err(dev->dev, "GEM init failed for %lld\n", size);
  82                return -ENOMEM;
  83        }
  84        /* Limit the object to 32bit mappings */
  85        mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
  86        /* Give the object a handle so we can carry it more easily */
  87        ret = drm_gem_handle_create(file, &r->gem, &handle);
  88        if (ret) {
  89                dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
  90                                                        &r->gem, size);
  91                drm_gem_object_release(&r->gem);
  92                psb_gtt_free_range(dev, r);
  93                return ret;
  94        }
  95        /* We have the initial and handle reference but need only one now */
  96        drm_gem_object_put(&r->gem);
  97        *handlep = handle;
  98        return 0;
  99}
 100
 101/**
 102 *      psb_gem_dumb_create     -       create a dumb buffer
 103 *      @file: our client file
 104 *      @dev: our device
 105 *      @args: the requested arguments copied from userspace
 106 *
 107 *      Allocate a buffer suitable for use for a frame buffer of the
 108 *      form described by user space. Give userspace a handle by which
 109 *      to reference it.
 110 */
 111int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
 112                        struct drm_mode_create_dumb *args)
 113{
 114        args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
 115        args->size = args->pitch * args->height;
 116        return psb_gem_create(file, dev, args->size, &args->handle, 0,
 117                              PAGE_SIZE);
 118}
 119
 120/**
 121 *      psb_gem_fault           -       pagefault handler for GEM objects
 122 *      @vmf: fault detail
 123 *
 124 *      Invoked when a fault occurs on an mmap of a GEM managed area. GEM
 125 *      does most of the work for us including the actual map/unmap calls
 126 *      but we need to do the actual page work.
 127 *
 128 *      This code eventually needs to handle faulting objects in and out
 129 *      of the GTT and repacking it when we run out of space. We can put
 130 *      that off for now and for our simple uses
 131 *
 132 *      The VMA was set up by GEM. In doing so it also ensured that the
 133 *      vma->vm_private_data points to the GEM object that is backing this
 134 *      mapping.
 135 */
 136static vm_fault_t psb_gem_fault(struct vm_fault *vmf)
 137{
 138        struct vm_area_struct *vma = vmf->vma;
 139        struct drm_gem_object *obj;
 140        struct gtt_range *r;
 141        int err;
 142        vm_fault_t ret;
 143        unsigned long pfn;
 144        pgoff_t page_offset;
 145        struct drm_device *dev;
 146        struct drm_psb_private *dev_priv;
 147
 148        obj = vma->vm_private_data;     /* GEM object */
 149        dev = obj->dev;
 150        dev_priv = dev->dev_private;
 151
 152        r = container_of(obj, struct gtt_range, gem);   /* Get the gtt range */
 153
 154        /* Make sure we don't parallel update on a fault, nor move or remove
 155           something from beneath our feet */
 156        mutex_lock(&dev_priv->mmap_mutex);
 157
 158        /* For now the mmap pins the object and it stays pinned. As things
 159           stand that will do us no harm */
 160        if (r->mmapping == 0) {
 161                err = psb_gtt_pin(r);
 162                if (err < 0) {
 163                        dev_err(dev->dev, "gma500: pin failed: %d\n", err);
 164                        ret = vmf_error(err);
 165                        goto fail;
 166                }
 167                r->mmapping = 1;
 168        }
 169
 170        /* Page relative to the VMA start - we must calculate this ourselves
 171           because vmf->pgoff is the fake GEM offset */
 172        page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
 173
 174        /* CPU view of the page, don't go via the GART for CPU writes */
 175        if (r->stolen)
 176                pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
 177        else
 178                pfn = page_to_pfn(r->pages[page_offset]);
 179        ret = vmf_insert_pfn(vma, vmf->address, pfn);
 180fail:
 181        mutex_unlock(&dev_priv->mmap_mutex);
 182
 183        return ret;
 184}
 185