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