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
  21static vm_fault_t psb_gem_fault(struct vm_fault *vmf);
  22
  23static 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
  35static 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
  41const 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 */
  57int 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 */
 108int 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 */
 134static 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);
 178fail:
 179        mutex_unlock(&dev_priv->mmap_mutex);
 180
 181        return ret;
 182}
 183