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(&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}