1/*
  2 *  psb GEM interface
  3 *
  4 * Copyright (c) 2011, Intel Corporation.
  5 *
  6 * This program is free software; you can redistribute it and/or modify it
  7 * under the terms and conditions of the GNU General Public License,
  8 * version 2, as published by the Free Software Foundation.
  9 *
 10 * This program is distributed in the hope it will be useful, but WITHOUT
 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 13 * more details.
 14 *
 15 * You should have received a copy of the GNU General Public License along with
 16 * this program; if not, write to the Free Software Foundation, Inc.,
 17 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 18 *
 19 * Authors: Alan Cox
 20 *
 21 * TODO:
 22 *	-	we need to work out if the MMU is relevant (eg for
 23 *		accelerated operations on a GEM object)
 24 */
 25
 26#include <drm/drmP.h>
 27#include <drm/drm.h>
 28#include <drm/gma_drm.h>
 29#include <drm/drm_vma_manager.h>
 30#include "psb_drv.h"
 31
 32void psb_gem_free_object(struct drm_gem_object *obj)
 33{
 34	struct gtt_range *gtt = container_of(obj, struct gtt_range, gem);
 35
 36	/* Remove the list map if one is present */
 37	drm_gem_free_mmap_offset(obj);
 38	drm_gem_object_release(obj);
 39
 40	/* This must occur last as it frees up the memory of the GEM object */
 41	psb_gtt_free_range(obj->dev, gtt);
 42}
 43
 44int psb_gem_get_aperture(struct drm_device *dev, void *data,
 45				struct drm_file *file)
 46{
 47	return -EINVAL;
 48}
 49
 50/**
 51 *	psb_gem_dumb_map_gtt	-	buffer mapping for dumb interface
 52 *	@file: our drm client file
 53 *	@dev: drm device
 54 *	@handle: GEM handle to the object (from dumb_create)
 55 *
 56 *	Do the necessary setup to allow the mapping of the frame buffer
 57 *	into user memory. We don't have to do much here at the moment.
 58 */
 59int psb_gem_dumb_map_gtt(struct drm_file *file, struct drm_device *dev,
 60			 uint32_t handle, uint64_t *offset)
 61{
 62	int ret = 0;
 63	struct drm_gem_object *obj;
 64
 65	mutex_lock(&dev->struct_mutex);
 66
 67	/* GEM does all our handle to object mapping */
 68	obj = drm_gem_object_lookup(dev, file, handle);
 69	if (obj == NULL) {
 70		ret = -ENOENT;
 71		goto unlock;
 72	}
 73	/* What validation is needed here ? */
 74
 75	/* Make it mmapable */
 76	ret = drm_gem_create_mmap_offset(obj);
 77	if (ret)
 78		goto out;
 79	*offset = drm_vma_node_offset_addr(&obj->vma_node);
 80out:
 81	drm_gem_object_unreference(obj);
 82unlock:
 83	mutex_unlock(&dev->struct_mutex);
 84	return ret;
 85}
 86
 87/**
 88 *	psb_gem_create		-	create a mappable object
 89 *	@file: the DRM file of the client
 90 *	@dev: our device
 91 *	@size: the size requested
 92 *	@handlep: returned handle (opaque number)
 93 *
 94 *	Create a GEM object, fill in the boilerplate and attach a handle to
 95 *	it so that userspace can speak about it. This does the core work
 96 *	for the various methods that do/will create GEM objects for things
 97 */
 98int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size,
 99		   u32 *handlep, int stolen, u32 align)
100{
101	struct gtt_range *r;
102	int ret;
103	u32 handle;
104
105	size = roundup(size, PAGE_SIZE);
106
107	/* Allocate our object - for now a direct gtt range which is not
108	   stolen memory backed */
109	r = psb_gtt_alloc_range(dev, size, "gem", 0, PAGE_SIZE);
110	if (r == NULL) {
111		dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
112		return -ENOSPC;
113	}
114	/* Initialize the extra goodies GEM needs to do all the hard work */
115	if (drm_gem_object_init(dev, &r->gem, size) != 0) {
116		psb_gtt_free_range(dev, r);
117		/* GEM doesn't give an error code so use -ENOMEM */
118		dev_err(dev->dev, "GEM init failed for %lld\n", size);
119		return -ENOMEM;
120	}
121	/* Limit the object to 32bit mappings */
122	mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
123	/* Give the object a handle so we can carry it more easily */
124	ret = drm_gem_handle_create(file, &r->gem, &handle);
125	if (ret) {
126		dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
127							&r->gem, size);
128		drm_gem_object_release(&r->gem);
129		psb_gtt_free_range(dev, r);
130		return ret;
131	}
132	/* We have the initial and handle reference but need only one now */
133	drm_gem_object_unreference(&r->gem);
134	*handlep = handle;
135	return 0;
136}
137
138/**
139 *	psb_gem_dumb_create	-	create a dumb buffer
140 *	@drm_file: our client file
141 *	@dev: our device
142 *	@args: the requested arguments copied from userspace
143 *
144 *	Allocate a buffer suitable for use for a frame buffer of the
145 *	form described by user space. Give userspace a handle by which
146 *	to reference it.
147 */
148int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
149			struct drm_mode_create_dumb *args)
150{
151	args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
152	args->size = args->pitch * args->height;
153	return psb_gem_create(file, dev, args->size, &args->handle, 0,
154			      PAGE_SIZE);
155}
156
157/**
158 *	psb_gem_fault		-	pagefault handler for GEM objects
159 *	@vma: the VMA of the GEM object
160 *	@vmf: fault detail
161 *
162 *	Invoked when a fault occurs on an mmap of a GEM managed area. GEM
163 *	does most of the work for us including the actual map/unmap calls
164 *	but we need to do the actual page work.
165 *
166 *	This code eventually needs to handle faulting objects in and out
167 *	of the GTT and repacking it when we run out of space. We can put
168 *	that off for now and for our simple uses
169 *
170 *	The VMA was set up by GEM. In doing so it also ensured that the
171 *	vma->vm_private_data points to the GEM object that is backing this
172 *	mapping.
173 */
174int psb_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
175{
176	struct drm_gem_object *obj;
177	struct gtt_range *r;
178	int ret;
179	unsigned long pfn;
180	pgoff_t page_offset;
181	struct drm_device *dev;
182	struct drm_psb_private *dev_priv;
183
184	obj = vma->vm_private_data;	/* GEM object */
185	dev = obj->dev;
186	dev_priv = dev->dev_private;
187
188	r = container_of(obj, struct gtt_range, gem);	/* Get the gtt range */
189
190	/* Make sure we don't parallel update on a fault, nor move or remove
191	   something from beneath our feet */
192	mutex_lock(&dev->struct_mutex);
193
194	/* For now the mmap pins the object and it stays pinned. As things
195	   stand that will do us no harm */
196	if (r->mmapping == 0) {
197		ret = psb_gtt_pin(r);
198		if (ret < 0) {
199			dev_err(dev->dev, "gma500: pin failed: %d\n", ret);
200			goto fail;
201		}
202		r->mmapping = 1;
203	}
204
205	/* Page relative to the VMA start - we must calculate this ourselves
206	   because vmf->pgoff is the fake GEM offset */
207	page_offset = ((unsigned long) vmf->virtual_address - vma->vm_start)
208				>> PAGE_SHIFT;
209
210	/* CPU view of the page, don't go via the GART for CPU writes */
211	if (r->stolen)
212		pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
213	else
214		pfn = page_to_pfn(r->pages[page_offset]);
215	ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, pfn);
216
217fail:
218	mutex_unlock(&dev->struct_mutex);
219	switch (ret) {
220	case 0:
221	case -ERESTARTSYS:
222	case -EINTR:
223		return VM_FAULT_NOPAGE;
224	case -ENOMEM:
225		return VM_FAULT_OOM;
226	default:
227		return VM_FAULT_SIGBUS;
228	}
229}