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	/* GEM does all our handle to object mapping */
 66	obj = drm_gem_object_lookup(file, handle);
 67	if (obj == NULL)
 68		return -ENOENT;
 69
 70	/* Make it mmapable */
 71	ret = drm_gem_create_mmap_offset(obj);
 72	if (ret)
 73		goto out;
 74	*offset = drm_vma_node_offset_addr(&obj->vma_node);
 75out:
 76	drm_gem_object_unreference_unlocked(obj);
 77	return ret;
 78}
 79
 80/**
 81 *	psb_gem_create		-	create a mappable object
 82 *	@file: the DRM file of the client
 83 *	@dev: our device
 84 *	@size: the size requested
 85 *	@handlep: returned handle (opaque number)
 86 *
 87 *	Create a GEM object, fill in the boilerplate and attach a handle to
 88 *	it so that userspace can speak about it. This does the core work
 89 *	for the various methods that do/will create GEM objects for things
 90 */
 91int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size,
 92		   u32 *handlep, int stolen, u32 align)
 93{
 94	struct gtt_range *r;
 95	int ret;
 96	u32 handle;
 97
 98	size = roundup(size, PAGE_SIZE);
 99
100	/* Allocate our object - for now a direct gtt range which is not
101	   stolen memory backed */
102	r = psb_gtt_alloc_range(dev, size, "gem", 0, PAGE_SIZE);
103	if (r == NULL) {
104		dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
105		return -ENOSPC;
106	}
107	/* Initialize the extra goodies GEM needs to do all the hard work */
108	if (drm_gem_object_init(dev, &r->gem, size) != 0) {
109		psb_gtt_free_range(dev, r);
110		/* GEM doesn't give an error code so use -ENOMEM */
111		dev_err(dev->dev, "GEM init failed for %lld\n", size);
112		return -ENOMEM;
113	}
114	/* Limit the object to 32bit mappings */
115	mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
116	/* Give the object a handle so we can carry it more easily */
117	ret = drm_gem_handle_create(file, &r->gem, &handle);
118	if (ret) {
119		dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
120							&r->gem, size);
121		drm_gem_object_release(&r->gem);
122		psb_gtt_free_range(dev, r);
123		return ret;
124	}
125	/* We have the initial and handle reference but need only one now */
126	drm_gem_object_unreference_unlocked(&r->gem);
127	*handlep = handle;
128	return 0;
129}
130
131/**
132 *	psb_gem_dumb_create	-	create a dumb buffer
133 *	@drm_file: our client file
134 *	@dev: our device
135 *	@args: the requested arguments copied from userspace
136 *
137 *	Allocate a buffer suitable for use for a frame buffer of the
138 *	form described by user space. Give userspace a handle by which
139 *	to reference it.
140 */
141int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
142			struct drm_mode_create_dumb *args)
143{
144	args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
145	args->size = args->pitch * args->height;
146	return psb_gem_create(file, dev, args->size, &args->handle, 0,
147			      PAGE_SIZE);
148}
149
150/**
151 *	psb_gem_fault		-	pagefault handler for GEM objects
152 *	@vma: the VMA of the GEM object
153 *	@vmf: fault detail
154 *
155 *	Invoked when a fault occurs on an mmap of a GEM managed area. GEM
156 *	does most of the work for us including the actual map/unmap calls
157 *	but we need to do the actual page work.
158 *
159 *	This code eventually needs to handle faulting objects in and out
160 *	of the GTT and repacking it when we run out of space. We can put
161 *	that off for now and for our simple uses
162 *
163 *	The VMA was set up by GEM. In doing so it also ensured that the
164 *	vma->vm_private_data points to the GEM object that is backing this
165 *	mapping.
166 */
167int psb_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
168{
169	struct drm_gem_object *obj;
170	struct gtt_range *r;
171	int ret;
172	unsigned long pfn;
173	pgoff_t page_offset;
174	struct drm_device *dev;
175	struct drm_psb_private *dev_priv;
176
177	obj = vma->vm_private_data;	/* GEM object */
178	dev = obj->dev;
179	dev_priv = dev->dev_private;
180
181	r = container_of(obj, struct gtt_range, gem);	/* Get the gtt range */
182
183	/* Make sure we don't parallel update on a fault, nor move or remove
184	   something from beneath our feet */
185	mutex_lock(&dev_priv->mmap_mutex);
186
187	/* For now the mmap pins the object and it stays pinned. As things
188	   stand that will do us no harm */
189	if (r->mmapping == 0) {
190		ret = psb_gtt_pin(r);
191		if (ret < 0) {
192			dev_err(dev->dev, "gma500: pin failed: %d\n", ret);
193			goto fail;
194		}
195		r->mmapping = 1;
196	}
197
198	/* Page relative to the VMA start - we must calculate this ourselves
199	   because vmf->pgoff is the fake GEM offset */
200	page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
201
202	/* CPU view of the page, don't go via the GART for CPU writes */
203	if (r->stolen)
204		pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
205	else
206		pfn = page_to_pfn(r->pages[page_offset]);
207	ret = vm_insert_pfn(vma, vmf->address, pfn);
208
209fail:
210	mutex_unlock(&dev_priv->mmap_mutex);
211	switch (ret) {
212	case 0:
213	case -ERESTARTSYS:
214	case -EINTR:
215		return VM_FAULT_NOPAGE;
216	case -ENOMEM:
217		return VM_FAULT_OOM;
218	default:
219		return VM_FAULT_SIGBUS;
220	}
221}