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_create		-	create a mappable object
 52 *	@file: the DRM file of the client
 53 *	@dev: our device
 54 *	@size: the size requested
 55 *	@handlep: returned handle (opaque number)
 56 *
 57 *	Create a GEM object, fill in the boilerplate and attach a handle to
 58 *	it so that userspace can speak about it. This does the core work
 59 *	for the various methods that do/will create GEM objects for things
 60 */
 61int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size,
 62		   u32 *handlep, int stolen, u32 align)
 63{
 64	struct gtt_range *r;
 65	int ret;
 66	u32 handle;
 67
 68	size = roundup(size, PAGE_SIZE);
 69
 70	/* Allocate our object - for now a direct gtt range which is not
 71	   stolen memory backed */
 72	r = psb_gtt_alloc_range(dev, size, "gem", 0, PAGE_SIZE);
 73	if (r == NULL) {
 74		dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
 75		return -ENOSPC;
 76	}
 77	/* Initialize the extra goodies GEM needs to do all the hard work */
 78	if (drm_gem_object_init(dev, &r->gem, size) != 0) {
 79		psb_gtt_free_range(dev, r);
 80		/* GEM doesn't give an error code so use -ENOMEM */
 81		dev_err(dev->dev, "GEM init failed for %lld\n", size);
 82		return -ENOMEM;
 83	}
 84	/* Limit the object to 32bit mappings */
 85	mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
 86	/* Give the object a handle so we can carry it more easily */
 87	ret = drm_gem_handle_create(file, &r->gem, &handle);
 88	if (ret) {
 89		dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
 90							&r->gem, size);
 91		drm_gem_object_release(&r->gem);
 92		psb_gtt_free_range(dev, r);
 93		return ret;
 94	}
 95	/* We have the initial and handle reference but need only one now */
 96	drm_gem_object_unreference_unlocked(&r->gem);
 97	*handlep = handle;
 98	return 0;
 99}
100
101/**
102 *	psb_gem_dumb_create	-	create a dumb buffer
103 *	@drm_file: our client file
104 *	@dev: our device
105 *	@args: the requested arguments copied from userspace
106 *
107 *	Allocate a buffer suitable for use for a frame buffer of the
108 *	form described by user space. Give userspace a handle by which
109 *	to reference it.
110 */
111int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
112			struct drm_mode_create_dumb *args)
113{
114	args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
115	args->size = args->pitch * args->height;
116	return psb_gem_create(file, dev, args->size, &args->handle, 0,
117			      PAGE_SIZE);
118}
119
120/**
121 *	psb_gem_fault		-	pagefault handler for GEM objects
122 *	@vma: the VMA of the GEM object
123 *	@vmf: fault detail
124 *
125 *	Invoked when a fault occurs on an mmap of a GEM managed area. GEM
126 *	does most of the work for us including the actual map/unmap calls
127 *	but we need to do the actual page work.
128 *
129 *	This code eventually needs to handle faulting objects in and out
130 *	of the GTT and repacking it when we run out of space. We can put
131 *	that off for now and for our simple uses
132 *
133 *	The VMA was set up by GEM. In doing so it also ensured that the
134 *	vma->vm_private_data points to the GEM object that is backing this
135 *	mapping.
136 */
137int psb_gem_fault(struct vm_fault *vmf)
138{
139	struct vm_area_struct *vma = vmf->vma;
140	struct drm_gem_object *obj;
141	struct gtt_range *r;
142	int ret;
143	unsigned long pfn;
144	pgoff_t page_offset;
145	struct drm_device *dev;
146	struct drm_psb_private *dev_priv;
147
148	obj = vma->vm_private_data;	/* GEM object */
149	dev = obj->dev;
150	dev_priv = dev->dev_private;
151
152	r = container_of(obj, struct gtt_range, gem);	/* Get the gtt range */
153
154	/* Make sure we don't parallel update on a fault, nor move or remove
155	   something from beneath our feet */
156	mutex_lock(&dev_priv->mmap_mutex);
157
158	/* For now the mmap pins the object and it stays pinned. As things
159	   stand that will do us no harm */
160	if (r->mmapping == 0) {
161		ret = psb_gtt_pin(r);
162		if (ret < 0) {
163			dev_err(dev->dev, "gma500: pin failed: %d\n", ret);
164			goto fail;
165		}
166		r->mmapping = 1;
167	}
168
169	/* Page relative to the VMA start - we must calculate this ourselves
170	   because vmf->pgoff is the fake GEM offset */
171	page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
172
173	/* CPU view of the page, don't go via the GART for CPU writes */
174	if (r->stolen)
175		pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
176	else
177		pfn = page_to_pfn(r->pages[page_offset]);
178	ret = vm_insert_pfn(vma, vmf->address, pfn);
179
180fail:
181	mutex_unlock(&dev_priv->mmap_mutex);
182	switch (ret) {
183	case 0:
184	case -ERESTARTSYS:
185	case -EINTR:
186		return VM_FAULT_NOPAGE;
187	case -ENOMEM:
188		return VM_FAULT_OOM;
189	default:
190		return VM_FAULT_SIGBUS;
191	}
192}