xref: /openbmc/linux/drivers/gpu/drm/gma500/gem.c (revision 151f4e2b)
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 
32 void 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 
44 int 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  */
61 int 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_put_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  */
111 int 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  */
137 vm_fault_t 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 err;
143 	vm_fault_t ret;
144 	unsigned long pfn;
145 	pgoff_t page_offset;
146 	struct drm_device *dev;
147 	struct drm_psb_private *dev_priv;
148 
149 	obj = vma->vm_private_data;	/* GEM object */
150 	dev = obj->dev;
151 	dev_priv = dev->dev_private;
152 
153 	r = container_of(obj, struct gtt_range, gem);	/* Get the gtt range */
154 
155 	/* Make sure we don't parallel update on a fault, nor move or remove
156 	   something from beneath our feet */
157 	mutex_lock(&dev_priv->mmap_mutex);
158 
159 	/* For now the mmap pins the object and it stays pinned. As things
160 	   stand that will do us no harm */
161 	if (r->mmapping == 0) {
162 		err = psb_gtt_pin(r);
163 		if (err < 0) {
164 			dev_err(dev->dev, "gma500: pin failed: %d\n", err);
165 			ret = vmf_error(err);
166 			goto fail;
167 		}
168 		r->mmapping = 1;
169 	}
170 
171 	/* Page relative to the VMA start - we must calculate this ourselves
172 	   because vmf->pgoff is the fake GEM offset */
173 	page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
174 
175 	/* CPU view of the page, don't go via the GART for CPU writes */
176 	if (r->stolen)
177 		pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
178 	else
179 		pfn = page_to_pfn(r->pages[page_offset]);
180 	ret = vmf_insert_pfn(vma, vmf->address, pfn);
181 fail:
182 	mutex_unlock(&dev_priv->mmap_mutex);
183 
184 	return ret;
185 }
186