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}
175