2 * Copyright (C) 2008 The Android Open Source Project
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
25 #include <sys/types.h>
27 #include <cutils/log.h>
28 #include <cutils/atomic.h>
30 #include <hardware/hardware.h>
31 #include <hardware/gralloc.h>
33 #include "gralloc_priv.h"
36 /*****************************************************************************/
38 static int gralloc_map(gralloc_module_t const* /*module*/,
39 buffer_handle_t handle,
42 private_handle_t* hnd = (private_handle_t*)handle;
43 if (!(hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER)) {
44 size_t size = hnd->size;
45 void* mappedAddress = mmap(0, size,
46 PROT_READ|PROT_WRITE, MAP_SHARED, hnd->fd, 0);
47 if (mappedAddress == MAP_FAILED) {
48 ALOGE("Could not mmap %s", strerror(errno));
51 hnd->base = uintptr_t(mappedAddress) + hnd->offset;
52 //ALOGD("gralloc_map() succeeded fd=%d, off=%d, size=%d, vaddr=%p",
53 // hnd->fd, hnd->offset, hnd->size, mappedAddress);
55 *vaddr = (void*)hnd->base;
59 static int gralloc_unmap(gralloc_module_t const* /*module*/,
60 buffer_handle_t handle)
62 private_handle_t* hnd = (private_handle_t*)handle;
63 if (!(hnd->flags & private_handle_t::PRIV_FLAGS_FRAMEBUFFER)) {
64 void* base = (void*)hnd->base;
65 size_t size = hnd->size;
66 //ALOGD("unmapping from %p, size=%d", base, size);
67 if (munmap(base, size) < 0) {
68 ALOGE("Could not unmap %s", strerror(errno));
75 /*****************************************************************************/
77 int gralloc_register_buffer(gralloc_module_t const* module,
78 buffer_handle_t handle)
80 if (private_handle_t::validate(handle) < 0)
83 // *** WARNING WARNING WARNING ***
85 // If a buffer handle is passed from the process that allocated it to a
86 // different process, and then back to the allocator process, we will
87 // create a second mapping of the buffer. If the process reads and writes
88 // through both mappings, normal memory ordering guarantees may be
89 // violated, depending on the processor cache implementation*.
91 // If you are deriving a new gralloc implementation from this code, don't
92 // do this. A "real" gralloc should provide a single reference-counted
93 // mapping for each buffer in a process.
95 // In the current system, there is one case that needs a buffer to be
96 // registered in the same process that allocated it. The SurfaceFlinger
97 // process acts as the IGraphicBufferAlloc Binder provider, so all gralloc
98 // allocations happen in its process. After returning the buffer handle to
99 // the IGraphicBufferAlloc client, SurfaceFlinger free's its handle to the
100 // buffer (unmapping it from the SurfaceFlinger process). If
101 // SurfaceFlinger later acts as the producer end of the buffer queue the
102 // buffer belongs to, it will get a new handle to the buffer in response
103 // to IGraphicBufferProducer::requestBuffer(). Like any buffer handle
104 // received through Binder, the SurfaceFlinger process will register it.
105 // Since it already freed its original handle, it will only end up with
106 // one mapping to the buffer and there will be no problem.
108 // Currently SurfaceFlinger only acts as a buffer producer for a remote
109 // consumer when taking screenshots and when using virtual displays.
111 // Eventually, each application should be allowed to make its own gralloc
112 // allocations, solving the problem. Also, this ashmem-based gralloc
113 // should go away, replaced with a real ion-based gralloc.
115 // * Specifically, associative virtually-indexed caches are likely to have
116 // problems. Most modern L1 caches fit that description.
118 private_handle_t* hnd = (private_handle_t*)handle;
119 ALOGD_IF(hnd->pid == getpid(),
120 "Registering a buffer in the process that created it. "
121 "This may cause memory ordering problems.");
124 return gralloc_map(module, handle, &vaddr);
127 int gralloc_unregister_buffer(gralloc_module_t const* module,
128 buffer_handle_t handle)
130 if (private_handle_t::validate(handle) < 0)
133 private_handle_t* hnd = (private_handle_t*)handle;
135 gralloc_unmap(module, handle);
140 int mapBuffer(gralloc_module_t const* module,
141 private_handle_t* hnd)
144 return gralloc_map(module, hnd, &vaddr);
147 int terminateBuffer(gralloc_module_t const* module,
148 private_handle_t* hnd)
151 // this buffer was mapped, unmap it now
152 gralloc_unmap(module, hnd);
158 int gralloc_lock(gralloc_module_t const* /*module*/,
159 buffer_handle_t handle, int /*usage*/,
160 int /*l*/, int /*t*/, int /*w*/, int /*h*/,
163 // this is called when a buffer is being locked for software
164 // access. in thin implementation we have nothing to do since
165 // not synchronization with the h/w is needed.
166 // typically this is used to wait for the h/w to finish with
167 // this buffer if relevant. the data cache may need to be
168 // flushed or invalidated depending on the usage bits and the
171 if (private_handle_t::validate(handle) < 0)
174 private_handle_t* hnd = (private_handle_t*)handle;
175 *vaddr = (void*)hnd->base;
179 int gralloc_unlock(gralloc_module_t const* /*module*/,
180 buffer_handle_t handle)
182 // we're done with a software buffer. nothing to do in this
183 // implementation. typically this is used to flush the data cache.
185 if (private_handle_t::validate(handle) < 0)