2 * (C) Copyright 2012 Stephen Warren
4 * See file CREDITS for list of people who contributed to this
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License as
9 * published by the Free Software Foundation; either version 2 of
10 * the License, or (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
18 #ifndef _BCM2835_MBOX_H
19 #define _BCM2835_MBOX_H
21 #include <linux/compiler.h>
24 * The BCM2835 SoC contains (at least) two CPUs; the VideoCore (a/k/a "GPU")
25 * and the ARM CPU. The ARM CPU is often thought of as the main CPU.
26 * However, the VideoCore actually controls the initial SoC boot, and hides
27 * much of the hardware behind a protocol. This protocol is transported
28 * using the SoC's mailbox hardware module.
30 * The mailbox hardware supports passing 32-bit values back and forth.
31 * Presumably by software convention of the firmware, the bottom 4 bits of the
32 * value are used to indicate a logical channel, and the upper 28 bits are the
33 * actual payload. Various channels exist using these simple raw messages. See
34 * https://github.com/raspberrypi/firmware/wiki/Mailboxes for a list. As an
35 * example, the messages on the power management channel are a bitmask of
36 * devices whose power should be enabled.
38 * The property mailbox channel passes messages that contain the (16-byte
39 * aligned) ARM physical address of a memory buffer. This buffer is passed to
40 * the VC for processing, is modified in-place by the VC, and the address then
41 * passed back to the ARM CPU as the response mailbox message to indicate
42 * request completion. The buffers have a generic and extensible format; each
43 * buffer contains a standard header, a list of "tags", and a terminating zero
44 * entry. Each tag contains an ID indicating its type, and length fields for
45 * generic parsing. With some limitations, an arbitrary set of tags may be
46 * combined together into a single message buffer. This file defines structs
47 * representing the header and many individual tag layouts and IDs.
52 #define BCM2835_MBOX_PHYSADDR 0x2000b880
54 struct bcm2835_mbox_regs {
62 #define BCM2835_MBOX_STATUS_WR_FULL 0x80000000
63 #define BCM2835_MBOX_STATUS_RD_EMPTY 0x40000000
65 /* Lower 4-bits are channel ID */
66 #define BCM2835_CHAN_MASK 0xf
67 #define BCM2835_MBOX_PACK(chan, data) (((data) & (~BCM2835_CHAN_MASK)) | \
68 (chan & BCM2835_CHAN_MASK))
69 #define BCM2835_MBOX_UNPACK_CHAN(val) ((val) & BCM2835_CHAN_MASK)
70 #define BCM2835_MBOX_UNPACK_DATA(val) ((val) & (~BCM2835_CHAN_MASK))
72 /* Property mailbox buffer structures */
74 #define BCM2835_MBOX_PROP_CHAN 8
76 /* All message buffers must start with this header */
77 struct bcm2835_mbox_hdr {
82 #define BCM2835_MBOX_REQ_CODE 0
83 #define BCM2835_MBOX_RESP_CODE_SUCCESS 0x80000000
85 #define BCM2835_MBOX_INIT_HDR(_m_) { \
86 memset((_m_), 0, sizeof(*(_m_))); \
87 (_m_)->hdr.buf_size = sizeof(*(_m_)); \
88 (_m_)->hdr.code = 0; \
93 * A message buffer contains a list of tags. Each tag must also start with
94 * a standardized header.
96 struct bcm2835_mbox_tag_hdr {
102 #define BCM2835_MBOX_INIT_TAG(_t_, _id_) { \
103 (_t_)->tag_hdr.tag = BCM2835_MBOX_TAG_##_id_; \
104 (_t_)->tag_hdr.val_buf_size = sizeof((_t_)->body); \
105 (_t_)->tag_hdr.val_len = sizeof((_t_)->body.req); \
108 #define BCM2835_MBOX_INIT_TAG_NO_REQ(_t_, _id_) { \
109 (_t_)->tag_hdr.tag = BCM2835_MBOX_TAG_##_id_; \
110 (_t_)->tag_hdr.val_buf_size = sizeof((_t_)->body); \
111 (_t_)->tag_hdr.val_len = 0; \
114 /* When responding, the VC sets this bit in val_len to indicate a response */
115 #define BCM2835_MBOX_TAG_VAL_LEN_RESPONSE 0x80000000
118 * Below we define the ID and struct for many possible tags. This header only
119 * defines individual tag structs, not entire message structs, since in
120 * general an arbitrary set of tags may be combined into a single message.
121 * Clients of the mbox API are expected to define their own overall message
122 * structures by combining the header, a set of tags, and a terminating
123 * entry. For example,
126 * struct bcm2835_mbox_hdr hdr;
127 * struct bcm2835_mbox_tag_get_arm_mem get_arm_mem;
128 * ... perhaps other tags here ...
133 #define BCM2835_MBOX_TAG_GET_ARM_MEMORY 0x00010005
135 struct bcm2835_mbox_tag_get_arm_mem {
136 struct bcm2835_mbox_tag_hdr tag_hdr;
147 #define BCM2835_MBOX_TAG_GET_CLOCK_RATE 0x00030002
149 #define BCM2835_MBOX_CLOCK_ID_EMMC 1
150 #define BCM2835_MBOX_CLOCK_ID_UART 2
151 #define BCM2835_MBOX_CLOCK_ID_ARM 3
152 #define BCM2835_MBOX_CLOCK_ID_CORE 4
153 #define BCM2835_MBOX_CLOCK_ID_V3D 5
154 #define BCM2835_MBOX_CLOCK_ID_H264 6
155 #define BCM2835_MBOX_CLOCK_ID_ISP 7
156 #define BCM2835_MBOX_CLOCK_ID_SDRAM 8
157 #define BCM2835_MBOX_CLOCK_ID_PIXEL 9
158 #define BCM2835_MBOX_CLOCK_ID_PWM 10
160 struct bcm2835_mbox_tag_get_clock_rate {
161 struct bcm2835_mbox_tag_hdr tag_hdr;
173 #define BCM2835_MBOX_TAG_ALLOCATE_BUFFER 0x00040001
175 struct bcm2835_mbox_tag_allocate_buffer {
176 struct bcm2835_mbox_tag_hdr tag_hdr;
188 #define BCM2835_MBOX_TAG_RELEASE_BUFFER 0x00048001
190 struct bcm2835_mbox_tag_release_buffer {
191 struct bcm2835_mbox_tag_hdr tag_hdr;
200 #define BCM2835_MBOX_TAG_BLANK_SCREEN 0x00040002
202 struct bcm2835_mbox_tag_blank_screen {
203 struct bcm2835_mbox_tag_hdr tag_hdr;
206 /* bit 0 means on, other bots reserved */
215 /* Physical means output signal */
216 #define BCM2835_MBOX_TAG_GET_PHYSICAL_W_H 0x00040003
217 #define BCM2835_MBOX_TAG_TEST_PHYSICAL_W_H 0x00044003
218 #define BCM2835_MBOX_TAG_SET_PHYSICAL_W_H 0x00048003
220 struct bcm2835_mbox_tag_physical_w_h {
221 struct bcm2835_mbox_tag_hdr tag_hdr;
223 /* req not used for get */
235 /* Virtual means display buffer */
236 #define BCM2835_MBOX_TAG_GET_VIRTUAL_W_H 0x00040004
237 #define BCM2835_MBOX_TAG_TEST_VIRTUAL_W_H 0x00044004
238 #define BCM2835_MBOX_TAG_SET_VIRTUAL_W_H 0x00048004
240 struct bcm2835_mbox_tag_virtual_w_h {
241 struct bcm2835_mbox_tag_hdr tag_hdr;
243 /* req not used for get */
255 #define BCM2835_MBOX_TAG_GET_DEPTH 0x00040005
256 #define BCM2835_MBOX_TAG_TEST_DEPTH 0x00044005
257 #define BCM2835_MBOX_TAG_SET_DEPTH 0x00048005
259 struct bcm2835_mbox_tag_depth {
260 struct bcm2835_mbox_tag_hdr tag_hdr;
262 /* req not used for get */
272 #define BCM2835_MBOX_TAG_GET_PIXEL_ORDER 0x00040006
273 #define BCM2835_MBOX_TAG_TEST_PIXEL_ORDER 0x00044005
274 #define BCM2835_MBOX_TAG_SET_PIXEL_ORDER 0x00048006
276 #define BCM2835_MBOX_PIXEL_ORDER_BGR 0
277 #define BCM2835_MBOX_PIXEL_ORDER_RGB 1
279 struct bcm2835_mbox_tag_pixel_order {
280 struct bcm2835_mbox_tag_hdr tag_hdr;
282 /* req not used for get */
292 #define BCM2835_MBOX_TAG_GET_ALPHA_MODE 0x00040007
293 #define BCM2835_MBOX_TAG_TEST_ALPHA_MODE 0x00044007
294 #define BCM2835_MBOX_TAG_SET_ALPHA_MODE 0x00048007
296 #define BCM2835_MBOX_ALPHA_MODE_0_OPAQUE 0
297 #define BCM2835_MBOX_ALPHA_MODE_0_TRANSPARENT 1
298 #define BCM2835_MBOX_ALPHA_MODE_IGNORED 2
300 struct bcm2835_mbox_tag_alpha_mode {
301 struct bcm2835_mbox_tag_hdr tag_hdr;
303 /* req not used for get */
313 #define BCM2835_MBOX_TAG_GET_PITCH 0x00040008
315 struct bcm2835_mbox_tag_pitch {
316 struct bcm2835_mbox_tag_hdr tag_hdr;
326 /* Offset of display window within buffer */
327 #define BCM2835_MBOX_TAG_GET_VIRTUAL_OFFSET 0x00040009
328 #define BCM2835_MBOX_TAG_TEST_VIRTUAL_OFFSET 0x00044009
329 #define BCM2835_MBOX_TAG_SET_VIRTUAL_OFFSET 0x00048009
331 struct bcm2835_mbox_tag_virtual_offset {
332 struct bcm2835_mbox_tag_hdr tag_hdr;
334 /* req not used for get */
346 #define BCM2835_MBOX_TAG_GET_OVERSCAN 0x0004000a
347 #define BCM2835_MBOX_TAG_TEST_OVERSCAN 0x0004400a
348 #define BCM2835_MBOX_TAG_SET_OVERSCAN 0x0004800a
350 struct bcm2835_mbox_tag_overscan {
351 struct bcm2835_mbox_tag_hdr tag_hdr;
353 /* req not used for get */
368 #define BCM2835_MBOX_TAG_GET_PALETTE 0x0004000b
370 struct bcm2835_mbox_tag_get_palette {
371 struct bcm2835_mbox_tag_hdr tag_hdr;
381 #define BCM2835_MBOX_TAG_TEST_PALETTE 0x0004400b
383 struct bcm2835_mbox_tag_test_palette {
384 struct bcm2835_mbox_tag_hdr tag_hdr;
397 #define BCM2835_MBOX_TAG_SET_PALETTE 0x0004800b
399 struct bcm2835_mbox_tag_set_palette {
400 struct bcm2835_mbox_tag_hdr tag_hdr;
414 * Pass a raw u32 message to the VC, and receive a raw u32 back.
416 * Returns 0 for success, any other value for error.
418 int bcm2835_mbox_call_raw(u32 chan, u32 send, u32 *recv);
421 * Pass a complete property-style buffer to the VC, and wait until it has
424 * This function expects a pointer to the mbox_hdr structure in an attempt
425 * to ensure some degree of type safety. However, some number of tags and
426 * a termination value are expected to immediately follow the header in
427 * memory, as required by the property protocol.
429 * Returns 0 for success, any other value for error.
431 int bcm2835_mbox_call_prop(u32 chan, struct bcm2835_mbox_hdr *buffer);