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/*
* (C) Copyright 2012 Stephen Warren
*
* SPDX-License-Identifier: GPL-2.0+
*/
#ifndef _BCM2835_MBOX_H
#define _BCM2835_MBOX_H
#include <linux/compiler.h>
/*
* The BCM2835 SoC contains (at least) two CPUs; the VideoCore (a/k/a "GPU")
* and the ARM CPU. The ARM CPU is often thought of as the main CPU.
* However, the VideoCore actually controls the initial SoC boot, and hides
* much of the hardware behind a protocol. This protocol is transported
* using the SoC's mailbox hardware module.
*
* The mailbox hardware supports passing 32-bit values back and forth.
* Presumably by software convention of the firmware, the bottom 4 bits of the
* value are used to indicate a logical channel, and the upper 28 bits are the
* actual payload. Various channels exist using these simple raw messages. See
* https://github.com/raspberrypi/firmware/wiki/Mailboxes for a list. As an
* example, the messages on the power management channel are a bitmask of
* devices whose power should be enabled.
*
* The property mailbox channel passes messages that contain the (16-byte
* aligned) ARM physical address of a memory buffer. This buffer is passed to
* the VC for processing, is modified in-place by the VC, and the address then
* passed back to the ARM CPU as the response mailbox message to indicate
* request completion. The buffers have a generic and extensible format; each
* buffer contains a standard header, a list of "tags", and a terminating zero
* entry. Each tag contains an ID indicating its type, and length fields for
* generic parsing. With some limitations, an arbitrary set of tags may be
* combined together into a single message buffer. This file defines structs
* representing the header and many individual tag layouts and IDs.
*/
/* Raw mailbox HW */
#define BCM2835_MBOX_PHYSADDR 0x2000b880
struct bcm2835_mbox_regs {
u32 read;
u32 rsvd0[5];
u32 status;
u32 config;
u32 write;
};
#define BCM2835_MBOX_STATUS_WR_FULL 0x80000000
#define BCM2835_MBOX_STATUS_RD_EMPTY 0x40000000
/* Lower 4-bits are channel ID */
#define BCM2835_CHAN_MASK 0xf
#define BCM2835_MBOX_PACK(chan, data) (((data) & (~BCM2835_CHAN_MASK)) | \
(chan & BCM2835_CHAN_MASK))
#define BCM2835_MBOX_UNPACK_CHAN(val) ((val) & BCM2835_CHAN_MASK)
#define BCM2835_MBOX_UNPACK_DATA(val) ((val) & (~BCM2835_CHAN_MASK))
/* Property mailbox buffer structures */
#define BCM2835_MBOX_PROP_CHAN 8
/* All message buffers must start with this header */
struct bcm2835_mbox_hdr {
u32 buf_size;
u32 code;
};
#define BCM2835_MBOX_REQ_CODE 0
#define BCM2835_MBOX_RESP_CODE_SUCCESS 0x80000000
#define BCM2835_MBOX_INIT_HDR(_m_) { \
memset((_m_), 0, sizeof(*(_m_))); \
(_m_)->hdr.buf_size = sizeof(*(_m_)); \
(_m_)->hdr.code = 0; \
(_m_)->end_tag = 0; \
}
/*
* A message buffer contains a list of tags. Each tag must also start with
* a standardized header.
*/
struct bcm2835_mbox_tag_hdr {
u32 tag;
u32 val_buf_size;
u32 val_len;
};
#define BCM2835_MBOX_INIT_TAG(_t_, _id_) { \
(_t_)->tag_hdr.tag = BCM2835_MBOX_TAG_##_id_; \
(_t_)->tag_hdr.val_buf_size = sizeof((_t_)->body); \
(_t_)->tag_hdr.val_len = sizeof((_t_)->body.req); \
}
#define BCM2835_MBOX_INIT_TAG_NO_REQ(_t_, _id_) { \
(_t_)->tag_hdr.tag = BCM2835_MBOX_TAG_##_id_; \
(_t_)->tag_hdr.val_buf_size = sizeof((_t_)->body); \
(_t_)->tag_hdr.val_len = 0; \
}
/* When responding, the VC sets this bit in val_len to indicate a response */
#define BCM2835_MBOX_TAG_VAL_LEN_RESPONSE 0x80000000
/*
* Below we define the ID and struct for many possible tags. This header only
* defines individual tag structs, not entire message structs, since in
* general an arbitrary set of tags may be combined into a single message.
* Clients of the mbox API are expected to define their own overall message
* structures by combining the header, a set of tags, and a terminating
* entry. For example,
*
* struct msg {
* struct bcm2835_mbox_hdr hdr;
* struct bcm2835_mbox_tag_get_arm_mem get_arm_mem;
* ... perhaps other tags here ...
* u32 end_tag;
* };
*/
#define BCM2835_MBOX_TAG_GET_ARM_MEMORY 0x00010005
struct bcm2835_mbox_tag_get_arm_mem {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
} req;
struct {
u32 mem_base;
u32 mem_size;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_CLOCK_RATE 0x00030002
#define BCM2835_MBOX_CLOCK_ID_EMMC 1
#define BCM2835_MBOX_CLOCK_ID_UART 2
#define BCM2835_MBOX_CLOCK_ID_ARM 3
#define BCM2835_MBOX_CLOCK_ID_CORE 4
#define BCM2835_MBOX_CLOCK_ID_V3D 5
#define BCM2835_MBOX_CLOCK_ID_H264 6
#define BCM2835_MBOX_CLOCK_ID_ISP 7
#define BCM2835_MBOX_CLOCK_ID_SDRAM 8
#define BCM2835_MBOX_CLOCK_ID_PIXEL 9
#define BCM2835_MBOX_CLOCK_ID_PWM 10
struct bcm2835_mbox_tag_get_clock_rate {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
u32 clock_id;
} req;
struct {
u32 clock_id;
u32 rate_hz;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_ALLOCATE_BUFFER 0x00040001
struct bcm2835_mbox_tag_allocate_buffer {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
u32 alignment;
} req;
struct {
u32 fb_address;
u32 fb_size;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_RELEASE_BUFFER 0x00048001
struct bcm2835_mbox_tag_release_buffer {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
} req;
struct {
} resp;
} body;
};
#define BCM2835_MBOX_TAG_BLANK_SCREEN 0x00040002
struct bcm2835_mbox_tag_blank_screen {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
/* bit 0 means on, other bots reserved */
u32 state;
} req;
struct {
u32 state;
} resp;
} body;
};
/* Physical means output signal */
#define BCM2835_MBOX_TAG_GET_PHYSICAL_W_H 0x00040003
#define BCM2835_MBOX_TAG_TEST_PHYSICAL_W_H 0x00044003
#define BCM2835_MBOX_TAG_SET_PHYSICAL_W_H 0x00048003
struct bcm2835_mbox_tag_physical_w_h {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 width;
u32 height;
} req;
struct {
u32 width;
u32 height;
} resp;
} body;
};
/* Virtual means display buffer */
#define BCM2835_MBOX_TAG_GET_VIRTUAL_W_H 0x00040004
#define BCM2835_MBOX_TAG_TEST_VIRTUAL_W_H 0x00044004
#define BCM2835_MBOX_TAG_SET_VIRTUAL_W_H 0x00048004
struct bcm2835_mbox_tag_virtual_w_h {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 width;
u32 height;
} req;
struct {
u32 width;
u32 height;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_DEPTH 0x00040005
#define BCM2835_MBOX_TAG_TEST_DEPTH 0x00044005
#define BCM2835_MBOX_TAG_SET_DEPTH 0x00048005
struct bcm2835_mbox_tag_depth {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 bpp;
} req;
struct {
u32 bpp;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_PIXEL_ORDER 0x00040006
#define BCM2835_MBOX_TAG_TEST_PIXEL_ORDER 0x00044005
#define BCM2835_MBOX_TAG_SET_PIXEL_ORDER 0x00048006
#define BCM2835_MBOX_PIXEL_ORDER_BGR 0
#define BCM2835_MBOX_PIXEL_ORDER_RGB 1
struct bcm2835_mbox_tag_pixel_order {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 order;
} req;
struct {
u32 order;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_ALPHA_MODE 0x00040007
#define BCM2835_MBOX_TAG_TEST_ALPHA_MODE 0x00044007
#define BCM2835_MBOX_TAG_SET_ALPHA_MODE 0x00048007
#define BCM2835_MBOX_ALPHA_MODE_0_OPAQUE 0
#define BCM2835_MBOX_ALPHA_MODE_0_TRANSPARENT 1
#define BCM2835_MBOX_ALPHA_MODE_IGNORED 2
struct bcm2835_mbox_tag_alpha_mode {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 alpha;
} req;
struct {
u32 alpha;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_PITCH 0x00040008
struct bcm2835_mbox_tag_pitch {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
} req;
struct {
u32 pitch;
} resp;
} body;
};
/* Offset of display window within buffer */
#define BCM2835_MBOX_TAG_GET_VIRTUAL_OFFSET 0x00040009
#define BCM2835_MBOX_TAG_TEST_VIRTUAL_OFFSET 0x00044009
#define BCM2835_MBOX_TAG_SET_VIRTUAL_OFFSET 0x00048009
struct bcm2835_mbox_tag_virtual_offset {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 x;
u32 y;
} req;
struct {
u32 x;
u32 y;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_OVERSCAN 0x0004000a
#define BCM2835_MBOX_TAG_TEST_OVERSCAN 0x0004400a
#define BCM2835_MBOX_TAG_SET_OVERSCAN 0x0004800a
struct bcm2835_mbox_tag_overscan {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
/* req not used for get */
struct {
u32 top;
u32 bottom;
u32 left;
u32 right;
} req;
struct {
u32 top;
u32 bottom;
u32 left;
u32 right;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_GET_PALETTE 0x0004000b
struct bcm2835_mbox_tag_get_palette {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
} req;
struct {
u32 data[1024];
} resp;
} body;
};
#define BCM2835_MBOX_TAG_TEST_PALETTE 0x0004400b
struct bcm2835_mbox_tag_test_palette {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
u32 offset;
u32 num_entries;
u32 data[256];
} req;
struct {
u32 is_invalid;
} resp;
} body;
};
#define BCM2835_MBOX_TAG_SET_PALETTE 0x0004800b
struct bcm2835_mbox_tag_set_palette {
struct bcm2835_mbox_tag_hdr tag_hdr;
union {
struct {
u32 offset;
u32 num_entries;
u32 data[256];
} req;
struct {
u32 is_invalid;
} resp;
} body;
};
/*
* Pass a raw u32 message to the VC, and receive a raw u32 back.
*
* Returns 0 for success, any other value for error.
*/
int bcm2835_mbox_call_raw(u32 chan, u32 send, u32 *recv);
/*
* Pass a complete property-style buffer to the VC, and wait until it has
* been processed.
*
* This function expects a pointer to the mbox_hdr structure in an attempt
* to ensure some degree of type safety. However, some number of tags and
* a termination value are expected to immediately follow the header in
* memory, as required by the property protocol.
*
* Returns 0 for success, any other value for error.
*/
int bcm2835_mbox_call_prop(u32 chan, struct bcm2835_mbox_hdr *buffer);
#endif