/*
 * (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;
		} 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