path: root/drivers/mailbox/arm_mhuv3.c

// SPDX-License-Identifier: GPL-2.0
/*
 * ARM Message Handling Unit Version 3 (MHUv3) driver.
 *
 * Copyright (C) 2024 ARM Ltd.
 *
 * Based on ARM MHUv2 driver.
 */

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/bits.h>
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/mailbox_controller.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/sizes.h>
#include <linux/slab.h>
#include <linux/types.h>

/* ====== MHUv3 Registers ====== */

/* Maximum number of Doorbell channel windows */
#define MHUV3_DBCW_MAX			128
/* Number of DBCH combined interrupt status registers */
#define MHUV3_DBCH_CMB_INT_ST_REG_CNT	4

/* Number of FFCH combined interrupt status registers */
#define MHUV3_FFCH_CMB_INT_ST_REG_CNT	2

#define MHUV3_FLAG_BITS			32

/* Not a typo ... */
#define MHUV3_MAJOR_VERSION		2

enum {
	MHUV3_MBOX_CELL_TYPE,
	MHUV3_MBOX_CELL_CHWN,
	MHUV3_MBOX_CELL_PARAM,
	MHUV3_MBOX_CELLS
};

/* Padding bitfields/fields represents hole in the regs MMIO */

/* CTRL_Page */
struct blk_id {
#define id		GENMASK(3, 0)
	u32 val;
} __packed;

struct feat_spt0 {
#define	dbe_spt		GENMASK(3, 0)
#define	fe_spt		GENMASK(7, 4)
#define	fce_spt		GENMASK(11, 8)
	u32 val;
} __packed;

struct feat_spt1 {
#define	auto_op_spt	GENMASK(3, 0)
	u32 val;
} __packed;

struct dbch_cfg0 {
#define num_dbch	GENMASK(7, 0)
	u32 val;
} __packed;

struct ffch_cfg0 {
#define num_ffch	GENMASK(7, 0)
#define x8ba_spt	BIT(8)
#define x16ba_spt	BIT(9)
#define x32ba_spt	BIT(10)
#define x64ba_spt	BIT(11)
#define ffch_depth	GENMASK(25, 16)
	u32 val;
} __packed;

struct fch_cfg0 {
#define num_fch		GENMASK(9, 0)
#define fcgi_spt	BIT(10)		// MBX-only
#define num_fcg		GENMASK(15, 11)
#define num_fch_per_grp	GENMASK(20, 16)
#define fch_ws		GENMASK(28, 21)
	u32 val;
} __packed;

struct ctrl {
#define op_req		BIT(0)
#define	ch_op_mask	BIT(1)
	u32 val;
} __packed;

struct fch_ctrl {
#define _int_en		BIT(2)
	u32 val;
} __packed;

struct iidr {
#define implementer	GENMASK(11, 0)
#define revision	GENMASK(15, 12)
#define variant		GENMASK(19, 16)
#define product_id	GENMASK(31, 20)
	u32 val;
} __packed;

struct aidr {
#define arch_minor_rev	GENMASK(3, 0)
#define arch_major_rev	GENMASK(7, 4)
	u32 val;
} __packed;

struct ctrl_page {
	struct blk_id blk_id;
	u8 pad[12];
	struct feat_spt0 feat_spt0;
	struct feat_spt1 feat_spt1;
	u8 pad1[8];
	struct dbch_cfg0 dbch_cfg0;
	u8 pad2[12];
	struct ffch_cfg0 ffch_cfg0;
	u8 pad3[12];
	struct fch_cfg0 fch_cfg0;
	u8 pad4[188];
	struct ctrl x_ctrl;
	/*-- MBX-only registers --*/
	u8 pad5[60];
	struct fch_ctrl fch_ctrl;
	u32 fcg_int_en;
	u8 pad6[696];
	/*-- End of MBX-only ---- */
	u32 dbch_int_st[MHUV3_DBCH_CMB_INT_ST_REG_CNT];
	u32 ffch_int_st[MHUV3_FFCH_CMB_INT_ST_REG_CNT];
	/*-- MBX-only registers --*/
	u8 pad7[88];
	u32 fcg_int_st;
	u8 pad8[12];
	u32 fcg_grp_int_st[32];
	u8 pad9[2760];
	/*-- End of MBX-only ---- */
	struct iidr iidr;
	struct aidr aidr;
	u32 imp_def_id[12];
} __packed;

/* DBCW_Page */

struct xbcw_ctrl {
#define comb_en		BIT(0)
	u32 val;
} __packed;

struct pdbcw_int {
#define tfr_ack		BIT(0)
	u32 val;
} __packed;

struct pdbcw_page {
	u32 st;
	u8 pad[8];
	u32 set;
	struct pdbcw_int int_st;
	struct pdbcw_int int_clr;
	struct pdbcw_int int_en;
	struct xbcw_ctrl ctrl;
} __packed;

struct mdbcw_page {
	u32 st;
	u32 st_msk;
	u32 clr;
	u8 pad[4];
	u32 msk_st;
	u32 msk_set;
	u32 msk_clr;
	struct xbcw_ctrl ctrl;
} __packed;

struct dummy_page {
	u8 pad[SZ_4K];
} __packed;

struct mhu3_pbx_frame_reg {
	struct ctrl_page ctrl;
	struct pdbcw_page dbcw[MHUV3_DBCW_MAX];
	struct dummy_page ffcw;
	struct dummy_page fcw;
	u8 pad[SZ_4K * 11];
	struct dummy_page impdef;
} __packed;

struct mhu3_mbx_frame_reg {
	struct ctrl_page ctrl;
	struct mdbcw_page dbcw[MHUV3_DBCW_MAX];
	struct dummy_page ffcw;
	struct dummy_page fcw;
	u8 pad[SZ_4K * 11];
	struct dummy_page impdef;
} __packed;

/* Macro for reading a bitmask within a physically mapped packed struct */
#define readl_relaxed_bitmask(_regptr, _bitmask)			\
	({								\
		unsigned long _rval;					\
		_rval = readl_relaxed(_regptr);				\
		FIELD_GET(_bitmask, _rval);				\
	})

/* Macro for writing a bitmask within a physically mapped packed struct */
#define writel_relaxed_bitmask(_value, _regptr, _bitmask)		\
	({								\
		unsigned long _rval;					\
		typeof(_regptr) _rptr = _regptr;			\
		typeof(_bitmask) _bmask = _bitmask;			\
		_rval = readl_relaxed(_rptr);				\
		_rval &= ~(_bmask);					\
		_rval |= FIELD_PREP((unsigned long long)_bmask, _value);\
		writel_relaxed(_rval, _rptr);				\
	})

/* ====== MHUv3 data structures ====== */

enum mhuv3_frame {
	PBX_FRAME,
	MBX_FRAME,
};

static char *mhuv3_str[] = {
	"PBX",
	"MBX"
};

enum mhuv3_extension_type {
	DBE_EXT,
	FCE_EXT,
	FE_EXT,
	NUM_EXT
};

static char *mhuv3_ext_str[] = {
	"DBE",
	"FCE",
	"FE"
};

struct mhuv3;

/**
 * struct mhuv3_protocol_ops - MHUv3 operations
 *
 * @rx_startup: Receiver startup callback.
 * @rx_shutdown: Receiver shutdown callback.
 * @read_data: Read available Sender in-band LE data (if any).
 * @rx_complete: Acknowledge data reception to the Sender. Any out-of-band data
 *		 has to have been already retrieved before calling this.
 * @tx_startup: Sender startup callback.
 * @tx_shutdown: Sender shutdown callback.
 * @last_tx_done: Report back to the Sender if the last transfer has completed.
 * @send_data: Send data to the receiver.
 *
 * Each supported transport protocol provides its own implementation of
 * these operations.
 */
struct mhuv3_protocol_ops {
	in