core.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _FIREWIRE_CORE_H
#define _FIREWIRE_CORE_H

#include <linux/compiler.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <linux/xarray.h>
#include <linux/mm_types.h>
#include <linux/rwsem.h>
#include <linux/slab.h>
#include <linux/types.h>

#include <linux/refcount.h>

struct device;
struct fw_card;
struct fw_device;
struct fw_iso_buffer;
struct fw_iso_context;
struct fw_iso_packet;
struct fw_node;
struct fw_packet;


/* -card */

// This is the arbitrary value we use to indicate a mismatched gap count.
#define GAP_COUNT_MISMATCHED	0

#define isoc_cycles_to_jiffies(cycles) usecs_to_jiffies((u32)div_u64((u64)cycles * USEC_PER_SEC, 8000))

extern __printf(2, 3)
void fw_err(const struct fw_card *card, const char *fmt, ...);
extern __printf(2, 3)
void fw_notice(const struct fw_card *card, const char *fmt, ...);

/* bitfields within the PHY registers */
#define PHY_LINK_ACTIVE		0x80
#define PHY_CONTENDER		0x40
#define PHY_BUS_RESET		0x40
#define PHY_EXTENDED_REGISTERS	0xe0
#define PHY_BUS_SHORT_RESET	0x40
#define PHY_INT_STATUS_BITS	0x3c
#define PHY_ENABLE_ACCEL	0x02
#define PHY_ENABLE_MULTI	0x01
#define PHY_PAGE_SELECT		0xe0

#define BANDWIDTH_AVAILABLE_INITIAL	4915
#define BROADCAST_CHANNEL_INITIAL	(1 << 31 | 31)
#define BROADCAST_CHANNEL_VALID		(1 << 30)

#define CSR_STATE_BIT_CMSTR	(1 << 8)
#define CSR_STATE_BIT_ABDICATE	(1 << 10)

struct fw_card_driver {
	/*
	 * Enable the given card with the given initial config rom.
	 * This function is expected to activate the card, and either
	 * enable the PHY or set the link_on bit and initiate a bus
	 * reset.
	 */
	int (*enable)(struct fw_card *card,
		      const __be32 *config_rom, size_t length);

	// After returning the call, any function is no longer triggered to handle hardware event.
	void (*disable)(struct fw_card *card);

	int (*read_phy_reg)(struct fw_card *card, int address);
	int (*update_phy_reg)(struct fw_card *card, int address,
			      int clear_bits, int set_bits);

	/*
	 * Update the config rom for an enabled card.  This function
	 * should change the config rom that is presented on the bus
	 * and initiate a bus reset.
	 */
	int (*set_config_rom)(struct fw_card *card,
			      const __be32 *config_rom, size_t length);

	void (*send_request)(struct fw_card *card, struct fw_packet *packet);
	void (*send_response)(struct fw_card *card, struct fw_packet *packet);
	/* Calling cancel is valid once a packet has been submitted. */
	int (*cancel_packet)(struct fw_card *card, struct fw_packet *packet);

	/*
	 * Allow the specified node ID to do direct DMA out and in of
	 * host memory.  The card will disable this for all node when
	 * a bus reset happens, so driver need to re-enable this after
	 * bus reset.  Returns 0 on success, -ENODEV if the card
	 * doesn't support this, -ESTALE if the generation doesn't
	 * match.
	 */
	int (*enable_phys_dma)(struct fw_card *card,
			       int node_id, int generation);

	u32 (*read_csr)(struct fw_card *card, int csr_offset);
	void (*write_csr)(struct fw_card *card, int csr_offset, u32 value);

	struct fw_iso_context *
	(*allocate_iso_context)(struct fw_card *card,
				int type, int channel, size_t header_size);
	void (*free_iso_context)(struct fw_iso_context *ctx);

	int (*start_iso)(struct fw_iso_context *ctx,
			 s32 cycle, u32 sync, u32 tags);

	int (*set_iso_channels)(struct fw_iso_context *ctx, u64 *channels);

	int (*queue_iso)(struct fw_iso_context *ctx,
			 struct fw_iso_packet *packet,
			 struct fw_iso_buffer *buffer,
			 unsigned long payload);

	void (*flush_queue_iso)(struct fw_iso_context *ctx);

	int (*flush_iso_completions)(struct fw_iso_context *ctx);

	int (*stop_iso)(struct fw_iso_context *ctx);
};

void fw_card_initialize(struct fw_card *card,
		const struct fw_card_driver *driver, struct device *device);
int fw_card_add(struct fw_card *card, u32 max_receive, u32 link_speed, u64 guid,
		unsigned int supported_isoc_contexts);
void fw_core_remove_card(struct fw_card *card);
int fw_compute_block_crc(__be32 *block);
void fw_schedule_bm_work(struct fw_card *card, unsigned long delay);

/* -cdev */

extern const struct file_operations fw_device_ops;

void fw_device_cdev_update(struct fw_device *device);
void fw_device_cdev_remove(struct fw_device *device);
void fw_cdev_handle_phy_packet(struct fw_card *card, struct fw_packet *p);


/* -device */

extern struct rw_semaphore fw_device_rwsem;
extern struct xarray fw_device_xa;
extern int fw_cdev_major;

static inline struct fw_device *fw_device_get(struct fw_device *device)
{
	get_device(&device->device);

	return device;
}

static inline void fw_device_put(struct fw_device *device)
{
	put_device(&device->device);
}

struct fw_device *fw_device_get_by_devt(dev_t devt);
int fw_device_set_broadcast_channel(struct device *dev, void *gen);
void fw_node_event(struct fw_card *card, struct fw_node *node, int event);


/* -iso */

int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count);
int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
			  enum dma_data_direction direction);

static inline void fw_iso_context_init_work(struct fw_iso_context *ctx, work_func_t func)
{
	INIT_WORK(&ctx->work, func);
}


/* -topology */

// The initial value of BUS_MANAGER_ID register, to express nothing registered.
#define BUS_MANAGER_ID_NOT_REGISTERED	0x3f

enum {
	FW_NODE_CREATED,
	FW_NODE_UPDATED,
	FW_NODE_DESTROYED,
	FW_NODE_LINK_ON,
	FW_NODE_LINK_OFF,
	FW_NODE_INITIATED_RESET,
};

struct fw_node {
	u16 node_id;
	u8 color;
	u8 port_count;
	u8 link_on:1;
	u8 initiated_reset:1;
	u8 b_path:1;
	u8 phy_speed:2;	/* As in the self ID packet. */
	u8 max_speed:2;	/* Minimum of all phy-speeds on the path from the
			 * local node to this node. */
	u8 max_depth:4;	/* Maximum depth to any leaf node */
	u8 max_hops:4;	/* Max hops in this sub tree */

	struct kref kref;

	/* For serializing node topology into a list. */
	struct list_head link;

	// The device when already associated, else NULL.
	struct fw_device *device;

	struct fw_node *ports[] __counted_by(port_count);
};

static inline struct fw_node *fw_node_get(struct fw_node *node)
{
	kref_get(&node->kref);

	return node;
}

static void release_node(struct kref *kref)
{
	struct fw_node *node = container_of(kref, struct fw_node, kref);

	kfree(node);
}

static inline void fw_node_put(struct fw_node *node)
{
	kref_put(&node->kref, release_node);
}

static inline struct fw_device *fw_node_get_device(struct fw_node *node)
{
	return node->device;
}

static inline void fw_node_set_device(struct fw_node *node, struct fw_device *device)
{
	node->device = device;
}

void fw_core_handle_bus_reset(struct fw_card *card, int node_id,
	int generation, int self_id_count, u32 *self_ids, bool bm_abdicate);
void fw_destroy_nodes(struct fw_card *card);

/*
 * Check whether new_generation is the immediate successor of old_generation.
 * Take counter roll-over at 255 (as per OHCI) into account.
 */
static inline bool is_next_generation(int new_generation, int old_generation)
{
	return (new_generation & 0xff) == ((old_generation + 1) & 0xff);
}


/* -transaction */

#define TCODE_LINK_INTERNAL		0xe

static inline bool tcode_is_read_request(unsigned int tcode)
{
	return (tcode & ~1u) == 4u;
}

static inline bool tcode_is_block_packet(unsigned int tcode)
{
	return (tcode & 1u) != 0u;
}

static inline bool tcode_is_link_internal(unsigned int tcode)
{
	return (tcode == TCODE_LINK_INTERNAL);
}

#define LOCAL_BUS 0xffc0

/* OHCI-1394's default upper bound for physical DMA: 4 GB */
#define FW_MAX_PHYSICAL_RANGE		(1ULL << 32)

void fw_core_handle_request(struct fw_card *card, struct fw_packet *request);
void fw_core_handle_response(struct fw_card *card, struct fw_packet *packet);
int fw_get_response_length(struct fw_request *request);
void fw_fill_response(struct fw_packet *response, u32 *request_header,
		      int rcode, void *payload, size_t length);

void fw_request_get(struct fw_request *request);
void fw_request_put(struct fw_request *request);

void fw_cancel_pending_transactions(struct fw_card *card);

// Convert the value of IEEE 1394 CYCLE_TIME register to the format of timeStamp field in
// descriptors of 1394 OHCI.
static inline u32 cycle_time_to_ohci_tstamp(u32 tstamp)
{
	return (tstamp & 0x0ffff000) >> 12;
}

#define FW_PHY_CONFIG_NO_NODE_ID	-1
#define FW_PHY_CONFIG_CURRENT_GAP_COUNT	-1
void fw_send_phy_config(struct fw_card *card,
			int node_id, int generation, int gap_count);

static inline bool is_ping_packet(u32 *data)
{
	return (data[0] & 0xc0ffffff) == 0 && ~data[0] == data[1];
}

static inline bool is_in_fcp_region(u64 offset, size_t length)
{
	return offset >= (CSR_REGISTER_BASE | CSR_FCP_COMMAND) &&
		offset + length <= (CSR_REGISTER_BASE | CSR_FCP_END);
}

#endif /* _FIREWIRE_CORE_H */