path: root/drivers/char/hvc_iucv.c

/*
 * hvc_iucv.c - z/VM IUCV hypervisor console (HVC) device driver
 *
 * This HVC device driver provides terminal access using
 * z/VM IUCV communication paths.
 *
 * Copyright IBM Corp. 2008
 *
 * Author(s):	Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
 */
#define KMSG_COMPONENT		"hvc_iucv"
#define pr_fmt(fmt)		KMSG_COMPONENT ": " fmt

#include <linux/types.h>
#include <asm/ebcdic.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/mempool.h>
#include <linux/moduleparam.h>
#include <linux/tty.h>
#include <linux/wait.h>
#include <net/iucv/iucv.h>

#include "hvc_console.h"


/* General device driver settings */
#define HVC_IUCV_MAGIC		0xc9e4c3e5
#define MAX_HVC_IUCV_LINES	HVC_ALLOC_TTY_ADAPTERS
#define MEMPOOL_MIN_NR		(PAGE_SIZE / sizeof(struct iucv_tty_buffer)/4)

/* IUCV TTY message  */
#define MSG_VERSION		0x02	/* Message version */
#define MSG_TYPE_ERROR		0x01	/* Error message */
#define MSG_TYPE_TERMENV	0x02	/* Terminal environment variable */
#define MSG_TYPE_TERMIOS	0x04	/* Terminal IO struct update */
#define MSG_TYPE_WINSIZE	0x08	/* Terminal window size update */
#define MSG_TYPE_DATA		0x10	/* Terminal data */

struct iucv_tty_msg {
	u8	version;		/* Message version */
	u8	type;			/* Message type */
#define MSG_MAX_DATALEN		((u16)(~0))
	u16	datalen;		/* Payload length */
	u8	data[];			/* Payload buffer */
} __attribute__((packed));
#define MSG_SIZE(s)		((s) + offsetof(struct iucv_tty_msg, data))

enum iucv_state_t {
	IUCV_DISCONN	= 0,
	IUCV_CONNECTED	= 1,
	IUCV_SEVERED	= 2,
};

enum tty_state_t {
	TTY_CLOSED	= 0,
	TTY_OPENED	= 1,
};

struct hvc_iucv_private {
	struct hvc_struct	*hvc;		/* HVC struct reference */
	u8			srv_name[8];	/* IUCV service name (ebcdic) */
	unsigned char		is_console;	/* Linux console usage flag */
	enum iucv_state_t	iucv_state;	/* IUCV connection status */
	enum tty_state_t	tty_state;	/* TTY status */
	struct iucv_path	*path;		/* IUCV path pointer */
	spinlock_t		lock;		/* hvc_iucv_private lock */
#define SNDBUF_SIZE		(PAGE_SIZE)	/* must be < MSG_MAX_DATALEN */
	void			*sndbuf;	/* send buffer		  */
	size_t			sndbuf_len;	/* length of send buffer  */
#define QUEUE_SNDBUF_DELAY	(HZ / 25)
	struct delayed_work	sndbuf_work;	/* work: send iucv msg(s) */
	wait_queue_head_t	sndbuf_waitq;	/* wait for send completion */
	struct list_head	tty_outqueue;	/* outgoing IUCV messages */
	struct list_head	tty_inqueue;	/* incoming IUCV messages */
};

struct iucv_tty_buffer {
	struct list_head	list;	/* list pointer */
	struct iucv_message	msg;	/* store an IUCV message */
	size_t			offset;	/* data buffer offset */
	struct iucv_tty_msg	*mbuf;	/* buffer to store input/output data */
};

/* IUCV callback handler */
static	int hvc_iucv_path_pending(struct iucv_path *, u8[8], u8[16]);
static void hvc_iucv_path_severed(struct iucv_path *, u8[16]);
static void hvc_iucv_msg_pending(struct iucv_path *, struct iucv_message *);
static void hvc_iucv_msg_complete(struct iucv_path *, struct iucv_message *);


/* Kernel module parameter: use one terminal device as default */
static unsigned long hvc_iucv_devices = 1;

/* Array of allocated hvc iucv tty lines... */
static struct hvc_iucv_private *hvc_iucv_table[MAX_HVC_IUCV_LINES];
#define IUCV_HVC_CON_IDX	(0)
/* List of z/VM user ID filter entries (struct iucv_vmid_filter) */
#define MAX_VMID_FILTER		(500)
static size_t hvc_iucv_filter_size;
static void *hvc_iucv_filter;
static const char *hvc_iucv_filter_string;
static DEFINE_RWLOCK(hvc_iucv_filter_lock);

/* Kmem cache and mempool for iucv_tty_buffer elements */
static struct kmem_cache *hvc_iucv_buffer_cache;
static mempool_t *hvc_iucv_mempool;

/* IUCV handler callback functions */
static struct iucv_handler hvc_iucv_handler = {
	.path_pending  = hvc_iucv_path_pending,
	.path_severed  = hvc_iucv_path_severed,
	.message_complete<