// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM
*/
/* Host Virtual Serial Interface (HVSI) is a protocol between the hosted OS
* and the service processor on IBM pSeries servers. On these servers, there
* are no serial ports under the OS's control, and sometimes there is no other
* console available either. However, the service processor has two standard
* serial ports, so this over-complicated protocol allows the OS to control
* those ports by proxy.
*
* Besides data, the procotol supports the reading/writing of the serial
* port's DTR line, and the reading of the CD line. This is to allow the OS to
* control a modem attached to the service processor's serial port. Note that
* the OS cannot change the speed of the port through this protocol.
*/
#undef DEBUG
#include <linux/console.h>
#include <linux/ctype.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/major.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/sysrq.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <asm/hvcall.h>
#include <asm/hvconsole.h>
#include <asm/prom.h>
#include <linux/uaccess.h>
#include <asm/vio.h>
#include <asm/param.h>
#include <asm/hvsi.h>
#define HVSI_MAJOR 229
#define HVSI_MINOR 128
#define MAX_NR_HVSI_CONSOLES 4
#define HVSI_TIMEOUT (5*HZ)
#define HVSI_VERSION 1
#define HVSI_MAX_PACKET 256
#define HVSI_MAX_READ 16
#define HVSI_MAX_OUTGOING_DATA 12
#define N_OUTBUF 12
/*
* we pass data via two 8-byte registers, so we would like our char arrays
* properly aligned for those loads.
*/
#define __ALIGNED__ __attribute__((__aligned__(sizeof(long))))
struct hvsi_struct {
struct tty_port port;
struct delayed_work writer;
struct work_struct handshaker;
wait_queue_head_t emptyq; /* woken when outbuf is emptied */
wait_queue_head_t stateq; /* woken when HVSI state changes */
spinlock_t lock;
int index;
uint8_t throttle_buf[128];
uint8_t outbuf[N_OUTBUF]; /* to implement write_room and chars_in_buffer */
/* inbuf is for packet reassembly. leave a little room for leftovers. */
uint8_t inbuf[HVSI_MAX_PACKET + HVSI_MAX_READ];
uint8_t *inbuf_end;
int n_throttle;
int n_outbuf;
uint32_t vtermno;
uint32_t virq;
atomic_t seqno; /* HVSI packet sequence number */
uint16_t mctrl;
uint8_t state; /* HVSI protocol state */
uint8_t flags;
#ifdef CONFIG_MAGIC_SYSRQ
uint8_t sysrq;
#endif /* CONFIG_MAGIC_SYSRQ */
};
static struct hvsi_struct hvsi_ports[MAX_NR_HVSI_CONSOLES];
static struct tty_driver *hvsi_driver;
static int hvsi_count;
static int (*hvsi_wait)(struct hvsi_struct *hp, int state);
enum HVSI_PROTOCOL_STATE {
HVSI_CLOSED,
HVSI_WAIT_FOR_VER_RESPONSE,
HVSI_WAIT_FOR_VER_QUERY,
HVSI_OPEN,
HVSI_WAIT_FOR_MCTRL_RESPONSE,
HVSI_FSP_DIED,
};
#define HVSI_CONSOLE 0x1
static inline int is_console(struct hvsi_struct *hp)
{
return hp->flags & HVSI_CONSOLE;
}
static inline int is_open(struct hvsi_struct *hp)
{
/* if we're waiting for an mctrl then we're already open */
return (hp->state == HVSI_OPEN)
|| (hp->state == HVSI_WAIT_FOR_MCTRL_RESPONSE);
}
static inline void print_state(struct hvsi_struct *hp)
{
#ifdef DEBUG
static const char *state_names[] = {
"HVSI_CLOSED",
"HVSI_WAIT_FOR_VER_RESPONSE",
"HVSI_WAIT_FOR_VER_QUERY",
"HVSI_OPEN",
"HVSI_WAIT_FOR_MCTRL_RESPONSE",
"HVSI_FSP_DIED",
};
const char *name = (hp->state < ARRAY_SIZE(state_names))
? state_names[hp->state] : "UNKNOWN";
pr_debug("hvsi%i: state = %s\n", hp->index, name);
#endif /* DEBUG */
}
static