/* * Copyright (C) 2004 Hollis Blanchard <hollisb@us.ibm.com>, IBM * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /* 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 <asm/uaccess.h> #include <asm/vio.h> #include <asm/param.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 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; struct tty_struct *tty; unsigned int count; 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 #define VS_DATA_PACKET_HEADER 0xff #define VS_CONTROL_PACKET_HEADER 0xfe #define VS_QUERY_PACKET_HEADER 0xfd #define VS_QUERY_RESPONSE_PACKET_HEADER 0xfc /* control verbs */ #define VSV_SET_MODEM_CTL 1 /* to service processor only */ #define VSV_MODEM_CTL_UPDATE 2 /* from service processor only */ #define VSV_CLOSE_PROTOCOL 3 /* query verbs */ #define VSV_SEND_VERSION_NUMBER 1 #define VSV_SEND_MODEM_CTL_STATUS 2 /* yes, these masks are not consecutive. */ #define HVSI_TSDTR 0x01 #define HVSI_TSCD 0x20 struct hvsi_header { uint8_t type; uint8_t len; uint16_t seqno; } __attribute__((packed)); struct hvsi_data { uint8_t type; uint8_t len; uint16_t seqno; uint8_t data[HVSI_MAX_OUTGOING_DATA]; } __attribute__((packed)); struct hvsi_control { uint8_t type; uint8_t len; uint16_t seqno; uint16_t verb; /* optional depending on verb: */ uint32_t word; uint32_t mask; } __attribute__((packed)); struct hvsi_query { uint8_t type; uint8_t len; uint16_t seqno; uint16_t verb; } __attribute__((packed)); struct hvsi_query_response { uint8_t type; uint8_t len; uint16_t seqno; uint16_t verb; uint16_t query_seqno; union { uint8_t version; uint32_t mctrl_word; } u; } __attribute__((packed)); 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 = state_names[hp->state]; if (hp->state > ARRAY_SIZE(state_names)) name = "UNKNOWN"; pr_debug("hvsi%i: state = %s\n", hp->index, name); #endif /* DEBUG */ } static inline void __set_state(struct hvsi_struct *hp, int state) { hp->state = state; print_state(hp); wake_up_all(&hp->stateq); } static inline void set_state(struct hvsi_struct *hp, int state) { unsigned long flags; spin_lock_irqsave(&hp->lock, flags); __set_state(hp, state); spin_unlock_irqrestore(&hp->lock, flags); } static inline int len_packet(const uint8_t *packet) { return (int)((struct hvsi_header *)packet)->len; } static inline int is_header(const uint8_t *packet) { struct hvsi_header *header = (struct hvsi_header *)packet; return header->type >= VS_QUERY_RESPONSE_PACKET_HEADER; } static inline int got_packet(const struct hvsi_struct *hp, uint8_t *packet) { if (hp->inbuf_end < packet + sizeof(struct hvsi_header)) return 0; /* don't even have the packet header */ if (hp->inbuf_end < (packet + len_packet(packet))) return 0; /* don't have the rest of the packet */ return 1; } /* shift remaining bytes in packetbuf down */ static void compact_inbuf(struct hvsi_struct *hp, uint8_t *read_to) { int remaining = (int)(hp->inbuf_end - read_to); pr_debug("%s: %i chars remain\n", __func__, remaining); if (read_to != hp->inbuf) memmove(hp->inbuf, read_to, remaining); hp->inbuf_end = hp->inbuf + remaining; } #ifdef DEBUG #define dbg_dump_packet(packet) dump_packet(packet) #define dbg_dump_hex(data, len) dump_hex(data, len) #else #define dbg_dump_packet(packet) do { } while (0) #define dbg_dump_hex(data, len) do { } while (0) #endif static void dump_hex(const uint8_t *data, int len) { int i; printk(" "); for (i=0; i < len; i++) printk("%.2x", data[i]); printk("\n "); for (i=0; i < len; i++) { if (isprint(data[i])) printk("%c", data[i]); else printk("."); } printk("\n"); } static void dump_packet(uint8_t *packet) { struct hvsi_header *header = (struct hvsi_header *)packet; printk("type 0x%x, len %i, seqno %i:\n", header->type, header->len, header->seqno); dump_hex(packet, header->len); } static int hvsi_read(struct hvsi_struct *hp, char *buf, int count) { unsigned long got; got = hvc_get_chars(hp->vtermno, buf, count); return got; } static void hvsi_recv_control(struct hvsi_struct *hp, uint8_t *packet, struct tty_struct **to_hangup, struct hvsi_struct **to_handshake) { struct hvsi_control *header = (struct hvsi_control *)packet; switch (header->verb) { case VSV_MODEM_CTL_UPDATE: if ((header->word & HVSI_TSCD) == 0) { /* CD went away; no more connection */ pr_debug("hvsi%i: CD dropped\n", hp->index); hp->mctrl &= TIOCM_CD; /* If userland hasn't done an open(2) yet, hp->tty is NULL. */ if (hp->tty && !(hp->tty->flags & CLOCAL)) *to_hangup = hp->tty; } break; case VSV_CLOSE_PROTOCOL: pr_debug("hvsi%i: service processor came back\n", hp->index); if (hp->state != HVSI_CLOSED) { *to_handshake = hp; } break; default: printk(KERN_WARNING "hvsi%i: unknown HVSI control packet: ", hp->index); dump_packet(packet); break; } } static void hvsi_recv_response(struct hvsi_struct *hp, uint8_t *packet) { struct hvsi_query_response *resp = (struct hvsi_query_response *)packet; switch (hp->state) { case HVSI_WAIT_FOR_VER_RESPONSE: __set_state(hp, HVSI_WAIT_FOR_VER_QUERY); break; case HVSI_WAIT_FOR_MCTRL_RESPONSE: hp->mctrl = 0; if (resp->u.mctrl_word & HVSI_TSDTR) hp->mctrl |= TIOCM_DTR; if (resp->u.mctrl_word & HVSI_TSCD) hp->mctrl |= TIOCM_CD; __set_state(hp, HVSI_OPEN); break; default: printk(KERN_ERR "hvsi%i: unexpected query response: ", hp->index); dump_packet(packet); break; } } /* respond to service processor's version query */ static int hvsi_version_respond(struct hvsi_struct *hp, uint16_t query_seqno) { struct hvsi_query_response packet __ALIGNED__; int wrote; packet.type = VS_QUERY_RESPONSE_PACKET_HEADER; packet.len = sizeof(struct hvsi_query_response); packet.seqno = atomic_inc_return(&hp->seqno); packet.verb = VSV_SEND_VERSION_NUMBER; packet.u.version = HVSI_VERSION; packet.query_seqno = query_seqno+1; pr_debug("%s: sending %i bytes\n", __func__, packet.len); dbg_dump_hex((uint8_t*)&packet, packet.len); wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len); if (wrote != packet.len) { printk(KERN_ERR "hvsi%i: couldn't send query response!\n", hp->index); return -EIO; } return 0; } static void hvsi_recv_query(struct hvsi_struct *hp, uint8_t *packet) { struct hvsi_query *query = (struct hvsi_query *)packet; switch (hp->state) { case HVSI_WAIT_FOR_VER_QUERY: hvsi_version_respond(hp, query->seqno); __set_state(hp, HVSI_OPEN); break; default: printk(KERN_ERR "hvsi%i: unexpected query: ", hp->index); dump_packet(packet); break; } } static void hvsi_insert_chars(struct hvsi_struct *hp, const char *buf, int len) { int i; for (i=0; i < len; i++) { char c = buf[i]; #ifdef CONFIG_MAGIC_SYSRQ if (c == '\0') { hp->sysrq = 1; continue; } else if (hp->sysrq) { handle_sysrq(c, hp->tty); hp->sysrq = 0; continue; } #endif /* CONFIG_MAGIC_SYSRQ */ tty_insert_flip_char(hp->tty, c, 0); } } /* * We could get 252 bytes of data at once here. But the tty layer only * throttles us at TTY_THRESHOLD_THROTTLE (128) bytes, so we could overflow * it. Accordingly we won't send more than 128 bytes at a time to the flip * buffer, which will give the tty buffer a chance to throttle us. Should the * value of TTY_THRESHOLD_THROTTLE change in n_tty.c, this code should be * revisited. */ #define TTY_THRESHOLD_THROTTLE 128 static struct tty_struct *hvsi_recv_data(struct hvsi_struct *hp, const uint8_t *packet) { const struct hvsi_header *header = (const struct hvsi_header *)packet; const uint8_t *data = packet + sizeof(struct hvsi_header); int datalen = header->len - sizeof(struct hvsi_header); int overflow = datalen - TTY_THRESHOLD_THROTTLE; pr_debug("queueing %i chars '%.*s'\n", datalen, datalen, data); if (datalen == 0) return NULL; if (overflow > 0) { pr_debug("%s: got >TTY_THRESHOLD_THROTTLE bytes\n", __func__); datalen = TTY_THRESHOLD_THROTTLE; } hvsi_insert_chars(hp, data, datalen); if (overflow > 0) { /* * we still have more data to deliver, so we need to save off the * overflow and send it later */ pr_debug("%s: deferring overflow\n", __func__); memcpy(hp->throttle_buf, data + TTY_THRESHOLD_THROTTLE, overflow); hp->n_throttle = overflow; } return hp->tty; } /* * Returns true/false indicating data successfully read from hypervisor. * Used both to get packets for tty connections and to advance the state * machine during console handshaking (in which case tty = NULL and we ignore * incoming data). */ static int hvsi_load_chunk(struct hvsi_struct *hp, struct tty_struct **flip, struct tty_struct **hangup, struct hvsi_struct **handshake) { uint8_t *packet = hp->inbuf; int chunklen; *flip = NULL; *hangup = NULL; *handshake = NULL; chunklen = hvsi_read(hp, hp->inbuf_end, HVSI_MAX_READ); if (chunklen == 0) { pr_debug("%s: 0-length read\n", __func__); return 0; } pr_debug("%s: got %i bytes\n", __func__, chunklen); dbg_dump_hex(hp->inbuf_end, chunklen); hp->inbuf_end += chunklen; /* handle all completed packets */ while ((packet < hp->inbuf_end) && got_packet(hp, packet)) { struct hvsi_header *header = (struct hvsi_header *)packet; if (!is_header(packet)) { printk(KERN_ERR "hvsi%i: got malformed packet\n", hp->index); /* skip bytes until we find a header or run out of data */ while ((packet < hp->inbuf_end) && (!is_header(packet))) packet++; continue; } pr_debug("%s: handling %i-byte packet\n", __func__, len_packet(packet)); dbg_dump_packet(packet); switch (header->type) { case VS_DATA_PACKET_HEADER: if (!is_open(hp)) break; if (hp->tty == NULL) break; /* no tty buffer to put data in */ *flip = hvsi_recv_data(hp, packet); break; case VS_CONTROL_PACKET_HEADER: hvsi_recv_control(hp, packet, hangup, handshake); break; case VS_QUERY_RESPONSE_PACKET_HEADER: hvsi_recv_response(hp, packet); break; case VS_QUERY_PACKET_HEADER: hvsi_recv_query(hp, packet); break; default: printk(KERN_ERR "hvsi%i: unknown HVSI packet type 0x%x\n", hp->index, header->type); dump_packet(packet); break; } packet += len_packet(packet); if (*hangup || *handshake) { pr_debug("%s: hangup or handshake\n", __func__); /* * we need to send the hangup now before receiving any more data. * If we get "data, hangup, data", we can't deliver the second * data before the hangup. */ break; } } compact_inbuf(hp, packet); return 1; } static void hvsi_send_overflow(struct hvsi_struct *hp) { pr_debug("%s: delivering %i bytes overflow\n", __func__, hp->n_throttle); hvsi_insert_chars(hp, hp->throttle_buf, hp->n_throttle); hp->n_throttle = 0; } /* * must get all pending data because we only get an irq on empty->non-empty * transition */ static irqreturn_t hvsi_interrupt(int irq, void *arg) { struct hvsi_struct *hp = (struct hvsi_struct *)arg; struct tty_struct *flip; struct tty_struct *hangup; struct hvsi_struct *handshake; unsigned long flags; int again = 1; pr_debug("%s\n", __func__); while (again) { spin_lock_irqsave(&hp->lock, flags); again = hvsi_load_chunk(hp, &flip, &hangup, &handshake); spin_unlock_irqrestore(&hp->lock, flags); /* * we have to call tty_flip_buffer_push() and tty_hangup() outside our * spinlock. But we also have to keep going until we've read all the * available data. */ if (flip) { /* there was data put in the tty flip buffer */ tty_flip_buffer_push(flip); flip = NULL; } if (hangup) { tty_hangup(hangup); } if (handshake) { pr_debug("hvsi%i: attempting re-handshake\n", handshake->index); schedule_work(&handshake->handshaker); } } spin_lock_irqsave(&hp->lock, flags); if (hp->tty && hp->n_throttle && (!test_bit(TTY_THROTTLED, &hp->tty->flags))) { /* we weren't hung up and we weren't throttled, so we can deliver the * rest now */ flip = hp->tty; hvsi_send_overflow(hp); } spin_unlock_irqrestore(&hp->lock, flags); if (flip) { tty_flip_buffer_push(flip); } return IRQ_HANDLED; } /* for boot console, before the irq handler is running */ static int __init poll_for_state(struct hvsi_struct *hp, int state) { unsigned long end_jiffies = jiffies + HVSI_TIMEOUT; for (;;) { hvsi_interrupt(hp->virq, (void *)hp); /* get pending data */ if (hp->state == state) return 0; mdelay(5); if (time_after(jiffies, end_jiffies)) return -EIO; } } /* wait for irq handler to change our state */ static int wait_for_state(struct hvsi_struct *hp, int state) { int ret = 0; if (!wait_event_timeout(hp->stateq, (hp->state == state), HVSI_TIMEOUT)) ret = -EIO; return ret; } static int hvsi_query(struct hvsi_struct *hp, uint16_t verb) { struct hvsi_query packet __ALIGNED__; int wrote; packet.type = VS_QUERY_PACKET_HEADER; packet.len = sizeof(struct hvsi_query); packet.seqno = atomic_inc_return(&hp->seqno); packet.verb = verb; pr_debug("%s: sending %i bytes\n", __func__, packet.len); dbg_dump_hex((uint8_t*)&packet, packet.len); wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len); if (wrote != packet.len) { printk(KERN_ERR "hvsi%i: couldn't send query (%i)!\n", hp->index, wrote); return -EIO; } return 0; } static int hvsi_get_mctrl(struct hvsi_struct *hp) { int ret; set_state(hp, HVSI_WAIT_FOR_MCTRL_RESPONSE); hvsi_query(hp, VSV_SEND_MODEM_CTL_STATUS); ret = hvsi_wait(hp, HVSI_OPEN); if (ret < 0) { printk(KERN_ERR "hvsi%i: didn't get modem flags\n", hp->index); set_state(hp, HVSI_OPEN); return ret; } pr_debug("%s: mctrl 0x%x\n", __func__, hp->mctrl); return 0; } /* note that we can only set DTR */ static int hvsi_set_mctrl(struct hvsi_struct *hp, uint16_t mctrl) { struct hvsi_control packet __ALIGNED__; int wrote; packet.type = VS_CONTROL_PACKET_HEADER, packet.seqno = atomic_inc_return(&hp->seqno); packet.len = sizeof(struct hvsi_control); packet.verb = VSV_SET_MODEM_CTL; packet.mask = HVSI_TSDTR; if (mctrl & TIOCM_DTR) packet.word = HVSI_TSDTR; pr_debug("%s: sending %i bytes\n", __func__, packet.len); dbg_dump_hex((uint8_t*)&packet, packet.len); wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len); if (wrote != packet.len) { printk(KERN_ERR "hvsi%i: couldn't set DTR!\n", hp->index); return -EIO; } return 0; } static void hvsi_drain_input(struct hvsi_struct *hp) { uint8_t buf[HVSI_MAX_READ] __ALIGNED__; unsigned long end_jiffies = jiffies + HVSI_TIMEOUT; while (time_before(end_jiffies, jiffies)) if (0 == hvsi_read(hp, buf, HVSI_MAX_READ)) break; } static int hvsi_handshake(struct hvsi_struct *hp) { int ret; /* * We could have a CLOSE or other data waiting for us before we even try * to open; try to throw it all away so we don't get confused. (CLOSE * is the first message sent up the pipe when the FSP comes online. We * need to distinguish between "it came up a while ago and we're the first * user" and "it was just reset before it saw our handshake packet".) */ hvsi_drain_input(hp); set_state(hp, HVSI_WAIT_FOR_VER_RESPONSE); ret = hvsi_query(hp, VSV_SEND_VERSION_NUMBER); if (ret < 0) { printk(KERN_ERR "hvsi%i: couldn't send version query\n", hp->index); return ret; } ret = hvsi_wait(hp, HVSI_OPEN); if (ret < 0) return ret; return 0; } static void hvsi_handshaker(struct work_struct *work) { struct hvsi_struct *hp = container_of(work, struct hvsi_struct, handshaker); if (hvsi_handshake(hp) >= 0) return; printk(KERN_ERR "hvsi%i: re-handshaking failed\n", hp->index); if (is_console(hp)) { /* * ttys will re-attempt the handshake via hvsi_open, but * the console will not. */ printk(KERN_ERR "hvsi%i: lost console!\n", hp->index); } } static int hvsi_put_chars(struct hvsi_struct *hp, const char *buf, int count) { struct hvsi_data packet __ALIGNED__; int ret; BUG_ON(count > HVSI_MAX_OUTGOING_DATA); packet.type = VS_DATA_PACKET_HEADER; packet.seqno = atomic_inc_return(&hp->seqno); packet.len = count + sizeof(struct hvsi_header); memcpy(&packet.data, buf, count); ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.len); if (ret == packet.len) { /* return the number of chars written, not the packet length */ return count; } return ret; /* return any errors */ } static void hvsi_close_protocol(struct hvsi_struct *hp) { struct hvsi_control packet __ALIGNED__; packet.type = VS_CONTROL_PACKET_HEADER; packet.seqno = atomic_inc_return(&hp->seqno); packet.len = 6; packet.verb = VSV_CLOSE_PROTOCOL; pr_debug("%s: sending %i bytes\n", __func__, packet.len); dbg_dump_hex((uint8_t*)&packet, packet.len); hvc_put_chars(hp->vtermno, (char *)&packet, packet.len); } static int hvsi_open(struct tty_struct *tty, struct file *filp) { struct hvsi_struct *hp; unsigned long flags; int line = tty->index; int ret; pr_debug("%s\n", __func__); if (line < 0 || line >= hvsi_count) return -ENODEV; hp = &hvsi_ports[line]; tty->driver_data = hp; tty->low_latency = 1; /* avoid throttle/tty_flip_buffer_push race */ mb(); if (hp->state == HVSI_FSP_DIED) return -EIO; spin_lock_irqsave(&hp->lock, flags); hp->tty = tty; hp->count++; atomic_set(&hp->seqno, 0); h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE); spin_unlock_irqrestore(&hp->lock, flags); if (is_console(hp)) return 0; /* this has already been handshaked as the console */ ret = hvsi_handshake(hp); if (ret < 0) { printk(KERN_ERR "%s: HVSI handshaking failed\n", tty->name); return ret; } ret = hvsi_get_mctrl(hp); if (ret < 0) { printk(KERN_ERR "%s: couldn't get initial modem flags\n", tty->name); return ret; } ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR); if (ret < 0) { printk(KERN_ERR "%s: couldn't set DTR\n", tty->name); return ret; } return 0; } /* wait for hvsi_write_worker to empty hp->outbuf */ static void hvsi_flush_output(struct hvsi_struct *hp) { wait_event_timeout(hp->emptyq, (hp->n_outbuf <= 0), HVSI_TIMEOUT); /* 'writer' could still be pending if it didn't see n_outbuf = 0 yet */ cancel_delayed_work(&hp->writer); flush_scheduled_work(); /* * it's also possible that our timeout expired and hvsi_write_worker * didn't manage to push outbuf. poof. */ hp->n_outbuf = 0; } static void hvsi_close(struct tty_struct *tty, struct file *filp) { struct hvsi_struct *hp = tty->driver_data; unsigned long flags; pr_debug("%s\n", __func__); if (tty_hung_up_p(filp)) return; spin_lock_irqsave(&hp->lock, flags); if (--hp->count == 0) { hp->tty = NULL; hp->inbuf_end = hp->inbuf; /* discard remaining partial packets */ /* only close down connection if it is not the console */ if (!is_console(hp)) { h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); /* no more irqs */ __set_state(hp, HVSI_CLOSED); /* * any data delivered to the tty layer after this will be * discarded (except for XON/XOFF) */ tty->closing = 1; spin_unlock_irqrestore(&hp->lock, flags); /* let any existing irq handlers finish. no more will start. */ synchronize_irq(hp->virq); /* hvsi_write_worker will re-schedule until outbuf is empty. */ hvsi_flush_output(hp); /* tell FSP to stop sending data */ hvsi_close_protocol(hp); /* * drain anything FSP is still in the middle of sending, and let * hvsi_handshake drain the rest on the next open. */ hvsi_drain_input(hp); spin_lock_irqsave(&hp->lock, flags); } } else if (hp->count < 0) printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n", hp - hvsi_ports, hp->count); spin_unlock_irqrestore(&hp->lock, flags); } static void hvsi_hangup(struct tty_struct *tty) { struct hvsi_struct *hp = tty->driver_data; unsigned long flags; pr_debug("%s\n", __func__); spin_lock_irqsave(&hp->lock, flags); hp->count = 0; hp->n_outbuf = 0; hp->tty = NULL; spin_unlock_irqrestore(&hp->lock, flags); } /* called with hp->lock held */ static void hvsi_push(struct hvsi_struct *hp) { int n; if (hp->n_outbuf <= 0) return; n = hvsi_put_chars(hp, hp->outbuf, hp->n_outbuf); if (n > 0) { /* success */ pr_debug("%s: wrote %i chars\n", __func__, n); hp->n_outbuf = 0; } else if (n == -EIO) { __set_state(hp, HVSI_FSP_DIED); printk(KERN_ERR "hvsi%i: service processor died\n", hp->index); } } /* hvsi_write_worker will keep rescheduling itself until outbuf is empty */ static void hvsi_write_worker(struct work_struct *work) { struct hvsi_struct *hp = container_of(work, struct hvsi_struct, writer.work); unsigned long flags; #ifdef DEBUG static long start_j = 0; if (start_j == 0) start_j = jiffies; #endif /* DEBUG */ spin_lock_irqsave(&hp->lock, flags); pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf); if (!is_open(hp)) { /* * We could have a non-open connection if the service processor died * while we were busily scheduling ourselves. In that case, it could * be minutes before the service processor comes back, so only try * again once a second. */ schedule_delayed_work(&hp->writer, HZ); goto out; } hvsi_push(hp); if (hp->n_outbuf > 0) schedule_delayed_work(&hp->writer, 10); else { #ifdef DEBUG pr_debug("%s: outbuf emptied after %li jiffies\n", __func__, jiffies - start_j); start_j = 0; #endif /* DEBUG */ wake_up_all(&hp->emptyq); tty_wakeup(hp->tty); } out: spin_unlock_irqrestore(&hp->lock, flags); } static int hvsi_write_room(struct tty_struct *tty) { struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data; return N_OUTBUF - hp->n_outbuf; } static int hvsi_chars_in_buffer(struct tty_struct *tty) { struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data; return hp->n_outbuf; } static int hvsi_write(struct tty_struct *tty, const unsigned char *buf, int count) { struct hvsi_struct *hp = tty->driver_data; const char *source = buf; unsigned long flags; int total = 0; int origcount = count; spin_lock_irqsave(&hp->lock, flags); pr_debug("%s: %i chars in buffer\n", __func__, hp->n_outbuf); if (!is_open(hp)) { /* we're either closing or not yet open; don't accept data */ pr_debug("%s: not open\n", __func__); goto out; } /* * when the hypervisor buffer (16K) fills, data will stay in hp->outbuf * and hvsi_write_worker will be scheduled. subsequent hvsi_write() calls * will see there is no room in outbuf and return. */ while ((count > 0) && (hvsi_write_room(hp->tty) > 0)) { int chunksize = min(count, hvsi_write_room(hp->tty)); BUG_ON(hp->n_outbuf < 0); memcpy(hp->outbuf + hp->n_outbuf, source, chunksize); hp->n_outbuf += chunksize; total += chunksize; source += chunksize; count -= chunksize; hvsi_push(hp); } if (hp->n_outbuf > 0) { /* * we weren't able to write it all to the hypervisor. * schedule another push attempt. */ schedule_delayed_work(&hp->writer, 10); } out: spin_unlock_irqrestore(&hp->lock, flags); if (total != origcount) pr_debug("%s: wanted %i, only wrote %i\n", __func__, origcount, total); return total; } /* * I have never seen throttle or unthrottle called, so this little throttle * buffering scheme may or may not work. */ static void hvsi_throttle(struct tty_struct *tty) { struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data; pr_debug("%s\n", __func__); h_vio_signal(hp->vtermno, VIO_IRQ_DISABLE); } static void hvsi_unthrottle(struct tty_struct *tty) { struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data; unsigned long flags; int shouldflip = 0; pr_debug("%s\n", __func__); spin_lock_irqsave(&hp->lock, flags); if (hp->n_throttle) { hvsi_send_overflow(hp); shouldflip = 1; } spin_unlock_irqrestore(&hp->lock, flags); if (shouldflip) tty_flip_buffer_push(hp->tty); h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE); } static int hvsi_tiocmget(struct tty_struct *tty, struct file *file) { struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data; hvsi_get_mctrl(hp); return hp->mctrl; } static int hvsi_tiocmset(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear) { struct hvsi_struct *hp = (struct hvsi_struct *)tty->driver_data; unsigned long flags; uint16_t new_mctrl; /* we can only alter DTR */ clear &= TIOCM_DTR; set &= TIOCM_DTR; spin_lock_irqsave(&hp->lock, flags); new_mctrl = (hp->mctrl & ~clear) | set; if (hp->mctrl != new_mctrl) { hvsi_set_mctrl(hp, new_mctrl); hp->mctrl = new_mctrl; } spin_unlock_irqrestore(&hp->lock, flags); return 0; } static const struct tty_operations hvsi_ops = { .open = hvsi_open, .close = hvsi_close, .write = hvsi_write, .hangup = hvsi_hangup, .write_room = hvsi_write_room, .chars_in_buffer = hvsi_chars_in_buffer, .throttle = hvsi_throttle, .unthrottle = hvsi_unthrottle, .tiocmget = hvsi_tiocmget, .tiocmset = hvsi_tiocmset, }; static int __init hvsi_init(void) { int i; hvsi_driver = alloc_tty_driver(hvsi_count); if (!hvsi_driver) return -ENOMEM; hvsi_driver->owner = THIS_MODULE; hvsi_driver->driver_name = "hvsi"; hvsi_driver->name = "hvsi"; hvsi_driver->major = HVSI_MAJOR; hvsi_driver->minor_start = HVSI_MINOR; hvsi_driver->type = TTY_DRIVER_TYPE_SYSTEM; hvsi_driver->init_termios = tty_std_termios; hvsi_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL; hvsi_driver->init_termios.c_ispeed = 9600; hvsi_driver->init_termios.c_ospeed = 9600; hvsi_driver->flags = TTY_DRIVER_REAL_RAW; tty_set_operations(hvsi_driver, &hvsi_ops); for (i=0; i < hvsi_count; i++) { struct hvsi_struct *hp = &hvsi_ports[i]; int ret = 1; ret = request_irq(hp->virq, hvsi_interrupt, IRQF_DISABLED, "hvsi", hp); if (ret) printk(KERN_ERR "HVSI: couldn't reserve irq 0x%x (error %i)\n", hp->virq, ret); } hvsi_wait = wait_for_state; /* irqs active now */ if (tty_register_driver(hvsi_driver)) panic("Couldn't register hvsi console driver\n"); printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count); return 0; } device_initcall(hvsi_init); /***** console (not tty) code: *****/ static void hvsi_console_print(struct console *console, const char *buf, unsigned int count) { struct hvsi_struct *hp = &hvsi_ports[console->index]; char c[HVSI_MAX_OUTGOING_DATA] __ALIGNED__; unsigned int i = 0, n = 0; int ret, donecr = 0; mb(); if (!is_open(hp)) return; /* * ugh, we have to translate LF -> CRLF ourselves, in place. * copied from hvc_console.c: */ while (count > 0 || i > 0) { if (count > 0 && i < sizeof(c)) { if (buf[n] == '\n' && !donecr) { c[i++] = '\r'; donecr = 1; } else { c[i++] = buf[n++]; donecr = 0; --count; } } else { ret = hvsi_put_chars(hp, c, i); if (ret < 0) i = 0; i -= ret; } } } static struct tty_driver *hvsi_console_device(struct console *console, int *index) { *index = console->index; return hvsi_driver; } static int __init hvsi_console_setup(struct console *console, char *options) { struct hvsi_struct *hp = &hvsi_ports[console->index]; int ret; if (console->index < 0 || console->index >= hvsi_count) return -1; /* give the FSP a chance to change the baud rate when we re-open */ hvsi_close_protocol(hp); ret = hvsi_handshake(hp); if (ret < 0) return ret; ret = hvsi_get_mctrl(hp); if (ret < 0) return ret; ret = hvsi_set_mctrl(hp, hp->mctrl | TIOCM_DTR); if (ret < 0) return ret; hp->flags |= HVSI_CONSOLE; return 0; } static struct console hvsi_con_driver = { .name = "hvsi", .write = hvsi_console_print, .device = hvsi_console_device, .setup = hvsi_console_setup, .flags = CON_PRINTBUFFER, .index = -1, }; static int __init hvsi_console_init(void) { struct device_node *vty; hvsi_wait = poll_for_state; /* no irqs yet; must poll */ /* search device tree for vty nodes */ for (vty = of_find_compatible_node(NULL, "serial", "hvterm-protocol"); vty != NULL; vty = of_find_compatible_node(vty, "serial", "hvterm-protocol")) { struct hvsi_struct *hp; const uint32_t *vtermno, *irq; vtermno = of_get_property(vty, "reg", NULL); irq = of_get_property(vty, "interrupts", NULL); if (!vtermno || !irq) continue; if (hvsi_count >= MAX_NR_HVSI_CONSOLES) { of_node_put(vty); break; } hp = &hvsi_ports[hvsi_count]; INIT_DELAYED_WORK(&hp->writer, hvsi_write_worker); INIT_WORK(&hp->handshaker, hvsi_handshaker); init_waitqueue_head(&hp->emptyq); init_waitqueue_head(&hp->stateq); spin_lock_init(&hp->lock); hp->index = hvsi_count; hp->inbuf_end = hp->inbuf; hp->state = HVSI_CLOSED; hp->vtermno = *vtermno; hp->virq = irq_create_mapping(NULL, irq[0]); if (hp->virq == NO_IRQ) { printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n", __func__, irq[0]); continue; } hvsi_count++; } if (hvsi_count) register_console(&hvsi_con_driver); return 0; } console_initcall(hvsi_console_init);