diff options
Diffstat (limited to 'drivers/tty/hvc/hvsi.c')
| -rw-r--r-- | drivers/tty/hvc/hvsi.c | 1223 |
1 files changed, 1223 insertions, 0 deletions
diff --git a/drivers/tty/hvc/hvsi.c b/drivers/tty/hvc/hvsi.c new file mode 100644 index 000000000..73226337f --- /dev/null +++ b/drivers/tty/hvc/hvsi.c @@ -0,0 +1,1223 @@ +// 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 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 *tty, struct hvsi_struct **to_handshake) +{ + struct hvsi_control *header = (struct hvsi_control *)packet; + + switch (be16_to_cpu(header->verb)) { + case VSV_MODEM_CTL_UPDATE: + if ((be32_to_cpu(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 (tty && !C_CLOCAL(tty)) + tty_hangup(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; + uint32_t mctrl_word; + + 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; + mctrl_word = be32_to_cpu(resp->u.mctrl_word); + if (mctrl_word & HVSI_TSDTR) + hp->mctrl |= TIOCM_DTR; + if (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.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER; + packet.hdr.len = sizeof(struct hvsi_query_response); + packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno)); + packet.verb = cpu_to_be16(VSV_SEND_VERSION_NUMBER); + packet.u.version = HVSI_VERSION; + packet.query_seqno = cpu_to_be16(query_seqno+1); + + pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len); + dbg_dump_hex((uint8_t*)&packet, packet.hdr.len); + + wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len); + if (wrote != packet.hdr.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, be16_to_cpu(query->hdr.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->sysrq = 0; + continue; + } +#endif /* CONFIG_MAGIC_SYSRQ */ + tty_insert_flip_char(&hp->port, 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 bool 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 false; + + 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 true; +} + +/* + * 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 *tty, + struct hvsi_struct **handshake) +{ + uint8_t *packet = hp->inbuf; + int chunklen; + bool flip = false; + + *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; + flip = hvsi_recv_data(hp, packet); + break; + case VS_CONTROL_PACKET_HEADER: + hvsi_recv_control(hp, packet, tty, 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 (*handshake) { + pr_debug("%s: handshake\n", __func__); + break; + } + } + + compact_inbuf(hp, packet); + + if (flip) + tty_flip_buffer_push(&hp->port); + + 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 hvsi_struct *handshake; + struct tty_struct *tty; + unsigned long flags; + int again = 1; + + pr_debug("%s\n", __func__); + + tty = tty_port_tty_get(&hp->port); + + while (again) { + spin_lock_irqsave(&hp->lock, flags); + again = hvsi_load_chunk(hp, tty, &handshake); + spin_unlock_irqrestore(&hp->lock, flags); + + if (handshake) { + pr_debug("hvsi%i: attempting re-handshake\n", handshake->index); + schedule_work(&handshake->handshaker); + } + } + + spin_lock_irqsave(&hp->lock, flags); + if (tty && hp->n_throttle && !tty_throttled(tty)) { + /* we weren't hung up and we weren't throttled, so we can + * deliver the rest now */ + hvsi_send_overflow(hp); + tty_flip_buffer_push(&hp->port); + } + spin_unlock_irqrestore(&hp->lock, flags); + + tty_kref_put(tty); + + 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.hdr.type = VS_QUERY_PACKET_HEADER; + packet.hdr.len = sizeof(struct hvsi_query); + packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno)); + packet.verb = cpu_to_be16(verb); + + pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len); + dbg_dump_hex((uint8_t*)&packet, packet.hdr.len); + + wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len); + if (wrote != packet.hdr.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.hdr.type = VS_CONTROL_PACKET_HEADER; + packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno)); + packet.hdr.len = sizeof(struct hvsi_control); + packet.verb = cpu_to_be16(VSV_SET_MODEM_CTL); + packet.mask = cpu_to_be32(HVSI_TSDTR); + + if (mctrl & TIOCM_DTR) + packet.word = cpu_to_be32(HVSI_TSDTR); + + pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len); + dbg_dump_hex((uint8_t*)&packet, packet.hdr.len); + + wrote = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len); + if (wrote != packet.hdr.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.hdr.type = VS_DATA_PACKET_HEADER; + packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno)); + packet.hdr.len = count + sizeof(struct hvsi_header); + memcpy(&packet.data, buf, count); + + ret = hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len); + if (ret == packet.hdr.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.hdr.type = VS_CONTROL_PACKET_HEADER; + packet.hdr.seqno = cpu_to_be16(atomic_inc_return(&hp->seqno)); + packet.hdr.len = 6; + packet.verb = cpu_to_be16(VSV_CLOSE_PROTOCOL); + + pr_debug("%s: sending %i bytes\n", __func__, packet.hdr.len); + dbg_dump_hex((uint8_t*)&packet, packet.hdr.len); + + hvc_put_chars(hp->vtermno, (char *)&packet, packet.hdr.len); +} + +static int hvsi_open(struct tty_struct *tty, struct file *filp) +{ + struct hvsi_struct *hp; + unsigned long flags; + int ret; + + pr_debug("%s\n", __func__); + + hp = &hvsi_ports[tty->index]; + + tty->driver_data = hp; + + mb(); + if (hp->state == HVSI_FSP_DIED) + return -EIO; + + tty_port_tty_set(&hp->port, tty); + spin_lock_irqsave(&hp->lock, flags); + hp->port.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_sync(&hp->writer); + flush_work(&hp->handshaker); + + /* + * 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->port.count == 0) { + tty_port_tty_set(&hp->port, 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->port.count < 0) + printk(KERN_ERR "hvsi_close %lu: oops, count is %d\n", + hp - hvsi_ports, hp->port.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__); + + tty_port_tty_set(&hp->port, NULL); + + spin_lock_irqsave(&hp->lock, flags); + hp->port.count = 0; + hp->n_outbuf = 0; + 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_port_tty_wakeup(&hp->port); + } + +out: + spin_unlock_irqrestore(&hp->lock, flags); +} + +static int hvsi_write_room(struct tty_struct *tty) +{ + struct hvsi_struct *hp = tty->driver_data; + + return N_OUTBUF - hp->n_outbuf; +} + +static int hvsi_chars_in_buffer(struct tty_struct *tty) +{ + struct hvsi_struct *hp = 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(tty) > 0)) { + int chunksize = min(count, hvsi_write_room(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 = 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 = tty->driver_data; + unsigned long flags; + + pr_debug("%s\n", __func__); + + spin_lock_irqsave(&hp->lock, flags); + if (hp->n_throttle) { + hvsi_send_overflow(hp); + tty_flip_buffer_push(&hp->port); + } + spin_unlock_irqrestore(&hp->lock, flags); + + + h_vio_signal(hp->vtermno, VIO_IRQ_ENABLE); +} + +static int hvsi_tiocmget(struct tty_struct *tty) +{ + struct hvsi_struct *hp = tty->driver_data; + + hvsi_get_mctrl(hp); + return hp->mctrl; +} + +static int hvsi_tiocmset(struct tty_struct *tty, + unsigned int set, unsigned int clear) +{ + struct hvsi_struct *hp = 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, ret; + + hvsi_driver = alloc_tty_driver(hvsi_count); + if (!hvsi_driver) + return -ENOMEM; + + 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; + + tty_port_link_device(&hp->port, hvsi_driver, i); + + ret = request_irq(hp->virq, hvsi_interrupt, 0, "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 */ + + ret = tty_register_driver(hvsi_driver); + if (ret) { + pr_err("Couldn't register hvsi console driver\n"); + goto err_free_irq; + } + + printk(KERN_DEBUG "HVSI: registered %i devices\n", hvsi_count); + + return 0; +err_free_irq: + hvsi_wait = poll_for_state; + for (i = 0; i < hvsi_count; i++) { + struct hvsi_struct *hp = &hvsi_ports[i]; + + free_irq(hp->virq, hp); + } + tty_driver_kref_put(hvsi_driver); + + return ret; +} +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; + int ret; + + if (console->index < 0 || console->index >= hvsi_count) + return -1; + hp = &hvsi_ports[console->index]; + + /* 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_console = { + .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_each_compatible_node(vty, "serial", "hvterm-protocol") { + struct hvsi_struct *hp; + const __be32 *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); + tty_port_init(&hp->port); + hp->index = hvsi_count; + hp->inbuf_end = hp->inbuf; + hp->state = HVSI_CLOSED; + hp->vtermno = be32_to_cpup(vtermno); + hp->virq = irq_create_mapping(NULL, be32_to_cpup(irq)); + if (hp->virq == 0) { + printk(KERN_ERR "%s: couldn't create irq mapping for 0x%x\n", + __func__, be32_to_cpup(irq)); + tty_port_destroy(&hp->port); + continue; + } + + hvsi_count++; + } + + if (hvsi_count) + register_console(&hvsi_console); + return 0; +} +console_initcall(hvsi_console_init); |