powerpc/pseries: Move hvsi support into a library

This will allow a different backend to share it

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 21 insertions, 384 deletions

diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c
index d4e0850e805..ade73fae816 100644
--- a/drivers/tty/hvc/hvc_vio.c
+++ b/drivers/tty/hvc/hvc_vio.c
@@ -67,22 +67,10 @@ typedef enum hv_protocol {
         HV_PROTOCOL_HVSI
 } hv_protocol_t;
 
-#define HV_INBUF_SIZE           255
-
 struct hvterm_priv {
-        u32             termno;         /* HV term number */
-        hv_protocol_t   proto;          /* Raw data or HVSI packets */
-        unsigned int    inbuf_len;      /* Data in input buffer */
-        unsigned char   inbuf[HV_INBUF_SIZE];
-        unsigned int    inbuf_cur;      /* Cursor in input buffer */
-        unsigned int    inbuf_pktlen;   /* HVSI packet lenght from cursor */
-        atomic_t        seqno;          /* HVSI packet sequence number */
-        unsigned int    opened:1;       /* HVSI driver opened */
-        unsigned int    established:1;  /* HVSI protocol established */
-        unsigned int    is_console:1;   /* Used as a kernel console device */
-        unsigned int    mctrl_update:1; /* HVSI modem control updated */
-        unsigned short  mctrl;          /* HVSI modem control */
-        struct tty_struct *tty;         /* TTY structure */
+        u32                     termno; /* HV term number */
+        hv_protocol_t           proto;  /* Raw data or HVSI packets */
+        struct hvsi_priv        hvsi;   /* HVSI specific data */
 };
 static struct hvterm_priv *hvterm_privs[MAX_NR_HVC_CONSOLES];
 
@@ -139,348 +127,24 @@ static const struct hv_ops hvterm_raw_ops = {
         .notifier_hangup = notifier_hangup_irq,
 };
 
-static int hvterm_hvsi_send_packet(struct hvterm_priv *pv, struct hvsi_header *packet)
-{
-        packet->seqno = atomic_inc_return(&pv->seqno);
-
-        /* Assumes that always succeeds, works in practice */
-        return hvc_put_chars(pv->termno, (char *)packet, packet->len);
-}
-
-static void hvterm_hvsi_start_handshake(struct hvterm_priv *pv)
-{
-        struct hvsi_query q;
-
-        /* Reset state */
-        pv->established = 0;
-        atomic_set(&pv->seqno, 0);
-
-        pr_devel("HVSI@%x: Handshaking started\n", pv->termno);
-
-        /* Send version query */
-        q.hdr.type = VS_QUERY_PACKET_HEADER;
-        q.hdr.len = sizeof(struct hvsi_query);
-        q.verb = VSV_SEND_VERSION_NUMBER;
-        hvterm_hvsi_send_packet(pv, &q.hdr);
-}
-
-static int hvterm_hvsi_send_close(struct hvterm_priv *pv)
-{
-        struct hvsi_control ctrl;
-
-        pv->established = 0;
-
-        ctrl.hdr.type = VS_CONTROL_PACKET_HEADER;
-        ctrl.hdr.len = sizeof(struct hvsi_control);
-        ctrl.verb = VSV_CLOSE_PROTOCOL;
-        return hvterm_hvsi_send_packet(pv, &ctrl.hdr);
-}
-
-static void hvterm_cd_change(struct hvterm_priv *pv, int cd)
-{
-        if (cd)
-                pv->mctrl |= TIOCM_CD;
-        else {
-                pv->mctrl &= ~TIOCM_CD;
-
-                /* We copy the existing hvsi driver semantics
-                 * here which are to trigger a hangup when
-                 * we get a carrier loss.
-                 * Closing our connection to the server will
-                 * do just that.
-                 */
-                if (!pv->is_console && pv->opened) {
-                        pr_devel("HVSI@%x Carrier lost, hanging up !\n",
-                                 pv->termno);
-                        hvterm_hvsi_send_close(pv);
-                }
-        }
-}
-
-static void hvterm_hvsi_got_control(struct hvterm_priv *pv)
-{
-        struct hvsi_control *pkt = (struct hvsi_control *)pv->inbuf;
-
-        switch (pkt->verb) {
-        case VSV_CLOSE_PROTOCOL:
-                /* We restart the handshaking */
-                hvterm_hvsi_start_handshake(pv);
-                break;
-        case VSV_MODEM_CTL_UPDATE:
-                /* Transition of carrier detect */
-                hvterm_cd_change(pv, pkt->word & HVSI_TSCD);
-                break;
-        }
-}
-
-static void hvterm_hvsi_got_query(struct hvterm_priv *pv)
-{
-        struct hvsi_query *pkt = (struct hvsi_query *)pv->inbuf;
-        struct hvsi_query_response r;
-
-        /* We only handle version queries */
-        if (pkt->verb != VSV_SEND_VERSION_NUMBER)
-                return;
-
-        pr_devel("HVSI@%x: Got version query, sending response...\n",
-                 pv->termno);
-
-        /* Send version response */
-        r.hdr.type = VS_QUERY_RESPONSE_PACKET_HEADER;
-        r.hdr.len = sizeof(struct hvsi_query_response);
-        r.verb = VSV_SEND_VERSION_NUMBER;
-        r.u.version = HVSI_VERSION;
-        r.query_seqno = pkt->hdr.seqno;
-        hvterm_hvsi_send_packet(pv, &r.hdr);
-
-        /* Assume protocol is open now */
-        pv->established = 1;
-}
-
-static void hvterm_hvsi_got_response(struct hvterm_priv *pv)
-{
-        struct hvsi_query_response *r = (struct hvsi_query_response *)pv->inbuf;
-
-        switch(r->verb) {
-        case VSV_SEND_MODEM_CTL_STATUS:
-                hvterm_cd_change(pv, r->u.mctrl_word & HVSI_TSCD);
-                pv->mctrl_update = 1;
-                break;
-        }
-}
-
-static int hvterm_hvsi_check_packet(struct hvterm_priv *pv)
-{
-        u8 len, type;
-
-        /* Check header validity. If it's invalid, we ditch
-         * the whole buffer and hope we eventually resync
-         */
-        if (pv->inbuf[0] < 0xfc) {
-                pv->inbuf_len = pv->inbuf_pktlen = 0;
-                return 0;
-        }
-        type = pv->inbuf[0];
-        len = pv->inbuf[1];
-
-        /* Packet incomplete ? */
-        if (pv->inbuf_len < len)
-                return 0;
-
-        pr_devel("HVSI@%x: Got packet type %x len %d bytes:\n",
-                 pv->termno, type, len);
-
-        /* We have a packet, yay ! Handle it */
-        switch(type) {
-        case VS_DATA_PACKET_HEADER:
-                pv->inbuf_pktlen = len - 4;
-                pv->inbuf_cur = 4;
-                return 1;
-        case VS_CONTROL_PACKET_HEADER:
-                hvterm_hvsi_got_control(pv);
-                break;
-        case VS_QUERY_PACKET_HEADER:
-                hvterm_hvsi_got_query(pv);
-                break;
-        case VS_QUERY_RESPONSE_PACKET_HEADER:
-                hvterm_hvsi_got_response(pv);
-                break;
-        }
-
-        /* Swallow packet and retry */
-        pv->inbuf_len -= len;
-        memmove(pv->inbuf, &pv->inbuf[len], pv->inbuf_len);
-        return 1;
-}
-
-static int hvterm_hvsi_get_packet(struct hvterm_priv *pv)
-{
-        /* If we have room in the buffer, ask HV for more */
-        if (pv->inbuf_len < HV_INBUF_SIZE)
-                pv->inbuf_len += hvc_get_chars(pv->termno,
-                                               &pv->inbuf[pv->inbuf_len],
-                                               HV_INBUF_SIZE - pv->inbuf_len);
-        /*
-         * If we have at least 4 bytes in the buffer, check for
-         * a full packet and retry
-         */
-        if (pv->inbuf_len >= 4)
-                return hvterm_hvsi_check_packet(pv);
-        return 0;
-}
-
 static int hvterm_hvsi_get_chars(uint32_t vtermno, char *buf, int count)
 {
         struct hvterm_priv *pv = hvterm_privs[vtermno];
-        unsigned int tries, read = 0;
 
         if (WARN_ON(!pv))
                 return 0;
 
-        /* If we aren't open, dont do anything in order to avoid races
-         * with connection establishment. The hvc core will call this
-         * before we have returned from notifier_add(), and we need to
-         * avoid multiple users playing with the receive buffer
-         */
-        if (!pv->opened)
-                return 0;
-
-        /* We try twice, once with what data we have and once more
-         * after we try to fetch some more from the hypervisor
-         */
-        for (tries = 1; count && tries < 2; tries++) {
-                /* Consume existing data packet */
-                if (pv->inbuf_pktlen) {
-                        unsigned int l = min(count, (int)pv->inbuf_pktlen);
-                        memcpy(&buf[read], &pv->inbuf[pv->inbuf_cur], l);
-                        pv->inbuf_cur += l;
-                        pv->inbuf_pktlen -= l;
-                        count -= l;
-                        read += l;
-                }
-                if (count == 0)
-                        break;
-
-                /* Data packet fully consumed, move down remaning data */
-                if (pv->inbuf_cur) {
-                        pv->inbuf_len -= pv->inbuf_cur;
-                        memmove(pv->inbuf, &pv->inbuf[pv->inbuf_cur], pv->inbuf_len);
-                        pv->inbuf_cur = 0;
-                }
-
-                /* Try to get another packet */
-                if (hvterm_hvsi_get_packet(pv))
-                        tries--;
-        }
-        if (!pv->established) {
-                pr_devel("HVSI@%x: returning -EPIPE\n", pv->termno);
-                return -EPIPE;
-        }
-        return read;
+        return hvsi_get_chars(&pv->hvsi, buf, count);
 }
 
 static int hvterm_hvsi_put_chars(uint32_t vtermno, const char *buf, int count)
 {
         struct hvterm_priv *pv = hvterm_privs[vtermno];
-        struct hvsi_data dp;
-        int rc, adjcount = min(count, HVSI_MAX_OUTGOING_DATA);
 
         if (WARN_ON(!pv))
                 return 0;
 
-        dp.hdr.type = VS_DATA_PACKET_HEADER;
-        dp.hdr.len = adjcount + sizeof(struct hvsi_header);
-        memcpy(dp.data, buf, adjcount);
-        rc = hvterm_hvsi_send_packet(pv, &dp.hdr);
-        if (rc <= 0)
-                return rc;
-        return adjcount;
-}
-
-static void maybe_msleep(unsigned long ms)
-{
-        /* During early boot, IRQs are disabled, use mdelay */
-        if (irqs_disabled())
-                mdelay(ms);
-        else
-                msleep(ms);
-}
-
-static int hvterm_hvsi_read_mctrl(struct hvterm_priv *pv)
-{
-        struct hvsi_query q;
-        int rc, timeout;
-
-        pr_devel("HVSI@%x: Querying modem control status...\n",
-                 pv->termno);
-
-        pv->mctrl_update = 0;
-        q.hdr.type = VS_QUERY_PACKET_HEADER;
-        q.hdr.len = sizeof(struct hvsi_query);
-        q.hdr.seqno = atomic_inc_return(&pv->seqno);
-        q.verb = VSV_SEND_MODEM_CTL_STATUS;
-        rc = hvterm_hvsi_send_packet(pv, &q.hdr);
-        if (rc <= 0) {
-                pr_devel("HVSI@%x: Error %d...\n", pv->termno, rc);
-                return rc;
-        }
-
-        /* Try for up to 1s */
-        for (timeout = 0; timeout < 1000; timeout++) {
-                if (!pv->established)
-                        return -ENXIO;
-                if (pv->mctrl_update)
-                        return 0;
-                if (!hvterm_hvsi_get_packet(pv))
-                        maybe_msleep(1);
-        }
-        return -EIO;
-}
-
-static int hvterm_hvsi_write_mctrl(struct hvterm_priv *pv, int dtr)
-{
-        struct hvsi_control ctrl;
-
-        pr_devel("HVSI@%x: %s DTR...\n", pv->termno,
-                 dtr ? "Setting" : "Clearing");
-
-        ctrl.hdr.type = VS_CONTROL_PACKET_HEADER,
-        ctrl.hdr.len = sizeof(struct hvsi_control);
-        ctrl.verb = VSV_SET_MODEM_CTL;
-        ctrl.mask = HVSI_TSDTR;
-        ctrl.word = dtr ? HVSI_TSDTR : 0;
-        if (dtr)
-                pv->mctrl |= TIOCM_DTR;
-        else
-                pv->mctrl &= ~TIOCM_DTR;
-        return hvterm_hvsi_send_packet(pv, &ctrl.hdr);
-}
-
-static void hvterm_hvsi_establish(struct hvterm_priv *pv)
-{
-        int timeout;
-
-        /* Try for up to 10ms, there can be a packet to
-         * start the process waiting for us...
-         */
-        for (timeout = 0; timeout < 10; timeout++) {
-                if (pv->established)
-                        goto established;
-                if (!hvterm_hvsi_get_packet(pv))
-                        maybe_msleep(1);
-        }
-
-        /* Failed, send a close connection packet just
-         * in case
-         */
-        hvterm_hvsi_send_close(pv);
-
-        /* Then restart handshake */
-        hvterm_hvsi_start_handshake(pv);
-
-        /* Try for up to 100ms */
-        for (timeout = 0; timeout < 100; timeout++) {
-                if (pv->established)
-                        goto established;
-                if (!hvterm_hvsi_get_packet(pv))
-                        maybe_msleep(1);
-        }
-
-        if (!pv->established) {
-                pr_devel("HVSI@%x: Timeout handshaking, giving up !\n",
-                         pv->termno);
-                return;
-        }
- established:
-        /* Query modem control lines */
-        hvterm_hvsi_read_mctrl(pv);
-
-        /* Set our own DTR */
-        hvterm_hvsi_write_mctrl(pv, 1);
-
-        /* Set the opened flag so reads are allowed */
-        wmb();
-        pv->opened = 1;
+        return hvsi_put_chars(&pv->hvsi, buf, count);
 }
 
 static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
@@ -494,46 +158,16 @@ static int hvterm_hvsi_open(struct hvc_struct *hp, int data)
         if (rc)
                 return rc;
 
-        /* Keep track of the tty data structure */
-        pv->tty = tty_kref_get(hp->tty);
-
-        hvterm_hvsi_establish(pv);
-        return 0;
-}
-
-static void hvterm_hvsi_shutdown(struct hvc_struct *hp, struct hvterm_priv *pv)
-{
-        unsigned long flags;
-
-        if (!pv->is_console) {
-                pr_devel("HVSI@%x: Not a console, tearing down\n",
-                         pv->termno);
-
-                /* Clear opened, synchronize with khvcd */
-                spin_lock_irqsave(&hp->lock, flags);
-                pv->opened = 0;
-                spin_unlock_irqrestore(&hp->lock, flags);
-
-                /* Clear our own DTR */
-                if (!pv->tty || (pv->tty->termios->c_cflag & HUPCL))
-                        hvterm_hvsi_write_mctrl(pv, 0);
-
-                /* Tear down the connection */
-                hvterm_hvsi_send_close(pv);
-        }
-
-        if (pv->tty)
-                tty_kref_put(pv->tty);
-        pv->tty = NULL;
+        return hvsi_open(&pv->hvsi, hp);
 }
 
 static void hvterm_hvsi_close(struct hvc_struct *hp, int data)
 {
         struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 
-        pr_devel("HVSI@%x: close !\n", pv->termno);
+        pr_devel("HVSI@%x: do close !\n", pv->termno);
 
-        hvterm_hvsi_shutdown(hp, pv);
+        hvsi_close(&pv->hvsi, hp);
 
         notifier_del_irq(hp, data);
 }
@@ -542,9 +176,9 @@ void hvterm_hvsi_hangup(struct hvc_struct *hp, int data)
 {
         struct hvterm_priv *pv = hvterm_privs[hp->vtermno];
 
-        pr_devel("HVSI@%x: hangup !\n", pv->termno);
+        pr_devel("HVSI@%x: do hangup !\n", pv->termno);
 
-        hvterm_hvsi_shutdown(hp, pv);
+        hvsi_close(&pv->hvsi, hp);
 
         notifier_hangup_irq(hp, data);
 }
@@ -555,7 +189,7 @@ static int hvterm_hvsi_tiocmget(struct hvc_struct *hp)
 
         if (!pv)
                 return -EINVAL;
-        return pv->mctrl;
+        return pv->hvsi.mctrl;
 }
 
 static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
@@ -567,9 +201,9 @@ static int hvterm_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set,
                  pv->termno, set, clear);
 
         if (set & TIOCM_DTR)
-                hvterm_hvsi_write_mctrl(pv, 1);
+                hvsi_write_mctrl(&pv->hvsi, 1);
         else if (clear & TIOCM_DTR)
-                hvterm_hvsi_write_mctrl(pv, 0);
+                hvsi_write_mctrl(&pv->hvsi, 0);
 
         return 0;
 }
@@ -633,6 +267,8 @@ static int __devinit hvc_vio_probe(struct vio_dev *vdev,
                 pv->termno = vdev->unit_address;
                 pv->proto = proto;
                 hvterm_privs[termno] = pv;
+                hvsi_init(&pv->hvsi, hvc_get_chars, hvc_put_chars,
+                          pv->termno, 0);
         }
 
         hp = hvc_alloc(termno, vdev->irq, ops, MAX_VIO_PUT_CHARS);
@@ -770,7 +406,6 @@ void __init hvc_vio_init_early(void)
         if (termno == NULL)
                 goto out;
         hvterm_priv0.termno = *termno;
-        hvterm_priv0.is_console = 1;
         hvterm_privs[0] = &hvterm_priv0;
 
         /* Check the protocol */
@@ -781,8 +416,10 @@ void __init hvc_vio_init_early(void)
         else if (of_device_is_compatible(stdout_node, "hvterm-protocol")) {
                 hvterm_priv0.proto = HV_PROTOCOL_HVSI;
                 ops = &hvterm_hvsi_ops;
+                hvsi_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
+                          hvterm_priv0.termno, 1);
                 /* HVSI, perform the handshake now */
-                hvterm_hvsi_establish(&hvterm_priv0);
+                hvsi_establish(&hvterm_priv0.hvsi);
         } else
                 goto out;
         udbg_putc = udbg_hvc_putc;
@@ -810,7 +447,6 @@ void __init udbg_init_debug_lpar(void)
         hvterm_privs[0] = &hvterm_priv0;
         hvterm_priv0.termno = 0;
         hvterm_priv0.proto = HV_PROTOCOL_RAW;
-        hvterm_priv0.is_console = 1;
         udbg_putc = udbg_hvc_putc;
         udbg_getc = udbg_hvc_getc;
         udbg_getc_poll = udbg_hvc_getc_poll;
@@ -823,10 +459,11 @@ void __init udbg_init_debug_lpar_hvsi(void)
         hvterm_privs[0] = &hvterm_priv0;
         hvterm_priv0.termno = CONFIG_PPC_EARLY_DEBUG_HVSI_VTERMNO;
         hvterm_priv0.proto = HV_PROTOCOL_HVSI;
-        hvterm_priv0.is_console = 1;
         udbg_putc = udbg_hvc_putc;
         udbg_getc = udbg_hvc_getc;
         udbg_getc_poll = udbg_hvc_getc_poll;
-        hvterm_hvsi_establish(&hvterm_priv0);
+        hvsi_init(&hvterm_priv0.hvsi, hvc_get_chars, hvc_put_chars,
+                  hvterm_priv0.termno, 1);
+        hvsi_establish(&hvterm_priv0.hvsi);
 }
 #endif /* CONFIG_PPC_EARLY_DEBUG_LPAR_HVSI */