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>
diff --git a/drivers/tty/hvc/hvsi_lib.c b/drivers/tty/hvc/hvsi_lib.c
new file mode 100644
index 0000000..9401fcb
--- /dev/null
+++ b/drivers/tty/hvc/hvsi_lib.c
@@ -0,0 +1,426 @@
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <asm/hvsi.h>
+
+#include "hvc_console.h"
+
+static int hvsi_send_packet(struct hvsi_priv *pv, struct hvsi_header *packet)
+{
+ packet->seqno = atomic_inc_return(&pv->seqno);
+
+ /* Assumes that always succeeds, works in practice */
+ return pv->put_chars(pv->termno, (char *)packet, packet->len);
+}
+
+static void hvsi_start_handshake(struct hvsi_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;
+ hvsi_send_packet(pv, &q.hdr);
+}
+
+static int hvsi_send_close(struct hvsi_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 hvsi_send_packet(pv, &ctrl.hdr);
+}
+
+static void hvsi_cd_change(struct hvsi_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);
+ hvsi_send_close(pv);
+ }
+ }
+}
+
+static void hvsi_got_control(struct hvsi_priv *pv)
+{
+ struct hvsi_control *pkt = (struct hvsi_control *)pv->inbuf;
+
+ switch (pkt->verb) {
+ case VSV_CLOSE_PROTOCOL:
+ /* We restart the handshaking */
+ hvsi_start_handshake(pv);
+ break;
+ case VSV_MODEM_CTL_UPDATE:
+ /* Transition of carrier detect */
+ hvsi_cd_change(pv, pkt->word & HVSI_TSCD);
+ break;
+ }
+}
+
+static void hvsi_got_query(struct hvsi_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;
+ hvsi_send_packet(pv, &r.hdr);
+
+ /* Assume protocol is open now */
+ pv->established = 1;
+}
+
+static void hvsi_got_response(struct hvsi_priv *pv)
+{
+ struct hvsi_query_response *r =
+ (struct hvsi_query_response *)pv->inbuf;
+
+ switch(r->verb) {
+ case VSV_SEND_MODEM_CTL_STATUS:
+ hvsi_cd_change(pv, r->u.mctrl_word & HVSI_TSCD);
+ pv->mctrl_update = 1;
+ break;
+ }
+}
+
+static int hvsi_check_packet(struct hvsi_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:
+ hvsi_got_control(pv);
+ break;
+ case VS_QUERY_PACKET_HEADER:
+ hvsi_got_query(pv);
+ break;
+ case VS_QUERY_RESPONSE_PACKET_HEADER:
+ 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 hvsi_get_packet(struct hvsi_priv *pv)
+{
+ /* If we have room in the buffer, ask HV for more */
+ if (pv->inbuf_len < HVSI_INBUF_SIZE)
+ pv->inbuf_len += pv->get_chars(pv->termno,
+ &pv->inbuf[pv->inbuf_len],
+ HVSI_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 hvsi_check_packet(pv);
+ return 0;
+}
+
+int hvsi_get_chars(struct hvsi_priv *pv, char *buf, int count)
+{
+ unsigned int tries, read = 0;
+
+ if (WARN_ON(!pv))
+ return 0;
+
+ /* If we aren't open, don't 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 (hvsi_get_packet(pv))
+ tries--;
+ }
+ if (!pv->established) {
+ pr_devel("HVSI@%x: returning -EPIPE\n", pv->termno);
+ return -EPIPE;
+ }
+ return read;
+}
+
+int hvsi_put_chars(struct hvsi_priv *pv, const char *buf, int count)
+{
+ 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 = 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);
+}
+
+int hvsi_read_mctrl(struct hvsi_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 = 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 200ms */
+ for (timeout = 0; timeout < 20; timeout++) {
+ if (!pv->established)
+ return -ENXIO;
+ if (pv->mctrl_update)
+ return 0;
+ if (!hvsi_get_packet(pv))
+ maybe_msleep(10);
+ }
+ return -EIO;
+}
+
+int hvsi_write_mctrl(struct hvsi_priv *pv, int dtr)
+{
+ struct hvsi_control ctrl;
+ unsigned short mctrl;
+
+ mctrl = pv->mctrl;
+ if (dtr)
+ mctrl |= TIOCM_DTR;
+ else
+ mctrl &= ~TIOCM_DTR;
+ if (mctrl == pv->mctrl)
+ return 0;
+ pv->mctrl = mctrl;
+
+ 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;
+ return hvsi_send_packet(pv, &ctrl.hdr);
+}
+
+void hvsi_establish(struct hvsi_priv *pv)
+{
+ int timeout;
+
+ pr_devel("HVSI@%x: Establishing...\n", pv->termno);
+
+ /* Try for up to 200ms, there can be a packet to
+ * start the process waiting for us...
+ */
+ for (timeout = 0; timeout < 20; timeout++) {
+ if (pv->established)
+ goto established;
+ if (!hvsi_get_packet(pv))
+ maybe_msleep(10);
+ }
+
+ /* Failed, send a close connection packet just
+ * in case
+ */
+ pr_devel("HVSI@%x: ... sending close\n", pv->termno);
+
+ hvsi_send_close(pv);
+
+ /* Then restart handshake */
+
+ pr_devel("HVSI@%x: ... restarting handshake\n", pv->termno);
+
+ hvsi_start_handshake(pv);
+
+ pr_devel("HVSI@%x: ... waiting handshake\n", pv->termno);
+
+ /* Try for up to 200s */
+ for (timeout = 0; timeout < 20; timeout++) {
+ if (pv->established)
+ goto established;
+ if (!hvsi_get_packet(pv))
+ maybe_msleep(10);
+ }
+
+ if (!pv->established) {
+ pr_devel("HVSI@%x: Timeout handshaking, giving up !\n",
+ pv->termno);
+ return;
+ }
+ established:
+ /* Query modem control lines */
+
+ pr_devel("HVSI@%x: ... established, reading mctrl\n", pv->termno);
+
+ hvsi_read_mctrl(pv);
+
+ /* Set our own DTR */
+
+ pr_devel("HVSI@%x: ... setting mctrl\n", pv->termno);
+
+ hvsi_write_mctrl(pv, 1);
+
+ /* Set the opened flag so reads are allowed */
+ wmb();
+ pv->opened = 1;
+}
+
+int hvsi_open(struct hvsi_priv *pv, struct hvc_struct *hp)
+{
+ pr_devel("HVSI@%x: open !\n", pv->termno);
+
+ /* Keep track of the tty data structure */
+ pv->tty = tty_kref_get(hp->tty);
+
+ hvsi_establish(pv);
+
+ return 0;
+}
+
+void hvsi_close(struct hvsi_priv *pv, struct hvc_struct *hp)
+{
+ unsigned long flags;
+
+ pr_devel("HVSI@%x: close !\n", pv->termno);
+
+ 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))
+ hvsi_write_mctrl(pv, 0);
+
+ /* Tear down the connection */
+ hvsi_send_close(pv);
+ }
+
+ if (pv->tty)
+ tty_kref_put(pv->tty);
+ pv->tty = NULL;
+}
+
+void hvsi_init(struct hvsi_priv *pv,
+ int (*get_chars)(uint32_t termno, char *buf, int count),
+ int (*put_chars)(uint32_t termno, const char *buf,
+ int count),
+ int termno, int is_console)
+{
+ memset(pv, 0, sizeof(*pv));
+ pv->get_chars = get_chars;
+ pv->put_chars = put_chars;
+ pv->termno = termno;
+ pv->is_console = is_console;
+}