Merge branch 'sparc64-LDC-changes-for-porting-VCC-driver-into-upstream-kernel'

Jag Raman says:

====================
sparc64: LDC changes for porting VCC driver into upstream kernel

This series of patches is part of an effort to add VCC (Virtual Console
Concentrator) support to Linux.

VCC enables the virtualization of serial console on SPARC processors. VCC
provides access to the guest domain's serial console.

VCC depends on some core functionalities in the linux kernel for SPARC. The
functionalities include LDC (Logical Domain Channels), MDESC (Machine
Descriptor) and VIO (Virtual IO protocol). In order for VCC to be enabled,
it requires that these core functionalities support them.

This series of patches adds LDC support to enable VCC on Linux. It
is the first batch of changes to enable VCC.

This version 4 of the series addresses the following changes
suggested by Dave Miller
Patch 1/5: Modifies ldc_print/__ldc_print to print caller name. Fixes
indentation of wrapped lines.
====================

Signed-off-by: David S. Miller <[e-mail]>

arch/sparc/include/asm/ldc.h

···
 #define LDC_STATE_READY		0x03
 #define LDC_STATE_CONNECTED	0x04
 
+#define	LDC_PACKET_SIZE		64
+
 struct ldc_channel;
 
 /* Allocate state for a channel.  */
···
 int ldc_disconnect(struct ldc_channel *lp);
 
 int ldc_state(struct ldc_channel *lp);
+void ldc_set_state(struct ldc_channel *lp, u8 state);
+int ldc_mode(struct ldc_channel *lp);
+void __ldc_print(struct ldc_channel *lp, const char *caller);
+int ldc_rx_reset(struct ldc_channel *lp);
+
+#define	ldc_print(chan)	__ldc_print(chan, __func__)
 
 /* Read and write operations.  Only valid when the link is up.  */
 int ldc_write(struct ldc_channel *lp, const void *buf,

arch/sparc/kernel/ldc.c

···
 
 static char version[] =
 	DRV_MODULE_NAME ".c:v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
-#define LDC_PACKET_SIZE		64
 
 /* Packet header layout for unreliable and reliable mode frames.
  * When in RAW mode, packets are simply straight 64-byte payloads
···
 		printk(KERN_INFO PFX "ID[%lu] " f, lp->id, ## a); \
 } while (0)
 
+#define	LDC_ABORT(lp)	ldc_abort((lp), __func__)
+
 static const char *state_to_str(u8 state)
 {
 	switch (state) {
···
 	default:
 		return "<UNKNOWN>";
 	}
-}
-
-static void ldc_set_state(struct ldc_channel *lp, u8 state)
-{
-	ldcdbg(STATE, "STATE (%s) --> (%s)\n",
-	       state_to_str(lp->state),
-	       state_to_str(state));
-
-	lp->state = state;
 }
 
 static unsigned long __advance(unsigned long off, unsigned long num_entries)
···
 	return err;
 }
 
-static int ldc_abort(struct ldc_channel *lp)
+static int ldc_abort(struct ldc_channel *lp, const char *msg)
 {
 	unsigned long hv_err;
 
-	ldcdbg(STATE, "ABORT\n");
+	ldcdbg(STATE, "ABORT[%s]\n", msg);
+	ldc_print(lp);
 
 	/* We report but do not act upon the hypervisor errors because
 	 * there really isn't much we can do if they fail at this point.
···
 		}
 	}
 	if (err)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	return 0;
 }
···
 	if (lp->hs_state == LDC_HS_GOTVERS) {
 		if (lp->ver.major != vp->major ||
 		    lp->ver.minor != vp->minor)
-			return ldc_abort(lp);
+			return LDC_ABORT(lp);
 	} else {
 		lp->ver = *vp;
 		lp->hs_state = LDC_HS_GOTVERS;
 	}
 	if (send_rts(lp))
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 	return 0;
 }
 
···
 	unsigned long new_tail;
 
 	if (vp->major == 0 && vp->minor == 0)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	vap = find_by_major(vp->major);
 	if (!vap)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	p = handshake_compose_ctrl(lp, LDC_INFO, LDC_VERS,
 					   vap, sizeof(*vap),
 					   &new_tail);
 	if (!p)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	return send_tx_packet(lp, p, new_tail);
 }
···
 		return process_ver_nack(lp, vp);
 
 	default:
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 	}
 }
 
···
 	if (p->stype     != LDC_INFO	   ||
 	    lp->hs_state != LDC_HS_GOTVERS ||
 	    p->env       != lp->cfg.mode)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	lp->snd_nxt = p->seqid;
 	lp->rcv_nxt = p->seqid;
 	lp->hs_state = LDC_HS_SENTRTR;
 	if (send_rtr(lp))
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	return 0;
 }
···
 
 	if (p->stype     != LDC_INFO ||
 	    p->env       != lp->cfg.mode)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	lp->snd_nxt = p->seqid;
 	lp->hs_state = LDC_HS_COMPLETE;
···
 
 	if (p->stype != LDC_INFO ||
 	    !(rx_seq_ok(lp, p->seqid)))
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	lp->rcv_nxt = p->seqid;
 
···
 		return process_rdx(lp, p);
 
 	default:
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 	}
 }
 
 static int process_error_frame(struct ldc_channel *lp,
 			       struct ldc_packet *p)
 {
-	return ldc_abort(lp);
+	return LDC_ABORT(lp);
 }
 
 static int process_data_ack(struct ldc_channel *lp,
···
 			return 0;
 		}
 		if (head == lp->tx_tail)
-			return ldc_abort(lp);
+			return LDC_ABORT(lp);
 	}
 
 	return 0;
···
 		lp->hs_state = LDC_HS_COMPLETE;
 		ldc_set_state(lp, LDC_STATE_CONNECTED);
 
-		event_mask |= LDC_EVENT_UP;
-
-		orig_state = lp->chan_state;
+		/*
+		 * Generate an LDC_EVENT_UP event if the channel
+		 * was not already up.
+		 */
+		if (orig_state != LDC_CHANNEL_UP) {
+			event_mask |= LDC_EVENT_UP;
+			orig_state = lp->chan_state;
+		}
 	}
 
 	/* If we are in reset state, flush the RX queue and ignore
 	 * everything.
 	 */
 	if (lp->flags & LDC_FLAG_RESET) {
-		(void) __set_rx_head(lp, lp->rx_tail);
+		(void) ldc_rx_reset(lp);
 		goto out;
 	}
 
···
 			break;
 
 		default:
-			err = ldc_abort(lp);
+			err = LDC_ABORT(lp);
 			break;
 		}
 
···
 
 		err = __set_rx_head(lp, new);
 		if (err < 0) {
-			(void) ldc_abort(lp);
+			(void) LDC_ABORT(lp);
 			break;
 		}
 		if (lp->hs_state == LDC_HS_COMPLETE)
···
 		lp->hs_state = LDC_HS_COMPLETE;
 		ldc_set_state(lp, LDC_STATE_CONNECTED);
 
-		event_mask |= LDC_EVENT_UP;
+		/*
+		 * Generate an LDC_EVENT_UP event if the channel
+		 * was not already up.
+		 */
+		if (orig_state != LDC_CHANNEL_UP) {
+			event_mask |= LDC_EVENT_UP;
+			orig_state = lp->chan_state;
+		}
 	}
 
 	spin_unlock_irqrestore(&lp->lock, flags);
···
 }
 EXPORT_SYMBOL(ldc_state);
 
+void ldc_set_state(struct ldc_channel *lp, u8 state)
+{
+	ldcdbg(STATE, "STATE (%s) --> (%s)\n",
+	       state_to_str(lp->state),
+	       state_to_str(state));
+
+	lp->state = state;
+}
+
+int ldc_mode(struct ldc_channel *lp)
+{
+	return lp->cfg.mode;
+}
+
+int ldc_rx_reset(struct ldc_channel *lp)
+{
+	return __set_rx_head(lp, lp->rx_tail);
+}
+
+void __ldc_print(struct ldc_channel *lp, const char *caller)
+{
+	pr_info("%s: id=0x%lx flags=0x%x state=%s cstate=0x%lx hsstate=0x%x\n"
+		"\trx_h=0x%lx rx_t=0x%lx rx_n=%ld\n"
+		"\ttx_h=0x%lx tx_t=0x%lx tx_n=%ld\n"
+		"\trcv_nxt=%u snd_nxt=%u\n",
+		caller, lp->id, lp->flags, state_to_str(lp->state),
+		lp->chan_state, lp->hs_state,
+		lp->rx_head, lp->rx_tail, lp->rx_num_entries,
+		lp->tx_head, lp->tx_tail, lp->tx_num_entries,
+		lp->rcv_nxt, lp->snd_nxt);
+}
+
 static int write_raw(struct ldc_channel *lp, const void *buf, unsigned int size)
 {
 	struct ldc_packet *p;
-	unsigned long new_tail;
+	unsigned long new_tail, hv_err;
 	int err;
+
+	hv_err = sun4v_ldc_tx_get_state(lp->id, &lp->tx_head, &lp->tx_tail,
+					&lp->chan_state);
+	if (unlikely(hv_err))
+		return -EBUSY;
+
+	if (unlikely(lp->chan_state != LDC_CHANNEL_UP))
+		return LDC_ABORT(lp);
 
 	if (size > LDC_PACKET_SIZE)
 		return -EMSGSIZE;
···
 					&lp->rx_tail,
 					&lp->chan_state);
 	if (hv_err)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	if (lp->chan_state == LDC_CHANNEL_DOWN ||
 	    lp->chan_state == LDC_CHANNEL_RESETTING)
···
 		return -EBUSY;
 
 	if (unlikely(lp->chan_state != LDC_CHANNEL_UP))
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	if (!tx_has_space_for(lp, size))
 		return -EAGAIN;
···
 	if (err)
 		return err;
 
-	err = __set_rx_head(lp, lp->rx_tail);
+	err = ldc_rx_reset(lp);
 	if (err < 0)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	return 0;
 }
···
 			return err;
 	}
 	if (p->stype & LDC_NACK)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	return 0;
 }
···
 						&lp->rx_tail,
 						&lp->chan_state);
 		if (hv_err)
-			return ldc_abort(lp);
+			return LDC_ABORT(lp);
 
 		if (lp->chan_state == LDC_CHANNEL_DOWN ||
 		    lp->chan_state == LDC_CHANNEL_RESETTING)
···
 	int err = __set_rx_head(lp, head);
 
 	if (err < 0)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	lp->rx_head = head;
 	return 0;
···
 					&lp->rx_tail,
 					&lp->chan_state);
 	if (hv_err)
-		return ldc_abort(lp);
+		return LDC_ABORT(lp);
 
 	if (lp->chan_state == LDC_CHANNEL_DOWN ||
 	    lp->chan_state == LDC_CHANNEL_RESETTING)
···
 
 		lp->rcv_nxt = p->seqid;
 
+		/*
+		 * If this is a control-only packet, there is nothing
+		 * else to do but advance the rx queue since the packet
+		 * was already processed above.
+		 */
 		if (!(p->type & LDC_DATA)) {
 			new = rx_advance(lp, new);
-			goto no_data;
+			break;
 		}
 		if (p->stype & (LDC_ACK | LDC_NACK)) {
 			err = data_ack_nack(lp, p);
···
 	unsigned long flags;
 	int err;
 
+	ldcdbg(RX, "%s: entered size=%d\n", __func__, size);
+
 	if (!buf)
 		return -EINVAL;
 
···
 		err = lp->mops->read(lp, buf, size);
 
 	spin_unlock_irqrestore(&lp->lock, flags);
+
+	ldcdbg(RX, "%s: mode=%d, head=%lu, tail=%lu rv=%d\n", __func__,
+	       lp->cfg.mode, lp->rx_head, lp->rx_tail, err);
 
 	return err;
 }