mei: add support for mei extended header.

Add an extend header beyond existing 4 bytes of the mei message header.
The extension is of variable length, starting with meta header
that contains the number of headers and the overall size of
the extended headers excluding meta header itself followed by
TLV list of extended headers. Currently only supported extension is
the vtag. From the HW perspective the extended headers is already
part of the payload.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20200818115147.2567012-5-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 133 insertions, 56 deletions

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 2572887d99b6..a52799590dc7 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -378,6 +378,8 @@ static struct mei_cl_cb *mei_io_cb_init(struct mei_cl *cl,
 	cb->cl = cl;
 	cb->buf_idx = 0;
 	cb->fop_type = type;
+	cb->vtag = 0;
+
 	return cb;
 }
 
@@ -1518,21 +1520,67 @@ nortpm:
 	return rets;
 }
 
+static inline u8 mei_ext_hdr_set_vtag(struct mei_ext_hdr *ext, u8 vtag)
+{
+	ext->type = MEI_EXT_HDR_VTAG;
+	ext->ext_payload[0] = vtag;
+	ext->length = mei_data2slots(sizeof(*ext));
+	return ext->length;
+}
+
 /**
- * mei_msg_hdr_init - initialize mei message header
+ * mei_msg_hdr_init - allocate and initialize mei message header
  *
- * @mei_hdr: mei message header
  * @cb: message callback structure
+ *
+ * Return: a pointer to initialized header
  */
-static void mei_msg_hdr_init(struct mei_msg_hdr *mei_hdr, struct mei_cl_cb *cb)
+static struct mei_msg_hdr *mei_msg_hdr_init(const struct mei_cl_cb *cb)
 {
+	size_t hdr_len;
+	struct mei_ext_meta_hdr *meta;
+	struct mei_ext_hdr *ext;
+	struct mei_msg_hdr *mei_hdr;
+	bool is_ext, is_vtag;
+
+	if (!cb)
+		return ERR_PTR(-EINVAL);
+
+	/* Extended header for vtag is attached only on the first fragment */
+	is_vtag = (cb->vtag && cb->buf_idx == 0);
+	is_ext = is_vtag;
+
+	/* Compute extended header size */
+	hdr_len = sizeof(*mei_hdr);
+
+	if (!is_ext)
+		goto setup_hdr;
+
+	hdr_len += sizeof(*meta);
+	if (is_vtag)
+		hdr_len += sizeof(*ext);
+
+setup_hdr:
+	mei_hdr = kzalloc(hdr_len, GFP_KERNEL);
+	if (!mei_hdr)
+		return ERR_PTR(-ENOMEM);
+
 	mei_hdr->host_addr = mei_cl_host_addr(cb->cl);
 	mei_hdr->me_addr = mei_cl_me_id(cb->cl);
-	mei_hdr->length = 0;
-	mei_hdr->reserved = 0;
-	mei_hdr->msg_complete = 0;
-	mei_hdr->dma_ring = 0;
 	mei_hdr->internal = cb->internal;
+	mei_hdr->extended = is_ext;
+
+	if (!is_ext)
+		goto out;
+
+	meta = (struct mei_ext_meta_hdr *)mei_hdr->extension;
+	if (is_vtag) {
+		meta->count++;
+		meta->size += mei_ext_hdr_set_vtag(meta->hdrs, cb->vtag);
+	}
+out:
+	mei_hdr->length = hdr_len - sizeof(*mei_hdr);
+	return mei_hdr;
 }
 
 /**
@@ -1550,10 +1598,11 @@ int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 {
 	struct mei_device *dev;
 	struct mei_msg_data *buf;
-	struct mei_msg_hdr mei_hdr;
-	size_t hdr_len = sizeof(mei_hdr);
-	size_t len;
+	struct mei_msg_hdr *mei_hdr = NULL;
+	size_t hdr_len;
 	size_t hbuf_len, dr_len;
+	size_t buf_len;
+	size_t data_len;
 	int hbuf_slots;
 	u32 dr_slots;
 	u32 dma_len;
@@ -1579,7 +1628,7 @@ int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 		return 0;
 	}
 
-	len = buf->size - cb->buf_idx;
+	buf_len = buf->size - cb->buf_idx;
 	data = buf->data + cb->buf_idx;
 	hbuf_slots = mei_hbuf_empty_slots(dev);
 	if (hbuf_slots < 0) {
@@ -1591,42 +1640,54 @@ int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 	dr_slots = mei_dma_ring_empty_slots(dev);
 	dr_len = mei_slots2data(dr_slots);
 
-	mei_msg_hdr_init(&mei_hdr, cb);
+	mei_hdr = mei_msg_hdr_init(cb);
+	if (IS_ERR(mei_hdr)) {
+		rets = PTR_ERR(mei_hdr);
+		mei_hdr = NULL;
+		goto err;
+	}
+
+	cl_dbg(dev, cl, "Extended Header %d vtag = %d\n",
+	       mei_hdr->extended, cb->vtag);
+
+	hdr_len = sizeof(*mei_hdr) + mei_hdr->length;
 
 	/**
 	 * Split the message only if we can write the whole host buffer
 	 * otherwise wait for next time the host buffer is empty.
 	 */
-	if (len + hdr_len <= hbuf_len) {
-		mei_hdr.length = len;
-		mei_hdr.msg_complete = 1;
+	if (hdr_len + buf_len <= hbuf_len) {
+		data_len = buf_len;
+		mei_hdr->msg_complete = 1;
 	} else if (dr_slots && hbuf_len >= hdr_len + sizeof(dma_len)) {
-		mei_hdr.dma_ring = 1;
-		if (len > dr_len)
-			len = dr_len;
+		mei_hdr->dma_ring = 1;
+		if (buf_len > dr_len)
+			buf_len = dr_len;
 		else
-			mei_hdr.msg_complete = 1;
+			mei_hdr->msg_complete = 1;
 
-		mei_hdr.length = sizeof(dma_len);
-		dma_len = len;
+		data_len = sizeof(dma_len);
+		dma_len = buf_len;
 		data = &dma_len;
 	} else if ((u32)hbuf_slots == mei_hbuf_depth(dev)) {
-		len = hbuf_len - hdr_len;
-		mei_hdr.length = len;
+		buf_len = hbuf_len - hdr_len;
+		data_len = buf_len;
 	} else {
+		kfree(mei_hdr);
 		return 0;
 	}
+	mei_hdr->length += data_len;
 
-	if (mei_hdr.dma_ring)
-		mei_dma_ring_write(dev, buf->data + cb->buf_idx, len);
+	if (mei_hdr->dma_ring)
+		mei_dma_ring_write(dev, buf->data + cb->buf_idx, buf_len);
+	rets = mei_write_message(dev, mei_hdr, hdr_len, data, data_len);
 
-	rets = mei_write_message(dev, &mei_hdr, hdr_len, data, mei_hdr.length);
 	if (rets)
 		goto err;
 
 	cl->status = 0;
 	cl->writing_state = MEI_WRITING;
-	cb->buf_idx += len;
+	cb->buf_idx += buf_len;
 
 	if (first_chunk) {
 		if (mei_cl_tx_flow_ctrl_creds_reduce(cl)) {
@@ -1635,12 +1696,14 @@ int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 		}
 	}
 
-	if (mei_hdr.msg_complete)
+	if (mei_hdr->msg_complete)
 		list_move_tail(&cb->list, &dev->write_waiting_list);
 
+	kfree(mei_hdr);
 	return 0;
 
 err:
+	kfree(mei_hdr);
 	cl->status = rets;
 	list_move_tail(&cb->list, cmpl_list);
 	return rets;
@@ -1659,9 +1722,11 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
 {
 	struct mei_device *dev;
 	struct mei_msg_data *buf;
-	struct mei_msg_hdr mei_hdr;
-	size_t hdr_len = sizeof(mei_hdr);
-	size_t len, hbuf_len, dr_len;
+	struct mei_msg_hdr *mei_hdr = NULL;
+	size_t hdr_len;
+	size_t hbuf_len, dr_len;
+	size_t buf_len;
+	size_t data_len;
 	int hbuf_slots;
 	u32 dr_slots;
 	u32 dma_len;
@@ -1678,9 +1743,9 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
 	dev = cl->dev;
 
 	buf = &cb->buf;
-	len = buf->size;
+	buf_len = buf->size;
 
-	cl_dbg(dev, cl, "len=%zd\n", len);
+	cl_dbg(dev, cl, "buf_len=%zd\n", buf_len);
 
 	blocking = cb->blocking;
 	data = buf->data;
@@ -1700,17 +1765,27 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
 	if (rets < 0)
 		goto err;
 
-	mei_msg_hdr_init(&mei_hdr, cb);
+	mei_hdr = mei_msg_hdr_init(cb);
+	if (IS_ERR(mei_hdr)) {
+		rets = -PTR_ERR(mei_hdr);
+		mei_hdr = NULL;
+		goto err;
+	}
+
+	cl_dbg(dev, cl, "Extended Header %d vtag = %d\n",
+	       mei_hdr->extended, cb->vtag);
+
+	hdr_len = sizeof(*mei_hdr) + mei_hdr->length;
 
 	if (rets == 0) {
 		cl_dbg(dev, cl, "No flow control credentials: not sending.\n");
-		rets = len;
+		rets = buf_len;
 		goto out;
 	}
 
 	if (!mei_hbuf_acquire(dev)) {
 		cl_dbg(dev, cl, "Cannot acquire the host buffer: not sending.\n");
-		rets = len;
+		rets = buf_len;
 		goto out;
 	}
 
@@ -1724,29 +1799,30 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
 	dr_slots = mei_dma_ring_empty_slots(dev);
 	dr_len =  mei_slots2data(dr_slots);
 
-	if (len + hdr_len <= hbuf_len) {
-		mei_hdr.length = len;
-		mei_hdr.msg_complete = 1;
+	if (hdr_len + buf_len <= hbuf_len) {
+		data_len = buf_len;
+		mei_hdr->msg_complete = 1;
 	} else if (dr_slots && hbuf_len >= hdr_len + sizeof(dma_len)) {
-		mei_hdr.dma_ring = 1;
-		if (len > dr_len)
-			len = dr_len;
+		mei_hdr->dma_ring = 1;
+		if (buf_len > dr_len)
+			buf_len = dr_len;
 		else
-			mei_hdr.msg_complete = 1;
+			mei_hdr->msg_complete = 1;
 
-		mei_hdr.length = sizeof(dma_len);
-		dma_len = len;
+		data_len = sizeof(dma_len);
+		dma_len = buf_len;
 		data = &dma_len;
 	} else {
-		len = hbuf_len - hdr_len;
-		mei_hdr.length = len;
+		buf_len = hbuf_len - hdr_len;
+		data_len = buf_len;
 	}
 
-	if (mei_hdr.dma_ring)
-		mei_dma_ring_write(dev, buf->data, len);
+	mei_hdr->length += data_len;
+
+	if (mei_hdr->dma_ring)
+		mei_dma_ring_write(dev, buf->data, buf_len);
+	rets = mei_write_message(dev, mei_hdr, hdr_len, data, data_len);
 
-	rets = mei_write_message(dev, &mei_hdr, hdr_len,
-				 data, mei_hdr.length);
 	if (rets)
 		goto err;
 
@@ -1755,12 +1831,12 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
 		goto err;
 
 	cl->writing_state = MEI_WRITING;
-	cb->buf_idx = len;
+	cb->buf_idx = buf_len;
 	/* restore return value */
-	len = buf->size;
+	buf_len = buf->size;
 
 out:
-	if (mei_hdr.msg_complete)
+	if (mei_hdr->msg_complete)
 		mei_tx_cb_enqueue(cb, &dev->write_waiting_list);
 	else
 		mei_tx_cb_enqueue(cb, &dev->write_list);
@@ -1785,7 +1861,7 @@ out:
 		}
 	}
 
-	rets = len;
+	rets = buf_len;
 err:
 	cl_dbg(dev, cl, "rpm: autosuspend\n");
 	pm_runtime_mark_last_busy(dev->dev);
@@ -1793,10 +1869,11 @@ err:
 free:
 	mei_io_cb_free(cb);
 
+	kfree(mei_hdr);
+
 	return rets;
 }
 
-
 /**
  * mei_cl_complete - processes completed operation for a client
  *