quoted

quoted

+/**
+ * scmi_one_xfer_get() - Allocate one message
+ *
+ * @handle: SCMI entity handle
+ *
+ * Helper function which is used by various command functions that are
+ * exposed to clients of this driver for allocating a message traffic event.
+ *
+ * This function can sleep depending on pending requests already in the system
+ * for the SCMI entity. Further, this also holds a spinlock to maintain
+ * integrity of internal data structures.
+ *
+ * Return: 0 if all went fine, else corresponding error.
+ */
+static struct scmi_xfer *scmi_one_xfer_get(const struct scmi_handle *handle)  

Maybe it's just me, but I think this would be more clearly named as
scmi_xfer_alloc.
  

Agreed to some extent. The reason I didn't have it as alloc as they are
preallocated and this just returns a reference to free slot in that
preallocated array.

quoted

I'd assume we were dealing with one anyway as it's not called scmi_xfers_get
and the get to my mind implies a reference counter rather than allocating
an xfer for use...
  

Ah OK, I get your concerne with _get/_put but _alloc/_free is equally
bad then in the contect of preallocated buffers.

Sure, this is always a fun question.  Lots of other options
_assign _deassign works but never feels nice.

...

quoted

quoted

+	.max_msg = 20,		/* Limited by MBOX_TX_QUEUE_LEN */
+	.max_msg_size = 128,
+};
+
+/* Each compatible listed below must have descriptor associated with it */
+static const struct of_device_id scmi_of_match[] = {
+	{ .compatible = "arm,scmi", .data = &scmi_generic_desc },
+	{ /* Sentinel */ },
+};
+
+MODULE_DEVICE_TABLE(of, scmi_of_match);
+
+static int scmi_xfer_info_init(struct scmi_info *sinfo)
+{
+	int i;
+	struct scmi_xfer *xfer;
+	struct device *dev = sinfo->dev;
+	const struct scmi_desc *desc = sinfo->desc;
+	struct scmi_xfers_info *info = &sinfo->minfo;
+
+	/* Pre-allocated messages, no more than what hdr.seq can support */
+	if (WARN_ON(desc->max_msg >= (MSG_TOKEN_ID_MASK + 1))) {
+		dev_err(dev, "Maximum message of %d exceeds supported %d\n",
+			desc->max_msg, MSG_TOKEN_ID_MASK + 1);
+		return -EINVAL;
+	}
+
+	info->xfer_block = devm_kcalloc(dev, desc->max_msg,
+					sizeof(*info->xfer_block), GFP_KERNEL);
+	if (!info->xfer_block)
+		return -ENOMEM;
+
+	info->xfer_alloc_table = devm_kcalloc(dev, BITS_TO_LONGS(desc->max_msg),
+					      sizeof(long), GFP_KERNEL);
+	if (!info->xfer_alloc_table)
+		return -ENOMEM;  

Hmm. I wonder if it is worth adding a devm_bitmap_alloc?
  

OK

quoted

quoted

+
+	bitmap_zero(info->xfer_alloc_table, desc->max_msg);  

kcalloc zeros the memory.
  

quoted

+
+	/* Pre-initialize the buffer pointer to pre-allocated buffers */
+	for (i = 0, xfer = info->xfer_block; i < desc->max_msg; i++, xfer++) {
+		xfer->rx.buf = devm_kcalloc(dev, sizeof(u8), desc->max_msg_size,
+					    GFP_KERNEL);
+		if (!xfer->rx.buf)
+			return -ENOMEM;
+
+		xfer->tx.buf = xfer->rx.buf;
+		init_completion(&xfer->done);
+	}
+
+	spin_lock_init(&info->xfer_lock);
+
+	return 0;
+}
+
+static int scmi_mailbox_check(struct device_node *np)
+{
+	struct of_phandle_args arg;
+
+	return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells", 0, &arg);
+}
+
+static int scmi_mbox_free_channel(struct scmi_info *info)  

Some of the naming in here could do with being adjusted to be obviously
'balanced'.  The moment I see a free I expect a matched alloc but in this
case the alloc is done in scmi_mbox_chan_setup which at very least
should be scmi_mbox_setup_channel and should really imply that it is
doing allocation as well.
  

That's inline with mailbox APIs.

oh goody.  Fair enough if ugly

...

OK