[PATCH v8 01/17] firmware: arm_scmi: Refactor xfer in-flight registration routines

Cristian Marussi
2023-01-18T12:16:34Z

Move the whole xfer in-flight registration process out of scmi_xfer_get
and while at that, split the sequence number selection steps from the
in-flight registration procedure itself.

No functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
drivers/firmware/arm_scmi/driver.c | 102 +++++++++++++++++++----------
1 file changed, 68 insertions(+), 34 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 50267eef10fa..3400bd124a38 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -411,8 +411,6 @@ static int scmi_xfer_token_set(struct scmi_xfers_info *minfo,
if (xfer_id != next_token)
atomic_add((int)(xfer_id - next_token), &transfer_last_id);

- /* Set in-flight */
- set_bit(xfer_id, minfo->xfer_alloc_table);
xfer->hdr.seq = (u16)xfer_id;

return 0;
@@ -430,33 +428,77 @@ static inline void scmi_xfer_token_clear(struct scmi_xfers_info *minfo,
clear_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
}

+/**
+ * scmi_xfer_inflight_register_unlocked - Register the xfer as in-flight
+ *
+ * @xfer: The xfer to register
+ * @minfo: Pointer to Tx/Rx Message management info based on channel type
+ *
+ * Note that this helper assumes that the xfer to be registered as in-flight
+ * had been built using an xfer sequence number which still corresponds to a
+ * free slot in the xfer_alloc_table.
+ *
+ * Context: Assumes to be called with @xfer_lock already acquired.
+ */
+static inline void
+scmi_xfer_inflight_register_unlocked(struct scmi_xfer *xfer,
+ struct scmi_xfers_info *minfo)
+{
+ /* Set in-flight */
+ set_bit(xfer->hdr.seq, minfo->xfer_alloc_table);
+ hash_add(minfo->pending_xfers, &xfer->node, xfer->hdr.seq);
+ xfer->pending = true;
+}
+
+/**
+ * scmi_xfer_pending_set - Pick a proper sequence number and mark the xfer
+ * as pending in-flight
+ *
+ * @xfer: The xfer to act upon
+ * @minfo: Pointer to Tx/Rx Message management info based on channel type
+ *
+ * Return: 0 on Success or error otherwise
+ */
+static inline int scmi_xfer_pending_set(struct scmi_xfer *xfer,
+ struct scmi_xfers_info *minfo)
+{
+ int ret;
+ unsigned long flags;
+
+ spin_lock_irqsave(&minfo->xfer_lock, flags);
+ /* Set a new monotonic token as the xfer sequence number */
+ ret = scmi_xfer_token_set(minfo, xfer);
+ if (!ret)
+ scmi_xfer_inflight_register_unlocked(xfer, minfo);
+ spin_unlock_irqrestore(&minfo->xfer_lock, flags);
+
+ return ret;
+}
+
/**
* scmi_xfer_get() - Allocate one message
*
* @handle: Pointer to SCMI entity handle
* @minfo: Pointer to Tx/Rx Message management info based on channel type
- * @set_pending: If true a monotonic token is picked and the xfer is added to
- * the pending hash table.
*
* Helper function which is used by various message functions that are
* exposed to clients of this driver for allocating a message traffic event.
*
- * Picks an xfer from the free list @free_xfers (if any available) and, if
- * required, sets a monotonically increasing token and stores the inflight xfer
- * into the @pending_xfers hashtable for later retrieval.
+ * Picks an xfer from the free list @free_xfers (if any available) and perform
+ * a basic initialization.
+ *
+ * Note that, at this point, still no sequence number is assigned to the
+ * allocated xfer, nor it is registered as a pending transaction.
*
* The successfully initialized xfer is refcounted.
*
- * Context: Holds @xfer_lock while manipulating @xfer_alloc_table and
- * @free_xfers.
+ * Context: Holds @xfer_lock while manipulating @free_xfers.
*
- * Return: 0 if all went fine, else corresponding error.
+ * Return: An initialized xfer if all went fine, else pointer error.
*/
static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
- struct scmi_xfers_info *minfo,
- bool set_pending)
+ struct scmi_xfers_info *minfo)
{
- int ret;
unsigned long flags;
struct scmi_xfer *xfer;

@@ -476,25 +518,8 @@ static struct scmi_xfer *scmi_xfer_get(const struct scmi_handle *handle,
*/
xfer->transfer_id = atomic_inc_return(&transfer_last_id);

- if (set_pending) {
- /* Pick and set monotonic token */
- ret = scmi_xfer_token_set(minfo, xfer);
- if (!ret) {
- hash_add(minfo->pending_xfers, &xfer->node,
- xfer->hdr.seq);
- xfer->pending = true;
- } else {
- dev_err(handle->dev,
- "Failed to get monotonic token %d\n", ret);
- hlist_add_head(&xfer->node, &minfo->free_xfers);
- xfer = ERR_PTR(ret);
- }
- }
-
- if (!IS_ERR(xfer)) {
- refcount_set(&xfer->users, 1);
- atomic_set(&xfer->busy, SCMI_XFER_FREE);
- }
+ refcount_set(&xfer->users, 1);
+ atomic_set(&xfer->busy, SCMI_XFER_FREE);
spin_unlock_irqrestore(&minfo->xfer_lock, flags);

return xfer;
@@ -752,7 +777,7 @@ static void scmi_handle_notification(struct scmi_chan_info *cinfo,
ktime_t ts;

ts = ktime_get_boottime();
- xfer = scmi_xfer_get(cinfo->handle, minfo, false);
+ xfer = scmi_xfer_get(cinfo->handle, minfo);
if (IS_ERR(xfer)) {
dev_err(dev, "failed to get free message slot (%ld)\n",
PTR_ERR(xfer));
@@ -1143,13 +1168,22 @@ static int xfer_get_init(const struct scmi_protocol_handle *ph,
tx_size > info->desc->max_msg_size)
return -ERANGE;

- xfer = scmi_xfer_get(pi->handle, minfo, true);
+ xfer = scmi_xfer_get(pi->handle, minfo);
if (IS_ERR(xfer)) {
ret = PTR_ERR(xfer);
dev_err(dev, "failed to get free message slot(%d)\n", ret);
return ret;
}

+ /* Pick a sequence number and register this xfer as in-flight */
+ ret = scmi_xfer_pending_set(xfer, minfo);
+ if (ret) {
+ dev_err(pi->handle->dev,
+ "Failed to get monotonic token %d\n", ret);
+ __scmi_xfer_put(minfo, xfer);
+ return ret;
+ }
+
xfer->tx.len = tx_size;
xfer->rx.len = rx_size ? : info->desc->max_msg_size;
xfer->hdr.type = MSG_TYPE_COMMAND;