[PATCH v7 03/16] firmware: arm_scmi: Refactor message response path

Cristian Marussi
2021-11-29T19:14:47Z

Refactor code path waiting for message responses into a dedicated helper
function.

No functional change.

Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
---
drivers/firmware/arm_scmi/driver.c | 88 +++++++++++++++++++-----------
1 file changed, 56 insertions(+), 32 deletions(-)

diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
index 568562121f64..9a8d6bfd4ebb 100644
--- a/drivers/firmware/arm_scmi/driver.c
+++ b/drivers/firmware/arm_scmi/driver.c
@@ -738,6 +738,61 @@ static bool scmi_xfer_done_no_timeout(struct scmi_chan_info *cinfo,
ktime_after(ktime_get(), stop);
}

+/**
+ * scmi_wait_for_message_response - An helper to group all the possible ways of
+ * waiting for a synchronous message response.
+ *
+ * @cinfo: SCMI channel info
+ * @xfer: Reference to the transfer being waited for.
+ *
+ * Chooses waiting strategy (sleep-waiting vs busy-waiting) depending on
+ * configuration flags like xfer->hdr.poll_completion.
+ *
+ * Return: 0 on Success, error otherwise.
+ */
+static int scmi_wait_for_message_response(struct scmi_chan_info *cinfo,
+ struct scmi_xfer *xfer)
+{
+ struct scmi_info *info = handle_to_scmi_info(cinfo->handle);
+ struct device *dev = info->dev;
+ int ret = 0, timeout_ms = info->desc->max_rx_timeout_ms;
+
+ if (xfer->hdr.poll_completion) {
+ ktime_t stop = ktime_add_ms(ktime_get(), timeout_ms);
+
+ spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer, stop));
+ if (ktime_before(ktime_get(), stop)) {
+ unsigned long flags;
+
+ /*
+ * Do not fetch_response if an out-of-order delayed
+ * response is being processed.
+ */
+ spin_lock_irqsave(&xfer->lock, flags);
+ if (xfer->state == SCMI_XFER_SENT_OK) {
+ info->desc->ops->fetch_response(cinfo, xfer);
+ xfer->state = SCMI_XFER_RESP_OK;
+ }
+ spin_unlock_irqrestore(&xfer->lock, flags);
+ } else {
+ dev_err(dev,
+ "timed out in resp(caller: %pS) - polling\n",
+ (void *)_RET_IP_);
+ ret = -ETIMEDOUT;
+ }
+ } else {
+ /* And we wait for the response. */
+ if (!wait_for_completion_timeout(&xfer->done,
+ msecs_to_jiffies(timeout_ms))) {
+ dev_err(dev, "timed out in resp(caller: %pS)\n",
+ (void *)_RET_IP_);
+ ret = -ETIMEDOUT;
+ }
+ }
+
+ return ret;
+}
+
/**
* do_xfer() - Do one transfer
*
@@ -752,7 +807,6 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
struct scmi_xfer *xfer)
{
int ret;
- int timeout;
const struct scmi_protocol_instance *pi = ph_to_pi(ph);
struct scmi_info *info = handle_to_scmi_info(pi->handle);
struct device *dev = info->dev;
@@ -796,37 +850,7 @@ static int do_xfer(const struct scmi_protocol_handle *ph,
return ret;
}

- if (xfer->hdr.poll_completion) {
- ktime_t stop = ktime_add_ms(ktime_get(),
- info->desc->max_rx_timeout_ms);
-
- spin_until_cond(scmi_xfer_done_no_timeout(cinfo, xfer, stop));
- if (ktime_before(ktime_get(), stop)) {
- unsigned long flags;
-
- /*
- * Do not fetch_response if an out-of-order delayed
- * response is being processed.
- */
- spin_lock_irqsave(&xfer->lock, flags);
- if (xfer->state == SCMI_XFER_SENT_OK) {
- info->desc->ops->fetch_response(cinfo, xfer);
- xfer->state = SCMI_XFER_RESP_OK;
- }
- spin_unlock_irqrestore(&xfer->lock, flags);
- } else {
- ret = -ETIMEDOUT;
- }
- } else {
- /* And we wait for the response. */
- timeout = msecs_to_jiffies(info->desc->max_rx_timeout_ms);
- if (!wait_for_completion_timeout(&xfer->done, timeout)) {
- dev_err(dev, "timed out in resp(caller: %pS)\n",
- (void *)_RET_IP_);
- ret = -ETIMEDOUT;
- }
- }
-
+ ret = scmi_wait_for_message_response(cinfo, xfer);
if (!ret && xfer->hdr.status)
ret = scmi_to_linux_errno(xfer->hdr.status);

--
2.17.1