net: ipa: use usleep_range()

65;6003;1c
The use of msleep() for small periods (less than 20 milliseconds) is
not recommended because the actual delay can be much different than
expected.

We use msleep(1) in several places in the IPA driver to insert short
delays.  Replace them with usleep_range calls, which should reliably
delay a period in the range requested.

Signed-off-by: Alex Elder <elder@linaro.org>
Reviewed-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ipa/gsi.c

@@ -611,7 +611,8 @@ static void gsi_channel_reset_command(struct gsi_channel *channel)
 	struct device *dev = channel->gsi->dev;
 	enum gsi_channel_state state;
 
-	msleep(1);	/* A short delay is required before a RESET command */
+	/* A short delay is required before a RESET command */
+	usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 
 	state = gsi_channel_state(channel);
 	if (state != GSI_CHANNEL_STATE_STOPPED &&
@@ -900,7 +901,7 @@ int gsi_channel_stop(struct gsi *gsi, u32 channel_id)
 		ret = gsi_channel_stop_command(channel);
 		if (ret != -EAGAIN)
 			break;
-		msleep(1);
+		usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 	} while (retries--);
 
 	mutex_unlock(&gsi->mutex);

drivers/net/ipa/ipa_endpoint.c

@@ -1378,7 +1378,7 @@ static int ipa_endpoint_reset_rx_aggr(struct ipa_endpoint *endpoint)
 	do {
 		if (!ipa_endpoint_aggr_active(endpoint))
 			break;
-		msleep(1);
+		usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 	} while (retries--);
 
 	/* Check one last time */
@@ -1399,7 +1399,7 @@ static int ipa_endpoint_reset_rx_aggr(struct ipa_endpoint *endpoint)
 	 */
 	gsi_channel_reset(gsi, endpoint->channel_id, true);
 
-	msleep(1);
+	usleep_range(USEC_PER_MSEC, 2 * USEC_PER_MSEC);
 
 	goto out_suspend_again;