rsi: buffer full check optimization

We get buffer full event from firmware whenever Tx queue is full
Host should stop writing packets after this and resume after
buffer free event.
Buffer status checking is optimized for once in 4 times if
BUFF_FULL condition is not set, otherwise once for every
packet.

Signed-off-by: Karun Eagalapati <karun256@gmail.com>
Signed-off-by: Amitkumar Karwar <amit.karwar@redpinesignals.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/rsi/rsi_91x_sdio_ops.c

@@ -271,6 +271,7 @@ void rsi_interrupt_handler(struct rsi_hw *adapter)
 					"%s: ==> BUFFER_AVAILABLE <==\n",
 					__func__);
 				dev->rx_info.buf_available_counter++;
+				dev->buff_status_updated = true;
 				break;
 
 			case FIRMWARE_ASSERT_IND:
@@ -333,7 +334,14 @@ int rsi_sdio_check_buffer_status(struct rsi_hw *adapter, u8 q_num)
 		(struct rsi_91x_sdiodev *)adapter->rsi_dev;
 	u8 buf_status = 0;
 	int status = 0;
+	static int counter = 4;
 
+	if (!dev->buff_status_updated && counter) {
+		counter--;
+		goto out;
+	}
+
+	dev->buff_status_updated = false;
 	status = rsi_sdio_read_register(common->priv,
 					RSI_DEVICE_BUFFER_STATUS_REGISTER,
 					&buf_status);
@@ -368,10 +376,16 @@ int rsi_sdio_check_buffer_status(struct rsi_hw *adapter, u8 q_num)
 		dev->rx_info.semi_buffer_full = false;
 	}
 
+	if (dev->rx_info.mgmt_buffer_full || dev->rx_info.buf_full_counter)
+		counter = 1;
+	else
+		counter = 4;
+
+out:
 	if ((q_num == MGMT_SOFT_Q) && (dev->rx_info.mgmt_buffer_full))
 		return QUEUE_FULL;
 
-	if (dev->rx_info.buffer_full)
+	if ((q_num < MGMT_SOFT_Q) && (dev->rx_info.buffer_full))
 		return QUEUE_FULL;
 
 	return QUEUE_NOT_FULL;

drivers/net/wireless/rsi/rsi_sdio.h

@@ -114,6 +114,7 @@ struct rsi_91x_sdiodev {
 	u8 prev_desc[16];
 	u16 tx_blk_size;
 	u8 write_fail;
+	bool buff_status_updated;
 };
 
 void rsi_interrupt_handler(struct rsi_hw *adapter);