mwifiex: flush TX ring for PCIe after disconnect or bss stop

This patch adds handler to clean PCIe TX rings after disconnect
or bss stop is called for PCIe based mwifiex driver.
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/mwifiex/main.h

@@ -602,6 +602,7 @@ struct mwifiex_if_ops {
 	int (*init_fw_port) (struct mwifiex_adapter *);
 	int (*dnld_fw) (struct mwifiex_adapter *, struct mwifiex_fw_image *);
 	void (*card_reset) (struct mwifiex_adapter *);
+	int (*clean_pcie_ring) (struct mwifiex_adapter *adapter);
 };
 
 struct mwifiex_adapter {

drivers/net/wireless/mwifiex/pcie.c

@@ -764,6 +764,37 @@ static int mwifiex_pcie_delete_sleep_cookie_buf(struct mwifiex_adapter *adapter)
 	return 0;
 }
 
+/* This function flushes the TX buffer descriptor ring
+ * This function defined as handler is also called while cleaning TXRX
+ * during disconnect/ bss stop.
+ */
+static int mwifiex_clean_pcie_ring_buf(struct mwifiex_adapter *adapter)
+{
+	struct pcie_service_card *card = adapter->card;
+	u32 rdptr;
+
+	/* Read the TX ring read pointer set by firmware */
+	if (mwifiex_read_reg(adapter, REG_TXBD_RDPTR, &rdptr)) {
+		dev_err(adapter->dev,
+			"Flush TXBD: failed to read REG_TXBD_RDPTR\n");
+		return -1;
+	}
+
+	if (!mwifiex_pcie_txbd_empty(card, rdptr)) {
+		card->txbd_flush = 1;
+		/* write pointer already set at last send
+		 * send dnld-rdy intr again, wait for completion.
+		 */
+		if (mwifiex_write_reg(adapter, PCIE_CPU_INT_EVENT,
+				      CPU_INTR_DNLD_RDY)) {
+			dev_err(adapter->dev,
+				"failed to assert dnld-rdy interrupt.\n");
+			return -1;
+		}
+	}
+	return 0;
+}
+
 /*
  * This function sends data buffer to device
  */
@@ -1995,6 +2026,7 @@ static struct mwifiex_if_ops pcie_ops = {
 	.update_mp_end_port =		NULL,
 	.cleanup_mpa_buf =		NULL,
 	.init_fw_port =			mwifiex_pcie_init_fw_port,
+	.clean_pcie_ring =		mwifiex_clean_pcie_ring_buf,
 };
 
 /*

drivers/net/wireless/mwifiex/pcie.h

@@ -114,6 +114,7 @@ struct pcie_service_card {
 	struct pci_dev *dev;
 	struct mwifiex_adapter *adapter;
 
+	u8 txbd_flush;
 	u32 txbd_wrptr;
 	u32 txbd_rdptr;
 	u32 txbd_ring_size;
@@ -146,4 +147,16 @@ struct pcie_service_card {
 	void __iomem *pci_mmap1;
 };
 
+static inline int
+mwifiex_pcie_txbd_empty(struct pcie_service_card *card, u32 rdptr)
+{
+	if (((card->txbd_wrptr & MWIFIEX_TXBD_MASK) ==
+			(rdptr & MWIFIEX_TXBD_MASK)) &&
+	    ((card->txbd_wrptr & MWIFIEX_BD_FLAG_ROLLOVER_IND) !=
+			(rdptr & MWIFIEX_BD_FLAG_ROLLOVER_IND)))
+		return 1;
+
+	return 0;
+}
+
 #endif /* _MWIFIEX_PCIE_H */

drivers/net/wireless/mwifiex/wmm.c

@@ -568,6 +568,8 @@ mwifiex_clean_txrx(struct mwifiex_private *priv)
 	mwifiex_wmm_delete_all_ralist(priv);
 	memcpy(tos_to_tid, ac_to_tid, sizeof(tos_to_tid));
 
+	if (priv->adapter->if_ops.clean_pcie_ring)
+		priv->adapter->if_ops.clean_pcie_ring(priv->adapter);
 	spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock, flags);
 }