mwifiex: use pci_dma_sync_single* APIs

On some platforms, driver is unable read sleep cookie signature even
if firmware has written it through DMA. The problem is fixed by using
pci_dma_sync_single* APIs while reading DMA buffer shared with firmware.
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/marvell/mwifiex/pcie.c

@@ -439,9 +439,14 @@ static void mwifiex_delay_for_sleep_cookie(struct mwifiex_adapter *adapter,
 	struct pcie_service_card *card = adapter->card;
 	u8 *buffer;
 	u32 sleep_cookie, count;
+	struct sk_buff *cmdrsp = card->cmdrsp_buf;
 
 	for (count = 0; count < max_delay_loop_cnt; count++) {
-		buffer = card->cmdrsp_buf->data;
+		pci_dma_sync_single_for_cpu(card->dev,
+					    MWIFIEX_SKB_DMA_ADDR(cmdrsp),
+					    sizeof(sleep_cookie),
+					    PCI_DMA_FROMDEVICE);
+		buffer = cmdrsp->data;
 		sleep_cookie = READ_ONCE(*(u32 *)buffer);
 
 		if (sleep_cookie == MWIFIEX_DEF_SLEEP_COOKIE) {
@@ -449,6 +454,10 @@ static void mwifiex_delay_for_sleep_cookie(struct mwifiex_adapter *adapter,
 				    "sleep cookie found at count %d\n", count);
 			break;
 		}
+		pci_dma_sync_single_for_device(card->dev,
+					       MWIFIEX_SKB_DMA_ADDR(cmdrsp),
+					       sizeof(sleep_cookie),
+					       PCI_DMA_FROMDEVICE);
 		usleep_range(20, 30);
 	}