wil6210: enlarge TX/RX buffer length

HW supports upto 2304 packet size on the air.
HW is responsible for adding (Tx) or removing (Rx) the following headers:
802.11 hdr: 26B
SNAP: 8B
CRC: 4B
Security (optional): 24B
HW adds max 62B to the payload passed from driver. It means driver can use
max packet size of 2304-62 = 2242B

Signed-off-by: Dedy Lansky <qca_dlansky@qca.qualcomm.com>
Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/wil6210/netdev.c

@@ -17,6 +17,7 @@
 #include <linux/etherdevice.h>
 
 #include "wil6210.h"
+#include "txrx.h"
 
 static int wil_open(struct net_device *ndev)
 {
@@ -40,8 +41,10 @@ static int wil_change_mtu(struct net_device *ndev, int new_mtu)
 {
 	struct wil6210_priv *wil = ndev_to_wil(ndev);
 
-	if (new_mtu < 68 || new_mtu > IEEE80211_MAX_DATA_LEN_DMG)
+	if (new_mtu < 68 || new_mtu > (TX_BUF_LEN - ETH_HLEN)) {
+		wil_err(wil, "invalid MTU %d\n", new_mtu);
 		return -EINVAL;
+	}
 
 	wil_dbg_misc(wil, "change MTU %d -> %d\n", ndev->mtu, new_mtu);
 	ndev->mtu = new_mtu;

drivers/net/wireless/ath/wil6210/txrx.c

@@ -668,7 +668,8 @@ int wil_vring_init_tx(struct wil6210_priv *wil, int id, int size,
 	struct vring *vring = &wil->vring_tx[id];
 	struct vring_tx_data *txdata = &wil->vring_tx_data[id];
 
-	wil_dbg_misc(wil, "%s()\n", __func__);
+	wil_dbg_misc(wil, "%s() max_mpdu_size %d\n", __func__,
+		     cmd.vring_cfg.tx_sw_ring.max_mpdu_size);
 
 	if (vring->va) {
 		wil_err(wil, "Tx ring [%d] already allocated\n", id);

drivers/net/wireless/ath/wil6210/txrx.h

@@ -20,9 +20,9 @@
 #define BUF_SW_OWNED    (1)
 #define BUF_HW_OWNED    (0)
 
-/* size of max. Rx packet */
-#define RX_BUF_LEN      (2048)
-#define TX_BUF_LEN      (2048)
+/* size of max. Tx/Rx buffers, as supported by FW */
+#define RX_BUF_LEN      (2242)
+#define TX_BUF_LEN      (2242)
 /* how many bytes to reserve for rtap header? */
 #define WIL6210_RTAP_SIZE (128)