wil6210: support 8KB RX buffers

The 11ad spec requires 11ad devices to be able to receive 8KB
packets over the air. Currently this is only possible by
loading the driver with mtu_max=7912 but this also forces
a smaller block ACK window size which reduces performance
for stations which transmit normal sized packets (<2KB).
Fix this problem as follows:
1. Add a module parameter rx_large_buf that when set,
will allocate 8KB RX buffers regardless of mtu_max
setting.
2. When receiving block ACK request agree to any window
size not above our maximum, regardless of the mtu_max setting.
This means if the other side transmits small packets (2KB)
it can still set up block ACK with a large window size,
and get better performance.

Signed-off-by: Lior David <qca_liord@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

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

@@ -343,8 +343,16 @@ __acquires(&sta->tid_rx_lock) __releases(&sta->tid_rx_lock)
 		wil_err(wil, "BACK requested unsupported ba_policy == 1\n");
 		status = WLAN_STATUS_INVALID_QOS_PARAM;
 	}
-	if (status == WLAN_STATUS_SUCCESS)
-		agg_wsize = wil_agg_size(wil, req_agg_wsize);
+	if (status == WLAN_STATUS_SUCCESS) {
+		if (req_agg_wsize == 0) {
+			wil_dbg_misc(wil, "Suggest BACK wsize %d\n",
+				     WIL_MAX_AGG_WSIZE);
+			agg_wsize = WIL_MAX_AGG_WSIZE;
+		} else {
+			agg_wsize = min_t(u16,
+					  WIL_MAX_AGG_WSIZE, req_agg_wsize);
+		}
+	}
 
 	rc = wmi_addba_rx_resp(wil, cid, tid, dialog_token, status,
 			       agg_amsdu, agg_wsize, agg_timeout);

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

@@ -37,6 +37,10 @@ bool rx_align_2;
 module_param(rx_align_2, bool, 0444);
 MODULE_PARM_DESC(rx_align_2, " align Rx buffers on 4*n+2, default - no");
 
+bool rx_large_buf;
+module_param(rx_large_buf, bool, 0444);
+MODULE_PARM_DESC(rx_large_buf, " allocate 8KB RX buffers, default - no");
+
 static inline uint wil_rx_snaplen(void)
 {
 	return rx_align_2 ? 6 : 0;
@@ -255,7 +259,7 @@ static int wil_vring_alloc_skb(struct wil6210_priv *wil, struct vring *vring,
 			       u32 i, int headroom)
 {
 	struct device *dev = wil_to_dev(wil);
-	unsigned int sz = mtu_max + ETH_HLEN + wil_rx_snaplen();
+	unsigned int sz = wil->rx_buf_len + ETH_HLEN + wil_rx_snaplen();
 	struct vring_rx_desc dd, *d = ⅆ
 	volatile struct vring_rx_desc *_d = &vring->va[i].rx;
 	dma_addr_t pa;
@@ -419,7 +423,7 @@ static struct sk_buff *wil_vring_reap_rx(struct wil6210_priv *wil,
 	struct sk_buff *skb;
 	dma_addr_t pa;
 	unsigned int snaplen = wil_rx_snaplen();
-	unsigned int sz = mtu_max + ETH_HLEN + snaplen;
+	unsigned int sz = wil->rx_buf_len + ETH_HLEN + snaplen;
 	u16 dmalen;
 	u8 ftype;
 	int cid;
@@ -780,6 +784,20 @@ void wil_rx_handle(struct wil6210_priv *wil, int *quota)
 	wil_rx_refill(wil, v->size);
 }
 
+static void wil_rx_buf_len_init(struct wil6210_priv *wil)
+{
+	wil->rx_buf_len = rx_large_buf ?
+		WIL_MAX_ETH_MTU : TXRX_BUF_LEN_DEFAULT - WIL_MAX_MPDU_OVERHEAD;
+	if (mtu_max > wil->rx_buf_len) {
+		/* do not allow RX buffers to be smaller than mtu_max, for
+		 * backward compatibility (mtu_max parameter was also used
+		 * to support receiving large packets)
+		 */
+		wil_info(wil, "Override RX buffer to mtu_max(%d)\n", mtu_max);
+		wil->rx_buf_len = mtu_max;
+	}
+}
+
 int wil_rx_init(struct wil6210_priv *wil, u16 size)
 {
 	struct vring *vring = &wil->vring_rx;
@@ -792,6 +810,8 @@ int wil_rx_init(struct wil6210_priv *wil, u16 size)
 		return -EINVAL;
 	}
 
+	wil_rx_buf_len_init(wil);
+
 	vring->size = size;
 	rc = wil_vring_alloc(wil, vring);
 	if (rc)

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

@@ -32,6 +32,7 @@ extern unsigned short rx_ring_overflow_thrsh;
 extern int agg_wsize;
 extern u32 vring_idle_trsh;
 extern bool rx_align_2;
+extern bool rx_large_buf;
 extern bool debug_fw;
 extern bool disable_ap_sme;
 
@@ -656,6 +657,7 @@ struct wil6210_priv {
 	struct work_struct probe_client_worker;
 	/* DMA related */
 	struct vring vring_rx;
+	unsigned int rx_buf_len;
 	struct vring vring_tx[WIL6210_MAX_TX_RINGS];
 	struct vring_tx_data vring_tx_data[WIL6210_MAX_TX_RINGS];
 	u8 vring2cid_tid[WIL6210_MAX_TX_RINGS][2]; /* [0] - CID, [1] - TID */

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

@@ -1398,7 +1398,8 @@ int wmi_rx_chain_add(struct wil6210_priv *wil, struct vring *vring)
 	struct wmi_cfg_rx_chain_cmd cmd = {
 		.action = WMI_RX_CHAIN_ADD,
 		.rx_sw_ring = {
-			.max_mpdu_size = cpu_to_le16(wil_mtu2macbuf(mtu_max)),
+			.max_mpdu_size = cpu_to_le16(
+				wil_mtu2macbuf(wil->rx_buf_len)),
 			.ring_mem_base = cpu_to_le64(vring->pa),
 			.ring_size = cpu_to_le16(vring->size),
 		},