wl12xx: Do end-of-transactions transfers only if needed

On newer hardware revisions, there is no need to write the host's
counter at the end of a RX transaction. The same applies to writing the
number of packets at the end of a TX transaction.

It is generally a good idea to avoid unnecessary SDIO/SPI transfers.
Throughput and CPU usage are improved when avoiding these.

Send the host's RX counter and the TX packet count only if needed, based
on the hardware revision.

[Changed WL12XX_QUIRK_END_OF_TRANSACTION to use BIT(0) -- Luca]
Signed-off-by: Ido Yariv <ido@wizery.com>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>
Reviewed-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>

drivers/net/wireless/wl12xx/boot.c

@@ -488,6 +488,9 @@ static void wl1271_boot_hw_version(struct wl1271 *wl)
 	fuse = (fuse & PG_VER_MASK) >> PG_VER_OFFSET;
 
 	wl->hw_pg_ver = (s8)fuse;
+
+	if (((wl->hw_pg_ver & PG_MAJOR_VER_MASK) >> PG_MAJOR_VER_OFFSET) < 3)
+		wl->quirks |= WL12XX_QUIRK_END_OF_TRANSACTION;
 }
 
 /* uploads NVS and firmware */

drivers/net/wireless/wl12xx/boot.h

@@ -59,6 +59,11 @@ struct wl1271_static_data {
 #define PG_VER_MASK          0x3c
 #define PG_VER_OFFSET        2
 
+#define PG_MAJOR_VER_MASK    0x3
+#define PG_MAJOR_VER_OFFSET  0x0
+#define PG_MINOR_VER_MASK    0xc
+#define PG_MINOR_VER_OFFSET  0x2
+
 #define CMD_MBOX_ADDRESS     0x407B4
 
 #define POLARITY_LOW         BIT(1)

drivers/net/wireless/wl12xx/main.c

@@ -3404,6 +3404,7 @@ struct ieee80211_hw *wl1271_alloc_hw(void)
 	wl->last_tx_hlid = 0;
 	wl->ap_ps_map = 0;
 	wl->ap_fw_ps_map = 0;
+	wl->quirks = 0;
 
 	memset(wl->tx_frames_map, 0, sizeof(wl->tx_frames_map));
 	for (i = 0; i < ACX_TX_DESCRIPTORS; i++)

drivers/net/wireless/wl12xx/rx.c

@@ -198,7 +198,13 @@ void wl1271_rx(struct wl1271 *wl, struct wl1271_fw_common_status *status)
 			pkt_offset += pkt_length;
 		}
 	}
-	wl1271_write32(wl, RX_DRIVER_COUNTER_ADDRESS, wl->rx_counter);
+
+	/*
+	 * Write the driver's packet counter to the FW. This is only required
+	 * for older hardware revisions
+	 */
+	if (wl->quirks & WL12XX_QUIRK_END_OF_TRANSACTION)
+		wl1271_write32(wl, RX_DRIVER_COUNTER_ADDRESS, wl->rx_counter);
 }
 
 void wl1271_set_default_filters(struct wl1271 *wl)

drivers/net/wireless/wl12xx/tx.c

@@ -506,8 +506,14 @@ void wl1271_tx_work_locked(struct wl1271 *wl)
 		sent_packets = true;
 	}
 	if (sent_packets) {
-		/* interrupt the firmware with the new packets */
-		wl1271_write32(wl, WL1271_HOST_WR_ACCESS, wl->tx_packets_count);
+		/*
+		 * Interrupt the firmware with the new packets. This is only
+		 * required for older hardware revisions
+		 */
+		if (wl->quirks & WL12XX_QUIRK_END_OF_TRANSACTION)
+			wl1271_write32(wl, WL1271_HOST_WR_ACCESS,
+				       wl->tx_packets_count);
+
 		wl1271_handle_tx_low_watermark(wl);
 	}
 

drivers/net/wireless/wl12xx/wl12xx.h

@@ -535,6 +535,9 @@ struct wl1271 {
 
 	/* AP-mode - a bitmap of links currently in PS mode in mac80211 */
 	unsigned long ap_ps_map;
+
+	/* Quirks of specific hardware revisions */
+	unsigned int quirks;
 };
 
 struct wl1271_station {
@@ -562,4 +565,9 @@ int wl1271_plt_stop(struct wl1271 *wl);
 #define HW_BG_RATES_MASK	0xffff
 #define HW_HT_RATES_OFFSET	16
 
+/* Quirks */
+
+/* Each RX/TX transaction requires an end-of-transaction transfer */
+#define WL12XX_QUIRK_END_OF_TRANSACTION	BIT(0)
+
 #endif