brcmfmac: add e-scan support.

This patch adds e-scan support (currently i-scan is in use). E-scan
is a more powerful and memory efficient method for scanning. E-scan
will be the default scan method and eventually, i-scan support will
be removed. The scan methods do not make any difference to the end-user.

Reviewed-by: Arend Van Spriel <arend@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/brcm80211/Kconfig

@@ -55,6 +55,14 @@ config BRCMFMAC_USB
 	  IEEE802.11n embedded FullMAC WLAN driver. Say Y if you want to
 	  use the driver for an USB wireless card.
 
+config BRCMISCAN
+	bool "Broadcom I-Scan (OBSOLETE)"
+	depends on BRCMFMAC
+	---help---
+	  This option enables the I-Scan method. By default fullmac uses the
+	  new E-Scan method which uses less memory in firmware and gives no
+	  limitation on the number of scan results.
+
 config BRCMDBG
 	bool "Broadcom driver debug functions"
 	depends on BRCMSMAC || BRCMFMAC

drivers/net/wireless/brcm80211/brcmfmac/dhd.h

@@ -130,6 +130,10 @@
 #define BRCMF_EVENT_MSG_FLUSHTXQ	0x02
 #define BRCMF_EVENT_MSG_GROUP		0x04
 
+#define BRCMF_ESCAN_REQ_VERSION 1
+
+#define WLC_BSS_RSSI_ON_CHANNEL		0x0002
+
 struct brcmf_event_msg {
 	__be16 version;
 	__be16 flags;
@@ -456,6 +460,24 @@ struct brcmf_scan_results_le {
 	__le32 count;
 };
 
+struct brcmf_escan_params_le {
+	__le32 version;
+	__le16 action;
+	__le16 sync_id;
+	struct brcmf_scan_params_le params_le;
+};
+
+struct brcmf_escan_result_le {
+	__le32 buflen;
+	__le32 version;
+	__le16 sync_id;
+	__le16 bss_count;
+	struct brcmf_bss_info_le bss_info_le;
+};
+
+#define WL_ESCAN_RESULTS_FIXED_SIZE (sizeof(struct brcmf_escan_result_le) - \
+	sizeof(struct brcmf_bss_info_le))
+
 /* used for association with a specific BSSID and chanspec list */
 struct brcmf_assoc_params_le {
 	/* 00:00:00:00:00:00: broadcast scan */

drivers/net/wireless/brcm80211/brcmfmac/dhd_common.c

@@ -205,7 +205,8 @@ brcmf_c_show_host_event(struct brcmf_event_msg *event, void *event_data)
 		BRCMF_E_ACTION_FRAME_COMPLETE, "ACTION FRAME TX COMPLETE"}, {
 		BRCMF_E_IF, "IF"}, {
 		BRCMF_E_RSSI, "RSSI"}, {
-		BRCMF_E_PFN_SCAN_COMPLETE, "SCAN_COMPLETE"}
+		BRCMF_E_PFN_SCAN_COMPLETE, "SCAN_COMPLETE"}, {
+		BRCMF_E_ESCAN_RESULT, "ESCAN_RESULT"}
 	};
 	uint event_type, flags, auth_type, datalen;
 	static u32 seqnum_prev;
@@ -350,6 +351,11 @@ brcmf_c_show_host_event(struct brcmf_event_msg *event, void *event_data)
 		brcmf_dbg(EVENT, "MACEVENT: %s\n", event_name);
 		break;
 
+	case BRCMF_E_ESCAN_RESULT:
+		brcmf_dbg(EVENT, "MACEVENT: %s\n", event_name);
+		datalen = 0;
+		break;
+
 	case BRCMF_E_PFN_NET_FOUND:
 	case BRCMF_E_PFN_NET_LOST:
 	case BRCMF_E_PFN_SCAN_COMPLETE: