brcmfmac: have sdio return -EIO when device communication is not possible

The bus interface functions txctl and rxctl may be used while the device
can not be accessed, eg. upon driver .remove() callback. This patch will
immediately return -EIO when this is the case which speeds up the module
unload.

Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

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

@@ -988,6 +988,7 @@ static void brcmf_sdiod_freezer_detach(struct brcmf_sdio_dev *sdiodev)
 
 static int brcmf_sdiod_remove(struct brcmf_sdio_dev *sdiodev)
 {
+	sdiodev->state = BRCMF_SDIOD_DOWN;
 	if (sdiodev->bus) {
 		brcmf_sdio_remove(sdiodev->bus);
 		sdiodev->bus = NULL;

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

@@ -2820,6 +2820,8 @@ static int brcmf_sdio_bus_txdata(struct device *dev, struct sk_buff *pkt)
 	struct brcmf_sdio *bus = sdiodev->bus;
 
 	brcmf_dbg(TRACE, "Enter: pkt: data %p len %d\n", pkt->data, pkt->len);
+	if (sdiodev->state != BRCMF_SDIOD_DATA)
+		return -EIO;
 
 	/* Add space for the header */
 	skb_push(pkt, bus->tx_hdrlen);
@@ -2948,6 +2950,8 @@ brcmf_sdio_bus_txctl(struct device *dev, unsigned char *msg, uint msglen)
 	int ret;
 
 	brcmf_dbg(TRACE, "Enter\n");
+	if (sdiodev->state != BRCMF_SDIOD_DATA)
+		return -EIO;
 
 	/* Send from dpc */
 	bus->ctrl_frame_buf = msg;
@@ -3238,6 +3242,8 @@ brcmf_sdio_bus_rxctl(struct device *dev, unsigned char *msg, uint msglen)
 	struct brcmf_sdio *bus = sdiodev->bus;
 
 	brcmf_dbg(TRACE, "Enter\n");
+	if (sdiodev->state != BRCMF_SDIOD_DATA)
+		return -EIO;
 
 	/* Wait until control frame is available */
 	timeleft = brcmf_sdio_dcmd_resp_wait(bus, &bus->rxlen, &pending);