add mt7601u driver

Add support for the simplest of MediaTek Wi-Fi devices - MT7601U.
It is a single stream bgn chip with no bells or whistles.
This driver is partially based on Felix's mt76 but IMHO it doesn't
make sense to merge the two right now because MT7601U is a design
somewhere between old Ralink devices and new Mediatek chips.  There
wouldn't be all that much code sharing with the devices mt76 supports.
Situation may obviously change when someone decides to extend m76 with
support for the more recent USB dongles.

The driver supports only station mode.  I'm hoping to add AP support
when time allows.

This driver sat on GitHub for quite a while and got some testing there:
http://github.com/kuba-moo/mt7601u

Signed-off-by: Jakub Kicinski <kubakici@wp.pl>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/drivers/net/wireless/mediatek/mt7601u/core.c b/drivers/net/wireless/mediatek/mt7601u/core.c
new file mode 100644
index 000000000000..0aabd790f985
--- /dev/null
+++ b/drivers/net/wireless/mediatek/mt7601u/core.c
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2014 Felix Fietkau <nbd@openwrt.org>
+ * Copyright (C) 2015 Jakub Kicinski <kubakici@wp.pl>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include "mt7601u.h"
+
+int mt7601u_wait_asic_ready(struct mt7601u_dev *dev)
+{
+	int i = 100;
+	u32 val;
+
+	do {
+		if (test_bit(MT7601U_STATE_REMOVED, &dev->state))
+			return -EIO;
+
+		val = mt7601u_rr(dev, MT_MAC_CSR0);
+		if (val && ~val)
+			return 0;
+
+		udelay(10);
+	} while (i--);
+
+	return -EIO;
+}
+
+bool mt76_poll(struct mt7601u_dev *dev, u32 offset, u32 mask, u32 val,
+	       int timeout)
+{
+	u32 cur;
+
+	timeout /= 10;
+	do {
+		if (test_bit(MT7601U_STATE_REMOVED, &dev->state))
+			return false;
+
+		cur = mt7601u_rr(dev, offset) & mask;
+		if (cur == val)
+			return true;
+
+		udelay(10);
+	} while (timeout-- > 0);
+
+	dev_err(dev->dev, "Error: Time out with reg %08x\n", offset);
+
+	return false;
+}
+
+bool mt76_poll_msec(struct mt7601u_dev *dev, u32 offset, u32 mask, u32 val,
+		    int timeout)
+{
+	u32 cur;
+
+	timeout /= 10;
+	do {
+		if (test_bit(MT7601U_STATE_REMOVED, &dev->state))
+			return false;
+
+		cur = mt7601u_rr(dev, offset) & mask;
+		if (cur == val)
+			return true;
+
+		msleep(10);
+	} while (timeout-- > 0);
+
+	dev_err(dev->dev, "Error: Time out with reg %08x\n", offset);
+
+	return false;
+}