Commit fee05843 authored by Lorenzo Bianconi's avatar Lorenzo Bianconi Committed by Kalle Valo
Browse files

mt7601u: make write with mask access atomic 



Introduce __mt7601u_rr and __mt7601u_vendor_single_wr routines in order
to make mt7601u_rmw and mt7601u_rmc atomic. This patch does not fix a
reported issue but makes the usb access more robust to concurrent
operations on the same register since it is theoretically possible that
read and write accesses of mt7601u_rmw/mt7601u_rmc can be interleaved with
a different write operation on the same register.
Moreover using __mt7601u_rr and __mt7601u_vendor_single_wr in
mt7601u_rmw/mt7601u_rmc allows to grab vendor_req_mutex mutex once
instead of twice

Signed-off-by: default avatarLorenzo Bianconi <lorenzo.bianconi@redhat.com>
Acked-by: default avatarJakub Kicinski <kubakici@wp.pl>
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
parent 7972326a

drivers/net/wireless/mediatek/mt7601u/mt7601u.h

+2 −1
Original line number Diff line number Diff line
@@ -147,7 +147,8 @@ enum { 
 * @rx_lock:		protects @rx_q.

 * @con_mon_lock:	protects @ap_bssid, @bcn_*, @avg_rssi.

 * @mutex:		ensures exclusive access from mac80211 callbacks.

 * @vendor_req_mutex:	protects @vend_buf, ensures atomicity of split writes.

 * @vendor_req_mutex:	protects @vend_buf, ensures atomicity of read/write

 *			accesses

 * @reg_atomic_mutex:	ensures atomicity of indirect register accesses

 *			(accesses to RF and BBP).

 * @hw_atomic_mutex:	ensures exclusive access to HW during critical

drivers/net/wireless/mediatek/mt7601u/usb.c

+37 −15
Original line number Diff line number Diff line
@@ -129,15 +129,14 @@ void mt7601u_vendor_reset(struct mt7601u_dev *dev) 
			       MT_VEND_DEV_MODE_RESET, 0, NULL, 0);

}



u32 mt7601u_rr(struct mt7601u_dev *dev, u32 offset)

/* should be called with vendor_req_mutex held */

static u32 __mt7601u_rr(struct mt7601u_dev *dev, u32 offset)

{

	int ret;

	u32 val = ~0;



	WARN_ONCE(offset > USHRT_MAX, "read high off:%08x", offset);



	mutex_lock(&dev->vendor_req_mutex);



	ret = mt7601u_vendor_request(dev, MT_VEND_MULTI_READ, USB_DIR_IN,

				     0, offset, dev->vend_buf, MT_VEND_BUF);

	if (ret == MT_VEND_BUF)
@@ -146,25 +145,41 @@ u32 mt7601u_rr(struct mt7601u_dev *dev, u32 offset) 
		dev_err(dev->dev, "Error: wrong size read:%d off:%08x\n",

			ret, offset);



	mutex_unlock(&dev->vendor_req_mutex);



	trace_reg_read(dev, offset, val);

	return val;

}



int mt7601u_vendor_single_wr(struct mt7601u_dev *dev, const u8 req,

			     const u16 offset, const u32 val)

u32 mt7601u_rr(struct mt7601u_dev *dev, u32 offset)

{

	int ret;

	u32 ret;



	mutex_lock(&dev->vendor_req_mutex);

	ret = __mt7601u_rr(dev, offset);

	mutex_unlock(&dev->vendor_req_mutex);



	ret = mt7601u_vendor_request(dev, req, USB_DIR_OUT,

	return ret;

}



/* should be called with vendor_req_mutex held */

static int __mt7601u_vendor_single_wr(struct mt7601u_dev *dev, const u8 req,

				      const u16 offset, const u32 val)

{

	int ret = mt7601u_vendor_request(dev, req, USB_DIR_OUT,

					 val & 0xffff, offset, NULL, 0);

	if (!ret)

		ret = mt7601u_vendor_request(dev, req, USB_DIR_OUT,

					     val >> 16, offset + 2, NULL, 0);

	trace_reg_write(dev, offset, val);

	return ret;

}



int mt7601u_vendor_single_wr(struct mt7601u_dev *dev, const u8 req,

			     const u16 offset, const u32 val)

{

	int ret;



	mutex_lock(&dev->vendor_req_mutex);

	ret = __mt7601u_vendor_single_wr(dev, req, offset, val);

	mutex_unlock(&dev->vendor_req_mutex);



	return ret;
@@ -175,23 +190,30 @@ void mt7601u_wr(struct mt7601u_dev *dev, u32 offset, u32 val) 
	WARN_ONCE(offset > USHRT_MAX, "write high off:%08x", offset);



	mt7601u_vendor_single_wr(dev, MT_VEND_WRITE, offset, val);

	trace_reg_write(dev, offset, val);

}



u32 mt7601u_rmw(struct mt7601u_dev *dev, u32 offset, u32 mask, u32 val)

{

	val |= mt7601u_rr(dev, offset) & ~mask;

	mt7601u_wr(dev, offset, val);

	mutex_lock(&dev->vendor_req_mutex);

	val |= __mt7601u_rr(dev, offset) & ~mask;

	__mt7601u_vendor_single_wr(dev, MT_VEND_WRITE, offset, val);

	mutex_unlock(&dev->vendor_req_mutex);



	return val;

}



u32 mt7601u_rmc(struct mt7601u_dev *dev, u32 offset, u32 mask, u32 val)

{

	u32 reg = mt7601u_rr(dev, offset);

	u32 reg;



	mutex_lock(&dev->vendor_req_mutex);

	reg = __mt7601u_rr(dev, offset);

	val |= reg & ~mask;

	if (reg != val)

		mt7601u_wr(dev, offset, val);

		__mt7601u_vendor_single_wr(dev, MT_VEND_WRITE,

					   offset, val);

	mutex_unlock(&dev->vendor_req_mutex);



	return val;

}

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