From 716ca530e1c4515d8683c9d5be3d56b301758b66 Mon Sep 17 00:00:00 2001
From: James <>
Date: Wed, 4 Nov 2015 11:49:21 +0000
Subject: trunk-47381

---
 ...00mmio-add-a-workaround-for-spurious-TX_F.patch | 136 +++++++++++++++++++++
 1 file changed, 136 insertions(+)
 create mode 100644 package/kernel/mac80211/patches/600-0034-rt2x00-rt2800mmio-add-a-workaround-for-spurious-TX_F.patch

(limited to 'package/kernel/mac80211/patches/600-0034-rt2x00-rt2800mmio-add-a-workaround-for-spurious-TX_F.patch')

diff --git a/package/kernel/mac80211/patches/600-0034-rt2x00-rt2800mmio-add-a-workaround-for-spurious-TX_F.patch b/package/kernel/mac80211/patches/600-0034-rt2x00-rt2800mmio-add-a-workaround-for-spurious-TX_F.patch
new file mode 100644
index 0000000..71f7bba
--- /dev/null
+++ b/package/kernel/mac80211/patches/600-0034-rt2x00-rt2800mmio-add-a-workaround-for-spurious-TX_F.patch
@@ -0,0 +1,136 @@
+From 5e67d4f8a46d19748b501c2ef86de3f50d3cfd51 Mon Sep 17 00:00:00 2001
+From: Gabor Juhos <juhosg@openwrt.org>
+Date: Sun, 24 Mar 2013 19:26:27 +0100
+Subject: [PATCH] rt2x00: rt2800mmio: add a workaround for spurious
+ TX_FIFO_STATUS interrupts
+
+Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
+---
+ drivers/net/wireless/rt2x00/rt2800mmio.c |   72 +++++++++++++++++++++++++-----
+ drivers/net/wireless/rt2x00/rt2x00.h     |    5 +++
+ 2 files changed, 65 insertions(+), 12 deletions(-)
+
+--- a/drivers/net/wireless/rt2x00/rt2800mmio.c
++++ b/drivers/net/wireless/rt2x00/rt2800mmio.c
+@@ -415,9 +415,9 @@ void rt2800mmio_autowake_tasklet(unsigne
+ }
+ EXPORT_SYMBOL_GPL(rt2800mmio_autowake_tasklet);
+ 
+-static void rt2800mmio_txstatus_interrupt(struct rt2x00_dev *rt2x00dev)
++static void rt2800mmio_txstatus_interrupt(struct rt2x00_dev *rt2x00dev,
++					  u32 status)
+ {
+-	u32 status;
+ 	int i;
+ 
+ 	/*
+@@ -438,29 +438,77 @@ static void rt2800mmio_txstatus_interrup
+ 	 * Since we have only one producer and one consumer we don't
+ 	 * need to lock the kfifo.
+ 	 */
+-	for (i = 0; i < rt2x00dev->tx->limit; i++) {
+-		rt2x00mmio_register_read(rt2x00dev, TX_STA_FIFO, &status);
+-
+-		if (!rt2x00_get_field32(status, TX_STA_FIFO_VALID))
+-			break;
+-
++	i = 0;
++	do {
+ 		if (!kfifo_put(&rt2x00dev->txstatus_fifo, status)) {
+-			rt2x00_warn(rt2x00dev, "TX status FIFO overrun, drop tx status report\n");
++			rt2x00_warn(rt2x00dev,
++				    "TX status FIFO overrun, drop TX status report\n");
+ 			break;
+ 		}
+-	}
++
++		if (++i >= rt2x00dev->tx->limit)
++			break;
++
++ 		rt2x00mmio_register_read(rt2x00dev, TX_STA_FIFO, &status);
++	} while (rt2x00_get_field32(status, TX_STA_FIFO_VALID));
+ 
+ 	/* Schedule the tasklet for processing the tx status. */
+ 	tasklet_schedule(&rt2x00dev->txstatus_tasklet);
+ }
+ 
++#define RT2800MMIO_TXSTATUS_IRQ_MAX_RETRIES	4
++
++static bool rt2800mmio_txstatus_is_spurious(struct rt2x00_dev *rt2x00dev,
++					   u32 txstatus)
++{
++	if (likely(rt2x00_get_field32(txstatus, TX_STA_FIFO_VALID))) {
++		rt2x00dev->txstatus_irq_retries = 0;
++		return false;
++	}
++
++	rt2x00dev->txstatus_irq_retries++;
++
++	/* Ensure that we don't go into an infinite IRQ loop. */
++	if (rt2x00dev->txstatus_irq_retries >=
++	    RT2800MMIO_TXSTATUS_IRQ_MAX_RETRIES) {
++		rt2x00_warn(rt2x00dev,
++			    "%u spurious TX_FIFO_STATUS interrupt(s)\n",
++			    rt2x00dev->txstatus_irq_retries);
++		rt2x00dev->txstatus_irq_retries = 0;
++		return false;
++	}
++
++	return true;
++}
++
+ irqreturn_t rt2800mmio_interrupt(int irq, void *dev_instance)
+ {
+ 	struct rt2x00_dev *rt2x00dev = dev_instance;
+ 	u32 reg, mask;
++	u32 txstatus = 0;
+ 
+-	/* Read status and ACK all interrupts */
++	/* Read status */
+ 	rt2x00mmio_register_read(rt2x00dev, INT_SOURCE_CSR, &reg);
++
++	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TX_FIFO_STATUS)) {
++		/* Due to unknown reason the hardware generates a
++		 * TX_FIFO_STATUS interrupt before the TX_STA_FIFO
++		 * register contain valid data. Read the TX status
++		 * here to see if we have to process the actual
++		 * request.
++		 */
++		rt2x00mmio_register_read(rt2x00dev, TX_STA_FIFO, &txstatus);
++		if (rt2800mmio_txstatus_is_spurious(rt2x00dev, txstatus)) {
++			/* Remove the TX_FIFO_STATUS bit so it won't be
++			 * processed in this turn. The hardware will
++			 * generate another IRQ for us.
++			 */
++			rt2x00_set_field32(&reg,
++					   INT_SOURCE_CSR_TX_FIFO_STATUS, 0);
++		}
++	}
++
++	/* ACK interrupts */
+ 	rt2x00mmio_register_write(rt2x00dev, INT_SOURCE_CSR, reg);
+ 
+ 	if (!reg)
+@@ -477,7 +525,7 @@ irqreturn_t rt2800mmio_interrupt(int irq
+ 	mask = ~reg;
+ 
+ 	if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TX_FIFO_STATUS)) {
+-		rt2800mmio_txstatus_interrupt(rt2x00dev);
++		rt2800mmio_txstatus_interrupt(rt2x00dev, txstatus);
+ 		/*
+ 		 * Never disable the TX_FIFO_STATUS interrupt.
+ 		 */
+--- a/drivers/net/wireless/rt2x00/rt2x00.h
++++ b/drivers/net/wireless/rt2x00/rt2x00.h
+@@ -989,6 +989,11 @@ struct rt2x00_dev {
+ 	int rf_channel;
+ 
+ 	/*
++	 * Counter for tx status irq retries (rt2800pci).
++	 */
++	unsigned int txstatus_irq_retries;
++
++	/*
+ 	 * Protect the interrupt mask register.
+ 	 */
+ 	spinlock_t irqmask_lock;
-- 
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