137 lines
4.1 KiB
Diff
137 lines
4.1 KiB
Diff
From 5e67d4f8a46d19748b501c2ef86de3f50d3cfd51 Mon Sep 17 00:00:00 2001
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From: Gabor Juhos <juhosg@openwrt.org>
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Date: Sun, 24 Mar 2013 19:26:27 +0100
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Subject: [PATCH] rt2x00: rt2800mmio: add a workaround for spurious
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TX_FIFO_STATUS interrupts
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Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
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---
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drivers/net/wireless/ralink/rt2x00/rt2800mmio.c | 72 +++++++++++++++++++++++++-----
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drivers/net/wireless/ralink/rt2x00/rt2x00.h | 5 +++
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2 files changed, 65 insertions(+), 12 deletions(-)
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--- a/drivers/net/wireless/ralink/rt2x00/rt2800mmio.c
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+++ b/drivers/net/wireless/ralink/rt2x00/rt2800mmio.c
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@@ -415,9 +415,9 @@ void rt2800mmio_autowake_tasklet(unsigne
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}
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EXPORT_SYMBOL_GPL(rt2800mmio_autowake_tasklet);
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-static void rt2800mmio_txstatus_interrupt(struct rt2x00_dev *rt2x00dev)
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+static void rt2800mmio_txstatus_interrupt(struct rt2x00_dev *rt2x00dev,
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+ u32 status)
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{
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- u32 status;
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int i;
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/*
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@@ -438,29 +438,77 @@ static void rt2800mmio_txstatus_interrup
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* Since we have only one producer and one consumer we don't
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* need to lock the kfifo.
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*/
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- for (i = 0; i < rt2x00dev->tx->limit; i++) {
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- rt2x00mmio_register_read(rt2x00dev, TX_STA_FIFO, &status);
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-
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- if (!rt2x00_get_field32(status, TX_STA_FIFO_VALID))
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- break;
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-
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+ i = 0;
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+ do {
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if (!kfifo_put(&rt2x00dev->txstatus_fifo, status)) {
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- rt2x00_warn(rt2x00dev, "TX status FIFO overrun, drop tx status report\n");
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+ rt2x00_warn(rt2x00dev,
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+ "TX status FIFO overrun, drop TX status report\n");
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break;
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}
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- }
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+
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+ if (++i >= rt2x00dev->tx->limit)
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+ break;
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+
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+ rt2x00mmio_register_read(rt2x00dev, TX_STA_FIFO, &status);
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+ } while (rt2x00_get_field32(status, TX_STA_FIFO_VALID));
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/* Schedule the tasklet for processing the tx status. */
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tasklet_schedule(&rt2x00dev->txstatus_tasklet);
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}
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+#define RT2800MMIO_TXSTATUS_IRQ_MAX_RETRIES 4
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+
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+static bool rt2800mmio_txstatus_is_spurious(struct rt2x00_dev *rt2x00dev,
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+ u32 txstatus)
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+{
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+ if (likely(rt2x00_get_field32(txstatus, TX_STA_FIFO_VALID))) {
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+ rt2x00dev->txstatus_irq_retries = 0;
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+ return false;
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+ }
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+
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+ rt2x00dev->txstatus_irq_retries++;
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+
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+ /* Ensure that we don't go into an infinite IRQ loop. */
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+ if (rt2x00dev->txstatus_irq_retries >=
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+ RT2800MMIO_TXSTATUS_IRQ_MAX_RETRIES) {
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+ rt2x00_warn(rt2x00dev,
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+ "%u spurious TX_FIFO_STATUS interrupt(s)\n",
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+ rt2x00dev->txstatus_irq_retries);
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+ rt2x00dev->txstatus_irq_retries = 0;
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+ return false;
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+ }
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+
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+ return true;
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+}
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+
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irqreturn_t rt2800mmio_interrupt(int irq, void *dev_instance)
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{
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struct rt2x00_dev *rt2x00dev = dev_instance;
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u32 reg, mask;
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+ u32 txstatus = 0;
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- /* Read status and ACK all interrupts */
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+ /* Read status */
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rt2x00mmio_register_read(rt2x00dev, INT_SOURCE_CSR, ®);
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+
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+ if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TX_FIFO_STATUS)) {
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+ /* Due to unknown reason the hardware generates a
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+ * TX_FIFO_STATUS interrupt before the TX_STA_FIFO
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+ * register contain valid data. Read the TX status
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+ * here to see if we have to process the actual
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+ * request.
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+ */
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+ rt2x00mmio_register_read(rt2x00dev, TX_STA_FIFO, &txstatus);
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+ if (rt2800mmio_txstatus_is_spurious(rt2x00dev, txstatus)) {
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+ /* Remove the TX_FIFO_STATUS bit so it won't be
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+ * processed in this turn. The hardware will
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+ * generate another IRQ for us.
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+ */
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+ rt2x00_set_field32(®,
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+ INT_SOURCE_CSR_TX_FIFO_STATUS, 0);
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+ }
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+ }
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+
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+ /* ACK interrupts */
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rt2x00mmio_register_write(rt2x00dev, INT_SOURCE_CSR, reg);
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if (!reg)
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@@ -477,7 +525,7 @@ irqreturn_t rt2800mmio_interrupt(int irq
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mask = ~reg;
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if (rt2x00_get_field32(reg, INT_SOURCE_CSR_TX_FIFO_STATUS)) {
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- rt2800mmio_txstatus_interrupt(rt2x00dev);
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+ rt2800mmio_txstatus_interrupt(rt2x00dev, txstatus);
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/*
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* Never disable the TX_FIFO_STATUS interrupt.
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*/
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--- a/drivers/net/wireless/ralink/rt2x00/rt2x00.h
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+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00.h
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@@ -991,6 +991,11 @@ struct rt2x00_dev {
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int rf_channel;
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/*
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+ * Counter for tx status irq retries (rt2800pci).
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+ */
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+ unsigned int txstatus_irq_retries;
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+
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+ /*
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* Protect the interrupt mask register.
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*/
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spinlock_t irqmask_lock;
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