From 5e67d4f8a46d19748b501c2ef86de3f50d3cfd51 Mon Sep 17 00:00:00 2001 From: Gabor Juhos 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 --- 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, ®); + + 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(®, + 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;