Return-path: Received: from fudo.makrotopia.org ([185.142.180.71]:39839 "EHLO fudo.makrotopia.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751281AbdAPDGE (ORCPT ); Sun, 15 Jan 2017 22:06:04 -0500 Date: Mon, 16 Jan 2017 04:05:47 +0100 From: Daniel Golle To: linux-wireless@vger.kernel.org Cc: Johannes Berg , Stanislaw Gruszka , roman@advem.lv, michel.stempin@wanadoo.fr, c.mignanti@gmail.com, evaxige@qq.com, Kalle Valo , Felix Fietkau , John Crispin , Gabor Juhos Subject: [PATCH v2 08/14] rt2x00: rt2800mmio: add a workaround for spurious TX_FIFO_STATUS interrupts Message-ID: <20170116030535.GA32238@makrotopia.org> (sfid-20170116_040607_369329_1AF5601A) References: <874m114lwq.fsf@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <874m114lwq.fsf@codeaurora.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Gabor Juhos Signed-off-by: Gabor Juhos Signed-off-by: Daniel Golle --- drivers/net/wireless/ralink/rt2x00/rt2800mmio.c | 72 ++++++++++++++++++++----- drivers/net/wireless/ralink/rt2x00/rt2x00.h | 5 ++ 2 files changed, 65 insertions(+), 12 deletions(-) diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800mmio.c b/drivers/net/wireless/ralink/rt2x00/rt2800mmio.c index 5f1936aa8fa7..750a9425b5be 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2800mmio.c +++ b/drivers/net/wireless/ralink/rt2x00/rt2800mmio.c @@ -415,9 +415,9 @@ void rt2800mmio_autowake_tasklet(unsigned long data) } 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_interrupt(struct rt2x00_dev *rt2x00dev) * 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, void *dev_instance) 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. */ diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00.h b/drivers/net/wireless/ralink/rt2x00/rt2x00.h index 034a07273038..c27408b494ef 100644 --- a/drivers/net/wireless/ralink/rt2x00/rt2x00.h +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00.h @@ -995,6 +995,11 @@ 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; -- 2.11.0