[PATCH] bcm43xx: Drain TX status before starting IRQs

Drain the Microcode TX-status-FIFO before we enable IRQs.
This is required, because the FIFO may still have entries left
from a previous run. Those would immediately fire after enabling
IRQs and would lead to an oops in the DMA TXstatus handling code.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/drivers/net/wireless/bcm43xx/bcm43xx_main.c b/drivers/net/wireless/bcm43xx/bcm43xx_main.c
index 65edb56107fd..62c2ff8dfb9f 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx_main.c
+++ b/drivers/net/wireless/bcm43xx/bcm43xx_main.c
@@ -1463,6 +1463,23 @@ static void handle_irq_transmit_status(struct bcm43xx_private *bcm)
         }
 }
 
+static void drain_txstatus_queue(struct bcm43xx_private *bcm)
+{
+        u32 dummy;
+
+        if (bcm->current_core->rev < 5)
+                return;
+        /* Read all entries from the microcode TXstatus FIFO
+         * and throw them away.
+         */
+        while (1) {
+                dummy = bcm43xx_read32(bcm, BCM43xx_MMIO_XMITSTAT_0);
+                if (!dummy)
+                        break;
+                dummy = bcm43xx_read32(bcm, BCM43xx_MMIO_XMITSTAT_1);
+        }
+}
+
 static void bcm43xx_generate_noise_sample(struct bcm43xx_private *bcm)
 {
         bcm43xx_shm_write16(bcm, BCM43xx_SHM_SHARED, 0x408, 0x7F7F);
@@ -3532,6 +3549,7 @@ int bcm43xx_select_wireless_core(struct bcm43xx_private *bcm,
         bcm43xx_macfilter_clear(bcm, BCM43xx_MACFILTER_ASSOC);
         bcm43xx_macfilter_set(bcm, BCM43xx_MACFILTER_SELF, (u8 *)(bcm->net_dev->dev_addr));
         bcm43xx_security_init(bcm);
+        drain_txstatus_queue(bcm);
         ieee80211softmac_start(bcm->net_dev);
 
         /* Let's go! Be careful after enabling the IRQs.