1 files changed, 20 insertions, 8 deletions

diff --git a/drivers/net/wireless/p54/p54spi.c b/drivers/net/wireless/p54/p54spi.c
index e830a2e6845..40aeb4387dc 100644
--- a/drivers/net/wireless/p54/p54spi.c
+++ b/drivers/net/wireless/p54/p54spi.c
@@ -371,32 +371,44 @@ static int p54spi_rx(struct p54s_priv *priv)
 {
         struct sk_buff *skb;
         u16 len;
+        u16 rx_head[2];
+#define READAHEAD_SZ (sizeof(rx_head)-sizeof(u16))
 
         if (p54spi_wakeup(priv) < 0)
                 return -EBUSY;
 
-        /* dummy read to flush SPI DMA controller bug */
-        p54spi_read16(priv, SPI_ADRS_GEN_PURP_1);
-
-        len = p54spi_read16(priv, SPI_ADRS_DMA_DATA);
+        /* Read data size and first data word in one SPI transaction
+         * This is workaround for firmware/DMA bug,
+         * when first data word gets lost under high load.
+         */
+        p54spi_spi_read(priv, SPI_ADRS_DMA_DATA, rx_head, sizeof(rx_head));
+        len = rx_head[0];
 
         if (len == 0) {
-                dev_err(&priv->spi->dev, "rx request of zero bytes");
+                p54spi_sleep(priv);
+                dev_err(&priv->spi->dev, "rx request of zero bytes\n");
                 return 0;
         }
 
-
         /* Firmware may insert up to 4 padding bytes after the lmac header,
          * but it does not amend the size of SPI data transfer.
          * Such packets has correct data size in header, thus referencing
          * past the end of allocated skb. Reserve extra 4 bytes for this case */
         skb = dev_alloc_skb(len + 4);
         if (!skb) {
+                p54spi_sleep(priv);
                 dev_err(&priv->spi->dev, "could not alloc skb");
-                return 0;
+                return -ENOMEM;
         }
 
-        p54spi_spi_read(priv, SPI_ADRS_DMA_DATA, skb_put(skb, len), len);
+        if (len <= READAHEAD_SZ) {
+                memcpy(skb_put(skb, len), rx_head + 1, len);
+        } else {
+                memcpy(skb_put(skb, READAHEAD_SZ), rx_head + 1, READAHEAD_SZ);
+                p54spi_spi_read(priv, SPI_ADRS_DMA_DATA,
+                                skb_put(skb, len - READAHEAD_SZ),
+                                len - READAHEAD_SZ);
+        }
         p54spi_sleep(priv);
         /* Put additional bytes to compensate for the possible
          * alignment-caused truncation */