p54spi: use firmware/DMA bug workaround that work under hight load in p54spi_rx

[pandora-kernel.git] / drivers / net / wireless / p54 / p54spi.c

diff --git a/drivers/net/wireless/p54/p54spi.c b/drivers/net/wireless/p54/p54spi.c
index e830a2e..40aeb43 100644 (file)
--- 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 */