ioat: ignore reserved bits for chancnt and xfercap

[pandora-kernel.git] / drivers / dma / ioat / dma_v2.c

diff --git a/drivers/dma/ioat/dma_v2.c b/drivers/dma/ioat/dma_v2.c
index ca11342..137cf87 100644 (file)
--- a/drivers/dma/ioat/dma_v2.c
+++ b/drivers/dma/ioat/dma_v2.c
@@ -359,7 +359,14 @@ static int ioat2_enumerate_channels(struct ioatdma_device *device)
 
        INIT_LIST_HEAD(&dma->channels);
        dma->chancnt = readb(device->reg_base + IOAT_CHANCNT_OFFSET);
+       dma->chancnt &= 0x1f; /* bits [4:0] valid */
+       if (dma->chancnt > ARRAY_SIZE(device->idx)) {
+               dev_warn(dev, "(%d) exceeds max supported channels (%zu)\n",
+                        dma->chancnt, ARRAY_SIZE(device->idx));
+               dma->chancnt = ARRAY_SIZE(device->idx);
+       }
        xfercap_log = readb(device->reg_base + IOAT_XFERCAP_OFFSET);
+       xfercap_log &= 0x1f; /* bits [4:0] valid */
        if (xfercap_log == 0)
                return 0;
        dev_dbg(dev, "%s: xfercap = %d\n", __func__, 1 << xfercap_log);