net/macb: add comment in macb_probe_queues

As we access the MID register directly, we need to tell why
we don't use the macb_is_gem() dedicated function.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index ac1f181..68d59b3 100644 (file)
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -2161,9 +2161,13 @@ static void macb_probe_queues(void __iomem *mem,
        *queue_mask = 0x1;
        *num_queues = 1;
 
-       /* is it macb or gem ? */
+       /* is it macb or gem ?
+        *
+        * We need to read directly from the hardware here because
+        * we are early in the probe process and don't have the
+        * MACB_CAPS_MACB_IS_GEM flag positioned
+        */
        mid = readl_relaxed(mem + MACB_MID);
-
        if (MACB_BFEXT(IDNUM, mid) < 0x2)
                return;