-----Original Message-----
From: Arnd Bergmann [mailto:arnd@arndb.de]
Sent: Wednesday, July 29, 2015 11:02 AM
To: linuxppc-dev@lists.ozlabs.org; netdev@vger.kernel.org; Manoil Claudiu=

-

B08782; Wood Scott-B07421
Subject: Re: [PATCH] gianfar: Fix warnings when built on 64-bit
=20
On Wednesday 29 July 2015 00:24:37 Scott Wood wrote:
=20

quoted

Alternatively, if there's a desire to not mess with this code (I don't
know how to trigger this code path to test it), this driver should be
given dependencies that ensure that it only builds on 32-bit.

=20

[...]

quoted

@@ -2964,8 +2967,13 @@ int gfar_clean_rx_ring(struct gfar_priv_rx_q

*rx_queue, int rx_work_limit)

quoted

 		gfar_init_rxbdp(rx_queue, bdp, bufaddr);

 		/* Update Last Free RxBD pointer for LFC */
-		if (unlikely(rx_queue->rfbptr && priv->tx_actual_en))
-			gfar_write(rx_queue->rfbptr, (u32)bdp);
+		if (unlikely(rx_queue->rfbptr && priv->tx_actual_en)) {
+			u32 bdp_dma;
+
+			bdp_dma =3D lower_32_bits(rx_queue-
rx_bd_dma_base);
+			bdp_dma +=3D (uintptr_t)bdp - (uintptr_t)base;
+			gfar_write(rx_queue->rfbptr, bdp_dma);
+		}

 		/* Update to the next pointer */
 		bdp =3D next_bd(bdp, base, rx_queue->rx_ring_size);

=20
You are fixing two problems here: the warning about a size cast, and
the fact that the driver is using the wrong pointer. I'd suggest
explaining it in the changelog.
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What would be the wrong pointer here? "base"?
"base" is " rx_queue->rx_bd_base".

Note that we normally rely on void pointer arithmetic in the kernel, so
I'd write it without the uintptr_t casts as
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	bdp_dma =3D lower_32_bits(rx_queue->rx_bd_dma_base + (base -
bdp));

I think you mean: (bdp-base)

Claudiu