From mboxrd@z Thu Jan  1 00:00:00 1970
From: Beniamino Galvani <b.galvani@gmail.com>
Date: Sun, 17 Apr 2016 13:14:22 +0200
Subject: [U-Boot] [PATCH v4 1/3] net: designware: fix descriptor layout
 and warnings on 64-bit archs
In-Reply-To: <57135DEA.4000609@denx.de>
References: <1460879338-7671-1-git-send-email-b.galvani@gmail.com>
 <1460879338-7671-2-git-send-email-b.galvani@gmail.com>
 <57135DEA.4000609@denx.de>
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On Sun, Apr 17, 2016 at 11:56:58AM +0200, Marek Vasut wrote:
> > -		desc_p->dmamac_addr = &txbuffs[idx * CONFIG_ETH_BUFSIZE];
> > -		desc_p->dmamac_next = &desc_table_p[idx + 1];
> > +		desc_p->dmamac_addr = (ulong)&txbuffs[idx * CONFIG_ETH_BUFSIZE];
> > +		desc_p->dmamac_next = (ulong)&desc_table_p[idx + 1];
> 
> Why don't you use u32 instead of ulong ? The u32 is well defined.
> DTTO all over the place.

&txbuffs[idx * CONFIG_ETH_BUFSIZE] is a pointer (and hence has the
size of a ulong) and casting it to u32 would give a warning on 64 bit
archs ("cast from pointer to integer of different size").

> btw just curious, but what will happen if the descriptors get allocated
> in area above 4GiB ? Will the code silently corrupt memory by discarding
> the top bits in the descriptor pointer?

No, if the driver private structure (which contains buffers and
descriptors) is above 4GiB, designware_initialize() will complain and
return an error.

Beniamino