Messages in this thread | | | From | Michal Nazarewicz <> | Subject | Re: [PATCH] spi: tegra: avoid unsigned->signed->unsigned promotion | Date | Mon, 02 Dec 2013 14:05:35 +0100 |
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> On Fri, Nov 29, 2013 at 06:12:44PM +0100, Michal Nazarewicz wrote: >> u8 type, which is unsigned, is promoted to int, which is singned, when >> doing a binary shift. Then, on 64-bit machines, it is further promoted >> to unsigned long which may lead to more significant half of the value >> to be all ones. To avoid this, explicitly promote to an unsigned type.
On Fri, Nov 29 2013, Thierry Reding wrote: > But I don't think there's a real issue here. Even on 64-bit platforms, > writel() will only write 32-bit registers, and therefore discard the > upper 32 bits. > > I think in general perhaps a more proper fix would be to use only u32 > instead of unsigned long for these cases, since then the problem goes > away. u32 is also the type of the value used by writel() so it makes > perfect sense to use it.
Yes, you're absolutely right. I dunno why I missed the fact it's used in writel only. I'll prepare a new patch soon(ish).
-- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +--<mpn@google.com>--<xmpp:mina86@jabber.org>--ooO--(_)--Ooo-- [unhandled content-type:application/pgp-signature] | |