From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave.Martin@arm.com (Dave Martin) Date: Tue, 8 Oct 2013 19:03:11 +0100 Subject: [PATCH 2/2] ARM: cci: driver need big endian fixes in asm code In-Reply-To: References: <1381207040-1623-1-git-send-email-victor.kamensky@linaro.org> <1381207040-1623-3-git-send-email-victor.kamensky@linaro.org> <20131008175136.GA3866@localhost.localdomain> Message-ID: <20131008180305.GA3919@localhost.localdomain> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Oct 08, 2013 at 01:57:48PM -0400, Nicolas Pitre wrote: > On Tue, 8 Oct 2013, Dave Martin wrote: > > > On Mon, Oct 07, 2013 at 09:37:20PM -0700, Victor Kamensky wrote: > > > cci_enable_port_for_self written in asm and it works with h/w > > > registers that are in little endian format. When run in big > > > endian mode it needs byte swap before/after it writes/reads > > > to/from such registers > > > > Lorenzo should comment on this if he's not already seen it. > > > > > > > > Signed-off-by: Victor Kamensky > > > --- > > > drivers/bus/arm-cci.c | 6 ++++++ > > > 1 file changed, 6 insertions(+) > > > > > > diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c > > > index 2009266..6db173e 100644 > > > --- a/drivers/bus/arm-cci.c > > > +++ b/drivers/bus/arm-cci.c > > > @@ -281,6 +281,9 @@ asmlinkage void __naked cci_enable_port_for_self(void) > > > /* Enable the CCI port */ > > > " ldr r0, [r0, %[offsetof_port_phys]] \n" > > > " mov r3, #"__stringify(CCI_ENABLE_REQ)" \n" > > > +#ifdef __ARMEB__ > > > +" rev r3, r3 \n" > > > +#endif /* __ARMEB__ */ > > > > Hmmm, this is a bit ugly, but we can't easily use ARM_BE8() here. > > In any case, it would be more efficient to swap the CCI_ENABLE_REQ > constant at compile time rather than doing it at run time with an extra > instruction. Indeed, but we can't stringify that. A different way of wedging it into the assembler would be needed... We might need to use ldr= too, which doesn't pay nice with inline asm. Cheers ---Dave