On Thu, Feb 3, 2011 at 7:30 PM, Santosh Shilimkar <santosh.shilimkar@xxxxxx> wrote: >> -----Original Message----- >> From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] >> Sent: Friday, February 04, 2011 12:38 AM >> To: Santosh Shilimkar >> Cc: Dave Martin; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Tony >> Lindgren; Nicolas Pitre; linux-omap@xxxxxxxxxxxxxxx; Jean Pihet-XID >> Subject: Re: [PATCH v2 1/5] ARM: omap4: Correct definition of >> do_wfi() forCONFIG_THUMB2_KERNEL >> >> On Fri, Feb 04, 2011 at 12:09:34AM +0530, Santosh Shilimkar wrote: >> > > -----Original Message----- >> > > From: Dave Martin [mailto:dave.martin@xxxxxxxxxx] >> > > Sent: Thursday, February 03, 2011 11:33 PM >> > > To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> > > Cc: Dave Martin; Tony Lindgren; Santosh Shilimkar; Jean Pihet; >> > > linux-omap@xxxxxxxxxxxxxxx; Nicolas Pitre >> > > Subject: [PATCH v2 1/5] ARM: omap4: Correct definition of >> do_wfi() >> > > for CONFIG_THUMB2_KERNEL >> > > >> > > For the Thumb-2 case, the "wfi" mnemonic is used, since in this >> > > case the tools will necessarily be new enough to support it. >> > > >> > > Signed-off-by: Dave Martin <dave.martin@xxxxxxxxxx> >> > >> > I guess, we discussed this patch in your previous post. >> > Acked-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> >> > >> > > --- >> > > arch/arm/mach-omap2/include/mach/omap4-common.h | 5 +++++ >> > > 1 files changed, 5 insertions(+), 0 deletions(-) >> > > >> > > diff --git a/arch/arm/mach-omap2/include/mach/omap4-common.h >> > > b/arch/arm/mach-omap2/include/mach/omap4-common.h >> > > index 5b0270b..68ce058 100644 >> > > --- a/arch/arm/mach-omap2/include/mach/omap4-common.h >> > > +++ b/arch/arm/mach-omap2/include/mach/omap4-common.h >> > > @@ -17,8 +17,13 @@ >> > > * wfi used in low power code. Directly opcode is used instead >> > > * of instruction to avoid mulit-omap build break >> > > */ >> > > +#ifdef CONFIG_THUMB2_KERNEL >> > > +#define do_wfi() \ >> > > + __asm__ __volatile__ ("wfi" : : : "memory") >> > > +#else >> > > #define do_wfi() \ >> > > __asm__ __volatile__ (".word 0xe320f003" : : : >> > > "memory") >> > > +#endif >> >> We actually have this: >> >> #if __LINUX_ARM_ARCH__ >= 7 || \ >> (__LINUX_ARM_ARCH__ == 6 && defined(CONFIG_CPU_32v6K)) >> #define sev() __asm__ __volatile__ ("sev" : : : "memory") >> #define wfe() __asm__ __volatile__ ("wfe" : : : "memory") >> #define wfi() __asm__ __volatile__ ("wfi" : : : "memory") >> #endif >> >> in asm/system.h, so maybe it should be using wfe() from asm/system.h >> ? > I assume you mean wfi here. > The problem is, omap2plus build breaks because it builds > CPU_32v6 and CPU_32v7 as well which doesn't support the wfi > instruction. Hence I used opcode directly to keep build > working. I guess that's right, OMAP2 is ARM1136 and doesn't have the K extensions. Would it make sense to have the v6 MCR equivalent as an altetnative? Something like: #elseif __LINUX_ARM_ARCH__ >= 6 #define wfi() __asm__ __volatile__ ( \ "mov r0, #0\n\t" \ "mcr p15, 0, r0, c7, c0, 4\n\t" \ ::: "r0" ) #endif This MCR is a mandatory part of the architecture for v6, but it's not mandatory for older processors. Cheers ---Dave -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
