> -----Original Message----- > From: Russell King - ARM Linux [mailto:linux@xxxxxxxxxxxxxxxx] > Sent: Saturday, May 16, 2009 3:59 PM > To: Shilimkar, Santosh > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxxxxx; > linux-omap@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/3] OMAP4: SMP: Add OMAP4430 SMP board files > > On Thu, May 07, 2009 at 12:59:24PM +0530, Santosh Shilimkar wrote: > > +/* > > + * OMAP4 specific entry point for secondary CPU to jump from ROM > > + * code. This routine also provides a holding flag into which > > + * secondary core is held until we're ready for it to initialise. > > + * The primary core will update the this flag using a hardware > > + * register AuxCoreBoot1. > > However, it's actually using the 'cpu_release' variable rather than > the AuxCoreBoot1 register. Maybe the comment needs updating, or the > code needs fixing? I planned update this bit later. AuxCoreBoot1 would be used instead of variable cpu_release Will add couple of FIXME comments here. > > + */ > > +ENTRY(omap_secondary_startup) > > + mrc p15, 0, r0, c0, c0, 5 > > + and r0, r0, #15 > > + adr r4, 1f > > + ldmia r4, {r5, r6} > > + sub r4, r4, r5 > > + add r6, r6, r4 > > +hold: ldr r7, [r6] @ read from AuxCoreBoot1 > > + cmp r7, r0 > > + bne hold > > + > > + /* > > + * we've been released from the holding pen: secondary_stack > > + * should now contain the SVC stack for this core > > + */ > > + b secondary_startup > > + > > +1: .long . > > + .long cpu_release > > + > > diff --git a/arch/arm/mach-omap2/omap-smp.c > b/arch/arm/mach-omap2/omap-smp.c > > new file mode 100644 > > index 0000000..1d18acb > > --- /dev/null > > +++ b/arch/arm/mach-omap2/omap-smp.c > > @@ -0,0 +1,238 @@ > > +int __cpuinit boot_secondary(unsigned int cpu, struct > task_struct *idle) > > +{ > > + unsigned long timeout; > > + > > + /* > > + * Set synchronisation state between this boot processor > > + * and the secondary one > > + */ > > + spin_lock(&boot_lock); > > + > > + /* > > + * The secondary processor is waiting for an event to > come out of > > + * wfe. Release it, then wait for it to flag that it has been > > + * released by resetting cpu_release. > > + * > > + * Singal the ROM code that the secondary core can be released > > + */ > > + cpu_release = cpu; > > + __raw_writel(cpu, OMAP4_AUXCOREBOOT_REG1); > > + flush_cache_all(); > > + /* > > + * Send a 'sev' to wake the secondary core again because > > + * ROM code will put core in WFE till the cpu_release > > + * flag is set. > > Not sure this comment is accurate. Surely the ROM code doesn't know > about our own cpu_release flag. Should be some thing like this-- >ROM code will put secondary core in WFE till we flag it using the AuxCoreBoot1 register to bring it up. > > -- > > 1.5.4.7 Regards, Santosh -- 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
