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Date: Thu, 03 Apr 2014 21:26:03 -0500
From: Alex Elder <elder@...aro.org>
To: mporter@...aro.org, bcm@...thebug.org, devicetree@...r.kernel.org,
arnd@...db.de, sboyd@...eaurora.org
CC: bcm-kernel-feedback-list@...adcom.com,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] ARM: add SMP support for Broadcom mobile SoCs
On 04/03/2014 09:18 PM, Alex Elder wrote:
> This patch adds SMP support for BCM281XX and BCM21664 family SoCs.
>
> This feature is controlled with a distinct config option such that a
> SMP-enabled multi-v7 binary can be configured to run these SoCs in
> uniprocessor mode. Since this SMP functionality is used for
> multiple Broadcom mobile chip families the config option is called
> ARCH_BCM_MOBILE_SMP (for lack of a better name).
>
> On SoCs of this type, the secondary core is not held in reset on
> power-on. Instead it loops in a ROM-based holding pen. To release
> it, one must write into a special register a jump address whose
> low-order bits have been replaced with a secondary core's id, then
> trigger an event with SEV. On receipt of an event, the ROM code
> will examine the register's contents, and if the low-order bits
> match its cpu id, it will clear them and write the value back to the
> register just prior to jumping to the address specified.
>
> The location of the special register is defined in the device tree
> using a "secondary-boot-reg" property in a node whose "enable-method"
> matches.
>
> Derived from code originally provided by Ray Jui <rjui@...adcom.com>
>
> Signed-off-by: Alex Elder <elder@...aro.org>
> ---
. . .
> diff --git a/arch/arm/mach-bcm/Makefile b/arch/arm/mach-bcm/Makefile
> index b2279e3..929579f 100644
> --- a/arch/arm/mach-bcm/Makefile
> +++ b/arch/arm/mach-bcm/Makefile
> @@ -15,7 +15,10 @@ obj-$(CONFIG_ARCH_BCM_281XX) += board_bcm281xx.o
> plus_sec := $(call as-instr,.arch_extension sec,+sec)
>
> # BCM21664
> -obj-$(CONFIG_ARCH_BCM_21664) += board_bcm21664.o
> +obj-$(CONFIG_ARCH_BCM_21664) := board_bcm21664.o
The above was a mistake, it should still be +=.
(I'll fix it.)
. . .
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