ARM: add SMP support for Broadcom mobile SoCs

This patch adds SMP support for BCM281XX and BCM21664 family SoCs.

This feature is controlled with a distinct config option such that
an 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@broadcom.com>

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Matt Porter <mporter@linaro.org>

1 files changed, 15 insertions, 3 deletions

diff --git a/arch/arm/mach-bcm/Kconfig b/arch/arm/mach-bcm/Kconfig
index 41c839167e87..6bafa2dbaece 100644
--- a/arch/arm/mach-bcm/Kconfig
+++ b/arch/arm/mach-bcm/Kconfig
@@ -9,7 +9,6 @@ config ARCH_BCM_MOBILE
         bool "Broadcom Mobile SoC Support" if ARCH_MULTI_V7
         select ARCH_REQUIRE_GPIOLIB
         select ARM_ERRATA_754322
-        select ARM_ERRATA_764369 if SMP
         select ARM_ERRATA_775420
         select ARM_GIC
         select GPIO_BCM_KONA
@@ -26,16 +25,18 @@ menu "Broadcom Mobile SoC Selection"
 config ARCH_BCM_281XX
         bool "Broadcom BCM281XX SoC family"
         default y
+        select HAVE_SMP
         help
-          Enable support for the the BCM281XX family, which includes
+          Enable support for the BCM281XX family, which includes
           BCM11130, BCM11140, BCM11351, BCM28145 and BCM28155
           variants.
 
 config ARCH_BCM_21664
         bool "Broadcom BCM21664 SoC family"
         default y
+        select HAVE_SMP
         help
-          Enable support for the the BCM21664 family, which includes
+          Enable support for the BCM21664 family, which includes
           BCM21663 and BCM21664 variants.
 
 config ARCH_BCM_MOBILE_L2_CACHE
@@ -49,6 +50,17 @@ config ARCH_BCM_MOBILE_SMC
         bool
         depends on ARCH_BCM_281XX || ARCH_BCM_21664
 
+config ARCH_BCM_MOBILE_SMP
+        bool "Broadcom mobile SoC SMP support"
+        depends on (ARCH_BCM_281XX || ARCH_BCM_21664) && SMP
+        default y
+        select HAVE_ARM_SCU
+        select ARM_ERRATA_764369
+        help
+          SMP support for the BCM281XX and BCM21664 SoC families.
+          Provided as an option so SMP support for SoCs of this type
+          can be disabled for an SMP-enabled kernel.
+
 endmenu
 
 endif