This series proposes creating a single implementation of the "pen release" (or spin-table) mechanism for starting secondary CPUs on ARM SMP systems. This mechanism is currently implemented at least 5 times in the kernel, each essentially identical to the other. There are other machines that use this method, but slight differences make it necessary to incorporate further work in order to accomodate them with a single set of functions. This work began with integrating SMP support for a Broadcom SoC. The code I started was another copy of the "pen release" code. Looking at how existing systems handled this, the duplication of code was obvious, but the fact that implementations were identical was less so. In addition, the arm64 (though not 32-bit arm) code supports the ability to define an "enable-method" property for CPUs in a machine's device tree (one of which is "spin-table"), allowing the secondary startup mechanism to be specified abstractly. My broader goal then was to set up the SMP support for the Broadcom SoC such that it could be defined in its device tree using a central "spin-table" enable method for secondary CPUs. The first step was to create a central spin-table implementation. I've tried to do this generally so it's usable by as many other platforms as possible. (An alternative would be to define a custom enable method for this platform, but I'd prefer to avoid that if I can.) I already have some code for the second step--which supports specifying the "spin-table" CPU enable method in device tree files. But before presenting that I wanted to post this series to get feedback on the approach. I've provided a little more information for each patch below. This code is available in the "review/common-spin-code" branch of the git repository here: http://git.linaro.org/landing-teams/working/broadcom/kernel.git -Alex Alex Elder (7): ARM: allow <asm/cputype.h> inclusion from assembly This patch is done specifically so the next one can use the value of MPIDR_HWID_BITMASK in secondary_holding_pen(), which is defined in asssembly. ARM: SMP: generic SMP spin-table method routines Define the common code (based on any of the others, but reportedly they all derive from ARM Realview.) Names are changed to be more like arch/arm64/kernel/smp_spin_table.c. ARM: realview: use central SMP spin-table routines ARM: vexpress: use central SMP spin-table routines ARM: versatile: kill off SMP support code The SMP code for realview and vexpress both use SMP code defined under mach-versatile, so these three go together. ARM: ux500: use generic SMP spin-table routines This one is a pretty straightforward switch to using the common code. ARM: spear: use central SMP spin-table routines This is straightforward as well, but it depends on the two prerequisite patches mentioned above (which together make this code roughly identical to the rest). arch/arm/include/asm/cputype.h | 4 ++ arch/arm/include/asm/smp.h | 5 ++ arch/arm/kernel/head.S | 33 +++++++++ arch/arm/kernel/smp.c | 77 ++++++++++++++++++++ arch/arm/mach-realview/platsmp.c | 8 +-- arch/arm/mach-spear/Makefile | 2 +- arch/arm/mach-spear/generic.h | 1 - arch/arm/mach-spear/headsmp.S | 47 ------------ arch/arm/mach-spear/platsmp.c | 75 +------------------ arch/arm/mach-ux500/Makefile | 2 +- arch/arm/mach-ux500/headsmp.S | 37 ---------- arch/arm/mach-ux500/platsmp.c | 72 +------------------ arch/arm/mach-vexpress/platsmp.c | 8 +-- arch/arm/mach-vexpress/v2m.c | 1 - arch/arm/plat-versatile/Makefile | 1 - arch/arm/plat-versatile/headsmp.S | 41 ----------- arch/arm/plat-versatile/include/plat/platsmp.h | 14 ---- arch/arm/plat-versatile/platsmp.c | 91 ------------------------ 18 files changed, 133 insertions(+), 386 deletions(-) delete mode 100644 arch/arm/mach-spear/headsmp.S delete mode 100644 arch/arm/mach-ux500/headsmp.S delete mode 100644 arch/arm/plat-versatile/headsmp.S delete mode 100644 arch/arm/plat-versatile/include/plat/platsmp.h delete mode 100644 arch/arm/plat-versatile/platsmp.c -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html