From 6213f70e7c10fd4a01b65bad3826648fc78df8a8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 13 Dec 2018 14:02:48 +0000 Subject: ARM: smp: remove arch-provided "pen_release" Consolidating the "pen_release" stuff amongst the various SoC implementations gives credence to having a CPU holding pen for secondary CPUs. However, this is far from the truth. Many SoC implementations cargo-cult copied various bits of the pen release implementation from the initial Realview/Versatile Express implementation without understanding what it was or why it existed. The reason it existed is because these are _development_ platforms, and some board firmware is unable to individually control the startup of secondary CPUs. Moreover, they do not have a way to power down or reset secondary CPUs for hot-unplug. Hence, the pen_release implementation was designed for ARM Ltd's development platforms to provide a working implementation, even though it is very far from what is required. It was decided a while back to reduce the duplication by consolidating the "pen_release" variable, but this only made the situation worse - we have ended up with several implementations that read this variable but do not write it - again, showing the cargo-cult mentality at work, lack of proper review of new code, and in some cases a lack of testing. While it would be preferable to remove pen_release entirely from the kernel, this is not possible without help from the SoC maintainers, which seems to be lacking. However, I want to remove pen_release from arch code to remove the credence that having it gives. This patch removes pen_release from the arch code entirely, adding private per-SoC definitions for it instead, and explicitly stating that write_pen_release() is cargo-cult copied and should not be copied any further. Rename write_pen_release() in a similar fashion as well. Signed-off-by: Russell King --- arch/arm/mach-spear/hotplug.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/arm/mach-spear/hotplug.c') diff --git a/arch/arm/mach-spear/hotplug.c b/arch/arm/mach-spear/hotplug.c index 12edd1cf8a12..0dd84f609627 100644 --- a/arch/arm/mach-spear/hotplug.c +++ b/arch/arm/mach-spear/hotplug.c @@ -16,6 +16,8 @@ #include #include +#include "generic.h" + static inline void cpu_enter_lowpower(void) { unsigned int v; @@ -57,7 +59,7 @@ static inline void spear13xx_do_lowpower(unsigned int cpu, int *spurious) for (;;) { wfi(); - if (pen_release == cpu) { + if (spear_pen_release == cpu) { /* * OK, proper wakeup, we're done */ -- cgit