diff options
author | Russell King <rmk+kernel@armlinux.org.uk> | 2018-12-13 14:02:48 +0000 |
---|---|---|
committer | Russell King <rmk+kernel@armlinux.org.uk> | 2019-02-01 22:05:23 +0000 |
commit | 6213f70e7c10fd4a01b65bad3826648fc78df8a8 (patch) | |
tree | c1296d53776c9668057f570485285754c2424ab5 /arch/arm/mach-spear/hotplug.c | |
parent | 70678554c4c40f2cf8de5e7cd53fdd2c73387e51 (diff) |
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 <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/mach-spear/hotplug.c')
-rw-r--r-- | arch/arm/mach-spear/hotplug.c | 4 |
1 files changed, 3 insertions, 1 deletions
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 <asm/cp15.h> #include <asm/smp_plat.h> +#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 */ |