On 01/09/2015 03:09 AM, Paul Walmsley wrote:
Hello Daniel
On Thu, 8 Jan 2015, Daniel Lezcano wrote:
On 12/09/2014 11:07 PM, Paul Walmsley wrote:
Like several of the other files in drivers/clocksource,
tegra20_timer.c contains code that can only compile when CONFIG_ARM is
enabled. This causes obvious problems when trying to compile this
code for NVIDIA ARM64-based SoCs, such as Tegra132. The same timer IP
blocks exist, so it seems appropriate to provide support for them.
So until we figure out a better way to partition this code, wrap the
delay_timer and persistent_clock support code with preprocessor tests
for CONFIG_ARM.
(The delay_timer code should not be needed at all on
ARM64 due to the presence of the ARMv8 architected timer. The
persistent_clock support code could become important once power
management modes are implemented that turn off the CPU complex.)
IIUC, the cpuidle driver is not yet ready, right ?
If it is the case, this driver is not needed yet, no ?
The point of the patch is to allow the hardware drivers selected by
CONFIG_ARCH_TEGRA to build for an arm64 kernel, just as they build for
32-bit ARM.
There's nothing CPUIdle-specific about the patch - that is, this timer can
be selected as a clockevent and clocksource provider without the use of
CPUIdle - although low-power PM idle is likely to be a primary use-case.
What I meant is this timer is not needed for the moment.
Perhaps you can rework a bit this driver in the meantime to have a better fix
than disabling the code with macros ?
I'm happy to do that, but it would be nice to get the driver compiling
first for ARM64 :-)
Otherwise, please try at least to group the code into a minimal set of macros.
So, would it be accurate to say that you would prefer a patch that changes
more lines of code, but minimizes preprocessor directives, to the current
patch?
Yes at least an attempt to factor out a bit the driver. Those #ifdef are
like #if 0, which is a quick fix. I am not strongly against this patch,
but it would be nice to take the opportunity to reorganize it a bit.
One comment below.
diff --git a/drivers/clocksource/tegra20_timer.c
b/drivers/clocksource/tegra20_timer.c
index d2616ef16770..83a8f5c9e139 100644
--- a/drivers/clocksource/tegra20_timer.c
+++ b/drivers/clocksource/tegra20_timer.c
@@ -29,8 +29,10 @@
#include <linux/sched_clock.h>
#include <linux/delay.h>
+#ifdef CONFIG_ARM
#include <asm/mach/time.h>
#include <asm/smp_twd.h>
Is smp_twd.h really needed ?
+#endif
No, it can be removed.
Would you be willing to ack or merge a revision of this patch with
1. the #include <asm/smp_twd.h> removed
2. a larger number of changed lines, in order to minimize the number of
new #ifdefs?
Yes.
Thanks
-- Daniel
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