Thread (13 messages) 13 messages, 4 authors, 2014-10-15

[PATCH v4 4/6] ARM: rockchip: add basic smp support for rk3288

From: Russell King - ARM Linux <hidden>
Date: 2014-10-14 23:36:27
Also in: lkml

On Tue, Oct 14, 2014 at 11:23:40PM +0200, Heiko St?bner wrote:
Am Dienstag, 14. Oktober 2014, 13:24:03 schrieb Doug Anderson:
quoted
Kever,

On Mon, Oct 13, 2014 at 1:12 PM, Kever Yang [off-list ref] 
wrote:
quoted
quoted
+       /*
+        * We need to soft reset the cpu when we turn off the cpu power
domain, +        * or else the active processors might be stalled when
the individual +        * processor is powered down.
+        */
+       if (read_cpuid_part_number() != ARM_CPU_PART_CORTEX_A9) {
I haven't done a full review of this patch, but it seems unlikely that
your uses of read_cpuid_part_number() and read_cpuid_part() in this
patch are correct.  You use both functions and in both cases compare
the results to ARM_CPU_PART_CORTEX_A9.
I think read_cpuid_part() would be the correct one, as it does

	read_cpuid_id() & ARM_CPU_PART_MASK

which in turn should mask the correct parts of the cpuid to match against 
ARM_CPU_PART_CORTEX_A9 [0].
The clue is the deprecated message.  Clearly the original author did not
even build test their code, or if they did, they ignored the warnings.
Either way, that's a fairly worrying issue which raises the question:
how well was this code tested in the first place?

Note that the above quoted if() evaluates to always-false.

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