Re: [PATCH v3 1/3] powerpc/powernv/idle: Replace CPU features checks with PVR checks
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2020-07-20 00:01:06
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Excerpts from Pratik Rajesh Sampat's message of July 18, 2020 4:53 am:
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As the idle framework's architecture is incomplete, hence instead of checking for just the processor type advertised in the device tree CPU features; check for the Processor Version Register (PVR) so that finer granularity can be leveraged while making processor checks. Signed-off-by: Pratik Rajesh Sampat <redacted> --- arch/powerpc/platforms/powernv/idle.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c index 2dd467383a88..f62904f70fc6 100644 --- a/arch/powerpc/platforms/powernv/idle.c +++ b/arch/powerpc/platforms/powernv/idle.c@@ -92,7 +92,7 @@ static int pnv_save_sprs_for_deep_states(void) if (rc != 0) return rc; - if (cpu_has_feature(CPU_FTR_ARCH_300)) { + if (pvr_version_is(PVR_POWER9)) { rc = opal_slw_set_reg(pir, P9_STOP_SPR_MSR, msr_val); if (rc) return rc;@@ -116,7 +116,7 @@ static int pnv_save_sprs_for_deep_states(void) return rc; /* Only p8 needs to set extra HID regiters */ - if (!cpu_has_feature(CPU_FTR_ARCH_300)) { + if (!pvr_version_is(PVR_POWER9)) { rc = opal_slw_set_reg(pir, SPRN_HID1, hid1_val); if (rc != 0)
What I think you should do is keep using CPU_FTR_ARCH_300 for this stuff which is written for power9 and we know is running on power9, because that's a faster test (static branch and does not have to read PVR. And then...
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@@ -1205,7 +1205,7 @@ static void __init pnv_probe_idle_states(void) return; } - if (cpu_has_feature(CPU_FTR_ARCH_300)) + if (pvr_version_is(PVR_POWER9)) pnv_power9_idle_init(); for (i = 0; i < nr_pnv_idle_states; i++)
Here is where you would put the version check. Once we have code that can also handle P10 (either by testing CPU_FTR_ARCH_31, or by adding an entirely new power10 idle function), then you can add the P10 version check here. Thanks, Nick