From: Nicholas Piggin <npiggin@gmail.com>
To: benh@kernel.crashing.org, ego@linux.vnet.ibm.com,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
mikey@neuling.org, mpe@ellerman.id.au, paulus@samba.org,
pratik.r.sampat@gmail.com,
Pratik Rajesh Sampat <psampat@linux.ibm.com>,
svaidy@linux.ibm.com
Subject: Re: [PATCH v3 1/3] powerpc/powernv/idle: Replace CPU features checks with PVR checks
Date: Mon, 20 Jul 2020 10:00:57 +1000 [thread overview]
Message-ID: <1595203067.oropk0x5c8.astroid@bobo.none> (raw)
In-Reply-To: <20200717185306.60607-2-psampat@linux.ibm.com>
Excerpts from Pratik Rajesh Sampat's message of July 18, 2020 4:53 am:
> 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 <psampat@linux.ibm.com>
> ---
> 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...
> @@ -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
next prev parent reply other threads:[~2020-07-20 0:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 18:53 [PATCH v3 0/3] powernv/idle: Power9 idle cleanup Pratik Rajesh Sampat
2020-07-17 18:53 ` [PATCH v3 1/3] powerpc/powernv/idle: Replace CPU features checks with PVR checks Pratik Rajesh Sampat
2020-07-20 0:00 ` Nicholas Piggin [this message]
2020-07-21 10:24 ` Pratik Sampat
2020-07-17 18:53 ` [PATCH v3 2/3] powerpc/powernv/idle: Rename pnv_first_spr_loss_level variable Pratik Rajesh Sampat
2020-07-19 23:57 ` Nicholas Piggin
2020-07-21 10:29 ` Pratik Sampat
2020-07-21 14:37 ` Nicholas Piggin
2020-07-21 14:55 ` Gautham R Shenoy
2020-07-17 18:53 ` [PATCH v3 3/3] powerpc/powernv/idle: Exclude mfspr on HID1,4,5 on P9 and above Pratik Rajesh Sampat
2020-07-20 0:01 ` Nicholas Piggin
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