Re: [PATCH v3 6/8] cpufreq: sun50i: Add H616 support

[Sudeep Holla <sudeep.holla@arm.com>]

On Wed, Mar 27, 2024 at 11:58:12AM +0000, Sudeep Holla wrote:
> On Wed, Mar 27, 2024 at 11:46:08AM +0000, Andre Przywara wrote:
> > On Tue, 26 Mar 2024 22:46:27 -0500
> > Samuel Holland <samuel@sholland.org> wrote:
> > 
> > Hi Samuel,
> > 
> > > On 3/26/24 06:47, Andre Przywara wrote:
> > > > From: Martin Botka <martin.botka@somainline.org>
> > > > 
> > > > The Allwinner H616/H618 SoCs have different OPP tables per SoC version
> > > > and die revision. The SoC version is stored in NVMEM, as before, though
> > > > encoded differently. The die revision is in a different register, in the
> > > > SRAM controller. Firmware already exports that value in a standardised
> > > > way, through the SMCCC SoCID mechanism. We need both values, as some chips
> > > > have the same SoC version, but they don't support the same frequencies and
> > > > they get differentiated by the die revision.
> > > > 
> > > > Add the new compatible string and tie the new translation function to
> > > > it. This mechanism not only covers the original H616 SoC, but also its
> > > > very close sibling SoCs H618 and H700, so add them to the list as well.
> > > > 
> > > > Signed-off-by: Martin Botka <martin.botka@somainline.org>
> > > > Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> > > > ---
> > > >  drivers/cpufreq/sun50i-cpufreq-nvmem.c | 61 ++++++++++++++++++++++++++
> > > >  1 file changed, 61 insertions(+)
> > > > 
> > > > diff --git a/drivers/cpufreq/sun50i-cpufreq-nvmem.c b/drivers/cpufreq/sun50i-cpufreq-nvmem.c
> > > > index bd170611c7906..f9e9fc340f848 100644
> > > > --- a/drivers/cpufreq/sun50i-cpufreq-nvmem.c
> > > > +++ b/drivers/cpufreq/sun50i-cpufreq-nvmem.c
> > > > @@ -10,6 +10,7 @@
> > > >  
> > > >  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > > >  
> > > > +#include <linux/arm-smccc.h>
> > > >  #include <linux/cpu.h>
> > > >  #include <linux/module.h>
> > > >  #include <linux/nvmem-consumer.h>
> > > > @@ -46,14 +47,71 @@ static u32 sun50i_h6_efuse_xlate(u32 speedbin)
> > > >  		return 0;
> > > >  }
> > > >  
> > > > +/*
> > > > + * Judging by the OPP tables in the vendor BSP, the quality order of the
> > > > + * returned speedbin index is 4 -> 0/2 -> 3 -> 1, from worst to best.
> > > > + * 0 and 2 seem identical from the OPP tables' point of view.
> > > > + */
> > > > +static u32 sun50i_h616_efuse_xlate(u32 speedbin)
> > > > +{
> > > > +	int ver_bits = arm_smccc_get_soc_id_revision();  
> > > 
> > > This needs a Kconfig dependency on ARM_SMCCC_SOC_ID.
> > 
> > That was my first impulse as well, but it's actually not true:
> > ARM_SMCCC_SOC_ID just protects the sysfs export code, not this function
> > here. That does just depend on HAVE_ARM_SMCCC_DISCOVERY, which gets
> > selected by ARM_GIC_V3, which gets selected by CONFIG_ARM64. So the
> > arm64 kernel is safe.
> 
> It is safe to add the dependency explicitly so that if GICV3 decides to drop
> it, this won't be affected. Thoughts ?

Ignore this as this will block the ARM(32) build of the driver which I suppose
is needed as well.

--
Regards,
Sudeep