Re: [PATCH 14/16] x86/amd_smn, platform/x86/amd/hsmp: Have HSMP use SMN

Yazen Ghannam
2024-10-24T16:06:34Z

On Thu, Oct 24, 2024 at 04:23:55PM +0300, Ilpo Järvinen wrote:
> On Wed, 23 Oct 2024, Yazen Ghannam wrote:
>
> > The HSMP interface is just an SMN interface with different offsets.
> >
> > Define an HSMP wrapper in the SMN code and have the HSMP platform driver
> > use that rather than a local solution.
> >
> > Also, remove the "root" member from AMD_NB, since there are no more
> > users of it.
> >
> > Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
> > ---
> > arch/x86/include/asm/amd_nb.h | 1 -
> > arch/x86/include/asm/amd_smn.h | 3 +++
> > arch/x86/kernel/amd_nb.c | 1 -
> > arch/x86/kernel/amd_smn.c | 9 +++++++++
> > drivers/platform/x86/amd/Kconfig | 2 +-
> > drivers/platform/x86/amd/hsmp.c | 32 +++++---------------------------
> > 6 files changed, 18 insertions(+), 30 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/amd_nb.h b/arch/x86/include/asm/amd_nb.h
> > index 55c03d3495bc..cbe31e316e39 100644
> > --- a/arch/x86/include/asm/amd_nb.h
> > +++ b/arch/x86/include/asm/amd_nb.h
> > @@ -27,7 +27,6 @@ struct amd_l3_cache {
> > };
> >
> > struct amd_northbridge {
> > - struct pci_dev *root;
> > struct pci_dev *misc;
> > struct pci_dev *link;
> > struct amd_l3_cache l3_cache;
> > diff --git a/arch/x86/include/asm/amd_smn.h b/arch/x86/include/asm/amd_smn.h
> > index 6850de69f863..f0eb12859c42 100644
> > --- a/arch/x86/include/asm/amd_smn.h
> > +++ b/arch/x86/include/asm/amd_smn.h
> > @@ -8,4 +8,7 @@
> > int __must_check amd_smn_read(u16 node, u32 address, u32 *value);
> > int __must_check amd_smn_write(u16 node, u32 address, u32 value);
> >
> > +/* Should only be used by the HSMP driver. */
> > +int __must_check amd_smn_hsmp_rdwr(u16 node, u32 address, u32 *value, bool write);
> > +
> > #endif /* _ASM_X86_AMD_SMN_H */
> > diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
> > index 10cdeddeda02..4c22317a6dfe 100644
> > --- a/arch/x86/kernel/amd_nb.c
> > +++ b/arch/x86/kernel/amd_nb.c
> > @@ -73,7 +73,6 @@ static int amd_cache_northbridges(void)
> > amd_northbridges.nb = nb;
> >
> > for (i = 0; i < amd_northbridges.num; i++) {
> > - node_to_amd_nb(i)->root = amd_node_get_root(i);
> > node_to_amd_nb(i)->misc = amd_node_get_func(i, 3);
> > node_to_amd_nb(i)->link = amd_node_get_func(i, 4);
> > }
> > diff --git a/arch/x86/kernel/amd_smn.c b/arch/x86/kernel/amd_smn.c
> > index 997fd3edd9c0..527dda8e3a2b 100644
> > --- a/arch/x86/kernel/amd_smn.c
> > +++ b/arch/x86/kernel/amd_smn.c
> > @@ -18,6 +18,9 @@ static DEFINE_MUTEX(smn_mutex);
> > #define SMN_INDEX_OFFSET 0x60
> > #define SMN_DATA_OFFSET 0x64
> >
> > +#define HSMP_INDEX_OFFSET 0xc4
> > +#define HSMP_DATA_OFFSET 0xc8
> > +
> > /*
> > * SMN accesses may fail in ways that are difficult to detect here in the called
> > * functions amd_smn_read() and amd_smn_write(). Therefore, callers must do
> > @@ -100,6 +103,12 @@ int __must_check amd_smn_write(u16 node, u32 address, u32 value)
> > }
> > EXPORT_SYMBOL_GPL(amd_smn_write);
> >
> > +int __must_check amd_smn_hsmp_rdwr(u16 node, u32 address, u32 *value, bool write)
> > +{
> > + return __amd_smn_rw(HSMP_INDEX_OFFSET, HSMP_DATA_OFFSET, node, address, value, write);
> > +}
> > +EXPORT_SYMBOL_GPL(amd_smn_hsmp_rdwr);
> > +
> > static int amd_cache_roots(void)
> > {
> > u16 node, num_nodes = amd_num_nodes();
> > diff --git a/drivers/platform/x86/amd/Kconfig b/drivers/platform/x86/amd/Kconfig
> > index f88682d36447..e100b315c62b 100644
> > --- a/drivers/platform/x86/amd/Kconfig
> > +++ b/drivers/platform/x86/amd/Kconfig
> > @@ -8,7 +8,7 @@ source "drivers/platform/x86/amd/pmc/Kconfig"
> >
> > config AMD_HSMP
> > tristate "AMD HSMP Driver"
> > - depends on AMD_NB && X86_64 && ACPI
> > + depends on AMD_SMN && X86_64 && ACPI
> > help
> > The driver provides a way for user space tools to monitor and manage
> > system management functionality on EPYC server CPUs from AMD.
> > diff --git a/drivers/platform/x86/amd/hsmp.c b/drivers/platform/x86/amd/hsmp.c
> > index 8fcf38eed7f0..544efb0255c0 100644
> > --- a/drivers/platform/x86/amd/hsmp.c
> > +++ b/drivers/platform/x86/amd/hsmp.c
>
> FYI, there has been major restructuring done for this driver in
> pdx86/for-next.
>

Yep, no problem. I can rebase these changes on top of those.

Any comments on the general approach?

Thanks,
Yazen