[PATCH v2 07/16] x86/amd_nb: Use topology info to get AMD node count

Yazen Ghannam
2024-12-06T16:12:37Z

Currently, the total AMD node count is determined by searching and
counting CPU/node devices using PCI IDs.

However, AMD node information is already available through topology
CPUID/MSRs. The recent topology rework has made this info easier to
access.

Replace the node counting code with a simple product of topology info.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---

Notes:
Link:
https://lore.kernel.org/20241023172150.659002-8-yazen.ghannam@amd.com

v1->v2:
* No change.

arch/x86/include/asm/amd_node.h | 5 +++++
arch/x86/kernel/amd_nb.c | 11 ++---------
2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/arch/x86/include/asm/amd_node.h b/arch/x86/include/asm/amd_node.h
index 3f097dd479f8..419a0ad13ef2 100644
--- a/arch/x86/include/asm/amd_node.h
+++ b/arch/x86/include/asm/amd_node.h
@@ -25,4 +25,9 @@
struct pci_dev *amd_node_get_func(u16 node, u8 func);
struct pci_dev *amd_node_get_root(u16 node);

+static inline u16 amd_num_nodes(void)
+{
+ return topology_amd_nodes_per_pkg() * topology_max_packages();
+}
+
#endif /*_ASM_X86_AMD_NODE_H_*/
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 6218a0428c77..371e33abbdc1 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -186,7 +186,6 @@ static int amd_cache_northbridges(void)
const struct pci_device_id *misc_ids = amd_nb_misc_ids;
struct pci_dev *misc;
struct amd_northbridge *nb;
- u16 misc_count = 0;
u16 i;

if (amd_northbridges.num)
@@ -196,19 +195,13 @@ static int amd_cache_northbridges(void)
misc_ids = hygon_nb_misc_ids;
}

- misc = NULL;
- while ((misc = next_northbridge(misc, misc_ids)))
- misc_count++;
-
- if (!misc_count)
- return -ENODEV;
+ amd_northbridges.num = amd_num_nodes();

- nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);
+ nb = kcalloc(amd_northbridges.num, sizeof(struct amd_northbridge), GFP_KERNEL);
if (!nb)
return -ENOMEM;

amd_northbridges.nb = nb;
- amd_northbridges.num = misc_count;

misc = NULL;
for (i = 0; i < amd_northbridges.num; i++) {
--
2.43.0