[PATCH AUTOSEL 6.9 33/44] platform/x86/amd/hsmp: Check HSMP support on AMD family of processors

Sasha Levin
2024-06-17T13:22:07Z

From: Suma Hegde <suma.hegde@amd.com>

[ Upstream commit 77f1972bdcf7513293e8bbe376b9fe837310ee9c ]

HSMP interface is supported only on few x86 processors from AMD.
Accessing HSMP registers on rest of the platforms might cause
unexpected behaviour. So add a check.

Also unavailability of this interface on rest of the processors
is not an error. Hence, use pr_info() instead of the pr_err() to
log the message.

Signed-off-by: Suma Hegde <suma.hegde@amd.com>
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@amd.com>
Link: https://lore.kernel.org/r/20240603081512.142909-1-suma.hegde@amd.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/platform/x86/amd/hsmp.c | 50 ++++++++++++++++++++++++++++-----
1 file changed, 43 insertions(+), 7 deletions(-)

diff --git a/drivers/platform/x86/amd/hsmp.c b/drivers/platform/x86/amd/hsmp.c
index 1927be901108e..272d32a95e216 100644
--- a/drivers/platform/x86/amd/hsmp.c
+++ b/drivers/platform/x86/amd/hsmp.c
@@ -907,16 +907,44 @@ static int hsmp_plat_dev_register(void)
return ret;
}

+/*
+ * This check is only needed for backward compatibility of previous platforms.
+ * All new platforms are expected to support ACPI based probing.
+ */
+static bool legacy_hsmp_support(void)
+{
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+ return false;
+
+ switch (boot_cpu_data.x86) {
+ case 0x19:
+ switch (boot_cpu_data.x86_model) {
+ case 0x00 ... 0x1F:
+ case 0x30 ... 0x3F:
+ case 0x90 ... 0x9F:
+ case 0xA0 ... 0xAF:
+ return true;
+ default:
+ return false;
+ }
+ case 0x1A:
+ switch (boot_cpu_data.x86_model) {
+ case 0x00 ... 0x1F:
+ return true;
+ default:
+ return false;
+ }
+ default:
+ return false;
+ }
+
+ return false;
+}
+
static int __init hsmp_plt_init(void)
{
int ret = -ENODEV;

- if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD || boot_cpu_data.x86 < 0x19) {
- pr_err("HSMP is not supported on Family:%x model:%x\n",
- boot_cpu_data.x86, boot_cpu_data.x86_model);
- return ret;
- }
-
/*
* amd_nb_num() returns number of SMN/DF interfaces present in the system
* if we have N SMN/DF interfaces that ideally means N sockets
@@ -930,7 +958,15 @@ static int __init hsmp_plt_init(void)
return ret;

if (!plat_dev.is_acpi_device) {
- ret = hsmp_plat_dev_register();
+ if (legacy_hsmp_support()) {
+ /* Not ACPI device, but supports HSMP, register a plat_dev */
+ ret = hsmp_plat_dev_register();
+ } else {
+ /* Not ACPI, Does not support HSMP */
+ pr_info("HSMP is not supported on Family:%x model:%x\n",
+ boot_cpu_data.x86, boot_cpu_data.x86_model);
+ ret = -ENODEV;
+ }
if (ret)
platform_driver_unregister(&amd_hsmp_driver);
}
--
2.43.0