On 4/23/2024 04:14, Suma Hegde wrote:
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@xxxxxxx>
Reviewed-by: Naveen Krishna Chatradhi <naveenkrishna.chatradhi@xxxxxxx>
---
drivers/platform/x86/amd/hsmp.c | 54 ++++++++++++++++++++++++++++-----
1 file changed, 47 insertions(+), 7 deletions(-)
diff --git a/drivers/platform/x86/amd/hsmp.c b/drivers/platform/x86/amd/hsmp.c
index 1927be901108..807a5066dacc 100644
--- a/drivers/platform/x86/amd/hsmp.c
+++ b/drivers/platform/x86/amd/hsmp.c
@@ -907,16 +907,48 @@ 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 is_hsmp_supported(void)
I think it's better to use "legacy" in this function name to make it
clear that this isn't a requirement for newer platforms going forward.
Maybe like
legacy_hsmp_support()?
+{
+ bool ret = true;
As this is a simple boolean return with no needing to clear memory, I
think you can just "return true" or "return false" everywhere in this
function.
+
+ 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:
+ break;
+ default:
+ ret = false;
+ }
+ break;
+ case 0x1A:
+ switch (boot_cpu_data.x86_model) {
+ case 0x00 ... 0x1F:
+ break;
There actually are going to be 0x1A platforms that don't use ACPI?
I guess I'm surprised.
+ default:
+ ret = false;
+ }
+ break;
+ default:
+ ret = false;
+ }
+
+ return ret;
+}
+
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 +962,15 @@ static int __init hsmp_plt_init(void)
return ret;
if (!plat_dev.is_acpi_device) {
- ret = hsmp_plat_dev_register();
+ if (is_hsmp_supported()) {
+ /* 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);
}
