Hi Marc,
On 3/15/23 03:34, Marc Zyngier wrote:
Please don't duplicate existing code. There is already the required
infrastructure in drivers/firmware/smccc/soc_id.c. All you need to do
is:
- disassociate the SMCCC probing from the device registration
- probe the SOC_ID early
- add accessors for the relevant data
- select ARM_SMCCC_SOD_ID/ARM_SMCCC_DISCOVERY from the GICv3 Kconfig
I have not modified soc_id.c as it expects to be loaded as a module with
the use of module_init() and module_exit() functions. The exported symbols
in soc_id driver cannot be accessed from the built-in code.
Agree, the SOD-ID discovery code was duplicated.
Please guide me if the below approach is okay?
1) Probe the SOC-ID in arm_smccc_version_init() and export two functions
arm_smccc_get_soc_id_version() and arm_smccc_get_soc_id_revision().
--- a/drivers/firmware/smccc/smccc.c
+++ b/drivers/firmware/smccc/smccc.c
@@ -17,9 +17,13 @@ static enum arm_smccc_conduit smccc_conduit = SMCCC_CONDUIT_NONE;
bool __ro_after_init smccc_trng_available = false;
u64 __ro_after_init smccc_has_sve_hint = false;
+s32 __ro_after_init smccc_soc_id_version = SMCCC_RET_NOT_SUPPORTED;
+s32 __ro_after_init smccc_soc_id_revision = SMCCC_RET_NOT_SUPPORTED;
void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit)
{
+ struct arm_smccc_res res;
+
smccc_version = version;
smccc_conduit = conduit;
@@ -27,6 +31,18 @@ void __init arm_smccc_version_init(u32 version, enum arm_smccc_conduit conduit)
if (IS_ENABLED(CONFIG_ARM64_SVE) &&
smccc_version >= ARM_SMCCC_VERSION_1_3)
smccc_has_sve_hint = true;
+
+ if ((smccc_version >= ARM_SMCCC_VERSION_1_2) &&
+ (smccc_conduit != SMCCC_CONDUIT_NONE)) {
+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
+ ARM_SMCCC_ARCH_SOC_ID, &res);
+ if ((s32)res.a0 >= 0) {
+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res);
+ smccc_soc_id_version = (s32)res.a0;
+ arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res);
+ smccc_soc_id_revision = (s32)res.a0;
+ }
+ }
}
+s32 arm_smccc_get_soc_id_version(void)
+{
+ return smccc_soc_id_version;
+}
+EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_version);
+
+s32 arm_smccc_get_soc_id_revision(void)
+{
+ return smccc_soc_id_revision;
+}
+EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_revision);
--- a/include/linux/arm-smccc.h
+++ b/include/linux/arm-smccc.h
+/**
+ * arm_smccc_get_soc_id_version()
+ *
+ * Returns the SOC ID version.
+ *
+ * When ARM_SMCCC_ARCH_SOC_ID is not present, returns SMCCC_RET_NOT_SUPPORTED.
+ */
+s32 arm_smccc_get_soc_id_version(void);
+/**
+ * arm_smccc_get_soc_id_revision()
+ *
+ * Returns the SOC ID revision.
+ *
+ * When ARM_SMCCC_ARCH_SOC_ID is not present, returns SMCCC_RET_NOT_SUPPORTED.
+ */
+s32 arm_smccc_get_soc_id_revision(void);
2) Use the exported functions in soc_id module.
--- a/drivers/firmware/smccc/soc_id.c
+++ b/drivers/firmware/smccc/soc_id.c
@@ -42,41 +42,23 @@ static int __init smccc_soc_init(void)
if (arm_smccc_get_version() < ARM_SMCCC_VERSION_1_2)
return 0;
- if (arm_smccc_1_1_get_conduit() == SMCCC_CONDUIT_NONE) {
- pr_err("%s: invalid SMCCC conduit\n", __func__);
- return -EOPNOTSUPP;
- }
-
- arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_FEATURES_FUNC_ID,
- ARM_SMCCC_ARCH_SOC_ID, &res);
-
- if ((int)res.a0 == SMCCC_RET_NOT_SUPPORTED) {
+ soc_id_version = arm_smccc_get_soc_id_version();
+ if (soc_id_version == SMCCC_RET_NOT_SUPPORTED) {
pr_info("ARCH_SOC_ID not implemented, skipping ....\n");
return 0;
}
- if ((int)res.a0 < 0) {
- pr_info("ARCH_FEATURES(ARCH_SOC_ID) returned error: %lx\n",
- res.a0);
- return -EINVAL;
- }
-
- arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 0, &res);
- if ((int)res.a0 < 0) {
+ if (soc_id_version < 0) {
pr_err("ARCH_SOC_ID(0) returned error: %lx\n", res.a0);
return -EINVAL;
}
- soc_id_version = res.a0;
-
- arm_smccc_1_1_invoke(ARM_SMCCC_ARCH_SOC_ID, 1, &res);
- if ((int)res.a0 < 0) {
+ soc_id_rev = arm_smccc_get_soc_id_revision();
+ if (soc_id_rev < 0) {
pr_err("ARCH_SOC_ID(1) returned error: %lx\n", res.a0);
return -EINVAL;
}
- soc_id_rev = res.a0;
Kconfig:
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -35,6 +35,7 @@ config ARM_GIC_V3
select IRQ_DOMAIN_HIERARCHY
select PARTITION_PERCPU
select GENERIC_IRQ_EFFECTIVE_AFF_MASK if SMP
+ select HAVE_ARM_SMCCC_DISCOVERY
