perf/arm_cspmu: Simplify initialisation

It's far simpler for implementations to literally override whichever
default ops they want to, by initialising to the default ops first. This
saves all the bother of checking what the impl_init_ops call has or
hasn't touched. Make the same clear distinction for the PMIIDR override
as well, in case we gain more sources for overriding that in future.

Reviewed-by: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/dd39718ee4890fd46a8e443c25303e87ae23f422.1706718007.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index 3513bf50fefa00dd80b0403ecc24d869bca1cdaa..95e78290571eb1f69ec463ad49c666a92b8442a0 100644 (file)
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -100,13 +100,6 @@
 #define ARM_CSPMU_ACTIVE_CPU_MASK              0x0
 #define ARM_CSPMU_ASSOCIATED_CPU_MASK          0x1
 
-/* Check and use default if implementer doesn't provide attribute callback */
-#define CHECK_DEFAULT_IMPL_OPS(ops, callback)                  \
-       do {                                                    \
-               if (!ops->callback)                             \
-                       ops->callback = arm_cspmu_ ## callback; \
-       } while (0)
-
 /*
  * Maximum poll count for reading counter value using high-low-high sequence.
  */
@@ -408,21 +401,32 @@ static struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr)
        return NULL;
 }
 
+#define DEFAULT_IMPL_OP(name)  .name = arm_cspmu_##name
+
 static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
 {
        int ret = 0;
-       struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
        struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(cspmu->dev);
        struct arm_cspmu_impl_match *match;
 
-       /*
-        * Get PMU implementer and product id from APMT node.
-        * If APMT node doesn't have implementer/product id, try get it
-        * from PMIIDR.
-        */
-       cspmu->impl.pmiidr =
-               (apmt_node->impl_id) ? apmt_node->impl_id :
-                                      readl(cspmu->base0 + PMIIDR);
+       /* Start with a default PMU implementation */
+       cspmu->impl.module = THIS_MODULE;
+       cspmu->impl.pmiidr = readl(cspmu->base0 + PMIIDR);
+       cspmu->impl.ops = (struct arm_cspmu_impl_ops) {
+               DEFAULT_IMPL_OP(get_event_attrs),
+               DEFAULT_IMPL_OP(get_format_attrs),
+               DEFAULT_IMPL_OP(get_identifier),
+               DEFAULT_IMPL_OP(get_name),
+               DEFAULT_IMPL_OP(is_cycle_counter_event),
+               DEFAULT_IMPL_OP(event_type),
+               DEFAULT_IMPL_OP(event_filter),
+               DEFAULT_IMPL_OP(set_ev_filter),
+               DEFAULT_IMPL_OP(event_attr_is_visible),
+       };
+
+       /* Firmware may override implementer/product ID from PMIIDR */
+       if (apmt_node->impl_id)
+               cspmu->impl.pmiidr = apmt_node->impl_id;
 
        /* Find implementer specific attribute ops. */
        match = arm_cspmu_impl_match_get(cspmu->impl.pmiidr);
@@ -450,24 +454,9 @@ static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
                }
 
                mutex_unlock(&arm_cspmu_lock);
+       }
 
-               if (ret)
-                       return ret;
-       } else
-               cspmu->impl.module = THIS_MODULE;
-
-       /* Use default callbacks if implementer doesn't provide one. */
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, get_event_attrs);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, get_format_attrs);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, get_identifier);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, get_name);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, is_cycle_counter_event);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, event_type);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, event_filter);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, event_attr_is_visible);
-       CHECK_DEFAULT_IMPL_OPS(impl_ops, set_ev_filter);
-
-       return 0;
+       return ret;
 }
 
 static struct attribute_group *

diff --git a/drivers/perf/arm_cspmu/nvidia_cspmu.c b/drivers/perf/arm_cspmu/nvidia_cspmu.c
index 0382b702f0920ae6e36b9383cfc445df827fd9b1..5b84b701ad622834511a3474324a5ab116142bee 100644 (file)
--- a/drivers/perf/arm_cspmu/nvidia_cspmu.c
+++ b/drivers/perf/arm_cspmu/nvidia_cspmu.c
@@ -388,12 +388,6 @@ static int nv_cspmu_init_ops(struct arm_cspmu *cspmu)
        impl_ops->get_format_attrs              = nv_cspmu_get_format_attrs;
        impl_ops->get_name                      = nv_cspmu_get_name;
 
-       /* Set others to NULL to use default callback. */
-       impl_ops->event_type                    = NULL;
-       impl_ops->event_attr_is_visible         = NULL;
-       impl_ops->get_identifier                = NULL;
-       impl_ops->is_cycle_counter_event        = NULL;
-
        return 0;
 }