[PATCH v2 1/9] firmware: qcom: pas: add qcom_pas_context_init() for pre-allocated context

[Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>]

devm_qcom_pas_context_alloc() allocates and initializes a struct
qcom_pas_context using devres.  Several callers, however, either live
entirely on the stack (short-lived helper functions) or embed the
context in a larger structure that is already managed by other means.
Forcing those callers through the devm allocation path is wasteful and,
in the case of functions called on every power cycle, causes a devres
entry to accumulate on every invocation.

Add qcom_pas_context_init() that initializes a caller-supplied struct
qcom_pas_context in place using memset + field assignment, with no
allocation at all.  Rework devm_qcom_pas_context_alloc() to delegate
to qcom_pas_context_init() after the kzalloc, so both helpers share
the same initialization logic.

Update the kernel-doc for qcom_mdt_pas_load() to reflect that the PAS
context may now be initialized by either qcom_pas_context_init() or
devm_qcom_pas_context_alloc().

Signed-off-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
---
 drivers/firmware/qcom/qcom_pas.c       | 26 ++++++++++++++++++++++----
 drivers/soc/qcom/mdt_loader.c          |  4 ++--
 include/linux/firmware/qcom/qcom_pas.h |  2 ++
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/drivers/firmware/qcom/qcom_pas.c b/drivers/firmware/qcom/qcom_pas.c
index d74dd7b4f332..fdf62003fbf1 100644
--- a/drivers/firmware/qcom/qcom_pas.c
+++ b/drivers/firmware/qcom/qcom_pas.c
@@ -14,6 +14,27 @@
 
 static struct qcom_pas_ops *ops_ptr;
 
+/**
+ * qcom_pas_context_init() - Initialize a peripheral authentication service
+ *			     context for a given peripheral
+ *
+ * @ctx:	  Caller-provided PAS context to initialize
+ * @dev:	  PAS firmware device
+ * @pas_id:	  peripheral authentication service id
+ * @mem_phys:	  Subsystem reserve memory start address
+ * @mem_size:	  Subsystem reserve memory size
+ */
+void qcom_pas_context_init(struct qcom_pas_context *ctx, struct device *dev,
+			   u32 pas_id, phys_addr_t mem_phys, size_t mem_size)
+{
+	memset(ctx, 0, sizeof(*ctx));
+	ctx->dev = dev;
+	ctx->pas_id = pas_id;
+	ctx->mem_phys = mem_phys;
+	ctx->mem_size = mem_size;
+}
+EXPORT_SYMBOL_GPL(qcom_pas_context_init);
+
 /**
  * devm_qcom_pas_context_alloc() - Allocate peripheral authentication service
  *				   context for a given peripheral
@@ -39,10 +60,7 @@ struct qcom_pas_context *devm_qcom_pas_context_alloc(struct device *dev,
 	if (!ctx)
 		return ERR_PTR(-ENOMEM);
 
-	ctx->dev = dev;
-	ctx->pas_id = pas_id;
-	ctx->mem_phys = mem_phys;
-	ctx->mem_size = mem_size;
+	qcom_pas_context_init(ctx, dev, pas_id, mem_phys, mem_size);
 
 	return ctx;
 }
diff --git a/drivers/soc/qcom/mdt_loader.c b/drivers/soc/qcom/mdt_loader.c
index 0d55e9e0af3f..c6ec67e1da09 100644
--- a/drivers/soc/qcom/mdt_loader.c
+++ b/drivers/soc/qcom/mdt_loader.c
@@ -476,8 +476,8 @@ EXPORT_SYMBOL_GPL(qcom_mdt_load);
  * firmware segments (e.g., .bXX files). Authentication of the segments done
  * by a separate call.
  *
- * The PAS context must be initialized using devm_qcom_pas_context_alloc()
- * prior to invoking this function.
+ * The PAS context must be initialized using qcom_pas_context_init() or
+ * devm_qcom_pas_context_alloc() prior to invoking this function.
  *
  * @ctx:        Pointer to the PAS (Peripheral Authentication Service) context
  * @fw:         Firmware object representing the .mdt file
diff --git a/include/linux/firmware/qcom/qcom_pas.h b/include/linux/firmware/qcom/qcom_pas.h
index 1d132e89536e..458075868bf5 100644
--- a/include/linux/firmware/qcom/qcom_pas.h
+++ b/include/linux/firmware/qcom/qcom_pas.h
@@ -36,6 +36,8 @@ static inline void __iomem *qcom_pas_ctx_map(struct qcom_pas_context *ctx)
 }
 
 bool qcom_pas_is_available(void);
+void qcom_pas_context_init(struct qcom_pas_context *ctx, struct device *dev,
+			   u32 pas_id, phys_addr_t mem_phys, size_t mem_size);
 struct qcom_pas_context *devm_qcom_pas_context_alloc(struct device *dev,
 						     u32 pas_id,
 						     phys_addr_t mem_phys,
-- 
2.55.0