[iwl-next v2 5/8] libie: add adminq helper for converting err to str

[Michal Swiatkowski <michal.swiatkowski@linux.intel.com>]

Add a new module for common handling of Admin Queue related logic.
Start by a helper for error to string conversion. This lives inside
libie/, but is a separate module what follows our logic of splitting
into topical modules, to avoid pulling in not needed stuff, and have
better organization in general.

Olek suggested how to better solve the error to string conversion.

It will be used in follow-up patches in ice, i40e and iavf.

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Suggested-by: Alexander Lobakin <aleksander.lobakin@intel.com>
Signed-off-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
---
 drivers/net/ethernet/intel/libie/Kconfig  |  6 +++
 drivers/net/ethernet/intel/libie/Makefile |  4 ++
 include/linux/net/intel/libie/adminq.h    |  2 +
 drivers/net/ethernet/intel/libie/adminq.c | 50 +++++++++++++++++++++++
 4 files changed, 62 insertions(+)
 create mode 100644 drivers/net/ethernet/intel/libie/adminq.c

diff --git a/drivers/net/ethernet/intel/libie/Kconfig b/drivers/net/ethernet/intel/libie/Kconfig
index 33aff6bc8f81..e6072758e3d8 100644
--- a/drivers/net/ethernet/intel/libie/Kconfig
+++ b/drivers/net/ethernet/intel/libie/Kconfig
@@ -8,3 +8,9 @@ config LIBIE
 	  libie (Intel Ethernet library) is a common library built on top of
 	  libeth and containing vendor-specific routines shared between several
 	  Intel Ethernet drivers.
+
+config LIBIE_ADMINQ
+	tristate
+	help
+	  Helper functions used by Intel Ethernet drivers for administration
+	  queue command interface (aka adminq).
diff --git a/drivers/net/ethernet/intel/libie/Makefile b/drivers/net/ethernet/intel/libie/Makefile
index ffd27fab916a..e98f00b865d3 100644
--- a/drivers/net/ethernet/intel/libie/Makefile
+++ b/drivers/net/ethernet/intel/libie/Makefile
@@ -4,3 +4,7 @@
 obj-$(CONFIG_LIBIE)	+= libie.o
 
 libie-y			:= rx.o
+
+obj-$(CONFIG_LIBIE_ADMINQ) 	+= libie_adminq.o
+
+libie_adminq-y			:= adminq.o
diff --git a/include/linux/net/intel/libie/adminq.h b/include/linux/net/intel/libie/adminq.h
index f8b3194b0742..92ec15f308b2 100644
--- a/include/linux/net/intel/libie/adminq.h
+++ b/include/linux/net/intel/libie/adminq.h
@@ -301,4 +301,6 @@ static inline void *libie_aq_raw(struct libie_aq_desc *desc)
 	return &desc->params.raw;
 }
 
+const char *libie_aq_str(enum libie_aq_err err);
+
 #endif /* __LIBIE_ADMINQ_H */
diff --git a/drivers/net/ethernet/intel/libie/adminq.c b/drivers/net/ethernet/intel/libie/adminq.c
new file mode 100644
index 000000000000..6c95619d1f2b
--- /dev/null
+++ b/drivers/net/ethernet/intel/libie/adminq.c
@@ -0,0 +1,50 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2025 Intel Corporation */
+
+#include <linux/module.h>
+#include <linux/net/intel/libie/adminq.h>
+
+static const char * const libie_aq_str_arr[] = {
+#define LIBIE_AQ_STR(x)					\
+	[LIBIE_AQ_RC_##x]	= "LIBIE_AQ_RC" #x
+	LIBIE_AQ_STR(OK),
+	LIBIE_AQ_STR(EPERM),
+	LIBIE_AQ_STR(ENOENT),
+	LIBIE_AQ_STR(ESRCH),
+	LIBIE_AQ_STR(EIO),
+	LIBIE_AQ_STR(EAGAIN),
+	LIBIE_AQ_STR(ENOMEM),
+	LIBIE_AQ_STR(EACCES),
+	LIBIE_AQ_STR(EBUSY),
+	LIBIE_AQ_STR(EEXIST),
+	LIBIE_AQ_STR(EINVAL),
+	LIBIE_AQ_STR(ENOSPC),
+	LIBIE_AQ_STR(ENOSYS),
+	LIBIE_AQ_STR(EMODE),
+	LIBIE_AQ_STR(ENOSEC),
+	LIBIE_AQ_STR(EBADSIG),
+	LIBIE_AQ_STR(ESVN),
+	LIBIE_AQ_STR(EBADMAN),
+	LIBIE_AQ_STR(EBADBUF),
+#undef LIBIE_AQ_STR
+	"LIBIE_AQ_RC_UNKNOWN",
+};
+
+#define __LIBIE_AQ_STR_NUM (ARRAY_SIZE(libie_aq_str_arr) - 1)
+
+/**
+ * libie_aq_str - get error string based on aq error
+ * @err: admin queue error type
+ */
+const char *libie_aq_str(enum libie_aq_err err)
+{
+	if (err >= ARRAY_SIZE(libie_aq_str_arr) ||
+	    !libie_aq_str_arr[err])
+		err = __LIBIE_AQ_STR_NUM;
+
+	return libie_aq_str_arr[err];
+}
+EXPORT_SYMBOL_NS_GPL(libie_aq_str, "LIBIE_ADMINQ");
+
+MODULE_DESCRIPTION("Intel(R) Ethernet common library - adminq helpers");
+MODULE_LICENSE("GPL");
-- 
2.42.0