[PATCH v8 1/7] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro

[Prabhakar <prabhakar.csengg@gmail.com>]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Introduce ALTERNATIVE_3() macro.

A vendor wants to replace an old_content, but another vendor has used
ALTERNATIVE_2() to patch its customized content at the same location.
In this case, this vendor can use macro ALTERNATIVE_3() and then replace
ALTERNATIVE_2() with ALTERNATIVE_3() to append its customized content.

While at it update comment above ALTERNATIVE_2() macro and make it generic
so that the comment holds good for any new addition of ALTERNATIVE_X()
macros.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
v5->v8
* Added RB tags from Conor and Heiko
* Fixed review comments pointed by Geert and Conor

v4->v5
* Rebased the patch on top of Andrew's series (now in Palmers for next-branch)
* Updated comment for ALTERNATIVE_x() as suggested by Heiko

RFC v3 -> v4
* New patch
---
 arch/riscv/include/asm/alternative-macros.h | 51 +++++++++++++++++++--
 1 file changed, 46 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
index b8c55fb3ab2c..fd5f99714f29 100644
--- a/arch/riscv/include/asm/alternative-macros.h
+++ b/arch/riscv/include/asm/alternative-macros.h
@@ -50,8 +50,17 @@
 	ALT_NEW_CONTENT \vendor_id_2, \patch_id_2, \enable_2, "\new_c_2"
 .endm
 
+.macro ALTERNATIVE_CFG_3 old_c, new_c_1, vendor_id_1, errata_id_1, enable_1,		\
+				new_c_2, vendor_id_2, errata_id_2, enable_2,		\
+				new_c_3, vendor_id_3, errata_id_3, enable_3
+	ALTERNATIVE_CFG_2 "\old_c", "\new_c_1", \vendor_id_1, \errata_id_1, \enable_1,	\
+				    "\new_c_2", \vendor_id_2, \errata_id_2, \enable_2
+	ALT_NEW_CONTENT \vendor_id_3, \errata_id_3, \enable_3, "\new_c_3"
+.endm
+
 #define __ALTERNATIVE_CFG(...)		ALTERNATIVE_CFG __VA_ARGS__
 #define __ALTERNATIVE_CFG_2(...)	ALTERNATIVE_CFG_2 __VA_ARGS__
+#define __ALTERNATIVE_CFG_3(...)	ALTERNATIVE_CFG_3 __VA_ARGS__
 
 #else /* !__ASSEMBLY__ */
 
@@ -98,6 +107,13 @@
 	__ALTERNATIVE_CFG(old_c, new_c_1, vendor_id_1, patch_id_1, enable_1)	\
 	ALT_NEW_CONTENT(vendor_id_2, patch_id_2, enable_2, new_c_2)
 
+#define __ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1,	\
+				   new_c_2, vendor_id_2, errata_id_2, enable_2,	\
+				   new_c_3, vendor_id_3, errata_id_3, enable_3)	\
+	__ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, errata_id_1, enable_1,	\
+				   new_c_2, vendor_id_2, errata_id_2, enable_2)	\
+	ALT_NEW_CONTENT(vendor_id_3, errata_id_3, enable_3, new_c_3)
+
 #endif /* __ASSEMBLY__ */
 
 #define _ALTERNATIVE_CFG(old_c, new_c, vendor_id, patch_id, CONFIG_k)	\
@@ -108,6 +124,13 @@
 	__ALTERNATIVE_CFG_2(old_c, new_c_1, vendor_id_1, patch_id_1, IS_ENABLED(CONFIG_k_1),	\
 				   new_c_2, vendor_id_2, patch_id_2, IS_ENABLED(CONFIG_k_2))
 
+#define _ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, CONFIG_k_1,		\
+				  new_c_2, vendor_id_2, errata_id_2, CONFIG_k_2,		\
+				  new_c_3, vendor_id_3, errata_id_3, CONFIG_k_3)		\
+	__ALTERNATIVE_CFG_3(old_c, new_c_1, vendor_id_1, errata_id_1, IS_ENABLED(CONFIG_k_1),	\
+				   new_c_2, vendor_id_2, errata_id_2, IS_ENABLED(CONFIG_k_2),	\
+				   new_c_3, vendor_id_3, errata_id_3, IS_ENABLED(CONFIG_k_3))
+
 #else /* CONFIG_RISCV_ALTERNATIVE */
 #ifdef __ASSEMBLY__
 
@@ -121,6 +144,9 @@
 #define _ALTERNATIVE_CFG_2(old_c, ...)	\
 	ALTERNATIVE_CFG old_c
 
+#define _ALTERNATIVE_CFG_3(old_c, ...)	\
+	ALTERNATIVE_CFG old_c
+
 #else /* !__ASSEMBLY__ */
 
 #define __ALTERNATIVE_CFG(old_c)	\
@@ -132,6 +158,9 @@
 #define _ALTERNATIVE_CFG_2(old_c, ...)	\
 	__ALTERNATIVE_CFG(old_c)
 
+#define _ALTERNATIVE_CFG_3(old_c, ...)	\
+	__ALTERNATIVE_CFG(old_c)
+
 #endif /* __ASSEMBLY__ */
 #endif /* CONFIG_RISCV_ALTERNATIVE */
 
@@ -152,15 +181,27 @@
 	_ALTERNATIVE_CFG(old_content, new_content, vendor_id, patch_id, CONFIG_k)
 
 /*
- * A vendor wants to replace an old_content, but another vendor has used
- * ALTERNATIVE() to patch its customized content at the same location. In
- * this case, this vendor can create a new macro ALTERNATIVE_2() based
- * on the following sample code and then replace ALTERNATIVE() with
- * ALTERNATIVE_2() to append its customized content.
+ * ALTERNATIVE_x macros allow providing multiple replacement options
+ * for an ALTERNATIVE code section. This is helpful if multiple
+ * implementation variants for the same functionality.
+ *
+ * Usage:
+ *   ALTERNATIVE_x(old_content,
+ *      new_content1, vendor_id1, errata_id1, CONFIG_k1,
+ *      new_content2, vendor_id2, errata_id2, CONFIG_k2,
+ *      ...
+ *      new_contentx, vendor_idx, errata_idx, CONFIG_kx)
  */
 #define ALTERNATIVE_2(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,		\
 				   new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2)		\
 	_ALTERNATIVE_CFG_2(old_content, new_content_1, vendor_id_1, patch_id_1, CONFIG_k_1,	\
 					new_content_2, vendor_id_2, patch_id_2, CONFIG_k_2)
 
+#define ALTERNATIVE_3(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1,		\
+				   new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2,		\
+				   new_content_3, vendor_id_3, errata_id_3, CONFIG_k_3)		\
+	_ALTERNATIVE_CFG_3(old_content, new_content_1, vendor_id_1, errata_id_1, CONFIG_k_1,	\
+					new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2,	\
+					new_content_3, vendor_id_3, errata_id_3, CONFIG_k_3)
+
 #endif
-- 
2.25.1