[RFC v5.1 1/9] riscv: asm: alternative-macros: Introduce ALTERNATIVE_3() macro

[Conor Dooley]

From: Lad Prabhakar <prabhakar.mahadev-lad.rj at 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 at bp.renesas.com>
Reviewed-by: Heiko Stuebner <heiko.stuebner at vrull.eu>
Reviewed-by: Conor Dooley <conor.dooley at microchip.com>
Signed-off-by: Conor Dooley <conor.dooley at microchip.com>
---
 arch/riscv/include/asm/alternative-macros.h | 46 ++++++++++++++++++---
 1 file changed, 41 insertions(+), 5 deletions(-)

diff --git a/arch/riscv/include/asm/alternative-macros.h b/arch/riscv/include/asm/alternative-macros.h
index 7226e2462584..a5b4691520da 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, \errata_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, errata_id_1, enable_1)	\
 	ALT_NEW_CONTENT(vendor_id_2, errata_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, errata_id, CONFIG_k)	\
@@ -108,6 +124,13 @@
 	__ALTERNATIVE_CFG_2(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))
 
+#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__
 
@@ -152,15 +175,28 @@
 	_ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_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 exist for
+ * different cpu cores.
+ *
+ * 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, errata_id_1, CONFIG_k_1,		\
 				   new_content_2, vendor_id_2, errata_id_2, CONFIG_k_2)		\
 	_ALTERNATIVE_CFG_2(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)
 
+#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
-- 
2.39.0