soc: litex: support little CSR ordering

litex supports little CSR ordering, also support
it in zephyr. historical the default is big ordering.

Signed-off-by: Fin Maaß <[email protected]>

Author: maass-hamburg

soc/litex/litex_vexriscv/Kconfig

@@ -16,4 +16,19 @@ config LITEX_CSR_DATA_WIDTH
 	int "Select Control/Status register width"
 	default 32
 
+choice LITEX_CSR_ORDERING
+	prompt "Select Control/Status register ordering"
+	default LITEX_CSR_ORDERING_BIG
+
+config LITEX_CSR_ORDERING_BIG
+	bool "Big-endian ordering"
+	help
+	  Use big-endian ordering for CSR accesses
+
+config LITEX_CSR_ORDERING_LITTLE
+	bool "Little-endian ordering"
+	help
+	  Use little-endian ordering for CSR accesses
+endchoice
+
 endif # SOC_LITEX_VEXRISCV

soc/litex/litex_vexriscv/soc.h

@@ -24,8 +24,13 @@ static inline uint8_t litex_read8(mem_addr_t addr)
 static inline uint16_t litex_read16(mem_addr_t addr)
 {
 #if CONFIG_LITEX_CSR_DATA_WIDTH == 8
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	return (sys_read8(addr) << 8)
 		| sys_read8(addr + 0x4);
+#else
+	return sys_read8(addr)
+		| (sys_read8(addr + 0x4) << 8);
+#endif
 #else /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
 	return sys_read16(addr);
 #endif
@@ -34,10 +39,17 @@ static inline uint16_t litex_read16(mem_addr_t addr)
 static inline uint32_t litex_read32(mem_addr_t addr)
 {
 #if CONFIG_LITEX_CSR_DATA_WIDTH == 8
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	return (sys_read8(addr) << 24)
 		| (sys_read8(addr + 0x4) << 16)
 		| (sys_read8(addr + 0x8) << 8)
 		| sys_read8(addr + 0xc);
+#else
+	return sys_read8(addr)
+		| (sys_read8(addr + 0x4) << 8)
+		| (sys_read8(addr + 0x8) << 16)
+		| (sys_read8(addr + 0xc) << 24);
+#endif
 #else /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
 	return sys_read32(addr);
 #endif
@@ -46,6 +58,7 @@ static inline uint32_t litex_read32(mem_addr_t addr)
 static inline uint64_t litex_read64(mem_addr_t addr)
 {
 #if CONFIG_LITEX_CSR_DATA_WIDTH == 8
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	return (((uint64_t)sys_read8(addr)) << 56)
 		| ((uint64_t)sys_read8(addr + 0x4) << 48)
 		| ((uint64_t)sys_read8(addr + 0x8) << 40)
@@ -54,8 +67,22 @@ static inline uint64_t litex_read64(mem_addr_t addr)
 		| ((uint64_t)sys_read8(addr + 0x14) << 16)
 		| ((uint64_t)sys_read8(addr + 0x18) << 8)
 		| (uint64_t)sys_read8(addr + 0x1c);
+#else
+	return (uint64_t)sys_read8(addr)
+		| ((uint64_t)sys_read8(addr + 0x4) << 8)
+		| ((uint64_t)sys_read8(addr + 0x8) << 16)
+		| ((uint64_t)sys_read8(addr + 0xc) << 24)
+		| ((uint64_t)sys_read8(addr + 0x10) << 32)
+		| ((uint64_t)sys_read8(addr + 0x14) << 40)
+		| ((uint64_t)sys_read8(addr + 0x18) << 48)
+		| ((uint64_t)sys_read8(addr + 0x1c) << 56);
+#endif
 #else /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	return ((uint64_t)sys_read32(addr) << 32) | (uint64_t)sys_read32(addr + 0x4);
+#else
+	return sys_read64(addr);
+#endif
 #endif
 }
 
@@ -67,8 +94,13 @@ static inline void litex_write8(uint8_t value, mem_addr_t addr)
 static inline void litex_write16(uint16_t value, mem_addr_t addr)
 {
 #if CONFIG_LITEX_CSR_DATA_WIDTH == 8
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	sys_write8(value >> 8, addr);
 	sys_write8(value, addr + 0x4);
+#else
+	sys_write8(value, addr);
+	sys_write8(value >> 8, addr + 0x4);
+#endif
 #else /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
 	sys_write16(value, addr);
 #endif
@@ -77,10 +109,17 @@ static inline void litex_write16(uint16_t value, mem_addr_t addr)
 static inline void litex_write32(uint32_t value, mem_addr_t addr)
 {
 #if CONFIG_LITEX_CSR_DATA_WIDTH == 8
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	sys_write8(value >> 24, addr);
 	sys_write8(value >> 16, addr + 0x4);
 	sys_write8(value >> 8, addr + 0x8);
 	sys_write8(value, addr + 0xC);
+#else
+	sys_write8(value, addr);
+	sys_write8(value >> 8, addr + 0x4);
+	sys_write8(value >> 16, addr + 0x8);
+	sys_write8(value >> 24, addr + 0xC);
+#endif
 #else /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
 	sys_write32(value, addr);
 #endif
@@ -89,6 +128,7 @@ static inline void litex_write32(uint32_t value, mem_addr_t addr)
 static inline void litex_write64(uint64_t value, mem_addr_t addr)
 {
 #if CONFIG_LITEX_CSR_DATA_WIDTH == 8
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	sys_write8(value >> 56, addr);
 	sys_write8(value >> 48, addr + 0x4);
 	sys_write8(value >> 40, addr + 0x8);
@@ -97,9 +137,23 @@ static inline void litex_write64(uint64_t value, mem_addr_t addr)
 	sys_write8(value >> 16, addr + 0x14);
 	sys_write8(value >> 8, addr + 0x18);
 	sys_write8(value, addr + 0x1C);
+#else
+	sys_write8(value, addr);
+	sys_write8(value >> 8, addr + 0x4);
+	sys_write8(value >> 16, addr + 0x8);
+	sys_write8(value >> 24, addr + 0xC);
+	sys_write8(value >> 32, addr + 0x10);
+	sys_write8(value >> 40, addr + 0x14);
+	sys_write8(value >> 48, addr + 0x18);
+	sys_write8(value >> 56, addr + 0x1C);
+#endif
 #else /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
+#ifdef CONFIG_LITEX_CSR_ORDERING_BIG
 	sys_write32(value >> 32, addr);
 	sys_write32(value, addr + 0x4);
+#else
+	sys_write64(value, addr);
+#endif
 #endif /* CONFIG_LITEX_CSR_DATA_WIDTH == 8 */
 }