riscv: lib: Split out support for T-Head cache management operations

Designed before a standard set of cache management operations defined in
RISC-V, earlier T-Head cores like C906 and C910 provide CMO through the
customized extension XTheadCMO, which has been used in the CV1800B port
of U-Boot.

This patch splits XTheadCMO-related code into a generic module, allowing
SoCs shipping T-Head cores to share the code.

Link: https://github.com/XUANTIE-RV/thead-extension-spec
Signed-off-by: Yao Zi <ziyao@disroot.org>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>

2 files changed, 46 insertions, 0 deletions

diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 189b35c24d3..db8d235c699 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_CMD_BOOTI) += bootm.o image.o
 obj-$(CONFIG_CMD_GO) += boot.o
 obj-y	+= cache.o
 obj-$(CONFIG_SIFIVE_CACHE) += sifive_cache.o
+obj-$(CONFIG_SYS_CACHE_THEAD_CMO) += thead_cmo.o
 ifeq ($(CONFIG_$(PHASE_)RISCV_MMODE),y)
 obj-$(CONFIG_$(PHASE_)RISCV_ACLINT) += aclint_ipi.o
 obj-$(CONFIG_ANDES_PLICSW) += andes_plicsw.o
diff --git a/arch/riscv/lib/thead_cmo.c b/arch/riscv/lib/thead_cmo.c
new file mode 100644
index 00000000000..b8051e29e02
--- /dev/null
+++ b/arch/riscv/lib/thead_cmo.c
@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2024, Kongyang Liu <seashell11234455@gmail.com>
+ */
+
+#include <cpu_func.h>
+
+/*
+ * dcache.ipa rs1 (invalidate)
+ * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
+ *   0000001    01010      rs1       000      00000  0001011
+ *
+ * dcache.cpa rs1 (clean)
+ * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
+ *   0000001    01001      rs1       000      00000  0001011
+ *
+ * dcache.cipa rs1 (clean then invalidate)
+ * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
+ *   0000001    01011      rs1       000      00000  0001011
+ *
+ * sync.s
+ * | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
+ *   0000000    11001     00000      000      00000  0001011
+ */
+#define DCACHE_IPA_A0	".long 0x02a5000b"
+#define DCACHE_CPA_A0	".long 0x0295000b"
+#define DCACHE_CIPA_A0	".long 0x02b5000b"
+
+#define SYNC_S		".long 0x0190000b"
+
+void invalidate_dcache_range(unsigned long start, unsigned long end)
+{
+	register unsigned long i asm("a0") = start & ~(CONFIG_SYS_CACHELINE_SIZE - 1);
+	for (; i < end; i += CONFIG_SYS_CACHELINE_SIZE)
+		__asm__ __volatile__(DCACHE_IPA_A0);
+	__asm__ __volatile__(SYNC_S);
+}
+
+void flush_dcache_range(unsigned long start, unsigned long end)
+{
+	register unsigned long i asm("a0") = start & ~(CONFIG_SYS_CACHELINE_SIZE - 1);
+	for (; i < end; i += CONFIG_SYS_CACHELINE_SIZE)
+		__asm__ __volatile__(DCACHE_CPA_A0);
+	__asm__ __volatile__(SYNC_S);
+}