[RFC PATCH V4 5/6] riscv: errata: Support T-HEAD custom dcache ops

[guoren@kernel.org]

From: Guo Ren <guoren@linux.alibaba.com>

Here are the DMA sync ops needed by Allwinner D1. RISC-V CMO
extension is still in progress, and D1 is using custom CMO
instructions:

 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 (completion barrier)
 | 31 - 25 | 24 - 20 | 19 - 15 | 14 - 12 | 11 - 7 | 6 - 0 |
   0000000    11001     00000      000      00000  0001011

TODO:
 - Using alternative patch_text based on Atish's patch.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Liu Shaohua <liush@allwinnertech.com>
Signed-off-by: Wei Fu <wefu@redhat.com>
Cc: Atish Patra <atish.patra@wdc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/errata/alternative.c      |  5 +++
 arch/riscv/errata/thead/errata.c     | 61 ++++++++++++++++++++++++++++
 arch/riscv/include/asm/alternative.h |  2 +
 3 files changed, 68 insertions(+)

diff --git a/arch/riscv/errata/alternative.c b/arch/riscv/errata/alternative.c
index b879aa546bc5..396aab1b62c2 100644
--- a/arch/riscv/errata/alternative.c
+++ b/arch/riscv/errata/alternative.c
@@ -46,6 +46,11 @@ static void __init init_alternative(void)
 	case SIFIVE_VENDOR_ID:
 		vendor_patch_func = sifive_errata_patch_func;
 		break;
+#endif
+#ifdef CONFIG_ERRATA_THEAD
+	case THEAD_VENDOR_ID:
+		vendor_patch_func = thead_errata_patch_func;
+		break;
 #endif
 	default:
 		vendor_patch_func = NULL;
diff --git a/arch/riscv/errata/thead/errata.c b/arch/riscv/errata/thead/errata.c
index 1f5c0f82bc23..9c0bf9b25be3 100644
--- a/arch/riscv/errata/thead/errata.c
+++ b/arch/riscv/errata/thead/errata.c
@@ -5,6 +5,7 @@
 #include <linux/bug.h>
 #include <asm/patch.h>
 #include <asm/alternative.h>
+#include <asm/dma-noncoherent.h>
 #include <asm/vendorid_list.h>
 #include <asm/errata_list.h>
 #include <asm/pgtable-bits.h>
@@ -45,3 +46,63 @@ void __init thead_errata_setup_vm(unsigned long archid, unsigned long impid)
 	__riscv_pbmt.mt[MT_IO]	= _PAGE_MT_IO;
 #endif
 }
+
+#ifdef CONFIG_RISCV_DMA_NONCOHERENT
+/*
+ * 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"
+
+#define CACHE_OP_RANGE(OP, start, size) \
+	register unsigned long i asm("a0") = start & ~(L1_CACHE_BYTES - 1); \
+	for (; i < ALIGN(start + size, L1_CACHE_BYTES); i += L1_CACHE_BYTES) \
+		__asm__ __volatile__(OP); \
+	 __asm__ __volatile__(SYNC_S);
+
+static void c900_cache_invalidate(phys_addr_t start, size_t size)
+{
+	CACHE_OP_RANGE(DCACHE_IPA_A0, start, size);
+}
+
+static void c900_cache_clean(phys_addr_t start, size_t size)
+{
+	CACHE_OP_RANGE(DCACHE_CPA_A0, start, size);
+}
+
+static void c900_cache_flush(phys_addr_t start, size_t size)
+{
+	CACHE_OP_RANGE(DCACHE_CIPA_A0, start, size);
+}
+
+static struct riscv_dma_cache_sync c900_dma_cache_sync = {
+	.cache_invalidate = c900_cache_invalidate,
+	.cache_clean = c900_cache_clean,
+	.cache_flush = c900_cache_flush,
+};
+#endif
+
+void __init thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+				     unsigned long archid, unsigned long impid)
+{
+#ifdef CONFIG_RISCV_DMA_NONCOHERENT
+	riscv_dma_cache_sync_set(&c900_dma_cache_sync);
+#endif
+}
diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h
index 3605894081a8..a519671fa7d1 100644
--- a/arch/riscv/include/asm/alternative.h
+++ b/arch/riscv/include/asm/alternative.h
@@ -35,6 +35,8 @@ struct errata_checkfunc_id {
 
 void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
 			      unsigned long archid, unsigned long impid);
+void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+			      unsigned long archid, unsigned long impid);
 
 void thead_errata_setup_vm(unsigned long archid, unsigned long impid);
 #endif
-- 
2.25.1