target/riscv: Add initial support for the Sdtrig extension

This adds initial support for the Sdtrig extension via the Trigger
Module, as defined in the RISC-V Debug Specification [1].

Only "Address / Data Match" trigger (type 2) is implemented as of now,
which is mainly used for hardware breakpoint and watchpoint. The number
of type 2 triggers implemented is 2, which is the number that we can
find in the SiFive U54/U74 cores.

[1] https://github.com/riscv/riscv-debug-spec/raw/master/riscv-debug-stable.pdf

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20220315065529.62198-2-bmeng.cn@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/debug.h

@@ -0,0 +1,108 @@
+/*
+ * QEMU RISC-V Native Debug Support
+ *
+ * Copyright (c) 2022 Wind River Systems, Inc.
+ *
+ * Author:
+ *   Bin Meng <bin.meng@windriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef RISCV_DEBUG_H
+#define RISCV_DEBUG_H
+
+/* trigger indexes implemented */
+enum {
+    TRIGGER_TYPE2_IDX_0 = 0,
+    TRIGGER_TYPE2_IDX_1,
+    TRIGGER_TYPE2_NUM,
+    TRIGGER_NUM = TRIGGER_TYPE2_NUM
+};
+
+/* register index of tdata CSRs */
+enum {
+    TDATA1 = 0,
+    TDATA2,
+    TDATA3,
+    TDATA_NUM
+};
+
+typedef enum {
+    TRIGGER_TYPE_NO_EXIST = 0,      /* trigger does not exist */
+    TRIGGER_TYPE_AD_MATCH = 2,      /* address/data match trigger */
+    TRIGGER_TYPE_INST_CNT = 3,      /* instruction count trigger */
+    TRIGGER_TYPE_INT = 4,           /* interrupt trigger */
+    TRIGGER_TYPE_EXCP = 5,          /* exception trigger */
+    TRIGGER_TYPE_AD_MATCH6 = 6,     /* new address/data match trigger */
+    TRIGGER_TYPE_EXT_SRC = 7,       /* external source trigger */
+    TRIGGER_TYPE_UNAVAIL = 15       /* trigger exists, but unavailable */
+} trigger_type_t;
+
+typedef struct {
+    target_ulong mcontrol;
+    target_ulong maddress;
+    struct CPUBreakpoint *bp;
+    struct CPUWatchpoint *wp;
+} type2_trigger_t;
+
+/* tdata field masks */
+
+#define RV32_TYPE(t)    ((uint32_t)(t) << 28)
+#define RV32_TYPE_MASK  (0xf << 28)
+#define RV32_DMODE      BIT(27)
+#define RV64_TYPE(t)    ((uint64_t)(t) << 60)
+#define RV64_TYPE_MASK  (0xfULL << 60)
+#define RV64_DMODE      BIT_ULL(59)
+
+/* mcontrol field masks */
+
+#define TYPE2_LOAD      BIT(0)
+#define TYPE2_STORE     BIT(1)
+#define TYPE2_EXEC      BIT(2)
+#define TYPE2_U         BIT(3)
+#define TYPE2_S         BIT(4)
+#define TYPE2_M         BIT(6)
+#define TYPE2_MATCH     (0xf << 7)
+#define TYPE2_CHAIN     BIT(11)
+#define TYPE2_ACTION    (0xf << 12)
+#define TYPE2_SIZELO    (0x3 << 16)
+#define TYPE2_TIMING    BIT(18)
+#define TYPE2_SELECT    BIT(19)
+#define TYPE2_HIT       BIT(20)
+#define TYPE2_SIZEHI    (0x3 << 21) /* RV64 only */
+
+/* access size */
+enum {
+    SIZE_ANY = 0,
+    SIZE_1B,
+    SIZE_2B,
+    SIZE_4B,
+    SIZE_6B,
+    SIZE_8B,
+    SIZE_10B,
+    SIZE_12B,
+    SIZE_14B,
+    SIZE_16B,
+    SIZE_NUM = 16
+};
+
+bool tdata_available(CPURISCVState *env, int tdata_index);
+
+target_ulong tselect_csr_read(CPURISCVState *env);
+void tselect_csr_write(CPURISCVState *env, target_ulong val);
+
+target_ulong tdata_csr_read(CPURISCVState *env, int tdata_index);
+void tdata_csr_write(CPURISCVState *env, int tdata_index, target_ulong val);
+
+#endif /* RISCV_DEBUG_H */