target/riscv: Allow AIA device emulation to set ireg rmw callback

The AIA device emulation (such as AIA IMSIC) should be able to set
(or provide) AIA ireg read-modify-write callback for each privilege
level of a RISC-V HART.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-id: 20220204174700.534953-9-anup@brainfault.org
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -256,6 +256,22 @@ struct CPURISCVState {
     uint64_t (*rdtime_fn)(uint32_t);
     uint32_t rdtime_fn_arg;
 
+    /* machine specific AIA ireg read-modify-write callback */
+#define AIA_MAKE_IREG(__isel, __priv, __virt, __vgein, __xlen) \
+    ((((__xlen) & 0xff) << 24) | \
+     (((__vgein) & 0x3f) << 20) | \
+     (((__virt) & 0x1) << 18) | \
+     (((__priv) & 0x3) << 16) | \
+     (__isel & 0xffff))
+#define AIA_IREG_ISEL(__ireg)                  ((__ireg) & 0xffff)
+#define AIA_IREG_PRIV(__ireg)                  (((__ireg) >> 16) & 0x3)
+#define AIA_IREG_VIRT(__ireg)                  (((__ireg) >> 18) & 0x1)
+#define AIA_IREG_VGEIN(__ireg)                 (((__ireg) >> 20) & 0x3f)
+#define AIA_IREG_XLEN(__ireg)                  (((__ireg) >> 24) & 0xff)
+    int (*aia_ireg_rmw_fn[4])(void *arg, target_ulong reg,
+        target_ulong *val, target_ulong new_val, target_ulong write_mask);
+    void *aia_ireg_rmw_fn_arg[4];
+
     /* True if in debugger mode.  */
     bool debugger;
 
@@ -433,6 +449,13 @@ uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value);
 #define BOOL_TO_MASK(x) (-!!(x)) /* helper for riscv_cpu_update_mip value */
 void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(uint32_t),
                              uint32_t arg);
+void riscv_cpu_set_aia_ireg_rmw_fn(CPURISCVState *env, uint32_t priv,
+                                   int (*rmw_fn)(void *arg,
+                                                 target_ulong reg,
+                                                 target_ulong *val,
+                                                 target_ulong new_val,
+                                                 target_ulong write_mask),
+                                   void *rmw_fn_arg);
 #endif
 void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv);
 

target/riscv/cpu_helper.c

@@ -396,6 +396,20 @@ void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(uint32_t),
     env->rdtime_fn_arg = arg;
 }
 
+void riscv_cpu_set_aia_ireg_rmw_fn(CPURISCVState *env, uint32_t priv,
+                                   int (*rmw_fn)(void *arg,
+                                                 target_ulong reg,
+                                                 target_ulong *val,
+                                                 target_ulong new_val,
+                                                 target_ulong write_mask),
+                                   void *rmw_fn_arg)
+{
+    if (priv <= PRV_M) {
+        env->aia_ireg_rmw_fn[priv] = rmw_fn;
+        env->aia_ireg_rmw_fn_arg[priv] = rmw_fn_arg;
+    }
+}
+
 void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv)
 {
     if (newpriv > PRV_M) {