[RFC PATCH 01/11] target/riscv: Add CLIC CSR mintstatus

[LIU Zhiwei <zhiwei_liu@c-sky.com>]

CSR mintstatus holds the active interrupt level for each supported
privilege mode. sintstatus, and user, uintstatus, provide restricted
views of mintstatus.

Signed-off-by: LIU Zhiwei <zhiwei_liu@c-sky.com>
---
 target/riscv/cpu.h      |  2 ++
 target/riscv/cpu_bits.h | 11 +++++++++++
 target/riscv/csr.c      | 26 ++++++++++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 0a33d387ba..1a44ca62c7 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -159,6 +159,7 @@ struct CPURISCVState {
     target_ulong mip;
 
     uint32_t miclaim;
+    uint32_t mintstatus; /* clic-spec */
 
     target_ulong mie;
     target_ulong mideleg;
@@ -243,6 +244,7 @@ struct CPURISCVState {
 
     /* Fields from here on are preserved across CPU reset. */
     QEMUTimer *timer; /* Internal timer */
+    void *clic;       /* clic interrupt controller */
 };
 
 OBJECT_DECLARE_TYPE(RISCVCPU, RISCVCPUClass,
diff --git a/target/riscv/cpu_bits.h b/target/riscv/cpu_bits.h
index caf4599207..c4ce6ec3d9 100644
--- a/target/riscv/cpu_bits.h
+++ b/target/riscv/cpu_bits.h
@@ -165,6 +165,7 @@
 #define CSR_MCAUSE          0x342
 #define CSR_MTVAL           0x343
 #define CSR_MIP             0x344
+#define CSR_MINTSTATUS      0x346 /* clic-spec-draft */
 
 /* Legacy Machine Trap Handling (priv v1.9.1) */
 #define CSR_MBADADDR        0x343
@@ -183,6 +184,7 @@
 #define CSR_SCAUSE          0x142
 #define CSR_STVAL           0x143
 #define CSR_SIP             0x144
+#define CSR_SINTSTATUS      0x146 /* clic-spec-draft */
 
 /* Legacy Supervisor Trap Handling (priv v1.9.1) */
 #define CSR_SBADADDR        0x143
@@ -585,6 +587,15 @@
 #define SIP_STIP                           MIP_STIP
 #define SIP_SEIP                           MIP_SEIP
 
+/* mintstatus */
+#define MINTSTATUS_MIL                     0xff000000 /* mil[7:0] */
+#define MINTSTATUS_SIL                     0x0000ff00 /* sil[7:0] */
+#define MINTSTATUS_UIL                     0x000000ff /* uil[7:0] */
+
+/* sintstatus */
+#define SINTSTATUS_SIL                     0x0000ff00 /* sil[7:0] */
+#define SINTSTATUS_UIL                     0x000000ff /* uil[7:0] */
+
 /* MIE masks */
 #define MIE_SEIE                           (1 << IRQ_S_EXT)
 #define MIE_UEIE                           (1 << IRQ_U_EXT)
diff --git a/target/riscv/csr.c b/target/riscv/csr.c
index d2585395bf..320b18ab60 100644
--- a/target/riscv/csr.c
+++ b/target/riscv/csr.c
@@ -188,6 +188,12 @@ static int pmp(CPURISCVState *env, int csrno)
 {
     return -!riscv_feature(env, RISCV_FEATURE_PMP);
 }
+
+static int clic(CPURISCVState *env, int csrno)
+{
+    return !!env->clic;
+}
+
 #endif
 
 /* User Floating-Point CSRs */
@@ -734,6 +740,12 @@ static int rmw_mip(CPURISCVState *env, int csrno, target_ulong *ret_value,
     return 0;
 }
 
+static int read_mintstatus(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    *val = env->mintstatus;
+    return 0;
+}
+
 /* Supervisor Trap Setup */
 static int read_sstatus(CPURISCVState *env, int csrno, target_ulong *val)
 {
@@ -893,6 +905,13 @@ static int rmw_sip(CPURISCVState *env, int csrno, target_ulong *ret_value,
     return ret;
 }
 
+static int read_sintstatus(CPURISCVState *env, int csrno, target_ulong *val)
+{
+    target_ulong mask = SINTSTATUS_SIL | SINTSTATUS_UIL;
+    *val = env->mintstatus & mask;
+    return 0;
+}
+
 /* Supervisor Protection and Translation */
 static int read_satp(CPURISCVState *env, int csrno, target_ulong *val)
 {
@@ -1644,5 +1663,12 @@ riscv_csr_operations csr_ops[CSR_TABLE_SIZE] = {
     [CSR_MHPMCOUNTER29H] = { "mhpmcounter29h", any32,  read_zero },
     [CSR_MHPMCOUNTER30H] = { "mhpmcounter30h", any32,  read_zero },
     [CSR_MHPMCOUNTER31H] = { "mhpmcounter31h", any32,  read_zero },
+
+    /* Machine Mode Core Level Interrupt Controller */
+    [CSR_MINTSTATUS] = { "mintstatus", clic,  read_mintstatus },
+
+    /* Supervisor Mode Core Level Interrupt Controller */
+    [CSR_SINTSTATUS] = { "sintstatus", clic,  read_sintstatus },
+
 #endif /* !CONFIG_USER_ONLY */
 };
-- 
2.25.1