[PATCH v8] target/hexagon: Add hex_interrupts support

[Brian Cain <brian.cain@oss.qualcomm.com>]

From: Brian Cain <bcain@quicinc.com>

Co-authored-by: Taylor Simpson <ltaylorsimpson@gmail.com>
Co-authored-by: Sid Manning <sidneym@quicinc.com>
Co-authored-by: Michael Lambert <mlambert@quicinc.com>
Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>
---
 target/hexagon/cpu.h            |   2 +
 target/hexagon/hex_interrupts.h |  15 ++
 target/hexagon/cpu.c            |   4 +
 target/hexagon/hex_interrupts.c | 371 ++++++++++++++++++++++++++++++++
 4 files changed, 392 insertions(+)
 create mode 100644 target/hexagon/hex_interrupts.h
 create mode 100644 target/hexagon/hex_interrupts.c

diff --git a/target/hexagon/cpu.h b/target/hexagon/cpu.h
index dbdc456d732..1b225e35abc 100644
--- a/target/hexagon/cpu.h
+++ b/target/hexagon/cpu.h
@@ -197,6 +197,8 @@ struct ArchCPU {
     bool short_circuit;
 #ifndef CONFIG_USER_ONLY
     HexagonTLBState *tlb;
+    uint32_t boot_addr;
+    HexagonGlobalRegState *globalregs;
     uint32_t htid;
 #endif
 };
diff --git a/target/hexagon/hex_interrupts.h b/target/hexagon/hex_interrupts.h
new file mode 100644
index 00000000000..6b6f5403633
--- /dev/null
+++ b/target/hexagon/hex_interrupts.h
@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef HEX_INTERRUPTS_H
+#define HEX_INTERRUPTS_H
+
+bool hex_check_interrupts(CPUHexagonState *env);
+void hex_clear_interrupts(CPUHexagonState *env, uint32_t mask, uint32_t type);
+void hex_raise_interrupts(CPUHexagonState *env, uint32_t mask, uint32_t type);
+void hex_interrupt_update(CPUHexagonState *env);
+
+#endif
diff --git a/target/hexagon/cpu.c b/target/hexagon/cpu.c
index 73aca0a4217..eb1f7049298 100644
--- a/target/hexagon/cpu.c
+++ b/target/hexagon/cpu.c
@@ -54,6 +54,9 @@ static const Property hexagon_cpu_properties[] = {
 #ifndef CONFIG_USER_ONLY
     DEFINE_PROP_LINK("tlb", HexagonCPU, tlb, TYPE_HEXAGON_TLB,
                      HexagonTLBState *),
+    DEFINE_PROP_UINT32("exec-start-addr", HexagonCPU, boot_addr, 0xffffffff),
+    DEFINE_PROP_LINK("global-regs", HexagonCPU, globalregs,
+        TYPE_HEXAGON_GLOBALREG, HexagonGlobalRegState *),
     DEFINE_PROP_UINT32("htid", HexagonCPU, htid, 0),
 #endif
     DEFINE_PROP_BOOL("lldb-compat", HexagonCPU, lldb_compat, false),
@@ -336,6 +339,7 @@ static void hexagon_cpu_reset_hold(Object *obj, ResetType type)
 
     env->t_sreg[HEX_SREG_HTID] = cpu->htid;
     env->threadId = cpu->htid;
+    env->gpr[HEX_REG_PC] = cpu->boot_addr;
 #endif
     env->cause_code = HEX_EVENT_NONE;
 }
diff --git a/target/hexagon/hex_interrupts.c b/target/hexagon/hex_interrupts.c
new file mode 100644
index 00000000000..3534481da24
--- /dev/null
+++ b/target/hexagon/hex_interrupts.c
@@ -0,0 +1,371 @@
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/main-loop.h"
+#include "cpu.h"
+#include "cpu_helper.h"
+#include "exec/cpu-interrupt.h"
+#include "hex_interrupts.h"
+#include "macros.h"
+#include "sys_macros.h"
+#include "system/cpus.h"
+#include "hw/hexagon/hexagon_globalreg.h"
+
+static bool hex_is_qualified_for_int(CPUHexagonState *env, int int_num);
+
+static bool get_syscfg_gie(CPUHexagonState *env)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t syscfg =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_SYSCFG,
+                               env->threadId);
+    return GET_SYSCFG_FIELD(SYSCFG_GIE, syscfg);
+}
+
+static bool get_ssr_ex(CPUHexagonState *env)
+{
+    uint32_t ssr = env->t_sreg[HEX_SREG_SSR];
+    return GET_SSR_FIELD(SSR_EX, ssr);
+}
+
+static bool get_ssr_ie(CPUHexagonState *env)
+{
+    uint32_t ssr = env->t_sreg[HEX_SREG_SSR];
+    return GET_SSR_FIELD(SSR_IE, ssr);
+}
+
+/* Do these together so we only have to call hexagon_modify_ssr once */
+static void set_ssr_ex_cause(CPUHexagonState *env, int ex, uint32_t cause)
+{
+    uint32_t old, new;
+
+    old = env->t_sreg[HEX_SREG_SSR];
+    SET_SYSTEM_FIELD(env, HEX_SREG_SSR, SSR_EX, ex);
+    SET_SYSTEM_FIELD(env, HEX_SREG_SSR, SSR_CAUSE, cause);
+    new = env->t_sreg[HEX_SREG_SSR];
+    hexagon_modify_ssr(env, new, old);
+}
+
+static bool get_iad_bit(CPUHexagonState *env, int int_num)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    uint32_t iad = GET_FIELD(IPENDAD_IAD, ipendad);
+    return extract32(iad, int_num, 1);
+}
+
+static void set_iad_bit(CPUHexagonState *env, int int_num, int val)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    uint32_t iad = GET_FIELD(IPENDAD_IAD, ipendad);
+    iad = deposit32(iad, int_num, 1, val);
+    fSET_FIELD(ipendad, IPENDAD_IAD, iad);
+    hexagon_globalreg_write(cpu->globalregs, HEX_SREG_IPENDAD,
+                            ipendad, env->threadId);
+}
+
+static uint32_t get_ipend(CPUHexagonState *env)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    return GET_FIELD(IPENDAD_IPEND, ipendad);
+}
+
+static inline bool get_ipend_bit(CPUHexagonState *env, int int_num)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    uint32_t ipend = GET_FIELD(IPENDAD_IPEND, ipendad);
+    return extract32(ipend, int_num, 1);
+}
+
+static void clear_ipend(CPUHexagonState *env, uint32_t mask)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    uint32_t ipend = GET_FIELD(IPENDAD_IPEND, ipendad);
+    ipend &= ~mask;
+    fSET_FIELD(ipendad, IPENDAD_IPEND, ipend);
+    hexagon_globalreg_write(cpu->globalregs, HEX_SREG_IPENDAD,
+                            ipendad, env->threadId);
+}
+
+static void set_ipend(CPUHexagonState *env, uint32_t mask)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    uint32_t ipend = GET_FIELD(IPENDAD_IPEND, ipendad);
+    ipend |= mask;
+    fSET_FIELD(ipendad, IPENDAD_IPEND, ipend);
+    hexagon_globalreg_write(cpu->globalregs, HEX_SREG_IPENDAD,
+                            ipendad, env->threadId);
+}
+
+static void set_ipend_bit(CPUHexagonState *env, int int_num, int val)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t ipendad =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_IPENDAD,
+                               env->threadId);
+    uint32_t ipend = GET_FIELD(IPENDAD_IPEND, ipendad);
+    ipend = deposit32(ipend, int_num, 1, val);
+    fSET_FIELD(ipendad, IPENDAD_IPEND, ipend);
+    hexagon_globalreg_write(cpu->globalregs, HEX_SREG_IPENDAD,
+                            ipendad, env->threadId);
+}
+
+static bool get_imask_bit(CPUHexagonState *env, int int_num)
+{
+    uint32_t imask = env->t_sreg[HEX_SREG_IMASK];
+    return extract32(imask, int_num, 1);
+}
+
+static uint32_t get_prio(CPUHexagonState *env)
+{
+    uint32_t stid = env->t_sreg[HEX_SREG_STID];
+    return extract32(stid, reg_field_info[STID_PRIO].offset,
+                     reg_field_info[STID_PRIO].width);
+}
+
+static void set_elr(CPUHexagonState *env, uint32_t val)
+{
+    env->t_sreg[HEX_SREG_ELR] = val;
+}
+
+static bool get_schedcfgen(CPUHexagonState *env)
+{
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t schedcfg =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_SCHEDCFG,
+                               env->threadId);
+    return extract32(schedcfg, reg_field_info[SCHEDCFG_EN].offset,
+                     reg_field_info[SCHEDCFG_EN].width);
+}
+
+static bool is_lowest_prio(CPUHexagonState *env, int int_num)
+{
+    uint32_t my_prio = get_prio(env);
+    CPUState *cs;
+
+    CPU_FOREACH(cs) {
+        CPUHexagonState *hex_env = cpu_env(cs);
+        if (!hex_is_qualified_for_int(hex_env, int_num)) {
+            continue;
+        }
+
+        /* Note that lower values indicate *higher* priority */
+        if (my_prio < get_prio(hex_env)) {
+            return false;
+        }
+    }
+    return true;
+}
+
+static bool hex_is_qualified_for_int(CPUHexagonState *env, int int_num)
+{
+    bool syscfg_gie = get_syscfg_gie(env);
+    bool iad = get_iad_bit(env, int_num);
+    bool ssr_ie = get_ssr_ie(env);
+    bool ssr_ex = get_ssr_ex(env);
+    bool imask = get_imask_bit(env, int_num);
+
+    return syscfg_gie && !iad && ssr_ie && !ssr_ex && !imask;
+}
+
+static void clear_pending_locks(CPUHexagonState *env)
+{
+    g_assert(bql_locked());
+    if (env->k0_lock_state == HEX_LOCK_WAITING) {
+        env->k0_lock_state = HEX_LOCK_UNLOCKED;
+    }
+    if (env->tlb_lock_state == HEX_LOCK_WAITING) {
+        env->tlb_lock_state = HEX_LOCK_UNLOCKED;
+    }
+}
+
+static bool should_not_exec(CPUHexagonState *env)
+{
+    return (get_exe_mode(env) == HEX_EXE_MODE_WAIT);
+}
+
+static void restore_state(CPUHexagonState *env, bool int_accepted)
+{
+    CPUState *cs = env_cpu(env);
+    cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD | CPU_INTERRUPT_SWI);
+    if (!int_accepted && should_not_exec(env)) {
+        cpu_interrupt(cs, CPU_INTERRUPT_HALT);
+    }
+}
+
+static void hex_accept_int(CPUHexagonState *env, int int_num)
+{
+    CPUState *cs = env_cpu(env);
+    HexagonCPU *cpu = env_archcpu(env);
+    uint32_t evb =
+        hexagon_globalreg_read(cpu->globalregs, HEX_SREG_EVB,
+                               env->threadId);
+    const int exe_mode = get_exe_mode(env);
+    const bool in_wait_mode = exe_mode == HEX_EXE_MODE_WAIT;
+
+    set_ipend_bit(env, int_num, 0);
+    set_iad_bit(env, int_num, 1);
+    set_ssr_ex_cause(env, 1, HEX_CAUSE_INT0 | int_num);
+    cs->exception_index = HEX_EVENT_INT0 + int_num;
+    env->cause_code = HEX_EVENT_INT0 + int_num;
+    clear_pending_locks(env);
+    if (in_wait_mode) {
+        qemu_log_mask(CPU_LOG_INT,
+            "%s: thread " TARGET_FMT_ld " resuming, exiting WAIT mode\n",
+            __func__, env->threadId);
+        set_elr(env, env->wait_next_pc);
+        clear_wait_mode(env);
+        cs->halted = false;
+    } else if (env->k0_lock_state == HEX_LOCK_WAITING) {
+        g_assert_not_reached();
+    } else {
+        set_elr(env, env->gpr[HEX_REG_PC]);
+    }
+    env->gpr[HEX_REG_PC] = evb | (cs->exception_index << 2);
+    if (get_ipend(env) == 0) {
+        restore_state(env, true);
+    }
+}
+
+
+bool hex_check_interrupts(CPUHexagonState *env)
+{
+    CPUState *cs = env_cpu(env);
+    bool int_handled = false;
+    bool ssr_ex = get_ssr_ex(env);
+    int max_ints = 32;
+    bool schedcfgen;
+
+    /* Early exit if nothing pending */
+    if (get_ipend(env) == 0) {
+        restore_state(env, false);
+        return false;
+    }
+
+    BQL_LOCK_GUARD();
+    /* Only check priorities when schedcfgen is set */
+    schedcfgen = get_schedcfgen(env);
+    for (int i = 0; i < max_ints; i++) {
+        if (!get_iad_bit(env, i) && get_ipend_bit(env, i)) {
+            bool syscfg_gie, iad, ssr_ie, imask;
+
+            qemu_log_mask(CPU_LOG_INT,
+                          "%s: thread[" TARGET_FMT_ld "] "
+                          "pc = 0x" TARGET_FMT_lx
+                          " found int %d\n",
+                          __func__, env->threadId,
+                          env->gpr[HEX_REG_PC], i);
+            if (hex_is_qualified_for_int(env, i) &&
+                (!schedcfgen || is_lowest_prio(env, i))) {
+                qemu_log_mask(CPU_LOG_INT,
+                              "%s: thread[" TARGET_FMT_ld "] int %d handled_\n",
+                              __func__, env->threadId, i);
+                hex_accept_int(env, i);
+                int_handled = true;
+                break;
+            }
+            syscfg_gie = get_syscfg_gie(env);
+            iad = get_iad_bit(env, i);
+            ssr_ie = get_ssr_ie(env);
+            imask = get_imask_bit(env, i);
+
+            qemu_log_mask(CPU_LOG_INT,
+                          "%s: thread[" TARGET_FMT_ld "] "
+                          "int %d not handled, qualified: %d, "
+                          "schedcfg_en: %d, low prio %d\n",
+                          __func__, env->threadId, i,
+                          hex_is_qualified_for_int(env, i), schedcfgen,
+                          is_lowest_prio(env, i));
+
+            qemu_log_mask(CPU_LOG_INT,
+                          "%s: thread[" TARGET_FMT_ld "] "
+                          "int %d not handled, GIE %d, iad %d, "
+                          "SSR:IE %d, SSR:EX: %d, imask bit %d\n",
+                          __func__, env->threadId, i, syscfg_gie, iad, ssr_ie,
+                          ssr_ex, imask);
+        }
+    }
+
+    /*
+     * If we didn't handle the interrupt and it wasn't
+     * because we were in EX state, then we won't be able
+     * to execute the interrupt on this CPU unless something
+     * changes in the CPU state.  Clear the interrupt_request bits
+     * while preserving the IPEND bits, and we can re-assert the
+     * interrupt_request bit(s) when we execute one of those instructions.
+     */
+    if (!int_handled && !ssr_ex) {
+        restore_state(env, int_handled);
+    } else if (int_handled) {
+        assert(!cs->halted);
+    }
+
+    return int_handled;
+}
+
+void hex_clear_interrupts(CPUHexagonState *env, uint32_t mask, uint32_t type)
+{
+    if (mask == 0) {
+        return;
+    }
+
+    /*
+     * Notify all CPUs that the interrupt has happened
+     */
+    BQL_LOCK_GUARD();
+    clear_ipend(env, mask);
+    hex_interrupt_update(env);
+}
+
+void hex_raise_interrupts(CPUHexagonState *env, uint32_t mask, uint32_t type)
+{
+    g_assert(bql_locked());
+    if (mask == 0) {
+        return;
+    }
+
+    /*
+     * Notify all CPUs that the interrupt has happened
+     */
+    set_ipend(env, mask);
+    hex_interrupt_update(env);
+}
+
+void hex_interrupt_update(CPUHexagonState *env)
+{
+    CPUState *cs;
+
+    g_assert(bql_locked());
+    if (get_ipend(env) != 0) {
+        CPU_FOREACH(cs) {
+            CPUHexagonState *hex_env = cpu_env(cs);
+            const int exe_mode = get_exe_mode(hex_env);
+            if (exe_mode != HEX_EXE_MODE_OFF) {
+                cpu_interrupt(cs, CPU_INTERRUPT_SWI);
+                cpu_resume(cs);
+            }
+        }
+    }
+}
-- 
2.34.1