[ot] hw/opentitan: ot_ibex_wrapper: Add NMI support to Ibex Wrapper

Adds support for NMIs to Earlgrey's Ibex wrapper, allowing incoming NMI
IRQ signals to be received by the device, which will then be propagated
through an external IRQ signal to the Ibex itself (the hart) with the
newly introduced IRQ_NMI value. This will allow support for hardware
raising NMIs via GPIO signals between the QEMU devices, such that NMI
support can be added to Earlgrey.

Signed-off-by: Alex Jones <[email protected]>

Author: AlexJones0

hw/opentitan/ot_ibex_wrapper_eg.c

@@ -83,8 +83,8 @@ REG32(DBUS_ADDR_MATCHING_1, 0x40u)
 REG32(DBUS_REMAP_ADDR_0, 0x44u)
 REG32(DBUS_REMAP_ADDR_1, 0x48u)
 REG32(NMI_ENABLE, 0x4cu)
-    SHARED_FIELD(NMI_ALERT_EN_BIT, 0u, 1u)
-    SHARED_FIELD(NMI_WDOG_EN_BIT, 1u, 1u)
+    SHARED_FIELD(NMI_ALERT_EN_BIT, OT_IBEX_NMI_ALERT, 1u)
+    SHARED_FIELD(NMI_WDOG_EN_BIT, OT_IBEX_NMI_WDOG, 1u)
 REG32(NMI_STATE, 0x50u)
 REG32(ERR_STATUS, 0x54u)
     FIELD(ERR_STATUS, REG_INTG, 0u, 1u)
@@ -225,6 +225,7 @@ struct OtIbexWrapperEgState {
     MemoryRegion mmio;
     MemoryRegion remappers[PARAM_NUM_REGIONS];
     qemu_irq alerts[PARAM_NUM_ALERTS];
+    IbexIRQ nmi_irq;
 
     uint32_t *regs;
     OtIbexTestLogEngine *log_engine;
@@ -770,6 +771,24 @@ static void ot_ibex_wrapper_eg_cpu_enable_recv(void *opaque, int n, int level)
     ot_ibex_wrapper_eg_update_exec(s);
 }
 
+static void ot_ibex_wrapper_eg_nmi_recv(void *opaque, int n, int level)
+{
+    OtIbexWrapperEgState *s = opaque;
+
+    g_assert((unsigned)n < OT_IBEX_NMI_COUNT);
+
+    /* NMI_STATE is rw1c, so must be cleared with a register write. */
+    if (level) {
+        s->regs[R_NMI_STATE] |= 1u << (unsigned)n;
+    }
+
+    trace_ot_ibex_wrapper_nmi_recv(s->ot_id ?: "", n ? "WDOG" : "ALERT",
+                                   (bool)level);
+
+    uint32_t nmi_active = s->regs[R_NMI_ENABLE] & s->regs[R_NMI_STATE];
+    ibex_irq_set(&s->nmi_irq, (bool)nmi_active);
+}
+
 static void ot_ibex_wrapper_eg_escalate_rx(void *opaque, int n, int level)
 {
     OtIbexWrapperEgState *s = opaque;
@@ -1020,9 +1039,13 @@ static void ot_ibex_wrapper_eg_init(Object *obj)
 
     qdev_init_gpio_in_named(DEVICE(obj), &ot_ibex_wrapper_eg_cpu_enable_recv,
                             OT_IBEX_WRAPPER_CPU_EN, OT_IBEX_CPU_EN_COUNT);
+    qdev_init_gpio_in_named(DEVICE(obj), &ot_ibex_wrapper_eg_nmi_recv,
+                            OT_IBEX_WRAPPER_NMI, OT_IBEX_NMI_COUNT);
     qdev_init_gpio_in_named(DEVICE(obj), &ot_ibex_wrapper_eg_escalate_rx,
                             OT_ALERT_ESCALATE, 1);
 
+    ibex_qdev_init_irq(obj, &s->nmi_irq, NULL);
+
     s->regs = g_new0(uint32_t, REGS_COUNT);
     s->log_engine = g_new0(OtIbexTestLogEngine, 1u);
 }

hw/opentitan/trace-events

@@ -228,6 +228,7 @@ ot_i2c_update_irqs(const char *id, uint32_t active, uint32_t mask, uint32_t eff)
 # ot_ibex_wrapper.c
 
 ot_ibex_wrapper_cpu_enable(const char *id, const char *ch, bool level) "%s: %s:%u"
+ot_ibex_wrapper_nmi_recv(const char *id, const char *ch, bool level) "%s: %s:%u"
 ot_ibex_wrapper_error(const char *id, const char *func, int line, const char *msg) "%s: %s:%d %s"
 ot_ibex_wrapper_escalate_rx(const char *id, bool level) "%s: %u"
 ot_ibex_wrapper_exit(const char *id, const char *msg, int val) "%s: %s (%d)"

hw/riscv/ot_earlgrey.c

@@ -1055,6 +1055,7 @@ static const IbexDeviceDef ot_eg_soc_devices[] = {
             { .base = 0x411f0000u }
         ),
         .gpio = IBEXGPIOCONNDEFS(
+            OT_EG_SOC_GPIO(0, HART, IRQ_NMI),
             OT_EG_SOC_GPIO_ALERT(0, 61),
             OT_EG_SOC_GPIO_ALERT(1, 62),
             OT_EG_SOC_GPIO_ALERT(2, 63),

include/hw/opentitan/ot_ibex_wrapper.h

@@ -45,11 +45,18 @@ struct OtIbexWrapperStateClass {
 };
 
 #define OT_IBEX_WRAPPER_CPU_EN TYPE_OT_IBEX_WRAPPER "-cpu-en"
+#define OT_IBEX_WRAPPER_NMI    TYPE_OT_IBEX_WRAPPER "-nmi"
 
 typedef enum {
     OT_IBEX_LC_CTRL_CPU_EN,
     OT_IBEX_PWRMGR_CPU_EN,
     OT_IBEX_CPU_EN_COUNT
 } OtIbexWrapperCpuEnable;
 
+typedef enum {
+    OT_IBEX_NMI_ALERT,
+    OT_IBEX_NMI_WDOG,
+    OT_IBEX_NMI_COUNT
+} OtIbexWrapperNmi;
+
 #endif /* HW_OPENTITAN_OT_IBEX_WRAPPER_H */