arm: Move M-profile RAS register block into its own device

Currently we implement the RAS register block within the NVIC device.
It isn't really very tightly coupled with the NVIC proper, so instead
move it out into a sysbus device of its own and have the top level
ARMv7M container create it and map it into memory at the right
address.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alexandre Iooss <erdnaxe@crans.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Message-id: 20210812093356.1946-2-peter.maydell@linaro.org

MAINTAINERS

@@ -617,6 +617,7 @@ F: hw/intc/gic_internal.h
 F: hw/misc/a9scu.c
 F: hw/misc/arm11scu.c
 F: hw/misc/arm_l2x0.c
+F: hw/misc/armv7m_ras.c
 F: hw/timer/a9gtimer*
 F: hw/timer/arm*
 F: include/hw/arm/arm*.h
@@ -626,6 +627,7 @@ F: include/hw/misc/arm11scu.h
 F: include/hw/timer/a9gtimer.h
 F: include/hw/timer/arm_mptimer.h
 F: include/hw/timer/armv7m_systick.h
+F: include/hw/misc/armv7m_ras.h
 F: tests/qtest/test-arm-mptimer.c
 
 Exynos

hw/arm/armv7m.c

@@ -231,6 +231,18 @@ static void armv7m_realize(DeviceState *dev, Error **errp)
     memory_region_add_subregion(&s->container, 0xe0000000,
                                 sysbus_mmio_get_region(sbd, 0));
 
+    /* If the CPU has RAS support, create the RAS register block */
+    if (cpu_isar_feature(aa32_ras, s->cpu)) {
+        object_initialize_child(OBJECT(dev), "armv7m-ras",
+                                &s->ras, TYPE_ARMV7M_RAS);
+        sbd = SYS_BUS_DEVICE(&s->ras);
+        if (!sysbus_realize(sbd, errp)) {
+            return;
+        }
+        memory_region_add_subregion_overlap(&s->container, 0xe0005000,
+                                            sysbus_mmio_get_region(sbd, 0), 1);
+    }
+
     for (i = 0; i < ARRAY_SIZE(s->bitband); i++) {
         if (s->enable_bitband) {
             Object *obj = OBJECT(&s->bitband[i]);

hw/intc/armv7m_nvic.c

@@ -2549,56 +2549,6 @@ static const MemoryRegionOps nvic_systick_ops = {
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
-
-static MemTxResult ras_read(void *opaque, hwaddr addr,
-                            uint64_t *data, unsigned size,
-                            MemTxAttrs attrs)
-{
-    if (attrs.user) {
-        return MEMTX_ERROR;
-    }
-
-    switch (addr) {
-    case 0xe10: /* ERRIIDR */
-        /* architect field = Arm; product/variant/revision 0 */
-        *data = 0x43b;
-        break;
-    case 0xfc8: /* ERRDEVID */
-        /* Minimal RAS: we implement 0 error record indexes */
-        *data = 0;
-        break;
-    default:
-        qemu_log_mask(LOG_UNIMP, "Read RAS register offset 0x%x\n",
-                      (uint32_t)addr);
-        *data = 0;
-        break;
-    }
-    return MEMTX_OK;
-}
-
-static MemTxResult ras_write(void *opaque, hwaddr addr,
-                             uint64_t value, unsigned size,
-                             MemTxAttrs attrs)
-{
-    if (attrs.user) {
-        return MEMTX_ERROR;
-    }
-
-    switch (addr) {
-    default:
-        qemu_log_mask(LOG_UNIMP, "Write to RAS register offset 0x%x\n",
-                      (uint32_t)addr);
-        break;
-    }
-    return MEMTX_OK;
-}
-
-static const MemoryRegionOps ras_ops = {
-    .read_with_attrs = ras_read,
-    .write_with_attrs = ras_write,
-    .endianness = DEVICE_NATIVE_ENDIAN,
-};
-
 /*
  * Unassigned portions of the PPB space are RAZ/WI for privileged
  * accesses, and fault for non-privileged accesses.
@@ -2946,12 +2896,6 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
                                             &s->systick_ns_mem, 1);
     }
 
-    if (cpu_isar_feature(aa32_ras, s->cpu)) {
-        memory_region_init_io(&s->ras_mem, OBJECT(s),
-                              &ras_ops, s, "nvic_ras", 0x1000);
-        memory_region_add_subregion(&s->container, 0x5000, &s->ras_mem);
-    }
-
     sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->container);
 }
 

hw/misc/armv7m_ras.c

@@ -0,0 +1,93 @@
+/*
+ * Arm M-profile RAS (Reliability, Availability and Serviceability) block
+ *
+ * Copyright (c) 2021 Linaro Limited
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/misc/armv7m_ras.h"
+#include "qemu/log.h"
+
+static MemTxResult ras_read(void *opaque, hwaddr addr,
+                            uint64_t *data, unsigned size,
+                            MemTxAttrs attrs)
+{
+    if (attrs.user) {
+        return MEMTX_ERROR;
+    }
+
+    switch (addr) {
+    case 0xe10: /* ERRIIDR */
+        /* architect field = Arm; product/variant/revision 0 */
+        *data = 0x43b;
+        break;
+    case 0xfc8: /* ERRDEVID */
+        /* Minimal RAS: we implement 0 error record indexes */
+        *data = 0;
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "Read RAS register offset 0x%x\n",
+                      (uint32_t)addr);
+        *data = 0;
+        break;
+    }
+    return MEMTX_OK;
+}
+
+static MemTxResult ras_write(void *opaque, hwaddr addr,
+                             uint64_t value, unsigned size,
+                             MemTxAttrs attrs)
+{
+    if (attrs.user) {
+        return MEMTX_ERROR;
+    }
+
+    switch (addr) {
+    default:
+        qemu_log_mask(LOG_UNIMP, "Write to RAS register offset 0x%x\n",
+                      (uint32_t)addr);
+        break;
+    }
+    return MEMTX_OK;
+}
+
+static const MemoryRegionOps ras_ops = {
+    .read_with_attrs = ras_read,
+    .write_with_attrs = ras_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+
+static void armv7m_ras_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    ARMv7MRAS *s = ARMV7M_RAS(obj);
+
+    memory_region_init_io(&s->iomem, obj, &ras_ops,
+                          s, "armv7m-ras", 0x1000);
+    sysbus_init_mmio(sbd, &s->iomem);
+}
+
+static void armv7m_ras_class_init(ObjectClass *klass, void *data)
+{
+    /* This device has no state: no need for vmstate or reset */
+}
+
+static const TypeInfo armv7m_ras_info = {
+    .name = TYPE_ARMV7M_RAS,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(ARMv7MRAS),
+    .instance_init = armv7m_ras_init,
+    .class_init = armv7m_ras_class_init,
+};
+
+static void armv7m_ras_register_types(void)
+{
+    type_register_static(&armv7m_ras_info);
+}
+
+type_init(armv7m_ras_register_types);

hw/misc/meson.build

@@ -17,6 +17,8 @@ softmmu_ss.add(when: 'CONFIG_INTEGRATOR_DEBUG', if_true: files('arm_integrator_d
 softmmu_ss.add(when: 'CONFIG_A9SCU', if_true: files('a9scu.c'))
 softmmu_ss.add(when: 'CONFIG_ARM11SCU', if_true: files('arm11scu.c'))
 
+softmmu_ss.add(when: 'CONFIG_ARM_V7M', if_true: files('armv7m_ras.c'))
+
 # Mac devices
 softmmu_ss.add(when: 'CONFIG_MOS6522', if_true: files('mos6522.c'))
 

include/hw/arm/armv7m.h

@@ -12,6 +12,7 @@
 
 #include "hw/sysbus.h"
 #include "hw/intc/armv7m_nvic.h"
+#include "hw/misc/armv7m_ras.h"
 #include "target/arm/idau.h"
 #include "qom/object.h"
 
@@ -58,6 +59,7 @@ struct ARMv7MState {
     NVICState nvic;
     BitBandState bitband[ARMV7M_NUM_BITBANDS];
     ARMCPU *cpu;
+    ARMv7MRAS ras;
 
     /* MemoryRegion we pass to the CPU, with our devices layered on
      * top of the ones the board provides in board_memory.

include/hw/intc/armv7m_nvic.h

@@ -83,7 +83,6 @@ struct NVICState {
     MemoryRegion sysreg_ns_mem;
     MemoryRegion systickmem;
     MemoryRegion systick_ns_mem;
-    MemoryRegion ras_mem;
     MemoryRegion container;
     MemoryRegion defaultmem;
 

include/hw/misc/armv7m_ras.h

@@ -0,0 +1,37 @@
+/*
+ * Arm M-profile RAS (Reliability, Availability and Serviceability) block
+ *
+ * Copyright (c) 2021 Linaro Limited
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+/*
+ * This is a model of the RAS register block of an M-profile CPU
+ * (the registers starting at 0xE0005000 with ERRFRn).
+ *
+ * QEMU interface:
+ *  + sysbus MMIO region 0: the register bank
+ *
+ * The QEMU implementation currently provides "minimal RAS" only.
+ */
+
+#ifndef HW_MISC_ARMV7M_RAS_H
+#define HW_MISC_ARMV7M_RAS_H
+
+#include "hw/sysbus.h"
+
+#define TYPE_ARMV7M_RAS "armv7m-ras"
+OBJECT_DECLARE_SIMPLE_TYPE(ARMv7MRAS, ARMV7M_RAS)
+
+struct ARMv7MRAS {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion iomem;
+};
+
+#endif