[PATCH v10 2/9] hw/fsi: Introduce IBM's FSI Bus and FSI slave

[Ninad Palsule <ninad@linux.ibm.com>]

This is a part of patchset where FSI bus is introduced.

The FSI bus is a simple bus where FSI master is attached.

The FSI slave: The slave is the terminal point of the FSI bus for
FSI symbols addressed to it. Slaves can be cascaded off of one
another. The slave's configuration registers appear in address space
of the CFAM to which it is attached.

[ clg: - removed include/hw/fsi/engine-scratchpad.h and
       	 hw/fsi/engine-scratchpad.c
       - dropped FSI_SCRATCHPAD
       - included FSIBus definition
       - dropped hw/fsi/trace-events changes ]

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
---
 include/hw/fsi/fsi.h |  38 +++++++++++++++
 hw/fsi/fsi.c         | 111 +++++++++++++++++++++++++++++++++++++++++++
 hw/fsi/meson.build   |   2 +-
 hw/fsi/trace-events  |   2 +
 4 files changed, 152 insertions(+), 1 deletion(-)
 create mode 100644 include/hw/fsi/fsi.h
 create mode 100644 hw/fsi/fsi.c

diff --git a/include/hw/fsi/fsi.h b/include/hw/fsi/fsi.h
new file mode 100644
index 0000000000..6e11747dd5
--- /dev/null
+++ b/include/hw/fsi/fsi.h
@@ -0,0 +1,38 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright (C) 2024 IBM Corp.
+ *
+ * IBM Flexible Service Interface
+ */
+#ifndef FSI_FSI_H
+#define FSI_FSI_H
+
+#include "exec/memory.h"
+#include "hw/qdev-core.h"
+#include "hw/fsi/lbus.h"
+#include "qemu/bitops.h"
+
+/* Bitwise operations at the word level. */
+#define BE_BIT(x)           BIT(31 - (x))
+#define BE_GENMASK(hb, lb)  MAKE_64BIT_MASK((lb), ((hb) - (lb) + 1))
+
+#define TYPE_FSI_BUS "fsi.bus"
+OBJECT_DECLARE_SIMPLE_TYPE(FSIBus, FSI_BUS)
+
+typedef struct FSIBus {
+    BusState bus;
+} FSIBus;
+
+#define TYPE_FSI_SLAVE "fsi.slave"
+OBJECT_DECLARE_SIMPLE_TYPE(FSISlaveState, FSI_SLAVE)
+
+#define FSI_SLAVE_CONTROL_NR_REGS ((0x40 >> 2) + 1)
+
+typedef struct FSISlaveState {
+    DeviceState parent;
+
+    MemoryRegion iomem;
+    uint32_t regs[FSI_SLAVE_CONTROL_NR_REGS];
+} FSISlaveState;
+
+#endif /* FSI_FSI_H */
diff --git a/hw/fsi/fsi.c b/hw/fsi/fsi.c
new file mode 100644
index 0000000000..0c73ca14ad
--- /dev/null
+++ b/hw/fsi/fsi.c
@@ -0,0 +1,111 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ * Copyright (C) 2024 IBM Corp.
+ *
+ * IBM Flexible Service Interface
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/log.h"
+#include "trace.h"
+
+#include "hw/fsi/fsi.h"
+
+static const TypeInfo fsi_bus_info = {
+    .name = TYPE_FSI_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(FSIBus),
+};
+
+static void fsi_bus_register_types(void)
+{
+    type_register_static(&fsi_bus_info);
+}
+
+type_init(fsi_bus_register_types);
+
+#define TO_REG(x)                               ((x) >> 2)
+
+static uint64_t fsi_slave_read(void *opaque, hwaddr addr, unsigned size)
+{
+    FSISlaveState *s = FSI_SLAVE(opaque);
+    int reg = TO_REG(addr);
+
+    trace_fsi_slave_read(addr, size);
+
+    if (reg >= FSI_SLAVE_CONTROL_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Out of bounds read: 0x%"HWADDR_PRIx" for %u\n",
+                      __func__, addr, size);
+        return 0;
+    }
+
+    return s->regs[reg];
+}
+
+static void fsi_slave_write(void *opaque, hwaddr addr, uint64_t data,
+                                 unsigned size)
+{
+    FSISlaveState *s = FSI_SLAVE(opaque);
+    int reg = TO_REG(addr);
+
+    trace_fsi_slave_write(addr, size, data);
+
+    if (reg >= FSI_SLAVE_CONTROL_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Out of bounds write: 0x%"HWADDR_PRIx" for %u\n",
+                      __func__, addr, size);
+        return;
+    }
+
+    s->regs[reg] = data;
+}
+
+static const struct MemoryRegionOps fsi_slave_ops = {
+    .read = fsi_slave_read,
+    .write = fsi_slave_write,
+    .endianness = DEVICE_BIG_ENDIAN,
+};
+
+static void fsi_slave_reset(DeviceState *dev)
+{
+    FSISlaveState *s = FSI_SLAVE(dev);
+    int i;
+
+    /* Initialize registers */
+    for (i = 0; i < FSI_SLAVE_CONTROL_NR_REGS; i++) {
+        s->regs[i] = 0;
+    }
+}
+
+static void fsi_slave_init(Object *o)
+{
+    FSISlaveState *s = FSI_SLAVE(o);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &fsi_slave_ops,
+                          s, TYPE_FSI_SLAVE, 0x400);
+}
+
+static void fsi_slave_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->bus_type = TYPE_FSI_BUS;
+    dc->desc = "FSI Slave";
+    dc->reset = fsi_slave_reset;
+}
+
+static const TypeInfo fsi_slave_info = {
+    .name = TYPE_FSI_SLAVE,
+    .parent = TYPE_DEVICE,
+    .instance_init = fsi_slave_init,
+    .instance_size = sizeof(FSISlaveState),
+    .class_init = fsi_slave_class_init,
+};
+
+static void fsi_slave_register_types(void)
+{
+    type_register_static(&fsi_slave_info);
+}
+
+type_init(fsi_slave_register_types);
diff --git a/hw/fsi/meson.build b/hw/fsi/meson.build
index 93ba19dd04..574f5f9289 100644
--- a/hw/fsi/meson.build
+++ b/hw/fsi/meson.build
@@ -1 +1 @@
-system_ss.add(when: 'CONFIG_FSI', if_true: files('lbus.c'))
+system_ss.add(when: 'CONFIG_FSI', if_true: files('lbus.c','fsi.c'))
diff --git a/hw/fsi/trace-events b/hw/fsi/trace-events
index c5753e2791..8f29adb7df 100644
--- a/hw/fsi/trace-events
+++ b/hw/fsi/trace-events
@@ -1,2 +1,4 @@
 fsi_scratchpad_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
 fsi_scratchpad_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
+fsi_slave_read(uint64_t addr, uint32_t size) "@0x%" PRIx64 " size=%d"
+fsi_slave_write(uint64_t addr, uint32_t size, uint64_t data) "@0x%" PRIx64 " size=%d value=0x%"PRIx64
-- 
2.39.2