ppc/pnv: Introduce user creatable pnv-phb4 devices

This patch introduces pnv-phb4 user creatable devices that are created
in a similar manner as pnv-phb3 devices, allowing the user to interact
with the PHBs directly instead of creating PCI Express Controllers that
will create a certain amount of PHBs per controller index.

We accomplish this by doing the following:

- add a pnv_phb4_get_stack() helper to retrieve which stack an user
created phb4 would occupy;

- when dealing with an user created pnv-phb4 (detected by checking if
phb->stack is NULL at the start of phb4_realize()), retrieve its stack
and initialize its properties as done in stk_realize();

- use 'defaults_enabled()' in stk_realize() to avoid creating and
initializing a 'stack->phb' qdev that might be overwritten by an user
created pnv-phb4 device. This process is wrapped into a new helper
called pnv_pec_stk_default_phb_realize().

Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20220111131027.599784-5-danielhb413@gmail.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

hw/pci-host/pnv_phb4.c

@@ -1487,15 +1487,85 @@ static void pnv_phb4_instance_init(Object *obj)
     object_initialize_child(obj, "source", &phb->xsrc, TYPE_XIVE_SOURCE);
 }
 
+static PnvPhb4PecStack *pnv_phb4_get_stack(PnvChip *chip, PnvPHB4 *phb,
+                                           Error **errp)
+{
+    Pnv9Chip *chip9 = PNV9_CHIP(chip);
+    int chip_id = phb->chip_id;
+    int index = phb->phb_id;
+    int i, j;
+
+    for (i = 0; i < chip->num_pecs; i++) {
+        /*
+         * For each PEC, check the amount of stacks it supports
+         * and see if the given phb4 index matches a stack.
+         */
+        PnvPhb4PecState *pec = &chip9->pecs[i];
+
+        for (j = 0; j < pec->num_stacks; j++) {
+            if (index == pnv_phb4_pec_get_phb_id(pec, j)) {
+                return &pec->stacks[j];
+            }
+        }
+    }
+
+    error_setg(errp,
+               "pnv-phb4 chip-id %d index %d didn't match any existing PEC",
+               chip_id, index);
+
+    return NULL;
+}
+
 static void pnv_phb4_realize(DeviceState *dev, Error **errp)
 {
     PnvPHB4 *phb = PNV_PHB4(dev);
     PCIHostState *pci = PCI_HOST_BRIDGE(dev);
     XiveSource *xsrc = &phb->xsrc;
+    Error *local_err = NULL;
     int nr_irqs;
     char name[32];
 
-    assert(phb->stack);
+    /* User created PHB */
+    if (!phb->stack) {
+        PnvMachineState *pnv = PNV_MACHINE(qdev_get_machine());
+        PnvChip *chip = pnv_get_chip(pnv, phb->chip_id);
+        PnvPhb4PecClass *pecc;
+        BusState *s;
+
+        if (!chip) {
+            error_setg(errp, "invalid chip id: %d", phb->chip_id);
+            return;
+        }
+
+        phb->stack = pnv_phb4_get_stack(chip, phb, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
+
+        /* All other phb properties but 'version' are already set */
+        pecc = PNV_PHB4_PEC_GET_CLASS(phb->stack->pec);
+        object_property_set_int(OBJECT(phb), "version", pecc->version,
+                                &error_fatal);
+
+        /*
+         * Assign stack->phb since pnv_phb4_update_regions() uses it
+         * to access the phb.
+         */
+        phb->stack->phb = phb;
+
+        /*
+         * Reparent user created devices to the chip to build
+         * correctly the device tree.
+         */
+        pnv_chip_parent_fixup(chip, OBJECT(phb), phb->phb_id);
+
+        s = qdev_get_parent_bus(DEVICE(chip));
+        if (!qdev_set_parent_bus(DEVICE(phb), s, &local_err)) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
 
     /* Set the "big_phb" flag */
     phb->big_phb = phb->phb_id == 0 || phb->phb_id == 3;
@@ -1600,7 +1670,7 @@ static void pnv_phb4_class_init(ObjectClass *klass, void *data)
     dc->realize         = pnv_phb4_realize;
     device_class_set_props(dc, pnv_phb4_properties);
     set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
-    dc->user_creatable  = false;
+    dc->user_creatable  = true;
 
     xfc->notify         = pnv_phb4_xive_notify;
 }

hw/pci-host/pnv_phb4_pec.c

@@ -19,6 +19,7 @@
 #include "hw/pci/pci_bus.h"
 #include "hw/ppc/pnv.h"
 #include "hw/qdev-properties.h"
+#include "sysemu/sysemu.h"
 
 #include <libfdt.h>
 
@@ -275,9 +276,9 @@ static const TypeInfo pnv_pec_type_info = {
     }
 };
 
-static void pnv_pec_stk_realize(DeviceState *dev, Error **errp)
+static void pnv_pec_stk_default_phb_realize(PnvPhb4PecStack *stack,
+                                            Error **errp)
 {
-    PnvPhb4PecStack *stack = PNV_PHB4_PEC_STACK(dev);
     PnvPhb4PecState *pec = stack->pec;
     PnvPhb4PecClass *pecc = PNV_PHB4_PEC_GET_CLASS(pec);
     int phb_id = pnv_phb4_pec_get_phb_id(pec, stack->stack_no);
@@ -292,11 +293,23 @@ static void pnv_pec_stk_realize(DeviceState *dev, Error **errp)
                             &error_fatal);
     object_property_set_link(OBJECT(stack->phb), "stack", OBJECT(stack),
                              &error_abort);
+
     if (!sysbus_realize(SYS_BUS_DEVICE(stack->phb), errp)) {
         return;
     }
 }
 
+static void pnv_pec_stk_realize(DeviceState *dev, Error **errp)
+{
+    PnvPhb4PecStack *stack = PNV_PHB4_PEC_STACK(dev);
+
+    if (!defaults_enabled()) {
+        return;
+    }
+
+    pnv_pec_stk_default_phb_realize(stack, errp);
+}
+
 static Property pnv_pec_stk_properties[] = {
         DEFINE_PROP_UINT32("stack-no", PnvPhb4PecStack, stack_no, 0),
         DEFINE_PROP_LINK("pec", PnvPhb4PecStack, pec, TYPE_PNV_PHB4_PEC,

hw/ppc/pnv.c

@@ -1960,6 +1960,8 @@ static void pnv_machine_power9_class_init(ObjectClass *oc, void *data)
     pmc->compat = compat;
     pmc->compat_size = sizeof(compat);
     pmc->dt_power_mgt = pnv_dt_power_mgt;
+
+    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_PNV_PHB4);
 }
 
 static void pnv_machine_power10_class_init(ObjectClass *oc, void *data)