[Qemu-devel] [PATCH v8 1/3] spapr_pci: enumerate and add PCI device tree

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

All the PCI enumeration and device node creation was off-loaded to
SLOF. With PCI hotplug support, code needed to be added to add device
node. This creates multiple copy of the code one in SLOF and other in
hotplug code. To unify this, the patch adds the pci device node
creation in Qemu. For backward compatibility, a flag
"qemu,phb-enumerated" is added to the phb, suggesting to SLOF to not
do device node creation.

Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
[ Squashed Michael's drc_index changes ]
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
---
 hw/ppc/spapr_pci.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 133 insertions(+), 17 deletions(-)

diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
index 9a7b270..25452a6 100644
--- a/hw/ppc/spapr_pci.c
+++ b/hw/ppc/spapr_pci.c
@@ -23,6 +23,7 @@
  * THE SOFTWARE.
  */
 #include "hw/hw.h"
+#include "hw/sysbus.h"
 #include "hw/pci/pci.h"
 #include "hw/pci/msi.h"
 #include "hw/pci/msix.h"
@@ -35,6 +36,7 @@
 #include "qemu/error-report.h"
 #include "qapi/qmp/qerror.h"
 
+#include "hw/pci/pci_bridge.h"
 #include "hw/pci/pci_bus.h"
 #include "hw/ppc/spapr_drc.h"
 #include "sysemu/device_tree.h"
@@ -966,30 +968,32 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int offset,
     return 0;
 }
 
+static uint32_t spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
+                                            PCIDevice *pdev);
+
 /* create OF node for pci device and required OF DT properties */
-static void *spapr_create_pci_child_dt(sPAPRPHBState *phb, PCIDevice *dev,
-                                       int drc_index, const char *drc_name,
-                                       int *dt_offset)
+static int spapr_create_pci_child_dt(sPAPRPHBState *phb, PCIDevice *dev,
+                                     int drc_index, const char *drc_name,
+                                     void *fdt, int node_offset)
 {
-    void *fdt;
-    int offset, ret, fdt_size;
+    int offset, ret;
     int slot = PCI_SLOT(dev->devfn);
     int func = PCI_FUNC(dev->devfn);
     char nodename[FDT_NAME_MAX];
 
-    fdt = create_device_tree(&fdt_size);
     if (func != 0) {
         snprintf(nodename, FDT_NAME_MAX, "pci@%x,%x", slot, func);
     } else {
         snprintf(nodename, FDT_NAME_MAX, "pci@%x", slot);
     }
-    offset = fdt_add_subnode(fdt, 0, nodename);
+    offset = fdt_add_subnode(fdt, node_offset, nodename);
     ret = spapr_populate_pci_child_dt(dev, fdt, offset, phb->index, drc_index,
                                       drc_name);
     g_assert(!ret);
-
-    *dt_offset = offset;
-    return fdt;
+    if (ret) {
+        return 0;
+    }
+    return offset;
 }
 
 static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
@@ -1002,19 +1006,22 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector *drc,
     int drc_index = drck->get_index(drc);
     const char *drc_name = drck->get_name(drc);
     void *fdt = NULL;
-    int fdt_start_offset = 0;
+    int fdt_start_offset = 0, fdt_size;
 
-    /* boot-time devices get their device tree node created by SLOF, but for
-     * hotplugged devices we need QEMU to generate it so the guest can fetch
-     * it via RTAS
-     */
     if (dev->hotplugged) {
-        fdt = spapr_create_pci_child_dt(phb, pdev, drc_index, drc_name,
-                                        &fdt_start_offset);
+        fdt = create_device_tree(&fdt_size);
+        fdt_start_offset = spapr_create_pci_child_dt(phb, pdev,
+                                                     drc_index, drc_name,
+                                                     fdt, 0);
+        if (!fdt_start_offset) {
+            error_setg(errp, "Failed to create pci child device tree node");
+            goto out;
+        }
     }
 
     drck->attach(drc, DEVICE(pdev),
                  fdt, fdt_start_offset, !dev->hotplugged, errp);
+out:
     if (*errp) {
         g_free(fdt);
     }
@@ -1056,6 +1063,20 @@ static sPAPRDRConnector *spapr_phb_get_pci_drc(sPAPRPHBState *phb,
                                     pdev->devfn);
 }
 
+static uint32_t spapr_phb_get_pci_drc_index(sPAPRPHBState *phb,
+                                            PCIDevice *pdev)
+{
+    sPAPRDRConnector *drc = spapr_phb_get_pci_drc(phb, pdev);
+    sPAPRDRConnectorClass *drck;
+
+    if (!drc) {
+        return 0;
+    }
+
+    drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
+    return drck->get_index(drc);
+}
+
 static void spapr_phb_hot_plug_child(HotplugHandler *plug_handler,
                                      DeviceState *plugged_dev, Error **errp)
 {
@@ -1480,6 +1501,87 @@ PCIHostState *spapr_create_phb(sPAPRMachineState *spapr, int index)
     return PCI_HOST_BRIDGE(dev);
 }
 
+typedef struct sPAPRFDT {
+    void *fdt;
+    int node_off;
+    sPAPRPHBState *sphb;
+} sPAPRFDT;
+
+static void spapr_populate_pci_devices_dt(PCIBus *bus, PCIDevice *pdev,
+                                          void *opaque)
+{
+    PCIBus *sec_bus;
+    sPAPRFDT *p = opaque;
+    int offset;
+    sPAPRFDT s_fdt;
+    uint32_t drc_index = spapr_phb_get_pci_drc_index(p->sphb, pdev);
+
+    offset = spapr_create_pci_child_dt(p->sphb, pdev,
+                                       drc_index, NULL,
+                                       p->fdt, p->node_off);
+    if (!offset) {
+        error_report("Failed to create pci child device tree node");
+        return;
+    }
+
+    if ((pci_default_read_config(pdev, PCI_HEADER_TYPE, 1) !=
+         PCI_HEADER_TYPE_BRIDGE)) {
+        return;
+    }
+
+    sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
+    if (!sec_bus) {
+        return;
+    }
+
+    s_fdt.fdt = p->fdt;
+    s_fdt.node_off = offset;
+    s_fdt.sphb = p->sphb;
+    pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
+                        spapr_populate_pci_devices_dt,
+                        &s_fdt);
+}
+
+static void spapr_phb_pci_enumerate_bridge(PCIBus *bus, PCIDevice *pdev,
+                                           void *opaque)
+{
+    unsigned int *bus_no = opaque;
+    unsigned int primary = *bus_no;
+    unsigned int subordinate = 0xff;
+    PCIBus *sec_bus = NULL;
+
+    if ((pci_default_read_config(pdev, PCI_HEADER_TYPE, 1) !=
+         PCI_HEADER_TYPE_BRIDGE)) {
+        return;
+    }
+
+    (*bus_no)++;
+    pci_default_write_config(pdev, PCI_PRIMARY_BUS, primary, 1);
+    pci_default_write_config(pdev, PCI_SECONDARY_BUS, *bus_no, 1);
+    pci_default_write_config(pdev, PCI_SUBORDINATE_BUS, *bus_no, 1);
+
+    sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
+    if (!sec_bus) {
+        return;
+    }
+
+    pci_default_write_config(pdev, PCI_SUBORDINATE_BUS, subordinate, 1);
+    pci_for_each_device(sec_bus, pci_bus_num(sec_bus),
+                        spapr_phb_pci_enumerate_bridge, bus_no);
+    pci_default_write_config(pdev, PCI_SUBORDINATE_BUS, *bus_no, 1);
+}
+
+static void spapr_phb_pci_enumerate(sPAPRPHBState *phb)
+{
+    PCIBus *bus = PCI_HOST_BRIDGE(phb)->bus;
+    unsigned int bus_no = 0;
+
+    pci_for_each_device(bus, pci_bus_num(bus),
+                        spapr_phb_pci_enumerate_bridge,
+                        &bus_no);
+
+}
+
 int spapr_populate_pci_dt(sPAPRPHBState *phb,
                           uint32_t xics_phandle,
                           void *fdt)
@@ -1519,6 +1621,8 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
         cpu_to_be32(b_ddddd(-1)|b_fff(0)), 0x0, 0x0, cpu_to_be32(-1)};
     uint32_t interrupt_map[PCI_SLOT_MAX * PCI_NUM_PINS][7];
     sPAPRTCETable *tcet;
+    PCIBus *bus = PCI_HOST_BRIDGE(phb)->bus;
+    sPAPRFDT s_fdt;
 
     /* Start populating the FDT */
     snprintf(nodename, FDT_NAME_MAX, "pci@%" PRIx64, phb->buid);
@@ -1568,6 +1672,18 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
                  tcet->liobn, tcet->bus_offset,
                  tcet->nb_table << tcet->page_shift);
 
+    /* Walk the bridges and program the bus numbers*/
+    spapr_phb_pci_enumerate(phb);
+    _FDT(fdt_setprop_cell(fdt, bus_off, "qemu,phb-enumerated", 0x1));
+
+    /* Populate tree nodes with PCI devices attached */
+    s_fdt.fdt = fdt;
+    s_fdt.node_off = bus_off;
+    s_fdt.sphb = phb;
+    pci_for_each_device(bus, pci_bus_num(bus),
+                        spapr_populate_pci_devices_dt,
+                        &s_fdt);
+
     ret = spapr_drc_populate_dt(fdt, bus_off, OBJECT(phb),
                                 SPAPR_DR_CONNECTOR_TYPE_PCI);
     if (ret) {
-- 
1.8.3.1