[Qemu-devel] [PATCH 9/9] PPC: E500: Add PlatBus device tree walker

[Alexander Graf <agraf@suse.de>]

We need to tell the guest where devices are in its physical address space
and how they are connected to IRQ lines.

This patch adds a simply PlatBus walker that generates device tree chunks
for every device it finds. The only device it knows how to handle today
is a serial port, but that may change in the future.

Signed-off-by: Alexander Graf <agraf@suse.de>
---
 hw/ppc/e500.c | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 50 insertions(+), 4 deletions(-)

diff --git a/hw/ppc/e500.c b/hw/ppc/e500.c
index 8548622..e0d0a19 100644
--- a/hw/ppc/e500.c
+++ b/hw/ppc/e500.c
@@ -38,6 +38,7 @@
 #include "hw/pci-host/ppce500.h"
 #include "hw/platbus/bridge.h"
 #include "hw/platbus/device.h"
+#include "hw/char/serial-platbus.h"
 
 #define EPAPR_MAGIC                (0x45504150)
 #define BINARY_DEVICE_TREE_FILE    "mpc8544ds.dtb"
@@ -108,7 +109,7 @@ static uint32_t *pci_map_create(void *fdt, uint32_t mpic, int first_slot,
 }
 
 static void dt_serial_create(void *fdt, unsigned long long offset,
-                             const char *soc, const char *mpic,
+                             const char *soc, const char *mpic, int irq,
                              const char *alias, int idx, bool defcon)
 {
     char ser[128];
@@ -120,7 +121,7 @@ static void dt_serial_create(void *fdt, unsigned long long offset,
     qemu_devtree_setprop_cells(fdt, ser, "reg", offset, 0x100);
     qemu_devtree_setprop_cell(fdt, ser, "cell-index", idx);
     qemu_devtree_setprop_cell(fdt, ser, "clock-frequency", 0);
-    qemu_devtree_setprop_cells(fdt, ser, "interrupts", 42, 2);
+    qemu_devtree_setprop_cells(fdt, ser, "interrupts", irq, 2);
     qemu_devtree_setprop_phandle(fdt, ser, "interrupt-parent", mpic);
     qemu_devtree_setprop_string(fdt, "/aliases", alias, ser);
 
@@ -129,6 +130,42 @@ static void dt_serial_create(void *fdt, unsigned long long offset,
     }
 }
 
+static void platbus_create_devtree(DeviceState *dev, void *fdt,
+                                   const char *node, uint64_t addr,
+                                   const char *mpic, int irq_start,
+                                   int nr_irqs)
+{
+    PlatBusBridgeState *s = PLATBUS_BRIDGE(dev);
+    BusChild *kid;
+    const char platcomp[] = "qemu,platbus\0simple-bus";
+    int serial_idx = 2;
+
+    qemu_devtree_setprop(fdt, node, "compatible", platcomp, sizeof(platcomp));
+    qemu_devtree_setprop_string(fdt, node, "device_type", "platbus");
+
+    /* Our platbus hole is less than 32bit big, so 1 cell is enough for address
+       and size */
+    qemu_devtree_setprop_cells(fdt, node, "#size-cells", 1);
+    qemu_devtree_setprop_cells(fdt, node, "#address-cells", 1);
+    qemu_devtree_setprop_cells(fdt, node, "ranges", 0, addr >> 32, addr,
+                               PLATBUS_HOLE);
+
+    qemu_devtree_setprop_phandle(fdt, node, "interrupt-parent", mpic);
+
+    QTAILQ_FOREACH(kid, &s->bus.parent_obj.children, sibling) {
+        DeviceState *dev = kid->child;
+        PlatBusDeviceState *pbd = PLATBUS_DEVICE(dev);
+
+        if (PLATBUS_SERIAL(dev)) {
+            char *alias = g_strdup_printf("serial%d", serial_idx);
+            dt_serial_create(fdt, pbd->plat_region_addrs[0], node,
+                             mpic, irq_start + pbd->plat_irqs[0], alias,
+                             serial_idx, serial_idx == 0);
+            serial_idx++;
+        }
+    }
+}
+
 static int ppce500_load_device_tree(PPCE500Params *params,
                                     hwaddr addr,
                                     hwaddr initrd_base,
@@ -136,6 +173,7 @@ static int ppce500_load_device_tree(PPCE500Params *params,
                                     bool dry_run)
 {
     CPUPPCState *env = first_cpu->env_ptr;
+    DeviceState *platbus;
     int ret = -1;
     uint64_t mem_reg_property[] = { 0, cpu_to_be64(params->ram_size) };
     int fdt_size;
@@ -310,9 +348,9 @@ static int ppce500_load_device_tree(PPCE500Params *params,
      * devices in reverse order to the dt.
      */
     dt_serial_create(fdt, MPC8544_SERIAL1_REGS_OFFSET,
-                     soc, mpic, "serial1", 1, false);
+                     soc, mpic, 42, "serial1", 1, false);
     dt_serial_create(fdt, MPC8544_SERIAL0_REGS_OFFSET,
-                     soc, mpic, "serial0", 0, true);
+                     soc, mpic, 42, "serial0", 0, true);
 
     snprintf(gutil, sizeof(gutil), "%s/global-utilities@%llx", soc,
              MPC8544_UTIL_OFFSET);
@@ -367,6 +405,14 @@ static int ppce500_load_device_tree(PPCE500Params *params,
     qemu_devtree_setprop_cell(fdt, pci, "#address-cells", 3);
     qemu_devtree_setprop_string(fdt, "/aliases", "pci0", pci);
 
+    platbus = qdev_find_recursive(sysbus_get_default(), "platbus");
+    if (platbus) {
+        qemu_devtree_add_subnode(fdt, "/platbus");
+        platbus_create_devtree(platbus, fdt, "/platbus", E500_PLATBUS_BASE,
+                               mpic, E500_PLATBUS_FIRST_IRQ,
+                               E500_PLATBUS_NUM_IRQS);
+    }
+
     params->fixup_devtree(params, fdt);
 
     if (toplevel_compat) {
-- 
1.8.1.4