Re: [Qemu-devel] [PULL 16/17] hw/pci-bridge: format special OFW unit address for PXB host

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

Hi Michael and Marcel,

(old patch...)

On 26/6/15 15:46, Michael S. Tsirkin wrote:
> From: Laszlo Ersek <lersek@redhat.com>
> 
> We have agreed that OpenFirmware device paths in the "bootorder" fw_cfg
> file should follow the pattern
> 
>    /pci@i0cf8,%x/...
> 
> for devices that live behind an extra root bus. The extra root bus in
> question is the %x'th among the extra root buses. (In other words, %x
> gives the position of the affected extra root bus relative to the other
> extra root buses, in bus_nr order.) %x starts at 1, and is formatted in
> hex.
> 
> The portion of the unit address that comes before the comma is dynamically
> taken from the main host bridge, similarly to sysbus_get_fw_dev_path().
> 
> Cc: Kevin O'Connor <kevin@koconnor.net>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Marcel Apfelbaum <marcel@redhat.com>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>   hw/pci-bridge/pci_expander_bridge.c | 53 +++++++++++++++++++++++++++++++++++++
>   1 file changed, 53 insertions(+)
> 
> diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
> index 70708ef..57f8a37 100644
> --- a/hw/pci-bridge/pci_expander_bridge.c
> +++ b/hw/pci-bridge/pci_expander_bridge.c
> @@ -43,6 +43,8 @@ typedef struct PXBDev {
>       uint16_t numa_node;
>   } PXBDev;
>   
> +static GList *pxb_dev_list;

This list is static ...

> +
>   #define TYPE_PXB_HOST "pxb-host"
>   
>   static int pxb_bus_num(PCIBus *bus)
> @@ -89,12 +91,45 @@ static const char *pxb_host_root_bus_path(PCIHostState *host_bridge,
>       return bus->bus_path;
>   }
>   
> +static char *pxb_host_ofw_unit_address(const SysBusDevice *dev)
> +{
> +    const PCIHostState *pxb_host;
> +    const PCIBus *pxb_bus;
> +    const PXBDev *pxb_dev;
> +    int position;
> +    const DeviceState *pxb_dev_base;
> +    const PCIHostState *main_host;
> +    const SysBusDevice *main_host_sbd;
> +
> +    pxb_host = PCI_HOST_BRIDGE(dev);
> +    pxb_bus = pxb_host->bus;
> +    pxb_dev = PXB_DEV(pxb_bus->parent_dev);
> +    position = g_list_index(pxb_dev_list, pxb_dev);
> +    assert(position >= 0);

... and for some reason when calling pxb_host_ofw_unit_address() twice
it triggers the following:

Assertion failed: (position >= 0), function pxb_host_ofw_unit_address, 
file pci_expander_bridge.c, line 154.

Any idea why it got implemented this way and how to modify to
avoid the assertion? All other devices implementing the
SysBusDeviceClass::explicit_ofw_unit_address handler don't abort
when being called multiple times, what is so particular here?

Thanks,

Phil.

> +
> +    pxb_dev_base = DEVICE(pxb_dev);
> +    main_host = PCI_HOST_BRIDGE(pxb_dev_base->parent_bus->parent);
> +    main_host_sbd = SYS_BUS_DEVICE(main_host);
> +
> +    if (main_host_sbd->num_mmio > 0) {
> +        return g_strdup_printf(TARGET_FMT_plx ",%x",
> +                               main_host_sbd->mmio[0].addr, position + 1);
> +    }
> +    if (main_host_sbd->num_pio > 0) {
> +        return g_strdup_printf("i%04x,%x",
> +                               main_host_sbd->pio[0], position + 1);
> +    }
> +    return NULL;
> +}
> +
>   static void pxb_host_class_init(ObjectClass *class, void *data)
>   {
>       DeviceClass *dc = DEVICE_CLASS(class);
> +    SysBusDeviceClass *sbc = SYS_BUS_DEVICE_CLASS(class);
>       PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(class);
>   
>       dc->fw_name = "pci";
> +    sbc->explicit_ofw_unit_address = pxb_host_ofw_unit_address;
>       hc->root_bus_path = pxb_host_root_bus_path;
>   }
>   
> @@ -149,6 +184,15 @@ static int pxb_map_irq_fn(PCIDevice *pci_dev, int pin)
>       return pin - PCI_SLOT(pxb->devfn);
>   }
>   
> +static gint pxb_compare(gconstpointer a, gconstpointer b)
> +{
> +    const PXBDev *pxb_a = a, *pxb_b = b;
> +
> +    return pxb_a->bus_nr < pxb_b->bus_nr ? -1 :
> +           pxb_a->bus_nr > pxb_b->bus_nr ?  1 :
> +           0;
> +}
> +
>   static int pxb_dev_initfn(PCIDevice *dev)
>   {
>       PXBDev *pxb = PXB_DEV(dev);
> @@ -192,9 +236,17 @@ static int pxb_dev_initfn(PCIDevice *dev)
>                                  PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK);
>       pci_config_set_class(dev->config, PCI_CLASS_BRIDGE_HOST);
>   
> +    pxb_dev_list = g_list_insert_sorted(pxb_dev_list, pxb, pxb_compare);
>       return 0;
>   }
>   
> +static void pxb_dev_exitfn(PCIDevice *pci_dev)
> +{
> +    PXBDev *pxb = PXB_DEV(pci_dev);
> +
> +    pxb_dev_list = g_list_remove(pxb_dev_list, pxb);
> +}
> +
>   static Property pxb_dev_properties[] = {
>       /* Note: 0 is not a legal a PXB bus number. */
>       DEFINE_PROP_UINT8("bus_nr", PXBDev, bus_nr, 0),
> @@ -208,6 +260,7 @@ static void pxb_dev_class_init(ObjectClass *klass, void *data)
>       PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
>   
>       k->init = pxb_dev_initfn;
> +    k->exit = pxb_dev_exitfn;
>       k->vendor_id = PCI_VENDOR_ID_REDHAT;
>       k->device_id = PCI_DEVICE_ID_REDHAT_PXB;
>       k->class_id = PCI_CLASS_BRIDGE_HOST;