Re: [Qemu-ppc] [Qemu-devel] [PATCH v5 3/4] spapr_pci: enumerate and add PCI device tree

[Nikunj A Dadhania]

Alexey Kardashevskiy <address@hidden> writes:

> On 05/19/2015 06:26 PM, Nikunj A Dadhania wrote:
>> 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 <address@hidden>
>> [ Squashed Michael's drc_index changes ]
>> Signed-off-by: Michael Roth <address@hidden>
>> Signed-off-by: Nikunj A Dadhania <address@hidden>
>> ---
>>   hw/ppc/spapr_pci.c | 188 
>> ++++++++++++++++++++++++++++++++++++++++++-----------
>>   1 file changed, 150 insertions(+), 38 deletions(-)
>>
>> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
>> index 8b02a3e..12f1b9c 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"
>> @@ -742,6 +744,31 @@ static AddressSpace *spapr_pci_dma_iommu(PCIBus *bus, 
>> void *opaque, int devfn)
>>       return &phb->iommu_as;
>>   }
>>
>> +
>> +static sPAPRDRConnector *spapr_phb_get_pci_drc(sPAPRPHBState *phb,
>> +                                               PCIDevice *pdev)
>> +{
>> +    uint32_t busnr = 
>> pci_bus_num(PCI_BUS(qdev_get_parent_bus(DEVICE(pdev))));
>> +    return spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_PCI,
>> +                                    (phb->index << 16) |
>> +                                    (busnr << 8) |
>> +                                    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);
>> +}
>> +
>>   /* Macros to operate with address in OF binding to PCI */
>>   #define b_x(x, p, l)    (((x) & ((1<<(l))-1)) << (p))
>>   #define b_n(x)          b_x((x), 31, 1) /* 0 if relocatable */
>> @@ -879,12 +906,13 @@ static void populate_resource_props(PCIDevice *d, 
>> ResourceProps *rp)
>>   }
>>
>>   static int spapr_populate_pci_child_dt(PCIDevice *dev, void *fdt, int 
>> offset,
>> -                                       int phb_index, int drc_index,
>> +                                       sPAPRPHBState *sphb,
>>                                          const char *drc_name)
>>   {
>>       ResourceProps rp;
>>       bool is_bridge = false;
>>       int pci_status;
>> +    uint32_t drc_index = spapr_phb_get_pci_drc_index(sphb, dev);
>
> Is this drc_index any different from the one which used to be passed to 
> this function? If no, then I do not see the point in changing the prototype 
> (or make another "this just makes code easier/nicer" patch).

Its the same, I can have a separate patch. As I was changing this code
the drc_index would need to be read in boot and hotplug code. So brought
over the code here.

> If yes, then it would be nice to see what the patch changed in this
> regard in the commit log.
>
>
>
>>       if (pci_default_read_config(dev, PCI_HEADER_TYPE, 1) ==
>>           PCI_HEADER_TYPE_BRIDGE) {
>> @@ -945,8 +973,13 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, 
>> void *fdt, int offset,
>>        * processed by OF beforehand
>>        */
>>       _FDT(fdt_setprop_string(fdt, offset, "name", "pci"));
>> -    _FDT(fdt_setprop(fdt, offset, "ibm,loc-code", drc_name, 
>> strlen(drc_name)));
>> -    _FDT(fdt_setprop_cell(fdt, offset, "ibm,my-drc-index", drc_index));
>> +    if (drc_name) {
>> +        _FDT(fdt_setprop(fdt, offset, "ibm,loc-code", drc_name,
>> +                         strlen(drc_name)));
>> +    }
>> +    if (drc_index) {
>> +        _FDT(fdt_setprop_cell(fdt, offset, "ibm,my-drc-index", drc_index));
>> +    }
>>
>>       _FDT(fdt_setprop_cell(fdt, offset, "#address-cells",
>>                             RESOURCE_CELLS_ADDRESS));
>> @@ -963,30 +996,34 @@ static int spapr_populate_pci_child_dt(PCIDevice *dev, 
>> void *fdt, int offset,
>>       return 0;
>>   }
>>
>> +typedef struct sPAPRFDT {
>> +    void *fdt;
>> +    int node_off;
>> +    sPAPRPHBState *sphb;
>> +} sPAPRFDT;
>> +
>>   /* 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(PCIDevice *pdev, sPAPRFDT *p,
>> +                                     const char *drc_name)
>
> Why s/dev/pdev/?

PCIDev thats the only reason.

>
>
>>   {
>> -    void *fdt;
>> -    int offset, ret, fdt_size;
>> -    int slot = PCI_SLOT(dev->devfn);
>> -    int func = PCI_FUNC(dev->devfn);
>> -    char nodename[512];
>> +    int offset, ret;
>> +    char nodename[64];
>
> Why s/512/64/?

Earlier this was called in recursion, so there was a comment in previous
series to reduce this to lesser number.

>
> This change and the one above hide what the patch really does to 
> spapr_create_pci_child_dt.
>
>
>> +    int slot = PCI_SLOT(pdev->devfn);
>> +    int func = PCI_FUNC(pdev->devfn);
>>
>> -    fdt = create_device_tree(&fdt_size);
>>       if (func != 0) {
>>           sprintf(nodename, "address@hidden,%d", slot, func);
>>       } else {
>>           sprintf(nodename, "address@hidden", slot);
>>       }
>> -    offset = fdt_add_subnode(fdt, 0, nodename);
>> -    ret = spapr_populate_pci_child_dt(dev, fdt, offset, phb->index, 
>> drc_index,
>> +    offset = fdt_add_subnode(p->fdt, p->node_off, nodename);
>> +    ret = spapr_populate_pci_child_dt(pdev, p->fdt, offset, p->sphb,
>>                                         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,
>> @@ -996,24 +1033,26 @@ static void spapr_phb_add_pci_device(sPAPRDRConnector 
>> *drc,
>>   {
>>       sPAPRDRConnectorClass *drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
>>       DeviceState *dev = DEVICE(pdev);
>> -    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;
>> +    sPAPRFDT s_fdt = {NULL, 0, NULL};
>>
>> -    /* 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) {
>
>
> I understand the patch is not changing this but still while we are here -
> spapr_phb_add_pci_device() is only called from spapr_phb_hot_plug_child(), 
> how can dev->hotplugged be not true in this function (if it cannot, you 
> could get rid of "out:"?

It gets called even when the devices are added during boot.

>
>> -        fdt = spapr_create_pci_child_dt(phb, pdev, drc_index, drc_name,
>> -                                        &fdt_start_offset);
>> +        s_fdt.fdt = create_device_tree(&fdt_size);
>> +        s_fdt.sphb = phb;
>> +        s_fdt.node_off = 0;
>> +        fdt_start_offset = spapr_create_pci_child_dt(pdev, &s_fdt, 
>> drc_name);
>> +        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);
>> +                 s_fdt.fdt, fdt_start_offset, !dev->hotplugged, errp);
>> +out:
>>       if (*errp) {
>> -        g_free(fdt);
>> +        g_free(s_fdt.fdt);
>>       }
>>   }
>>
>> @@ -1043,16 +1082,6 @@ static void 
>> spapr_phb_remove_pci_device(sPAPRDRConnector *drc,
>>       drck->detach(drc, DEVICE(pdev), spapr_phb_remove_pci_device_cb, phb, 
>> errp);
>>   }
>>
>> -static sPAPRDRConnector *spapr_phb_get_pci_drc(sPAPRPHBState *phb,
>> -                                               PCIDevice *pdev)
>
> Just adding forward declaration would make the patch shorter.

Yes, I can do that.

>
>> -{
>> -    uint32_t busnr = 
>> pci_bus_num(PCI_BUS(qdev_get_parent_bus(DEVICE(pdev))));
>> -    return spapr_dr_connector_by_id(SPAPR_DR_CONNECTOR_TYPE_PCI,
>> -                                    (phb->index << 16) |
>> -                                    (busnr << 8) |
>> -                                    pdev->devfn);
>> -}
>> -
>>   static void spapr_phb_hot_plug_child(HotplugHandler *plug_handler,
>>                                        DeviceState *plugged_dev, Error 
>> **errp)
>>   {
>> @@ -1482,6 +1511,75 @@ PCIHostState *spapr_create_phb(sPAPREnvironment 
>> *spapr, int index)
>>       return PCI_HOST_BRIDGE(dev);
>>   }
>>
>> +static void spapr_populate_pci_devices_dt(PCIBus *bus, PCIDevice *pdev,
>> +                                          void *opaque)
>> +{
>> +    PCIBus *sec_bus;
>> +    sPAPRFDT *p = opaque;
>> +    int offset;
>> +    sPAPRFDT s_fdt;
>> +
>> +    offset = spapr_create_pci_child_dt(pdev, p, NULL);
>> +    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 secondary;
>> +    unsigned int subordinate = 0xff;
>> +
>> +    if ((pci_default_read_config(pdev, PCI_HEADER_TYPE, 1) ==
>> +         PCI_HEADER_TYPE_BRIDGE)) {
>
>
> s/==/!=/ and "return" and no need in extra indent below.

Right.

>
>> +        PCIBus *sec_bus = pci_bridge_get_sec_bus(PCI_BRIDGE(pdev));
>> +        secondary = *bus_no + 1;
>
>
> (*bus_no)++;
> secondary = *bus_no;
>
> and remove "bus_no = *bus_no + 1" below?
> In fact, I do not need much sense in having "secondary" variable in this 
> function.
>
>> +        pci_default_write_config(pdev, PCI_PRIMARY_BUS, primary, 1);
>> +        pci_default_write_config(pdev, PCI_SECONDARY_BUS, secondary, 1);
>> +        pci_default_write_config(pdev, PCI_SUBORDINATE_BUS, secondary, 1);
>> +        *bus_no = *bus_no + 1;
>> +        if (sec_bus) {
>
> same here? Just like you did in spapr_populate_pci_devices_dt(). I do not 
> insist though. But having less scopes just makes it easier/nicer to wrap 
> long lines in QEMU coding style (new line starts under "(").
>
>
>> +            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)
>> @@ -1521,6 +1619,8 @@ 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 */
>>       sprintf(nodename, "address@hidden" PRIx64, phb->buid);
>> @@ -1570,6 +1670,18 @@ 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));
>
>
> Can we also add a hack here to scan for the "qemu,phb-enumerated" string in 
> the SLOF bin image?

Really ? That would be ugly.

>
>> +
>> +    /* 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) {
>>
>
>
> -- 
> Alexey