Re: [Qemu-ppc] [RFC PATCH v2 18/21] ppc/xive: add device tree support

[Cédric Le Goater]

On 09/19/2017 10:44 AM, David Gibson wrote:
> On Mon, Sep 11, 2017 at 07:12:32PM +0200, Cédric Le Goater wrote:
>> Like for XICS, the XIVE interface for the guest is described in the
>> device tree under the "interrupt-controller" node. A couple of new
>> properties are specific to XIVE :
>>
>>  - "reg"
>>
>>    contains the base address and size of the thread interrupt
>>    managnement areas (TIMA), also called rings, for the User level and
>>    for the Guest OS level. Only the Guest OS level is taken into
>>    account today.
>>
>>  - "ibm,xive-eq-sizes"
>>
>>    the size of the event queues. One cell per size supported, contains
>>    log2 of size, in ascending order.
>>
>>  - "ibm,xive-lisn-ranges"
>>
>>    the interrupt numbers ranges assigned to the guest. These are
>>    allocated using a simple bitmap.
>>
>> and also under the root node :
>>
>>  - "ibm,plat-res-int-priorities"
>>
>>    contains a list of priorities that the hypervisor has reserved for
>>    its own use. Simulate ranges as defined by the PowerVM Hypervisor.
>>
>> Signed-off-by: Cédric Le Goater <address@hidden>
>> ---
>>  hw/intc/spapr_xive_hcall.c  | 54 
>> +++++++++++++++++++++++++++++++++++++++++++++
>>  include/hw/ppc/spapr_xive.h |  1 +
>>  2 files changed, 55 insertions(+)
>>
>> diff --git a/hw/intc/spapr_xive_hcall.c b/hw/intc/spapr_xive_hcall.c
>> index 4c77b65683de..7b19ea6373dd 100644
>> --- a/hw/intc/spapr_xive_hcall.c
>> +++ b/hw/intc/spapr_xive_hcall.c
>> @@ -874,3 +874,57 @@ void spapr_xive_hcall_init(sPAPRMachineState *spapr)
>>      spapr_register_hypercall(H_INT_SYNC, h_int_sync);
>>      spapr_register_hypercall(H_INT_RESET, h_int_reset);
>>  }
>> +
>> +void spapr_xive_populate(sPAPRXive *xive, void *fdt, uint32_t phandle)
>> +{
>> +    int node;
>> +    uint64_t timas[2 * 2];
>> +    uint32_t lisn_ranges[] = {
>> +        cpu_to_be32(xive->nr_irqs - xive->nr_targets + xive->ics->offset),
>> +        cpu_to_be32(xive->nr_targets),
>> +    };
>> +    uint32_t eq_sizes[] = {
>> +        cpu_to_be32(12), /* 4K */
>> +        cpu_to_be32(16), /* 64K */
>> +        cpu_to_be32(21), /* 2M */
>> +        cpu_to_be32(24), /* 16M */
>> +    };
>> +
>> +    /* Use some ranges to exercise the Linux driver, which should
>> +     * result in Linux choosing priority 6. This is not strictly
>> +     * necessary
>> +     */
>> +    uint32_t reserved_priorities[] = {
>> +        cpu_to_be32(1),  /* start */
>> +        cpu_to_be32(2),  /* count */
>> +        cpu_to_be32(7),  /* start */
>> +        cpu_to_be32(0xf8),  /* count */
>> +    };
>> +    int i;
>> +
>> +    /* Thread Interrupt Management Areas : User and OS */
>> +    for (i = 0; i < 2; i++) {
>> +        timas[i * 2] = cpu_to_be64(xive->tm_base + i * (1 << 
>> xive->tm_shift));
>> +        timas[i * 2 + 1] = cpu_to_be64(1 << xive->tm_shift);
>> +    }
>> +
>> +    _FDT(node = fdt_add_subnode(fdt, 0, "interrupt-controller"));
>> +
>> +    _FDT(fdt_setprop_string(fdt, node, "name", "interrupt-controller"));
> 
> Shouldn't need this - SLOF will figure it out from the node name above.

It is in the specs. phyp has it. we might as well keep it.

> 
>> +    _FDT(fdt_setprop_string(fdt, node, "device_type", "power-ivpe"));
>> +    _FDT(fdt_setprop(fdt, node, "reg", timas, sizeof(timas)));
>> +
>> +    _FDT(fdt_setprop_string(fdt, node, "compatible", "ibm,power-ivpe"));
>> +    _FDT(fdt_setprop(fdt, node, "ibm,xive-eq-sizes", eq_sizes,
>> +                     sizeof(eq_sizes)));
>> +    _FDT(fdt_setprop(fdt, node, "ibm,xive-lisn-ranges", lisn_ranges,
>> +                     sizeof(lisn_ranges)));
> 
> I note this doesn't have the interrupt-controller or #interrupt-cells
> properties.  So what acts as the interrupt parent for all the devices
> in the tree with XIVE?

these properties are not in the specs anymore for the interrupt-controller
node and I don't think Linux makes use of them (even for XICS). So 
it just works fine.

C. 

>> +    /* For SLOF */
>> +    _FDT(fdt_setprop_cell(fdt, node, "linux,phandle", phandle));
>> +    _FDT(fdt_setprop_cell(fdt, node, "phandle", phandle));
>> +
>> +    /* top properties */
>> +    _FDT(fdt_setprop(fdt, 0, "ibm,plat-res-int-priorities",
>> +                     reserved_priorities, sizeof(reserved_priorities)));
>> +}
>> diff --git a/include/hw/ppc/spapr_xive.h b/include/hw/ppc/spapr_xive.h
>> index ae5ff89533c0..0a156f2d8591 100644
>> --- a/include/hw/ppc/spapr_xive.h
>> +++ b/include/hw/ppc/spapr_xive.h
>> @@ -69,5 +69,6 @@ struct sPAPRXive {
>>  typedef struct sPAPRMachineState sPAPRMachineState;
>>  
>>  void spapr_xive_hcall_init(sPAPRMachineState *spapr);
>> +void spapr_xive_populate(sPAPRXive *xive, void *fdt, uint32_t phandle);
>>  
>>  #endif /* PPC_SPAPR_XIVE_H */
>