Hi Alexey,
On Tuesday, 13 November 2018 7:28:07 PM AEDT Alexey Kardashevskiy wrote:
> static struct npu *npdev_to_npu(struct pci_dev *npdev)
> {
> - struct pnv_phb *nphb;
> + struct pci_controller *hose = pci_bus_to_host(npdev->bus);
> + struct npu *npu;
>
> - nphb = pci_bus_to_host(npdev->bus)->private_data;
> + list_for_each_entry(npu, &npu2_devices, next)
This is called from the ATSD path which is (or at least has been) quite a
performance critical path so searching through all the NPUs in a list may be
problematic.
I guess currently it wont make any practical difference as we only ever have 2
NPUs, but in future they may get divided into more logical NPUs. Would it be
possible to store a back-pointer somewhere so we can avoid the lookup?
> + if (hose == npu->hose)
> + return npu;
>
> - return &nphb->npu;
> + WARN_ON_ONCE(1);
> + return NULL;
> }
>
> /* Maximum number of nvlinks per npu */
> @@ -505,6 +531,9 @@ static void acquire_atsd_reg(struct npu_context
> *npu_context, continue;
>
> npu = npdev_to_npu(npdev);
> + if (!npu)
> + continue;
> +
> mmio_atsd_reg[i].npu = npu;
> mmio_atsd_reg[i].reg = get_mmio_atsd_reg(npu);
> while (mmio_atsd_reg[i].reg < 0) {
> @@ -701,6 +730,8 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev
> *gpdev,
>
> nphb = pci_bus_to_host(npdev->bus)->private_data;
> npu = npdev_to_npu(npdev);
> + if (!npu)
> + return ERR_PTR(-ENODEV);
>
> /*
> * Setup the NPU context table for a particular GPU. These need to be
> @@ -821,6 +852,8 @@ void pnv_npu2_destroy_context(struct npu_context
> *npu_context,
>
> nphb = pci_bus_to_host(npdev->bus)->private_data;
> npu = npdev_to_npu(npdev);
> + if (!npu)
> + return;
> nvlink_dn = of_parse_phandle(npdev->dev.of_node, "ibm,nvlink", 0);
> if (WARN_ON(of_property_read_u32(nvlink_dn, "ibm,npu-link-index",
> &nvlink_index)))
> @@ -898,9 +931,15 @@ int pnv_npu2_init(struct pnv_phb *phb)
> struct pci_dev *gpdev;
> static int npu_index;
> uint64_t rc = 0;
> + struct pci_controller *hose = phb->hose;
> + struct npu *npu;
> + int ret;
>
> - phb->npu.nmmu_flush =
> - of_property_read_bool(phb->hose->dn, "ibm,nmmu-flush");
> + npu = kzalloc(sizeof(*npu), GFP_KERNEL);
> + if (!npu)
> + return -ENOMEM;
> +
> + npu->nmmu_flush = of_property_read_bool(hose->dn, "ibm,nmmu-flush");
> for_each_child_of_node(phb->hose->dn, dn) {
> gpdev = pnv_pci_get_gpu_dev(get_pci_dev(dn));
> if (gpdev) {
> @@ -914,18 +953,31 @@ int pnv_npu2_init(struct pnv_phb *phb)
> }
> }
>
> - for (i = 0; !of_property_read_u64_index(phb->hose->dn, "ibm,mmio-atsd",
> + for (i = 0; !of_property_read_u64_index(hose->dn, "ibm,mmio-atsd",
> i, &mmio_atsd); i++)
> - phb->npu.mmio_atsd_regs[i] = ioremap(mmio_atsd, 32);
> + npu->mmio_atsd_regs[i] = ioremap(mmio_atsd, 32);
>
> - pr_info("NPU%lld: Found %d MMIO ATSD registers", phb->opal_id, i);
> - phb->npu.mmio_atsd_count = i;
> - phb->npu.mmio_atsd_usage = 0;
> + pr_info("NPU%d: Found %d MMIO ATSD registers", hose->global_number, i);
> + npu->mmio_atsd_count = i;
> + npu->mmio_atsd_usage = 0;
> npu_index++;
> - if (WARN_ON(npu_index >= NV_MAX_NPUS))
> - return -ENOSPC;
> + if (WARN_ON(npu_index >= NV_MAX_NPUS)) {
> + ret = -ENOSPC;
> + goto fail_exit;
> + }
> max_npu2_index = npu_index;
> - phb->npu.index = npu_index;
> + npu->index = npu_index;
> + npu->hose = hose;
> +
> + list_add(&npu->next, &npu2_devices);
Guess we don't need any locking here as the list gets setup once during boot
long before loading the driver and is never modified right?
- Alistair
> return 0;
> +
> +fail_exit:
> + for (i = 0; i < npu->mmio_atsd_count; ++i)
> + iounmap(npu->mmio_atsd_regs[i]);
> +
> + kfree(npu);
> +
> + return ret;
> }
