On Fri, Nov 23, 2018 at 04:52:49PM +1100, Alexey Kardashevskiy wrote:
> The powernv PCI code stores NPU data in the pnv_phb struct. The latter
> is referenced by pci_controller::private_data. We are going to have NPU2
> support in the pseries platform as well but it does not store any
> private_data in in the pci_controller struct; and even if it did,
> it would be a different data structure.
> 
> This makes npu a pointer and stores it one level higher in
> the pci_controller struct.
> 
> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
> ---
> Changes:
> v4:
> * changed subj from "powerpc/powernv: Detach npu struct from pnv_phb"
> * got rid of global list of npus - store them now in pci_controller
> * got rid of npdev_to_npu() helper
> ---
>  arch/powerpc/include/asm/pci-bridge.h    |  1 +
>  arch/powerpc/platforms/powernv/pci.h     | 16 -----
>  arch/powerpc/platforms/powernv/npu-dma.c | 81 ++++++++++++++++++------
>  3 files changed, 64 insertions(+), 34 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/pci-bridge.h 
> b/arch/powerpc/include/asm/pci-bridge.h
> index 94d4490..aee4fcc 100644
> --- a/arch/powerpc/include/asm/pci-bridge.h
> +++ b/arch/powerpc/include/asm/pci-bridge.h
> @@ -129,6 +129,7 @@ struct pci_controller {
>  #endif       /* CONFIG_PPC64 */
>  
>       void *private_data;
> +     struct npu *npu;
>  };
>  
>  /* These are used for config access before all the PCI probing
> diff --git a/arch/powerpc/platforms/powernv/pci.h 
> b/arch/powerpc/platforms/powernv/pci.h
> index 2131373..f2d50974 100644
> --- a/arch/powerpc/platforms/powernv/pci.h
> +++ b/arch/powerpc/platforms/powernv/pci.h
> @@ -8,9 +8,6 @@
>  
>  struct pci_dn;
>  
> -/* Maximum possible number of ATSD MMIO registers per NPU */
> -#define NV_NMMU_ATSD_REGS 8
> -
>  enum pnv_phb_type {
>       PNV_PHB_IODA1           = 0,
>       PNV_PHB_IODA2           = 1,
> @@ -176,19 +173,6 @@ struct pnv_phb {
>       unsigned int            diag_data_size;
>       u8                      *diag_data;
>  
> -     /* Nvlink2 data */
> -     struct npu {
> -             int index;
> -             __be64 *mmio_atsd_regs[NV_NMMU_ATSD_REGS];
> -             unsigned int mmio_atsd_count;
> -
> -             /* Bitmask for MMIO register usage */
> -             unsigned long mmio_atsd_usage;
> -
> -             /* Do we need to explicitly flush the nest mmu? */
> -             bool nmmu_flush;
> -     } npu;
> -
>       int p2p_target_count;
>  };
>  
> diff --git a/arch/powerpc/platforms/powernv/npu-dma.c 
> b/arch/powerpc/platforms/powernv/npu-dma.c
> index 91d488f..7dd5c0e5 100644
> --- a/arch/powerpc/platforms/powernv/npu-dma.c
> +++ b/arch/powerpc/platforms/powernv/npu-dma.c
> @@ -327,6 +327,25 @@ struct pnv_ioda_pe *pnv_pci_npu_setup_iommu(struct 
> pnv_ioda_pe *npe)
>       return gpe;
>  }
>  
> +/*
> + * NPU2 ATS
> + */
> +/* Maximum possible number of ATSD MMIO registers per NPU */
> +#define NV_NMMU_ATSD_REGS 8
> +
> +/* An NPU descriptor, valid for POWER9 only */
> +struct npu {
> +     int index;
> +     __be64 *mmio_atsd_regs[NV_NMMU_ATSD_REGS];
> +     unsigned int mmio_atsd_count;
> +
> +     /* Bitmask for MMIO register usage */
> +     unsigned long mmio_atsd_usage;
> +
> +     /* Do we need to explicitly flush the nest mmu? */
> +     bool nmmu_flush;
> +};
> +
>  /* Maximum number of nvlinks per npu */
>  #define NV_MAX_LINKS 6
>  
> @@ -478,7 +497,6 @@ static void acquire_atsd_reg(struct npu_context 
> *npu_context,
>       int i, j;
>       struct npu *npu;
>       struct pci_dev *npdev;
> -     struct pnv_phb *nphb;
>  
>       for (i = 0; i <= max_npu2_index; i++) {
>               mmio_atsd_reg[i].reg = -1;
> @@ -493,8 +511,10 @@ static void acquire_atsd_reg(struct npu_context 
> *npu_context,
>                       if (!npdev)
>                               continue;
>  
> -                     nphb = pci_bus_to_host(npdev->bus)->private_data;
> -                     npu = &nphb->npu;
> +                     npu = pci_bus_to_host(npdev->bus)->npu;
> +                     if (!npu)
> +                             continue;

This patch changes a bunch of places that used to unconditionally
locate an NPU now have a failure path.

Given that this used to always have an NPU, doesn't that mean that if
the NPU is not present something has already gone wrong, and we should
WARN_ON() or something?

>                       mmio_atsd_reg[i].npu = npu;
>                       mmio_atsd_reg[i].reg = get_mmio_atsd_reg(npu);
>                       while (mmio_atsd_reg[i].reg < 0) {
> @@ -662,6 +682,7 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev 
> *gpdev,
>       struct pnv_phb *nphb;
>       struct npu *npu;
>       struct npu_context *npu_context;
> +     struct pci_controller *hose;
>  
>       /*
>        * At present we don't support GPUs connected to multiple NPUs and I'm
> @@ -689,8 +710,11 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev 
> *gpdev,
>               return ERR_PTR(-EINVAL);
>       }
>  
> -     nphb = pci_bus_to_host(npdev->bus)->private_data;
> -     npu = &nphb->npu;
> +     hose = pci_bus_to_host(npdev->bus);
> +     nphb = hose->private_data;
> +     npu = hose->npu;
> +     if (!npu)
> +             return ERR_PTR(-ENODEV);
>  
>       /*
>        * Setup the NPU context table for a particular GPU. These need to be
> @@ -764,7 +788,7 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev 
> *gpdev,
>        */
>       WRITE_ONCE(npu_context->npdev[npu->index][nvlink_index], npdev);
>  
> -     if (!nphb->npu.nmmu_flush) {
> +     if (!npu->nmmu_flush) {
>               /*
>                * If we're not explicitly flushing ourselves we need to mark
>                * the thread for global flushes
> @@ -802,6 +826,7 @@ void pnv_npu2_destroy_context(struct npu_context 
> *npu_context,
>       struct pci_dev *npdev = pnv_pci_get_npu_dev(gpdev, 0);
>       struct device_node *nvlink_dn;
>       u32 nvlink_index;
> +     struct pci_controller *hose;
>  
>       if (WARN_ON(!npdev))
>               return;
> @@ -809,8 +834,11 @@ void pnv_npu2_destroy_context(struct npu_context 
> *npu_context,
>       if (!firmware_has_feature(FW_FEATURE_OPAL))
>               return;
>  
> -     nphb = pci_bus_to_host(npdev->bus)->private_data;
> -     npu = &nphb->npu;
> +     hose = pci_bus_to_host(npdev->bus);
> +     nphb = hose->private_data;
> +     npu = hose->npu;
> +     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)))
> @@ -888,9 +916,15 @@ 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) {
> @@ -904,18 +938,29 @@ 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;
> +     hose->npu = npu;
>  
>       return 0;
> +
> +fail_exit:
> +     for (i = 0; i < npu->mmio_atsd_count; ++i)
> +             iounmap(npu->mmio_atsd_regs[i]);
> +
> +     kfree(npu);
> +
> +     return ret;
>  }

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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