powerpc/powernv/npu: Clean up compound table group initialisation

Re-work the control flow a bit so what's going on is a little clearer.
This also ensures the table_group is only initialised once in the P9
case. This shouldn't be a functional change since all the GPU PCI
devices should have the same table_group configuration, but it does
look strange.

Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200406030745.24595-2-oohall@gmail.com

diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index b95b9e3..de61754 100644 (file)
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -427,7 +427,7 @@ static void pnv_comp_attach_table_group(struct npu_comp *npucomp,
 
 struct iommu_table_group *pnv_try_setup_npu_table_group(struct pnv_ioda_pe *pe)
 {
-       struct iommu_table_group *table_group;
+       struct iommu_table_group *compound_group;
        struct npu_comp *npucomp;
        struct pci_dev *gpdev = NULL;
        struct pci_controller *hose;
@@ -446,36 +446,32 @@ struct iommu_table_group *pnv_try_setup_npu_table_group(struct pnv_ioda_pe *pe)
        hose = pci_bus_to_host(npdev->bus);
 
        if (hose->npu) {
-               table_group = &hose->npu->npucomp.table_group;
-
-               if (!table_group->group) {
-                       table_group->ops = &pnv_npu_peers_ops;
-                       iommu_register_group(table_group,
-                                       hose->global_number,
-                                       pe->pe_number);
-               }
+               /* P9 case: compound group is per-NPU (all gpus, all links) */
+               npucomp = &hose->npu->npucomp;
        } else {
-               /* Create a group for 1 GPU and attached NPUs for POWER8 */
-               pe->npucomp = kzalloc(sizeof(*pe->npucomp), GFP_KERNEL);
-               table_group = &pe->npucomp->table_group;
-               table_group->ops = &pnv_npu_peers_ops;
-               iommu_register_group(table_group, hose->global_number,
-                               pe->pe_number);
+               /* P8 case: Compound group is per-GPU (1 gpu, 2 links) */
+               npucomp = pe->npucomp = kzalloc(sizeof(*npucomp), GFP_KERNEL);
        }
 
-       /* Steal capabilities from a GPU PE */
-       table_group->max_dynamic_windows_supported =
-               pe->table_group.max_dynamic_windows_supported;
-       table_group->tce32_start = pe->table_group.tce32_start;
-       table_group->tce32_size = pe->table_group.tce32_size;
-       table_group->max_levels = pe->table_group.max_levels;
-       if (!table_group->pgsizes)
-               table_group->pgsizes = pe->table_group.pgsizes;
+       compound_group = &npucomp->table_group;
+       if (!compound_group->group) {
+               compound_group->ops = &pnv_npu_peers_ops;
+               iommu_register_group(compound_group, hose->global_number,
+                               pe->pe_number);
+
+               /* Steal capabilities from a GPU PE */
+               compound_group->max_dynamic_windows_supported =
+                       pe->table_group.max_dynamic_windows_supported;
+               compound_group->tce32_start = pe->table_group.tce32_start;
+               compound_group->tce32_size = pe->table_group.tce32_size;
+               compound_group->max_levels = pe->table_group.max_levels;
+               if (!compound_group->pgsizes)
+                       compound_group->pgsizes = pe->table_group.pgsizes;
+       }
 
-       npucomp = container_of(table_group, struct npu_comp, table_group);
        pnv_comp_attach_table_group(npucomp, pe);
 
-       return table_group;
+       return compound_group;
 }
 
 struct iommu_table_group *pnv_npu_compound_attach(struct pnv_ioda_pe *pe)