powerpc/powernv/npu: Add set/unset window helpers

The upcoming NVLink passthrough support will require NPU code to cope
with two DMA windows.

This adds a pnv_npu_set_window() helper which programs 32bit window to
the hardware. This also adds multilevel TCE support.

This adds a pnv_npu_unset_window() helper which removes the DMA window
from the hardware. This does not make difference now as the caller -
pnv_npu_dma_set_bypass() - enables bypass in the hardware but the next
patch will use it to manage TCE table lists for TCE Kill handling.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-By: Alistair Popple <alistair@popple.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index bec9267bf303eeea989a93972679e43a2876c7a3..800d70f5d132fced94a7a7142e4b29e813aea8e8 100644 (file)
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -159,6 +159,56 @@ static struct pnv_ioda_pe *get_gpu_pci_dev_and_pe(struct pnv_ioda_pe *npe,
        return pe;
 }
 
+static long pnv_npu_set_window(struct pnv_ioda_pe *npe,
+               struct iommu_table *tbl)
+{
+       struct pnv_phb *phb = npe->phb;
+       int64_t rc;
+       const unsigned long size = tbl->it_indirect_levels ?
+               tbl->it_level_size : tbl->it_size;
+       const __u64 start_addr = tbl->it_offset << tbl->it_page_shift;
+       const __u64 win_size = tbl->it_size << tbl->it_page_shift;
+
+       pe_info(npe, "Setting up window %llx..%llx pg=%lx\n",
+                       start_addr, start_addr + win_size - 1,
+                       IOMMU_PAGE_SIZE(tbl));
+
+       rc = opal_pci_map_pe_dma_window(phb->opal_id,
+                       npe->pe_number,
+                       npe->pe_number,
+                       tbl->it_indirect_levels + 1,
+                       __pa(tbl->it_base),
+                       size << 3,
+                       IOMMU_PAGE_SIZE(tbl));
+       if (rc) {
+               pe_err(npe, "Failed to configure TCE table, err %lld\n", rc);
+               return rc;
+       }
+       pnv_pci_ioda2_tce_invalidate_entire(phb, false);
+
+       return 0;
+}
+
+static long pnv_npu_unset_window(struct pnv_ioda_pe *npe)
+{
+       struct pnv_phb *phb = npe->phb;
+       int64_t rc;
+
+       pe_info(npe, "Removing DMA window\n");
+
+       rc = opal_pci_map_pe_dma_window(phb->opal_id, npe->pe_number,
+                       npe->pe_number,
+                       0/* levels */, 0/* table address */,
+                       0/* table size */, 0/* page size */);
+       if (rc) {
+               pe_err(npe, "Unmapping failed, ret = %lld\n", rc);
+               return rc;
+       }
+       pnv_pci_ioda2_tce_invalidate_entire(phb, false);
+
+       return 0;
+}
+
 void pnv_npu_init_dma_pe(struct pnv_ioda_pe *npe)
 {
        struct pnv_ioda_pe *gpe;
@@ -200,10 +250,8 @@ void pnv_npu_init_dma_pe(struct pnv_ioda_pe *npe)
  */
 static void pnv_npu_dma_set_32(struct pnv_ioda_pe *npe)
 {
-       struct pnv_phb *phb = npe->phb;
        struct pci_dev *gpdev;
        struct pnv_ioda_pe *gpe;
-       struct iommu_table *tbl;
        int64_t rc;
 
        /*
@@ -217,14 +265,7 @@ static void pnv_npu_dma_set_32(struct pnv_ioda_pe *npe)
        if (!gpe)
                return;
 
-       tbl = gpe->table_group.tables[0];
-       rc = opal_pci_map_pe_dma_window(phb->opal_id, npe->pe_number,
-                                       npe->pe_number, 1, __pa(tbl->it_base),
-                                       tbl->it_size << 3,
-                                       IOMMU_PAGE_SIZE(tbl));
-       if (rc != OPAL_SUCCESS)
-               pr_warn("%s: Error %lld setting DMA window on PHB#%d-PE#%d\n",
-                       __func__, rc, phb->hose->global_number, npe->pe_number);
+       rc = pnv_npu_set_window(npe, gpe->table_group.tables[0]);
 
        /*
         * We don't initialise npu_pe->tce32_table as we always use
@@ -248,6 +289,10 @@ static int pnv_npu_dma_set_bypass(struct pnv_ioda_pe *npe)
        if (phb->type != PNV_PHB_NPU || !npe->pdev)
                return -EINVAL;
 
+       rc = pnv_npu_unset_window(npe);
+       if (rc != OPAL_SUCCESS)
+               return rc;
+
        /* Enable the bypass window */
 
        top = roundup_pow_of_two(top);