On Fri, 29 Apr 2016 18:55:22 Alexey Kardashevskiy wrote:
> 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 <a...@ozlabs.ru>
> ---
> arch/powerpc/platforms/powernv/npu-dma.c | 65
+++++++++++++++++++++++++++-----
> 1 file changed, 55 insertions(+), 10 deletions(-)
>
> diff --git a/arch/powerpc/platforms/powernv/npu-dma.c
b/arch/powerpc/platforms/powernv/npu-dma.c
> index bec9267..800d70f 100644
> --- 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);
As noted in the commit message you technically don't need to do this as the
subsequent OPAL call to enable the bypass window below will just overwrite the
same TVE. However I like the logic of clearing the existing TVE before writing
a new one anyway as it also ensures the TCE cache gets properly invalidated.
Other than that this patch looks like it doesn't change any existing
behaviour.
Reviewed-By: Alistair Popple <alist...@popple.id.au>
> + if (rc != OPAL_SUCCESS)
> + return rc;
> +
> /* Enable the bypass window */
>
> top = roundup_pow_of_two(top);
>
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