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[kernel] powerpc/powernv/npu: Do not attempt NPU2 setup on old P8's NPU

Message ID 20201113050457.73742-1-aik@ozlabs.ru
State Superseded
Headers show
Series [kernel] powerpc/powernv/npu: Do not attempt NPU2 setup on old P8's NPU | expand

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Context Check Description
snowpatch_ozlabs/needsstable warning Please consider tagging this patch for stable!
snowpatch_ozlabs/checkpatch success total: 0 errors, 0 warnings, 0 checks, 22 lines checked
snowpatch_ozlabs/build-pmac32 success Build succeeded
snowpatch_ozlabs/build-ppc64e success Build succeeded
snowpatch_ozlabs/build-ppc64be success Build succeeded
snowpatch_ozlabs/build-ppc64le success Build succeeded
snowpatch_ozlabs/apply_patch success Successfully applied on branch powerpc/merge (80ecbe16c827714ce3741ed1f1d34488b903e717)

Commit Message

Alexey Kardashevskiy Nov. 13, 2020, 5:04 a.m. UTC
We execute certain NPU2 setup code (such as mapping an LPID to a device
in NPU2) unconditionally if an Nvlink bridge is detected. However this
cannot succeed on P8+ machines and errors appear in dmesg. This is
harmless as skiboot returns an error and the only place we check it is
vfio-pci but that code does not get called on P8+ either.

This adds a check if pnv_npu2_xxx helpers are called on a machine with
NPU2 which initializes pnv_phb::npu in pnv_npu2_init();
pnv_phb::npu==NULL on P8+.

Fixes: 1b785611e119 ("powerpc/powernv/npu: Add release_ownership hook")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/platforms/powernv/npu-dma.c | 10 ++++++++++
 1 file changed, 10 insertions(+)
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Patch

diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index abeaa533b976..7b28b284a594 100644
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -623,6 +623,11 @@  int pnv_npu2_map_lpar_dev(struct pci_dev *gpdev, unsigned int lparid,
 		return -ENODEV;
 
 	hose = pci_bus_to_host(npdev->bus);
+	if (hose->npu == NULL) {
+		dev_info_once(&npdev->dev, "Nvlink1 does not support contexts");
+		return 0;
+	}
+
 	nphb = hose->private_data;
 
 	dev_dbg(&gpdev->dev, "Map LPAR opalid=%llu lparid=%u\n",
@@ -670,6 +675,11 @@  int pnv_npu2_unmap_lpar_dev(struct pci_dev *gpdev)
 		return -ENODEV;
 
 	hose = pci_bus_to_host(npdev->bus);
+	if (hose->npu == NULL) {
+		dev_info_once(&npdev->dev, "Nvlink1 does not support contexts");
+		return 0;
+	}
+
 	nphb = hose->private_data;
 
 	dev_dbg(&gpdev->dev, "destroy context opalid=%llu\n",