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authorAlistair Popple <alistair@popple.id.au>2017-09-06 11:49:00 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2017-11-13 08:00:30 +1100
commit1b2c2b12386f9bb009a2249eca00e01a9d76d7c1 (patch)
treee521dd43b3565c4f3157f277a9b4647393b37ea4
parent2a31ad093bb1b8c1f1e04cbe222ad17bc09c4534 (diff)
powerpc/powernv/npu: Don't explicitly flush nmmu tlb
The nest mmu required an explicit flush as a tlbi would not flush it in the same way as the core. However an alternate firmware fix exists which should eliminate the need for this flush, so instead add a device-tree property (ibm,nmmu-flush) on the NVLink2 PHB to enable it only if required. Signed-off-by: Alistair Popple <alistair@popple.id.au> Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/platforms/powernv/npu-dma.c28
-rw-r--r--arch/powerpc/platforms/powernv/pci.h3
2 files changed, 26 insertions, 5 deletions
diff --git a/arch/powerpc/platforms/powernv/npu-dma.c b/arch/powerpc/platforms/powernv/npu-dma.c
index 2fff9a65975b..f6cbc1a71472 100644
--- a/arch/powerpc/platforms/powernv/npu-dma.c
+++ b/arch/powerpc/platforms/powernv/npu-dma.c
@@ -395,6 +395,7 @@ struct npu_context {
struct pci_dev *npdev[NV_MAX_NPUS][NV_MAX_LINKS];
struct mmu_notifier mn;
struct kref kref;
+ bool nmmu_flush;
/* Callback to stop translation requests on a given GPU */
struct npu_context *(*release_cb)(struct npu_context *, void *);
@@ -545,11 +546,13 @@ static void mmio_invalidate(struct npu_context *npu_context, int va,
struct mmio_atsd_reg mmio_atsd_reg[NV_MAX_NPUS];
unsigned long pid = npu_context->mm->context.id;
- /*
- * Unfortunately the nest mmu does not support flushing specific
- * addresses so we have to flush the whole mm.
- */
- flush_all_mm(npu_context->mm);
+ if (npu_context->nmmu_flush)
+ /*
+ * Unfortunately the nest mmu does not support flushing specific
+ * addresses so we have to flush the whole mm once before
+ * shooting down the GPU translation.
+ */
+ flush_all_mm(npu_context->mm);
/*
* Loop over all the NPUs this process is active on and launch
@@ -722,6 +725,16 @@ struct npu_context *pnv_npu2_init_context(struct pci_dev *gpdev,
return ERR_PTR(-ENODEV);
npu_context->npdev[npu->index][nvlink_index] = npdev;
+ if (!nphb->npu.nmmu_flush) {
+ /*
+ * If we're not explicitly flushing ourselves we need to mark
+ * the thread for global flushes
+ */
+ npu_context->nmmu_flush = false;
+ mm_context_add_copro(mm);
+ } else
+ npu_context->nmmu_flush = true;
+
return npu_context;
}
EXPORT_SYMBOL(pnv_npu2_init_context);
@@ -731,6 +744,9 @@ static void pnv_npu2_release_context(struct kref *kref)
struct npu_context *npu_context =
container_of(kref, struct npu_context, kref);
+ if (!npu_context->nmmu_flush)
+ mm_context_remove_copro(npu_context->mm);
+
npu_context->mm->context.npu_context = NULL;
mmu_notifier_unregister(&npu_context->mn,
npu_context->mm);
@@ -819,6 +835,8 @@ int pnv_npu2_init(struct pnv_phb *phb)
static int npu_index;
uint64_t rc = 0;
+ phb->npu.nmmu_flush =
+ of_property_read_bool(phb->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) {
diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h
index 56d1f272d4ad..96151b3a2dd4 100644
--- a/arch/powerpc/platforms/powernv/pci.h
+++ b/arch/powerpc/platforms/powernv/pci.h
@@ -187,6 +187,9 @@ struct pnv_phb {
/* Bitmask for MMIO register usage */
unsigned long mmio_atsd_usage;
+
+ /* Do we need to explicitly flush the nest mmu? */
+ bool nmmu_flush;
} npu;
#ifdef CONFIG_CXL_BASE