diff options
| author | Alexey Kardashevskiy <aik@ozlabs.ru> | 2018-06-01 18:06:16 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-10-10 08:52:05 +0200 |
| commit | 6a9e681b391c6fe6679bf647571ccac6b335e417 (patch) | |
| tree | e3170641cbf5bde9c89f70e326f9fefc14bf1dae | |
| parent | ef9211bb9a767b058679ba7fdeca00e93f1d457c (diff) | |
powerpc/powernv/ioda2: Reduce upper limit for DMA window size
[ Upstream commit d3d4ffaae439981e1e441ebb125aa3588627c5d8 ]
We use PHB in mode1 which uses bit 59 to select a correct DMA window.
However there is mode2 which uses bits 59:55 and allows up to 32 DMA
windows per a PE.
Even though documentation does not clearly specify that, it seems that
the actual hardware does not support bits 59:55 even in mode1, in other
words we can create a window as big as 1<<58 but DMA simply won't work.
This reduces the upper limit from 59 to 55 bits to let the userspace know
about the hardware limits.
Fixes: 7aafac11e3 "powerpc/powernv/ioda2: Gracefully fail if too many TCE levels requested"
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/powerpc/platforms/powernv/pci-ioda.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c index eac3b7cc78c6..ab7b2594e0f6 100644 --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2270,7 +2270,7 @@ static long pnv_pci_ioda2_table_alloc_pages(int nid, __u64 bus_offset, level_shift = entries_shift + 3; level_shift = max_t(unsigned, level_shift, PAGE_SHIFT); - if ((level_shift - 3) * levels + page_shift >= 60) + if ((level_shift - 3) * levels + page_shift >= 55) return -EINVAL; /* Allocate TCE table */ |