Re: [PATCH 03/17] fpga: dfl: fme: support 512bit data width PR

On Wed, 2019-03-27 at 12:37 +0800, Wu Hao wrote:

On Tue, Mar 26, 2019 at 04:22:34PM -0500, Scott Wood wrote:

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On Tue, 2019-03-26 at 14:33 -0500, Alan Tull wrote:

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On Mon, Mar 25, 2019 at 5:58 PM Scott Wood [off-list ref] wrote:

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Hi Scott,

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On Mon, 2019-03-25 at 17:53 -0500, Scott Wood wrote:

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On Mon, 2019-03-25 at 11:07 +0800, Wu Hao wrote:

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+#else
+static inline void copy512(void *src, void __iomem *dst)
+{
+   WARN_ON_ONCE(1);
+}
+#endif

Likewise, this will be called if a revision 2 device is used on non-

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x86
(or on x86 with an old binutils).  The driver should fall back to
32-
bit
in such cases.

Unfortunately revision 2 is only for integrated FPGA solution, and it
doesn't
support any fallback solution (original 32bit data partial reconfiguration
is
not supported any more), so driver has to WARN in such path.

From the commit message it seemed like this was just an optimization, not

something necessary to support revision 2.

If there's no way to program the device without AVX512, then printing an
error message and returning an error to userspace would be better than
WARN_ON, since it's not actually a kernel bug.

-Scott