Re: [PATCH 2/3] net: socionext: Add Synquacer NetSec driver

From: Ard Biesheuvel <redacted>
Date: Thu, 30 Nov 2017 17:37:27 +0000

Well, the whole point of using memremap() instead of ioremap() is that
the region has memory semantics, i.e., we read the MAC address and the
DMA engine microcode from it. If memremap() itself is flawed in this
regard, I agree we should fix it. But as I understand it, this is
really an implementation problem in memremap() [the fact that it falls
back to ioremap()] and not a problem in this driver.

So what alternative would you propose in this case?

BTW, this should be IOREMAP_WC not IOREMAP_WT, because the EEPROM on
the platform in question does not tolerate cached mappings (or rather,
shareable mappings). ioremap_wt() happens to result in device mappings
rather than writethrough cacheable mappings, but this is another
problem in itself. Once arm64 fixes ioremap_wt(), this code will no
longer work on the SynQuacer SoC.

It doesn't "fall back", it directly uses ioremap_wt() for non-RAM
mappings.

It you look, most architectures do a "#define iomrep_wt ioremap"
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