| From: Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx>
| Sent: Thursday, March 22, 2018 9:28 AM
|
| | From: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
| | Date: Thursday, March 22, 2018 7:52 AM
| |
| | Isn't this a PowerPC problem? Why penalize other architectures?
|
| I worry it breaks PPC.
And all other architectures. Aparraently there isn't a formal API
description for writel_relaxed() and Co., nor __raw_writel(), etc. What I
think we need is a formal semantic definition of exactly what these APIs is
supposed to do and then we can make sure that they all do that. Till we
have a consistent definition/implementation, trying to use these APIs in
multi-platform code will be a problem.
For instance, and this is merely an example not a prescription of what I'm
talking about:
writel():
-- Ensures correct byte ordering.
-- Ensures no compiler reordering.
-- Ensures instruction level synchronization with respect
-- to previous and succeeding reads and writes.
writel_relaxed():
-- Ensures correct byte ordering.
-- Ensures no compiler reordering.
-- Ensures instruction level synchronization with respect
-- to previous writes.
__raw_writel():
-- Ensures correct byte ordering.
-- Ensures no compiler reordering.
| I appreciate you doing this.
As do I! I'm just worried that because the API semantic definitions don't
seem to be formalized for writel_relaxed() and Co., we're in danger of
getting wildly different results on one platform or another based on
differring implementation semantics.
Casey
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