[PATCH v4 1/2] iopoll: Introduce memory-mapped IO polling macros

On Tue, Oct 07 2014 at 06:47:59 PM, Mitchel Humpherys [off-list ref] wrote:

quoted

quoted

+#define readl_poll_timeout_atomic(addr, val, cond, max_reads, time_between_us) \
+({ \
+       int count; \
+       for (count = (max_reads); count > 0; count--) { \
+               (val) = readl(addr); \
+               if (cond) \
+                       break; \
+               udelay(time_between_us); \
+       } \
+       (cond) ? 0 : -ETIMEDOUT; \
+})

udelay has a large variability, I think it would be better to also use
ktime_compare here and make the interface the same as the other one.
You might want to add a warning if someone tries to pass more than a few
microseconds as the timeout.

Sounds good, will update in v5.

Except I'll probably hold off on adding a warning about udelay since
udelay already includes a "warning" (a compile error, actually) when
exceedingly large delays are requested.


-Mitch

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