[RFC/PATCH 3/7] iopoll: Introduce memory-mapped IO polling macros
From: Thierry Reding <hidden>
Date: 2014-06-30 19:46:37
Also in:
linux-arm-msm, linux-iommu
On Mon, Jun 30, 2014 at 09:51:52AM -0700, Olav Haugan wrote: [...]
quoted hunk
diff --git a/include/linux/iopoll.h b/include/linux/iopoll.h
[...]
+/** + * readl_poll_timeout - Periodically poll an address until a condition is met or a timeout occurs + * @addr: Address to poll + * @val: Variable to read the value into + * @cond: Break condition (usually involving @val) + * @sleep_us: Maximum time to sleep between reads in uS (0 tight-loops)
s/uS/us/ here and elsewhere. S is the symbol for Siemens.
+ * @timeout_us: Timeout in uS, 0 means never timeout
+ *
+ * Returns 0 on success and -ETIMEDOUT upon a timeout. In either
+ * case, the last read value at @addr is stored in @val. Must not
+ * be called from atomic context if sleep_us or timeout_us are used.
+ */
+#define readl_poll_timeout(addr, val, cond, sleep_us, timeout_us) \
+({ \
+ ktime_t timeout = ktime_add_us(ktime_get(), timeout_us); \
+ might_sleep_if(timeout_us); \
+ for (;;) { \
+ (val) = readl(addr); \
+ if (cond) \
+ break; \
+ if (timeout_us && ktime_compare(ktime_get(), timeout) > 0) { \
+ (val) = readl(addr); \
+ break; \
+ } \
+ if (sleep_us) \
+ usleep_range(DIV_ROUND_UP(sleep_us, 4), sleep_us); \
+ } \
+ (cond) ? 0 : -ETIMEDOUT; \
+})Why can't these be functions? Thierry -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 836 bytes Desc: not available URL: <http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20140630/67f196b9/attachment.sig>