Re: [PATCH v4 1/2] phy: qcom: Add driver for QCOM APQ8064 SATA PHY

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On 15/07/14 17:56, Bartlomiej Zolnierkiewicz wrote:
+
>+/* Helper function to do poll and timeout */
>+static int read_poll_timeout(void __iomem *addr, u32 mask)
>+{
>+	unsigned long timeout = jiffies + msecs_to_jiffies(TIMEOUT_MS);
>+
>+	do {
>+		if (readl_relaxed(addr) & mask)
>+			return 0;
>+
>+		 usleep_range(DELAY_INTERVAL_US, DELAY_INTERVAL_US + 50);
>+	} while (!time_after(jiffies, timeout));
>+
>+	return -ETIMEDOUT;
>+}
Thanks for reworking this code, unfortunately it still has a one
(unlikely but still theoretically possible) problem.  If there is
i.e. a big IRQ load between first usleep_range() call and first

Very unlikely but as you said it possible in theory :-)

time_after() check the function will timeout without checking
the register.  To fix it you needs to add an additonal register
checking before returning -ETIMEDOUT value or replace time_after()
condition with a fixed number of retries (100000 to cover 1sec
timeout).
I will send out a fix on top of my previous patches to fix this.

thanks,
srini
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