On 20/06/13 20:02, Arnd Bergmann wrote:

On Thursday 20 June 2013, Srinivas KANDAGATLA wrote:

quoted

+static u64 gt_counter_read(void)
+{
+       u64 counter;
+       u32 lower;
+       u32 upper, old_upper;
+
+       upper = __raw_readl(gt_base + GT_COUNTER1);
+       do {
+               old_upper = upper;
+               lower = __raw_readl(gt_base + GT_COUNTER0);
+               upper = __raw_readl(gt_base + GT_COUNTER1);
+       } while (upper != old_upper);
+
+       counter = upper;
+       counter <<= 32;
+       counter |= lower;
+       return counter;
+}

Please replace __raw_readl etc with the non-__raw variants
throughout the code.

The __raw accessors are not endian safe and are not meant
for device drivers. If you are worried about latency from
extra barriers, use readl_relaxed().

Endian safe is good point. I will move to using readl/writel which does
both ordering and byteswapping.
And use relaxed versions in gt_counter_read to reduce the latency.

looks like smp_twd.c too needs this type of change.

Thanks,
srini

	Arnd