On 04/17/2014 11:27 AM, Xiubo Li wrote:
For some clocksource devices, for example, the registers are 32-bit, while
the lower 16-bit is used for timer counting(And reading the upper 16-bit
will return 0).
For example, when the counter value is 0x00001111, and then the
~readl_relaxed(to_mmio_clksrc(c)->reg) will return the value of 0xFFFFEEEE,
but it should be 0x0000EEEE.
So just using the c->mask to mask the unused bits.
Signed-off-by: Xiubo Li <li.xi...@freescale.com>
---
drivers/clocksource/mmio.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/clocksource/mmio.c b/drivers/clocksource/mmio.c
index c0e2512..f17a0d1 100644
--- a/drivers/clocksource/mmio.c
+++ b/drivers/clocksource/mmio.c
@@ -27,7 +27,7 @@ cycle_t clocksource_mmio_readl_up(struct clocksource *c)
cycle_t clocksource_mmio_readl_down(struct clocksource *c)
{
- return ~readl_relaxed(to_mmio_clksrc(c)->reg);
+ return ~readl_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
}
cycle_t clocksource_mmio_readw_up(struct clocksource *c)
@@ -37,7 +37,7 @@ cycle_t clocksource_mmio_readw_up(struct clocksource *c)
cycle_t clocksource_mmio_readw_down(struct clocksource *c)
{
- return ~(unsigned)readw_relaxed(to_mmio_clksrc(c)->reg);
+ return ~(unsigned)readw_relaxed(to_mmio_clksrc(c)->reg) & c->mask;
}
/**
Hi,
I realize there is some type confusion here:
cycle_t -> u64
readl_relaxed -> u32
readw_relaxed -> u16
and clocksource_mmio_readw_down returns a cast to unsigned (u32)
This patch makes sense but it obfuscate more the types in these
functions. Worth to clarify the functions first ?
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