Hi,
I am trying to get rid of sparse's bitwise warnings in my
isp116x-hcd driver. Regardless of studying the explanations
about __bitwise, as for example in
http://kerneltrap.org/node/3848 I was still not able to get
rid of all the warnings. Could anybody please explain, how
to correctly resolve the ones below.
An example piece of problematic code, compiled on
little-endian ARM platform, is the following.
struct isp116x {
void __iomem *addr_reg;
....
};
static inline void isp116x_write_addr(struct isp116x *isp116x, unsigned reg)
{
writew(cpu_to_le16((__u16) (reg & 0xff)), isp116x->addr_reg);
isp116x_delay(isp116x, 300);
}
The sparse bitwise warnings about the writew(...) line
(#377) are the following.
drivers/usb/host/isp116x.h:377:6: warning: cast from restricted type
drivers/usb/host/isp116x.h:377:6: warning: incorrect type in
assignment (different base types)
drivers/usb/host/isp116x.h:377:6: expected unsigned short
volatile [unsigned] [short] [force] <noident>
drivers/usb/host/isp116x.h:377:6: got restricted unsigned
short [usertype] [force] <noident>
Here is the same function after preprocessing.
static inline __attribute__((always_inline))
void isp116x_write_addr(struct isp116x *isp116x, unsigned reg)
{
((void)0, *(volatile unsigned short
*)((isp116x->addr_reg)) = ((( __le16)(__u16)
((( __le16)(__u16)((__u16) (reg & 0xff)))))));
(isp116x)->board->delay(isp116x_to_hcd(isp116x)->self.controller,300);
}
Thanks in advance,
Olav
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