Hi,
I'm currently trying to write a USB driver for Linux. The device must be
configured by writing some values into the same register but I want to be
sure that the writing order is respected by either the compiler and the cpu.
For example, here is a bit of driver's code:
"""
#include <asm/io.h>
static inline void dev_out(u32 *reg, u32 value)
{
writel(value, regs);
}
void config_dev(void)
{
dev_out(reg_a, 0x0); /* first io */
dev_out(reg_a, 0xA); /* second io */
}
void config_dev_fixed(void)
{
dev_out(reg_a, 0x0); /* first io */
wmb();
dev_out(reg_a, 0xA); /* second io */
wmb();
}
"""
In this case, am I sure that the order will be respected ? can gcc remove
the first io while optimizing...If so, does "config_dev_fixed" fix it ?
thanks for your answers,
Francis
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