Read write to ioremap_nocache are still cached?

Subodh Nijsure subodh at
Wed Jul 11 12:35:45 EST 2001


I have mapped memory area using ioremap_nocache() and what I observered
through logica analyzer is when I do simple word read or write there are
multiple read/write cycles happening on  the same address.

Code looks something like this --

	printk("Write reset word to PLD and read new stauts\n");
	pld_base = ioremap_nocache( physical_pld_address );
	*(pld_base + 0x8) = 0xA;
	newStatus = *(pld_base + 0x4);
	printk("Status word is %X \n",newStatus);

If I just move this code to by bootrom read/writes happen exactly
as I expect,  but when I move this code to kernel I see multiple
 read and writes. What could be the reason? Note this routine is
not called multiple times.


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