Read write to ioremap_nocache are still cached?
subodh at best.com
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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