MPC5200b kernel module memory mapping
Steven Kaiser
skaiser.uci at gmail.com
Sun Sep 24 06:55:08 EST 2006
Markus:
> > sure I am setting up the LocalBus chip select registers ok.
>
> I would guess this is not the case. What kind of device is this?
You are correct. I was so concerned about the linux driver stuff (
request_region(), ioremap(), etc ), that I was locked into endless studies
on that and see now I clearly overlooked some simple chip setting up. Doh!
Thanks for reorienting my focus--
My chip is a Freescale MPC5200b:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPC5200B
So here's what I've doing that seems to work, as verified by an
oscilloscope:
// 64k I/O Port Space: 0x60000000 - 0x60001000 -> 0x60000000 - 0x60001000
#define MPC5xxx_MM_CS2_START (MPC5xxx_MBAR + 0x0014)
#define MPC5xxx_MM_CS2_STOP (MPC5xxx_MBAR + 0x0018)
#define MPC5xxx_MM_IPBI (MPC5xxx_MBAR + 0x0054)
#define MALab_MM_START 0x60000000U
#define MALab_MM_END 0x6000ffffU
#define MALab_MM_SIZE 0x00010000U
void *ioaddr = NULL;
int init_module(void) { ...
// reserve a page of memory for our hardware /proc/iomem
if ( check_region(MALab_MM_START,MALab_MM_SIZE) ) {
printk (KERN_ALERT "LED init_module: memory already in
use\n");
return -EBUSY;
}
request_region(MALab_MM_START,MALab_MM_SIZE,LED_DEVICE_NAME);
// enable LocalBus chip select CS2 to hit on our address range
*(volatile u32 *)MPC5xxx_MM_IPBI &= ~0x00040000;
*(volatile u16 *)(MPC5xxx_MM_CS2_START + 2) = MALab_MM_START >> 16;
*(volatile u16 *)(MPC5xxx_MM_CS2_STOP + 2) = MALab_MM_END >> 16;
*(volatile u32 *)MPC5xxx_MM_IPBI |= 0x00040000;
// LocalBus Chip Select 2 Configuration Register
*(volatile u32 *)(MPC5xxx_MBAR + 0x0308) = 0x03031110;
// LocalBus Chip Select Control Register
*(volatile u32 *)(MPC5xxx_MBAR + 0x0318) |= 0x01000000;
// map our physical address into kernal virtual address space
ioaddr = ioremap(MALab_MM_START,MALab_MM_SIZE);
printk(KERN_ALERT "ioaddr: 0x%08x\n", (u32)ioaddr);
then later, any of these calls work (even in interrupt routines it appears):
u32 buf[10];
*(volatile u16 *)ioaddr = 0x5555;
outw(0x5555,ioaddr);
outsw(ioaddr,buf,10);
I guess this is simple stuff for most everybody here.
Steve
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