Problem mapping GPIO regs on ppc440gx

Greetings:

We've been using a 2.4.30 kernel (with numerous patches) on a AMCC 440gx custom built board for quite some time now.

We're building some new hardware that forces us to go to a 2.6 kernel. So, I've downloaded 2.6.16.16 from kernel.org and am porting everything forward from our 2.4.30 kernel.

The problem lies in mapping the GPIO regs of the 440 to user space using /dev/mem:

   gpio_fd = open("/dev/mem", O_RDWR | O_SYNC);

   if (0 > gpio_fd) {
       perror("mbGpioGet(): Unable to open gpio");
       return(-1);
   }

addr = (ppc440_gpio_regs_t *)mmap(0, getpagesize() * 2,
PROT_READ | PROT_WRITE, MAP_SHARED, gpio_fd, (off_t)(0x40000000));

   if (MAP_FAILED == addr) {
       perror("mbGpioGet(): map error");
       close(gpio_fd);
       return(-1);
   }

   pGpioRegs = (ppc440_gpio_regs_t *)((uint32_t)addr + 0x700);

   data = pGpioRegs->in & (MB_GPIO_PRI_N_K | MB_GPIO_SEC_PRES_K);

   munmap(0, sizeof(ppc440_gpio_regs_t));
   close(gpio_fd);

The data I get back is 0. Always. /SEC_PRES_K should be 1 in this case.

(gdb) print /x addr
$7 = 0x30015000
(gdb) print /x pGpioRegs
$8 = 0x30015700

Checking /proc/<PID>/map shows the mapping:
30015000-30019000 rw-p 30015000 00:00 0

On a board running the 2.4.30 kernel, I show the SAME entry in /proc/<PID>/map but I do get data back.

Any idea what I'm doing wrong here?

TIA,

Travis Sawyer

Answering my own question here...

The above mmap call worked for 2.4.30, but for 2.6.16 I needed to change the offset to be a multiple of page size, so:
(off_t)(0x40000000/getpagesize());

-travis