Hello,
sorry, this might be a beginner question, but I couldn't find any
infos in the FAQ.
I'm writing a driver (module) for a PCI card with a neural processor
(NP-processor) on it for kernel 2.4.1. The registers of this processor
are mapped to a memory area. When I probe for the device, I request
that memory using:
np.adr = pci_resource_start (pcidev, 4);
np.len = pci_resource_len (pcidev, 4);
if (!request_mem_region (np.adr, np.len, "NP")) {
printk (KERN_INFO "NEURAL: Can't get memory region for NP!\n");
return -EBUSY;
}
np.mem = ioremap (np.adr, np.len);
I save the addresses in a global structure:
struct np_dev
{
unsigned long np_adr; /* bus address of NP memory */
unsigned char *np_mem; /* pointer to mapped memory */
unsigned long np_len;
};
struct muren_dev muren;
so that I can release the memory when I remove the device.
I access the different registers of the NP-processor with ioctl's
(there are 8bit and 16bit registers):
switch (cmd) {
case NP_IOCSGCR:
get_user (b, (byte *) arg);
writeb (b, np.mem + Z_GCR);
break;
case NP_IOCGGCR:
b = readb (np.mem + Z_GCR);
put_user (b, (byte *) arg);
break;
case NP_IOCSMIF:
get_user (w, (word *) arg);
writew (w, np.mem + Z_MIF);
break;
case NP_IOCGMIF:
w = readw (np.mem + Z_MIF);
put_user (w, (word *) arg);
break;
When I load the module and init the device, I can read the registers.
Some of them have default values after a reset of the chip and they
ar ok. But when I load data to the registers and let the NP-processor
categorize the data, strange things happen:
I wrote a program to test the driver which loads some data to the
NP-processor and tries to categorize it. The program prints its
result to STDOUT.
- everything works ok, results are correct, if I redirect STDOUT to a
file
- if I don't redirect, I get reproducibly wrong results when I print
to STDOUT
My first idea was to disable interrupts while reading/writing
to the register memory (using save_flags() and cli()), but it
didn't help.
Then I did something else for two weeks and came back to the
driver hoping to find a solution. I couldn't find any.
Has anybody ever seen something like this and knows a solution?
Thanks,
Armin.
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