andre@eicon.eicon.qc.ca (Andre Scheunemann) (11/21/90)
Help needed with RS/6000 AIX 3.1 device driver.
I am writing a device driver for a micro-channel card for the RS/6000 with
AIX 3.1. I'm using the BUSIO_ATT() and BUSMEM_ATT() macros from
<sys/adspace.h> to access the card I/O ports and card memory respectively.
There are no problems accessing the I/O ports. However, when I try to access
the card memory the system crashes with a 102 320 led error code.
The following code is used:
{
ulong io_addr, mem_addr;
io_addr = BUSIO_ATT(bus_id, card_io_addr);
mem_addr = BUSMEM_ATT(bus_id, card_mem_addr);
data = BUSIO_GETC(io_addr); /* this works and causes a read */
/* of the I/O register */
data = BUSIO_GETC(mem_addr); /* this causes a system crash !!!!! */
BUSIO_DET(io_addr);
BUSMEM_DET(mem_addr);
}
The BUSIO_GETC() is a macro from <sys/ioacc.h>. The same code is used in the
sample device drivers provided in the /usr/lpp/bos/samples directory.
I know that the card memory can be accessed because I can access it using
ioctl's on the /dev/bus0 device.
Can anyone tell me what I'm doing wrong?
Thanks in advance,
andre%eicon@iro.umontreal.ca
tif@doorstop.austin.ibm.com (Paul Chamberlain) (11/26/90)
andre@eicon.eicon.qc.ca (Andre Scheunemann) writes: > mem_addr = BUSMEM_ATT(bus_id, card_mem_addr); > data = BUSIO_GETC(mem_addr); /* this causes a system crash !!!!! */ I would make sure that the bus_id is correct and that the card_mem_addr does in fact have the correct address of the card. If you have the Hardware Technical Reference -- General Information, you should already be familiar with chapter 4. I see some particularly useful information about "Load and Store Error Conditions" on pages 32-34. You should be able to see the Channel Status Register (CSR) from the debugger if you turn the debugger on. Use "bosboot -a -D" I think. I would almost bet that the first nybble is a "0xB" for "Card Selected Feedback Error". This means that whatever you did, no card answered to that address. FYI, the crashes can be prevented and recovered from. A Data Storage Interrupt (DSI) eventually causes a longjmpx() which is the opposite of setjmpx(). These routines handle a _stack_ of recovery routines. If the stack is empty it crashes. A routine called pio_assist() assists in doing PIO and handling errors. I think that the library version of this routine was left out on the very first ship of AIX 3.1. I _think_ it is present in all others. Paul Chamberlain | I do NOT represent IBM. tif@doorstop, sc30661 at ausvm6 512/838-7008 | ...!cs.utexas.edu!ibmchs!auschs!doorstop.austin.ibm.com!tif