I want to thank Claus and Chirag for their responses. I believe that my access problems are more lower level than I originally thought.
In our searching's we were only able to find an XFree86 driver for the Silicon Motion LynxEM chip and one that was in the PPCBoot tree. I could not use the XFree86 driver, it was too dependent on support from the XFree86 environment, and even then the "VGA" stuff was from some other file. As "per usual" here, things were in crisis and we needed something ASAP. My original plan was to use the "generic" VGA stuff already in the MVL kernel to access the chip. The first problem had to do with the "canned" address that vga16fb.c was using, with the I/O registers being "offset 0 in I/O space" and the frame buffer at 0xA0000. Are these the "In the PC world" addresses? With the chip being accessed via the PCI bus, I did not understand how to "map" the chip via it's single BAR0 Register. After a while I realized that the chip has a "default" PCI I/O address of 0, all I needed to do was make sure that the COMMAND_IO bit was set as part of the PCI config cycles. I also needed to discover the proper PCI memory address by putting in some PCI search code, (only temporary honest!) into the vga16fb.c code to find the device and store it's PCI memory address. I was able to access the I/O registers, i.e. read the MISC and ISR0-1 and read frame buffer memory. But still nothing I did with /sbin/getty tty1, fbset or /dev/fb0 appeared to work at all! So all this rambling leads me to these questions to the distribution list: 1) Does the "generic" VGA stuff expect that the VGA device is already initialized and setup by the BIOS/LILO/BOOT code? 2) Does anyone know of a driver for the LynxEM chip that is not from the XFree86 code base? I am planning to "strategically advance to the rear" and go back to the PPCBoot code where I was able to get a few bands of color when the LOGO was supposed to be drawn on the screen. If I can get that to work I am hoping that I can form a better understanding of the LynxEM chip to either create a limited driver or hack up the vga16fb.c file some more before I work on a limited driver. Thank you for any help or information you can send my way. -------------------------------------------- John A. Gallant Sr. Embedded Software Engineer Vanteon Inc. 2851 Clover Street Pittsford, NY 14534 Phone: 585.248.0510 x279 Fax : 585.248.0537 email: jgallant at vanteon.com web: www.vanteon.com ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/
