[U-Boot] How can I make a second serial port on a motorola 8248 Chip known to Linux.
Hello,
I am working with a mpc8260ads(actually QUICC 8248 processor) based board. There are two hardware rs-232 ports available. I can switch the console between the two by switching the CONFIG_CONS_INDEX configuration variable between 1 and 4. I would like to have both ports in service, when Linux comes up. One as the console and the second to communicate with(i.e. acquire data from) a third party rs-232 device. Eventually, the third party device may be a telephone modem. Can anyone explain how to accomplish this, and if not, what constraints are blocking the accomplishment of my requirements. Any suggestions will be appreciated.
Thank You.
On Tue, Aug 25, 2009 at 08:37:11AM -0700, AGKohler wrote:
Hello,
I am working with a mpc8260ads(actually QUICC 8248 processor) based board. There are two hardware rs-232 ports available. I can switch the console between the two by switching the CONFIG_CONS_INDEX configuration variable between 1 and 4. I would like to have both ports in service, when Linux comes up. One as the console and the second to communicate with(i.e. acquire data from) a third party rs-232 device. Eventually, the third party device may be a telephone modem. Can anyone explain how to accomplish this, and if not, what constraints are blocking the accomplishment of my requirements. Any suggestions will be appreciated.
This isn't a U-Boot issue, except insofar as U-Boot passes a device tree to Linux (assuming it does even that -- you don't mention which kernel or u-boot version you're using).
If your device tree contains both serial ports, then Linux should be able to use them both. If it doesn't work, make sure all the pins are configured correctly, typically by Linux platform code for your board (though ideally U-Boot should set them up as well).
-Scott
I am using u-boot version 1.1.3, kernel, Linux(Debian) is version 2.6.12. I searched through the kernel configuration options via menuconfig, i could not find anything that configures the number of serial ports. In LINUX, i tried creating ttyS1 with "mknod -m 660 /dev/ttS1 c 4 65". A /dev/ttyS1 shows up in the directory listing, but I am unable to transmit/receive characters on it.
Thanks.
Scott Wood-2 wrote:
On Tue, Aug 25, 2009 at 08:37:11AM -0700, AGKohler wrote:
Hello,
I am working with a mpc8260ads(actually QUICC 8248 processor) based board. There are two hardware rs-232 ports available. I can switch the console between the two by switching the CONFIG_CONS_INDEX configuration variable between 1 and 4. I would like to have both ports in service, when Linux comes up. One as the console and the second to communicate with(i.e. acquire data from) a third party rs-232 device. Eventually, the third party device may be a telephone modem. Can anyone explain how to accomplish this, and if not, what constraints are blocking the accomplishment of my requirements. Any suggestions will be appreciated.
This isn't a U-Boot issue, except insofar as U-Boot passes a device tree to Linux (assuming it does even that -- you don't mention which kernel or u-boot version you're using).
If your device tree contains both serial ports, then Linux should be able to use them both. If it doesn't work, make sure all the pins are configured correctly, typically by Linux platform code for your board (though ideally U-Boot should set them up as well).
-Scott _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
On Wed, Aug 26, 2009 at 01:15:39PM -0700, AGKohler wrote:
I am using u-boot version 1.1.3, kernel, Linux(Debian) is version 2.6.12.
Both of thosed are extremely old. Our ability to help you with them is very limited. Please use the current code.
I searched through the kernel configuration options via menuconfig, i could not find anything that configures the number of serial ports. In LINUX, i tried creating ttyS1 with "mknod -m 660 /dev/ttS1 c 4 65". A /dev/ttyS1 shows up in the directory listing, but I am unable to transmit/receive characters on it.
You want /dev/ttyCPM1, and you should use udev or equivalent to create the device nodes.
-Scott
Dear AGKohler,
please do not top post-full quote.
Make sure to read http://www.netmeister.org/news/learn2quote.html
And please note that this still off topic on this list. It is a LINUX question, not an U-Boot one.
In message 25157108.post@talk.nabble.com you wrote:
I am using u-boot version 1.1.3, kernel, Linux(Debian) is version 2.6.12.
This is very, very old code, and you will probably find nobody willing to spend time and efforts for free to deal with issues that have been solved long, long ago.
Please update your code - say, use at least U-Boot v2009.03 (or later) and Linux 2.6.30 (or later), and if you still have issues, please ask on a Linux mailing list.
Best regards,
Wolfgang Denk
participants (3)
-
AGKohler -
Scott Wood -
Wolfgang Denk