Hi all again, -----Original Message----- From: Aristeu Sergio Rozanski Filho [mailto:[EMAIL PROTECTED] Sent: den 20 februari 2006 15:19 To: Bj?rn ?stby Cc: linuxppc-embedded at ozlabs.org; marcelo.tosatti at cyclades.com; fbl at conectiva.com.br Subject: Re: SCCx UART status on 8xx
On Mon, Feb 20, 2006 at 02:37:23PM +0100, Bj?rn ?stby wrote: > Hello, > I'm messing with a mpc823e based board trying to enable the SCC3 UART. > I'm using the 2.4.25 denx linux_ppc kernel and I've got SMC1 for console and > SMC2 up and running but I'm in desperate need of another rs232 port (which is > on SCC3 on my board). > Reading quite a lot of old posts on this mailing list got me confused whether > the SCCx UART support in the kernel is ready to be used on 8xx or if there > will take a large amount of hacking to get things going (reading the header > of 8xx_io/uart.c got me wondering even more). > Current situation is that I have enabled the SCC3 UART in the kernel, set the > correct CTS, RTS and CD signal options and finally disabled the SPI which (on > my board at least) can override the UART on the third SCC port. During boot > up I get the standard output: > > >ttyS0 at 0x0280 is on SMC1 using BRG1 > >ttyS1 at 0x0380 is on SMC2 using BRG2 > >ttyS2 at 0x0200 is on SCC3 using BRG3 > > Writing to ttyS0 and ttyS1 works fine (the result pop up in the > receiving terminal) but when trying ttyS2 nothing happens. I've > checked the Tx signal and it appears as if data is sent (the signal > gets noisy when starting the write procedure). I may also add that > restaring the write application causes the kernel to hang (for ttyS2 > only of course). > > I've read some posts saying that Linux don't init other uart ports > than the console port and that is the potential problem here, but it is > unclear if this >> >statement is true or not. I can also add to the problem description that my >SMC2 port works >fine for writing, but reading just hangs in the read() call. >So, can anyone confirm any > >status on the SMCx and SCCx UART drivers for 2.4? >please try the two attached patches. the first one configures each SCC to one >BRG. the second one, makes use always of dpram memory. we're working on a >decent fix. >Marcelo: if you find the first one ok, you may apply it, but don't apply the >second > >-- >Aristeu > I would like to thank everyone who has given input to the discussion. Unfortunately the problems remain. I have not been able to try the patches since I reckon they are for Linux 2.6 specific while I'm using the 2.4 kernel (could be good to have in for future projects though). I did however triy remove the CTS, RTS and CD signal from the config as suggested which stopped the kernel from hanging. Might be a step in the right direction. Best regards, Bjorn Ostby
