On Tuesday, May 24, 2011 5:52:32 pm N.J. Mann wrote: > In message <[email protected]>, > John Baldwin ([email protected]) wrote: > [snip] > > > > Ah, uart_puc_probe() always uses the 'uart_ns8250_class' uart driver which > > is defined in uart_dev_ns8250.c. ns8250_bus_probe() is what you want to > > instrument I think. > > ns8250_bus_probe() is called twice for each of the working devices as > follows: > > UART2: > ------ > ns8250_bus_probe:: entry > ns8250_probe::uart_getreg REG_IIR = 1 > ns8250_probe::uart_getreg REG_MCR = 0 > ns8250_bus_probe:: exit > ... > ns8250_bus_probe:: entry > ns8250_probe::uart_getreg REG_IIR = 193 > ns8250_probe::uart_getreg REG_MCR = 8 > ns8250_bus_probe:: exit > > UART3 > ----- > ns8250_bus_probe:: entry > ns8250_probe::uart_getreg REG_IIR = 1 > ns8250_probe::uart_getreg REG_MCR = 0 > ns8250_bus_probe:: exit > ... > ns8250_bus_probe:: entry > ns8250_probe::uart_getreg REG_IIR = 193 > ns8250_probe::uart_getreg REG_MCR = 8 > ns8250_bus_probe:: exit > > For the two devices that fail, ns8250_bus_probe() fails on the first > call: > > UART4 > ----- > ns8250_bus_probe:: entry > ns8250_probe::uart_getreg REG_IIR = 1 > ns8250_probe::uart_getreg REG_MCR = 64 > ns8250_bus_probe::ns8250_probe returned 6 > > UART5 > ----- > ns8250_bus_probe:: entry > ns8250_probe::uart_getreg REG_IIR = 1 > ns8250_probe::uart_getreg REG_MCR = 64 > ns8250_bus_probe::ns8250_probe returned 6 > > The value returned for the read of REG_MCR is 64, or 0x40, which causes > the premature exit: > > static int > ns8250_probe(struct uart_bas *bas) > { > u_char val; > > /* Check known 0 bits that don't depend on DLAB. */ > val = uart_getreg(bas, REG_IIR); > if (val & 0x30) > return (ENXIO); > val = uart_getreg(bas, REG_MCR); > if (val & 0xe0) > return (ENXIO); > > return (0); > } > > Do you need to know the contents of 'bas'?
This goes beyond my level of knowledge. I've cc'd Marcel (author of uart) who can hopefully help with this more. -- John Baldwin _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hardware To unsubscribe, send any mail to "[email protected]"
