On Thu, May 19, 2011 at 6:42 PM, Govindraj <govindraj.ti@xxxxxxxxx> wrote: > > On Thu, May 19, 2011 at 6:21 PM, Pavan Savoy <pavan_savoy@xxxxxxxx> wrote: >> >> On Thu, May 19, 2011 at 3:58 PM, Govindraj <govindraj.ti@xxxxxxxxx> wrote: >> > >> > On Thu, May 19, 2011 at 3:08 PM, Pavan Savoy <pavan_savoy@xxxxxxxx> >> > wrote: >> >> >> >> Hi, >> >> >> >> I have a device connected to my apps processor over UART, the serial >> >> core's hooked up with omap-serial UART driver. >> >> There is a scenario, where the device just fails to respond, and I >> >> should be closing the UART & opening it again to re-try the request. >> >> This is also coupled with power-cycling the chip. >> >> >> >> However a normal start/stop sequence where chip responds to every >> >> request & I close UART when I'm done - is something like this, >> >> [function name & line number in logs) >> >> uart_open(1) called >> >> uart_open: 1635 >> >> uart_open: 1651 >> >> uart_open: 1663 >> >> uart_open: 1674 >> >> omap-hsuart omap-hsuart.1: serial_omap_pm+1 >> >> omap-hsuart omap-hsuart.1: Enable CTS wakeup for UART 1 >> >> omap-hsuart omap-hsuart.1: serial_omap_startup+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_get_mctrl+1 >> >> uart_open: 1686 >> >> uart_open: 1694 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_termios+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> uart_open: 1705 >> >> uart_flush_buffer(1) called >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_termios+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_termios+1 >> >> uart_flush_buffer(1) called >> >> uart_flush_buffer(1) called >> >> uart_flush_buffer(1) called >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_termios+1 >> >> uart_wait_until_sent(1), jiffies=4294954470, expire=4294954474... >> >> omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1 >> >> uart_wait_until_sent(1), jiffies=4294954471, expire=4294954475... >> >> omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1 >> >> (stc): st_tty_open >> >> >> >> uart_flush_buffer(1) called >> >> uart_flush_buffer(1) called >> >> uart_flush_buffer(1) called >> >> (stk) :ldisc_install = 0 >> >> uart_close(1) called >> >> uart_close: 1295 >> >> uart_close: 1316 >> >> uart_wait_until_sent(1), jiffies=4294951992, expire=4294951996... >> >> omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1 >> >> uart_close: 1327 >> >> omap-hsuart omap-hsuart.1: Disable CTS wakeup for UART1 >> >> uart_wait_until_sent(1), jiffies=4294951994, expire=4294951996... >> >> omap-hsuart omap-hsuart.1: serial_omap_tx_empty+1 >> >> uart_close: 1345 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_shutdown+1 >> >> omap-hsuart omap-hsuart.1: serial_omap_set_mctrl+1 >> >> uart_flush_buffer(1) called >> >> uart_flush_buffer(1) called >> >> omap-hsuart omap-hsuart.1: serial_omap_pm+1 >> >> uart_close: 1368 >> >> (stc): st_tty_close >> >> >> >> However, in a scenario where the chip fails to respond to one of the >> >> requests, the start/stop sequence becomes something like this, >> >> uart_open(1) called >> >> uart_open: 1635 >> >> uart_open: 1651 >> >> uart_open: 1663 >> >> uart_open: 1705 >> >> >> >> So, the problem seems to be that the port->count in the serial_core >> >> isn't 1 & hence the call, >> >> Â Â Â Âif (port->count == 1) >> >> Â Â Â Â Â Â Â Âuart_change_pm(state, 0); >> > >> > Actually port count will be incremented based on number of times >> > the port will be opened. (file open do on the the given ttyOx interface) >> > for the first tty open the count gets incremented to one and sets state >> > to >> > active >> > (state, 0) >> > if you open multiple times then the serial_core knows port in active >> > state >> > so it is not necessary to call uart_change_pm(state, 0) >> >> Assuming multiple opens isn't that big a deal... >> But I get a tcgetattr() failure then, and thereby unable to set the >> default baud-rate >> and hence send data over UART. > > Whats the error number? strerror throws me Invalid arguments when the tcgetattr() fails. >> >> doesn't seem to be happening, which is very critical. Also no calls >> >> are made to uart_startup & hence omap-serial's startup. >> >> >> >> Where should I be looking as to why the port->count is messed up ? >> >> What is the this count used for? >> >> Also how is this related to chip not responding to certain commands? >> > >> > Is the uart_clks cut? Try keeping uart clocks active always. >> >> Need to check this then.... >> How do I make sure they stay on ? > > you an avoid setting uart timeouts from sysfs entry or > comment out omap_device_idle from */mach-omap2/serial.c file. Yes, kind of familiar with 2nd approach - but need help on the sysfs entry ... which one should I be looking for ? (hopefully available on all omap kernels..) >> >> > Govindraj.R >> > >> >> >> >> -- >> >> To unsubscribe from this list: send the line "unsubscribe linux-serial" >> >> in >> >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> >> More majordomo info at Âhttp://vger.kernel.org/majordomo-info.html >> > >> > > > -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
