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. >> 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 ? > 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
