From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andy Shevchenko Subject: Re: [PATCH v2 1/1] serial: 8250_dw: Allow hardware flow control to be used Date: Wed, 01 Mar 2017 20:50:20 +0200 Message-ID: <1488394220.20145.68.camel@linux.intel.com> References: <1484164100-9805-1-git-send-email-jason.uy@broadcom.com> <1484164100-9805-2-git-send-email-jason.uy@broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-subscribe: List-owner: List-post: List-archive: To: James Hogan , Jason Uy Cc: Greg Kroah-Hartman , Jiri Slaby , Kefeng Wang , Noam Camus , Heikki Krogerus , Wang Hongcheng , linux-serial@vger.kernel.org, LKML , bcm-kernel-feedback-list@broadcom.com, Linux MIPS Mailing List , David Daney List-Id: linux-serial@vger.kernel.org On Wed, 2017-03-01 at 18:02 +0000, James Hogan wrote: > On 11 January 2017 at 19:48, Jason Uy wrote: > > In the most common use case, the Synopsys DW UART driver does not > > set the set_termios callback function.  This prevents UPSTAT_AUTOCTS > > from being set when the UART flag CRTSCTS is set.  As a result, the > > driver will use software flow control as opposed to hardware flow > > control. > > > > To fix the problem, the set_termios callback function is set to the > > DW specific function.  The logic to set UPSTAT_AUTOCTS is moved so > > that any clock error will not affect setting the hardware flow > > control. > Bisection shows that this patch, commit > 6a171b29937984a5e0bf29d6577b055998f03edb, has broken boot of the > Cavium Octeon III based UTM-8 board (MIPS architecture). > > I now get the following warning: > [] uart_get_baud_rate+0xfc/0x1f0 > [] serial8250_do_set_termios+0xb0/0x440 > [] uart_set_options+0xe8/0x190 > [] serial8250_console_setup+0x84/0x158 > [] univ8250_console_setup+0x54/0x70 > [] register_console+0x1c8/0x418 > [] uart_add_one_port+0x434/0x4b0 > [] serial8250_register_8250_port+0x2d8/0x440 > [] dw8250_probe+0x388/0x5e8 > Then it hangs and the watchdog restarts the machine. > > Any ideas? 1. Does it use clock on that platform? 2. Check if termios is not NULL there. -- Andy Shevchenko Intel Finland Oy