From mboxrd@z Thu Jan 1 00:00:00 1970 From: Angelo Dureghello Subject: coldfire uart question Date: Sun, 15 Oct 2017 19:28:04 +0200 Message-ID: <1f18ad0d-d147-5c64-ad65-a4bc545d4bff@sysam.it> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from sysam.it ([5.39.81.93]:49047 "EHLO sysam.it" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751502AbdJOR2H (ORCPT ); Sun, 15 Oct 2017 13:28:07 -0400 Content-Language: en-US Sender: linux-m68k-owner@vger.kernel.org List-Id: linux-m68k@vger.kernel.org To: Linux/m68k Hi all, i was trying a file transfer with xmodem-1k and uClinux "rx" on the mcf54415 stnmark2 board side. This using a recent mainline kernel: / # cat /proc/version uClinux version 4.14.0-rc4stmark2-001-00118-g811fdbb62a9d / # So, as per xmodem-1k, i send 3 bytes header, a 1024 bytes block, and 2 bytes crc16. But "rx" timeouts waiting the block. Adding some traces to "rx", it timeouts since some bytes (5 to 10) randomly positioned in the block are not received. Of course they have been sent (scope checked). The same 1024 bytes transfer in u-boot (y-modem) always succeed. Since mcf54415 has a 4 slots RX fifo UART, i was wondering if the mcf.c uart driver is not fast enough to read the data, or, where the "linux" limitation could be. Regards, Angelo Dureghello