From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?B?RnJhbsOnb2lzIEJlYXVsaWVy?= Subject: Re: Linux board with 10 CANs Date: Mon, 18 May 2015 11:07:50 +0200 Message-ID: <5559ABE6.5030206@orange.fr> References: <5555A6A3.7090206@orange.fr> <5555FAAB.4090306@universalnet.at> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from smtp07.smtpout.orange.fr ([80.12.242.129]:29024 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752282AbbERJH4 (ORCPT ); Mon, 18 May 2015 05:07:56 -0400 In-Reply-To: <5555FAAB.4090306@universalnet.at> Sender: linux-can-owner@vger.kernel.org List-ID: To: Bernd Krumboeck , linux-can@vger.kernel.org Le 15/05/2015 15:54, Bernd Krumboeck a =C3=A9crit : > Hi! > > > I don't know much about this things, but what do you think about=20 > following: > > Use two 4 port usb hub (MICROCHIP USB4624I-1080HN) with 8 x STM32F072= =20 > or STR750FV2. > > You can flash the MCUs under linux with dfu-util=20 > (http://dfu-util.sourceforge.net/). > > A firmware for STR750FV2 is available here (please check license): > https://github.com/krumboeck/usb2can_firmware > > I don't know if it works, but there is also a gcc version available: > https://github.com/krumboeck/usb2can_firmware/tree/gcc-test > > > If you use this firmware or at least the same procotol, then the > hardware will be compatible with usb_8dev can driver. > > > regards, > Bernd > > Hi Bernd, Thank you for pointed out this USB solution. I didn't know such firmwar= e=20 existed. I looked in the gcc-test repository, and apart from ST files the licens= e=20 is not specified. Can you tell us more about license ? =46rancois > > > Am 2015-05-15 um 09:56 schrieb Fran=C3=A7ois Beaulier: >> Hi, >> >> I'm starting the design of a CPU board, based on a computer on modul= e=20 >> with a very common SOC like i.mx6 or am335x. >> I need to fit my board with at least 10 CAN ports, may be more. (The= =20 >> SOC have 2 CANs so i need 8 more) >> The board will run with Linux and of course i want a socketcan=20 >> interface for each bus ! >> CAN bitrate needed is quite low (50kbps) and latency is not critical= =20 >> but bus load may reach 100% sometimes. >> As far as possible i want to avoid driver development, or just doing= =20 >> slight modifications on an existing driver. >> I don't want to use MCP2515, i had trouble with it on a previous=20 >> design because of the lack of buffer in the chip. >> I can't imagine putting 8 MCP2515 and not missing any frame, but may= =20 >> be i'm wrong ? >> >> Here are the options i have considered, they involve using external=20 >> MCUs to provide enough CAN interfaces : >> >> - MCUs with SLCAN : SLCAN have the advantage of simplicity and it=20 >> should offer enough performance at low data rate. Problem is that it= =20 >> would require 8 UARTS. I could modify SLCAN driver to allow multiple= =20 >> CAN channels on the same UART, and so use MCUs with multiple CANs,=20 >> does it sounds reasonable ? >> >> - MCUs with SPI 1 : adapt MCP2515 driver in a way to make the SPI=20 >> protocol manageable on the MCU side (SPI slave). The MCU will be abl= e=20 >> to provide the buffer for CAN frames that the MCP does not have. Thi= s=20 >> option is just a way of trying to go fast, it is not very elegant,=20 >> and have the limitation of one CAN channel per SPI connection /=20 >> driver instance. >> >> - MCUs with SPI 2 : use the Stefano Babic SPI driver posted on this=20 >> list. This is probably the best choice for a long term and more=20 >> generic solution. But i'm afraid it may require too much work to=20 >> complete. What is the status of this driver right now ? Does anyone=20 >> have an idea of the remaining work to do to make it ready for=20 >> mainline ? Stefano are you available to spend more time on it ? I'm=20 >> also wondering whether multiple instances of the driver can run=20 >> concurently if i put more than one MCU ? >> >> Concerning the MCU software i could release it as an open-source=20 >> project, anyone interested in participating ? >> I'm very familiar with STM32 MCUs so i will probably use an STM32F07= 2=20 >> (low cost cortex M0 with one CAN). >> >> Any idea or advice is welcome, thank you for reading this much too=20 >> long post. >> >> Regards >> >> Francois Beaulier >> www.ingelibre.fr >> --=20 >> To unsubscribe from this list: send the line "unsubscribe linux-can"= in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >