From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D332C433E0 for ; Sat, 9 Jan 2021 04:28:37 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2ADF623A01 for ; Sat, 9 Jan 2021 04:28:35 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2ADF623A01 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.94) (envelope-from ) id 1ky5rJ-0002W1-E7; Fri, 08 Jan 2021 23:28:13 -0500 Received: from merlin.infradead.org ([2001:8b0:10b:1231::1]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1ky5rG-0002VC-WC for kernelnewbies@kernelnewbies.org; Fri, 08 Jan 2021 23:28:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:References:To:Subject:Sender: Reply-To:Cc:Content-ID:Content-Description; bh=5ybs85KnwdJTdYxDvsffu6jgXSJMmHUv2I+dnS09Jns=; b=vDwt8InBGxrCXKbuiUDIqSZdKJ 1A8vRIBIuIrM1zT0lWL5covgvH98H58XeFn4a3Q+2OKguEg8HalZiR4fNqO+FBJC6j3jPynLRrulN xnzJcRcptQlYXhJ3FN539hYyEfY523I8s9KVbsGVFh52Ga4P8JPX3ODRLuglWsJ4XgAWSIV8JvKYO lFewul64x/Vgo6F5VvYB59oZWru1oAJlthCS//KgnPXU+PsbVrw0ggRqxozBHSFYnVm/pgIer1p6w /Sn58Dm/upuuZ1y6agEBezEI9cvX/2Uyf6IKGn6HAKR6sURMhCBS7s/REKliI7yjJ9/Jfcskivonk xl+huWMg==; Received: from [2601:1c0:6280:3f0::79df] by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1ky5r9-00027q-Ee; Sat, 09 Jan 2021 04:28:03 +0000 Subject: Re: Tutorial for "drivers/mmc/*"? To: "Gabriel L. Somlo" , kernelnewbies@kernelnewbies.org Newsgroups: gmane.linux.kernel.kernelnewbies References: <20210107205419.GG2094049@errol.ini.cmu.edu> From: Randy Dunlap Message-ID: <85060973-8d39-156e-93db-3c8180060c54@infradead.org> Date: Fri, 8 Jan 2021 20:27:54 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 MIME-Version: 1.0 In-Reply-To: <20210107205419.GG2094049@errol.ini.cmu.edu> Content-Language: en-US X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kernelnewbies-bounces@kernelnewbies.org On 1/7/21 12:54 PM, Gabriel L. Somlo wrote: > Hi, > > I'm debugging a driver for a (fpga-based soft core) microSD card Linux > device, and the existing driver (in drivers/mmc/host/...) makes sense > at first sight, but, either due to shortcomings in the softcore > (Verilog by way of Migen) "hardware", or the actual Linux driver > itself, suffers from intermittent data transfer errors. > > I find myself wishing I could get a top-down idea of how the Linux mmc > layer is put together, so I could examine the driver in question with > a critical eye, rather than my current approach, which is best described > as "blind-man attempts to comprehend an elephant by touching various > locations on its body, hoping the collected experiences will suddenly > come into focus and begin to make sense". :D > > This latter approach gives me information that makes sense on first > sight, when taken uncritically, but doesn't help me figure out the > "unknown unknowns" :) > > The alternative, of course, would be to read the actual source code in > "drivers/mmc/core/..." until I "know it by heart", and then look at my > (and a few other existing) drivers in "drivers/mmc/host/..." to try and > get an idea of what I'm missing. > > I'll go with the latter if necessary, but would prefer a gentler > introduction to "drivers/mmc". Any (link, pointer to) a tutorial, > assuming one exists, would be MUCH appreciated! > > Thanks, > --Gabriel > Hi, The only & closest thing that I could find is https://www.slideshare.net/rampalliraj/linux-kernel-mmc-storage-driver-overview HTH. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9E219C433E0 for ; Sat, 9 Jan 2021 04:35:15 +0000 (UTC) Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0CC3B23A69 for ; Sat, 9 Jan 2021 04:35:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0CC3B23A69 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernelnewbies-bounces@kernelnewbies.org Received: from localhost ([::1] helo=shelob.surriel.com) by shelob.surriel.com with esmtp (Exim 4.94) (envelope-from ) id 1ky5xz-0003Oj-V8; Fri, 08 Jan 2021 23:35:07 -0500 Received: from ciao.gmane.io ([116.202.254.214]) by shelob.surriel.com with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94) (envelope-from ) id 1ky5xw-0003OS-UG for kernelnewbies@kernelnewbies.org; Fri, 08 Jan 2021 23:35:04 -0500 Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1ky5xu-0004nU-5S for kernelnewbies@kernelnewbies.org; Sat, 09 Jan 2021 05:35:02 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: kernelnewbies@kernelnewbies.org From: Randy Dunlap Subject: Re: Tutorial for "drivers/mmc/*"? Date: Fri, 8 Jan 2021 20:27:54 -0800 Message-ID: <85060973-8d39-156e-93db-3c8180060c54@infradead.org> References: <20210107205419.GG2094049@errol.ini.cmu.edu> Mime-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.4.0 In-Reply-To: <20210107205419.GG2094049@errol.ini.cmu.edu> Content-Language: en-US X-BeenThere: kernelnewbies@kernelnewbies.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Learn about the Linux kernel List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kernelnewbies-bounces@kernelnewbies.org Message-ID: <20210109042754.o1DOgpyHzeMXfKE6ceUNj4ETyR_tVUEquuhXoyEBTI8@z> On 1/7/21 12:54 PM, Gabriel L. Somlo wrote: > Hi, > > I'm debugging a driver for a (fpga-based soft core) microSD card Linux > device, and the existing driver (in drivers/mmc/host/...) makes sense > at first sight, but, either due to shortcomings in the softcore > (Verilog by way of Migen) "hardware", or the actual Linux driver > itself, suffers from intermittent data transfer errors. > > I find myself wishing I could get a top-down idea of how the Linux mmc > layer is put together, so I could examine the driver in question with > a critical eye, rather than my current approach, which is best described > as "blind-man attempts to comprehend an elephant by touching various > locations on its body, hoping the collected experiences will suddenly > come into focus and begin to make sense". :D > > This latter approach gives me information that makes sense on first > sight, when taken uncritically, but doesn't help me figure out the > "unknown unknowns" :) > > The alternative, of course, would be to read the actual source code in > "drivers/mmc/core/..." until I "know it by heart", and then look at my > (and a few other existing) drivers in "drivers/mmc/host/..." to try and > get an idea of what I'm missing. > > I'll go with the latter if necessary, but would prefer a gentler > introduction to "drivers/mmc". Any (link, pointer to) a tutorial, > assuming one exists, would be MUCH appreciated! > > Thanks, > --Gabriel > Hi, The only & closest thing that I could find is https://www.slideshare.net/rampalliraj/linux-kernel-mmc-storage-driver-overview HTH. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies