From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752037AbbHMLKp (ORCPT ); Thu, 13 Aug 2015 07:10:45 -0400 Received: from mail-ig0-f172.google.com ([209.85.213.172]:35175 "EHLO mail-ig0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751514AbbHMLKm (ORCPT ); Thu, 13 Aug 2015 07:10:42 -0400 MIME-Version: 1.0 In-Reply-To: <20150813110008.GD8782@x1> References: <1437990272-23111-1-git-send-email-lee.jones@linaro.org> <1437990272-23111-6-git-send-email-lee.jones@linaro.org> <20150812102328.GD18282@x1> <20150813091914.GB8782@x1> <20150813102335.GC8782@x1> <20150813110008.GD8782@x1> Date: Thu, 13 Aug 2015 16:40:42 +0530 Message-ID: Subject: Re: [PATCH v2 5/6] mailbox: Add generic mechanism for testing Mailbox Controllers From: Jassi Brar To: Lee Jones Cc: "linux-arm-kernel@lists.infradead.org" , Linux Kernel Mailing List , kernel@stlinux.com, Devicetree List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 13, 2015 at 4:30 PM, Lee Jones wrote: > On Thu, 13 Aug 2015, Jassi Brar wrote: > >> On Thu, Aug 13, 2015 at 3:53 PM, Lee Jones wrote: >> > On Thu, 13 Aug 2015, Jassi Brar wrote: >> > >> >> On Thu, Aug 13, 2015 at 2:49 PM, Lee Jones wrote: >> >> > On Thu, 13 Aug 2015, Jassi Brar wrote: >> >> >> >> >> >> > + >> >> >> >> > +static void mbox_test_prepare_message(struct mbox_client *client, void *message) >> >> >> >> > +{ >> >> >> >> > + struct mbox_test_device *tdev = dev_get_drvdata(client->dev); >> >> >> >> > + >> >> >> >> > + if (tdev->mmio) >> >> >> >> > + memcpy(tdev->mmio, message, MBOX_MAX_MSG_LEN); >> >> >> >> > >> >> >> >> This is unlikely to work. Those platforms that need to send a 2 part >> >> >> >> message, they do : >> >> >> >> (a) Signal/Command/Target code via some controller register (via >> >> >> >> mbox_send_message). >> >> >> >> (b) Setup the payload in Shared-Memory (via tx_prepare). >> >> >> >> >> >> >> >> This test driver assumes both are the same. I think you have to >> >> >> >> declare something like >> >> >> > >> >> >> > This driver assumes that the framework will call client->tx_prepare() >> >> >> > first, which satisfies (b). It then assumes controller->send_data() >> >> >> > will be invoked, which will send the platform specific >> >> >> > signal/command/target code, which then satisfies (a). >> >> >> > >> >> >> Yeah, but what would be that code? Who provides that? >> >> >> >> >> >> > In what way does it assume they are the same? >> >> >> > >> >> >> notice the 'message' pointer in >> >> >> mbox_send_message(tdev->tx_channel, message); >> >> >> and >> >> >> memcpy(tdev->mmio, message, MBOX_MAX_MSG_LEN); >> >> >> >> >> >> >> struct mbox_test_message { /* same for TX and RX */ >> >> >> >> unsigned sig_len; >> >> >> >> void *signal; /* rx/tx via mailbox api */ >> >> >> >> unsigned pl_len; >> >> >> >> void *payload; /* rx/tx via shared-memory */ >> >> >> >> }; >> >> >> > >> >> >> > How do you think this should be set and use these? >> >> >> > >> >> >> The userspace would want to specify the command code (32bits or not) >> >> >> that would be passed via the fifo/register of the controller. So we >> >> >> need signal[] >> >> >> >> >> >> The data to be passed via share-memory could be provided by userspace >> >> >> via the payload[] array. >> >> > >> >> > Okay, so would the solution be two userspace files 'signal' and >> >> > 'message', so in the case of a client specified signal we can write it >> >> > into there first. >> >> > >> >> > echo 255 > signal >> >> > echo test > message >> >> > >> >> > ... or in the case where no signal is required, or the controller >> >> > driver taking care of it, we just don't write anything to signal? >> >> > >> >> file_operations.write() should parse signal and message, coming from >> >> userspace, into a local structure before routing them via >> >> mbox_send_message and tx_prepare respectively. >> > >> > Okay. So before I code this up we should agree on syntax. >> > >> > How would you like to represent the break between signal and message? >> > Obviously ' ' would be a bad idea, as some clients may want to send >> > messages with white space contained. How about '\t' or '\n'? >> > >> Yeah, I am not a fan of markers and flags either. >> >> Maybe we should share with userspace >> struct mbox_test_message { /* same for TX and RX */ >> unsigned sig_len; >> void __user *signal; /* rx/tx via mailbox api */ >> unsigned pl_len; >> void __user *payload; /* rx/tx via shared-memory */ >> }; >> >> First copy_from_user the structure of length sizof(struct >> mbox_test_message) and then copy_from_user length sig_len and pl_len >> from signal[] and payload[] respectively (usually ioctls would carry >> such data). > > Simplicity and ease of use should be the goals here. Testers should > not have to write applications to use this driver. Can we come up > with a simple/effective method that uses SYSFS/DEBUGFS please? > > The easiest way I can think of which avoids markers/separators AND the > requirement for users to have to write applications is to have two > files, 'signal' and 'message' as mentioned before. Once both are > populated I can get this driver to draft the message appropriately and > fire it off. > And then write to more files for RX data? ... which should also be in the form of 'signal' and 'message'. BTW like for spi there is a stock application in Documentation/spi/spidev_test.c we could do the same?