From patchwork Thu Mar 31 16:57:34 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Klaus Jensen X-Patchwork-Id: 12797475 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A4DD1C433EF for ; Thu, 31 Mar 2022 17:04:01 +0000 (UTC) Received: from localhost ([::1]:36056 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nZyDI-0004mF-JR for qemu-devel@archiver.kernel.org; Thu, 31 Mar 2022 13:04:00 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53474) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nZy7K-0000Th-Pf; Thu, 31 Mar 2022 12:57:50 -0400 Received: from wout4-smtp.messagingengine.com ([64.147.123.20]:36777) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nZy7J-0000td-5U; Thu, 31 Mar 2022 12:57:50 -0400 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailout.west.internal (Postfix) with ESMTP id EEAE83201F80; Thu, 31 Mar 2022 12:57:46 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Thu, 31 Mar 2022 12:57:47 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=irrelevant.dk; h=cc:cc:content-transfer-encoding:date:date:from:from :in-reply-to:in-reply-to:message-id:mime-version:references :reply-to:sender:subject:subject:to:to; s=fm3; bh=w1PrQnTVn6Sfbh sCoP+N7JZNYIrLtITK7DHkgnGpV20=; b=blE3nlAvTRyNAbr7NaQNxwgvUNzDus AcFV23H1zq9kyCBcOe0I8PzIlWW1bWOzmKY7TfWoB7gnmkp1MTGndXhIAn3reHH/ QOwtliAJCVlThqv37Q6eR90Lltt5rit9rH916sKGUc6v7EjiYTM+pe2bZncoRjEf ODJww8STbU9qC4aEM6Lef9M6XA4gME3zp14FluqD0ftuhChh9mXPiC/5eQxvyqMO WwhvSU7g0GOOfuVt1fhhzdIY17kFaKPRYo4jDb84dM2EhEx3sHlefJlEW9yTmPGC 0NhFoFYu85XUtnAPlhp8ERofZW+ROTbtp3bp/O8fevAcAGtYYjWPrz2g== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding:date:date :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:sender:subject:subject:to:to:x-me-proxy :x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; bh=w1PrQn TVn6SfbhsCoP+N7JZNYIrLtITK7DHkgnGpV20=; b=GZxvRDzDomWRd1GVY24Hj0 BGUmhXcD8gOzTwY0gtIDmMzeOP1O9H9QtLEq/dJYYENY7BbqmBcwWBav/lXmMyli 1lAbff4l/NXIoJz8EgaBnE4NyJ9xnynspXwNCQcTZ+T1TgG+bE9xspu94MwBCH8t KrB3j+gRv0G+qH+Ns/5Q1mULSM1DU3gHRMzu/Fj7N7UJJqIHjpLOo053leYR3VnX SjgMHB6FgzyvUW5Mwkq+ahApaYwm8y05UbrShbRpTGlh0bx/bbNkYO2dc1ir+wF0 qxB5lAIW/ZwAMRd2t6y1FGyQ/M4XQpsuWMUeD6ym+F0mVsKjoJBcV4edqAfMdHrg == X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrudeigedguddtjecutefuodetggdotefrod ftvfcurfhrohhfihhlvgemucfhrghsthforghilhdpqfgfvfdpuffrtefokffrpgfnqfgh necuuegrihhlohhuthemuceftddtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmd enucfjughrpefhvffufffkofgjfhgggfestdekredtredttdenucfhrhhomhepmfhlrghu shculfgvnhhsvghnuceoihhtshesihhrrhgvlhgvvhgrnhhtrdgukheqnecuggftrfgrth htvghrnhepueelteegieeuhffgkeefgfevjeeigfetkeeitdfgtdeifefhtdfhfeeuffev gfeknecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepih htshesihhrrhgvlhgvvhgrnhhtrdgukh X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Thu, 31 Mar 2022 12:57:43 -0400 (EDT) From: Klaus Jensen To: qemu-devel@nongnu.org Subject: [RFC PATCH 1/4] hw/i2c: support multiple masters Date: Thu, 31 Mar 2022 18:57:34 +0200 Message-Id: <20220331165737.1073520-2-its@irrelevant.dk> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220331165737.1073520-1-its@irrelevant.dk> References: <20220331165737.1073520-1-its@irrelevant.dk> MIME-Version: 1.0 Received-SPF: pass client-ip=64.147.123.20; envelope-from=its@irrelevant.dk; helo=wout4-smtp.messagingengine.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Arun Kumar Kashinath Agasar , Corey Minyard , Andrew Jeffery , Klaus Jensen , =?utf-8?q?C=C3=A9dric_Le_Goater?= , qemu-arm@nongnu.org, Joel Stanley , Padmakar Kalghatgi , Matt Johnston , Jeremy Kerr Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Klaus Jensen Allow slaves to master the bus by registering a bottom halve. If the bus is busy, the bottom halve is queued up. When a slave has succesfully mastered the bus, the bottom halve is scheduled. Signed-off-by: Klaus Jensen --- hw/i2c/core.c | 34 +++++++++++++++++++++++++++++++++- include/hw/i2c/i2c.h | 14 ++++++++++++++ 2 files changed, 47 insertions(+), 1 deletion(-) diff --git a/hw/i2c/core.c b/hw/i2c/core.c index d0cb2d32fa44..145dce60782a 100644 --- a/hw/i2c/core.c +++ b/hw/i2c/core.c @@ -13,6 +13,7 @@ #include "migration/vmstate.h" #include "qapi/error.h" #include "qemu/module.h" +#include "qemu/main-loop.h" #include "trace.h" #define I2C_BROADCAST 0x00 @@ -62,6 +63,7 @@ I2CBus *i2c_init_bus(DeviceState *parent, const char *name) bus = I2C_BUS(qbus_new(TYPE_I2C_BUS, parent, name)); QLIST_INIT(&bus->current_devs); + QSIMPLEQ_INIT(&bus->pending_masters); vmstate_register(NULL, VMSTATE_INSTANCE_ID_ANY, &vmstate_i2c_bus, bus); return bus; } @@ -74,7 +76,7 @@ void i2c_slave_set_address(I2CSlave *dev, uint8_t address) /* Return nonzero if bus is busy. */ int i2c_bus_busy(I2CBus *bus) { - return !QLIST_EMPTY(&bus->current_devs); + return !QLIST_EMPTY(&bus->current_devs) || bus->bh; } bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast, @@ -180,6 +182,26 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, bool is_recv) : I2C_START_SEND); } +void i2c_bus_master(I2CBus *bus, QEMUBH *bh) +{ + if (i2c_bus_busy(bus)) { + I2CPendingMaster *node = g_new(struct I2CPendingMaster, 1); + node->bh = bh; + + QSIMPLEQ_INSERT_TAIL(&bus->pending_masters, node, entry); + + return; + } + + bus->bh = bh; + qemu_bh_schedule(bus->bh); +} + +void i2c_bus_release(I2CBus *bus) +{ + bus->bh = NULL; +} + int i2c_start_recv(I2CBus *bus, uint8_t address) { return i2c_do_start_transfer(bus, address, I2C_START_RECV); @@ -206,6 +228,16 @@ void i2c_end_transfer(I2CBus *bus) g_free(node); } bus->broadcast = false; + + if (!QSIMPLEQ_EMPTY(&bus->pending_masters)) { + I2CPendingMaster *node = QSIMPLEQ_FIRST(&bus->pending_masters); + bus->bh = node->bh; + + QSIMPLEQ_REMOVE_HEAD(&bus->pending_masters, entry); + g_free(node); + + qemu_bh_schedule(bus->bh); + } } int i2c_send(I2CBus *bus, uint8_t data) diff --git a/include/hw/i2c/i2c.h b/include/hw/i2c/i2c.h index 5ca3b708c0be..be8bb8b78a60 100644 --- a/include/hw/i2c/i2c.h +++ b/include/hw/i2c/i2c.h @@ -69,13 +69,25 @@ struct I2CNode { QLIST_ENTRY(I2CNode) next; }; +typedef struct I2CPendingMaster I2CPendingMaster; + +struct I2CPendingMaster { + QEMUBH *bh; + QSIMPLEQ_ENTRY(I2CPendingMaster) entry; +}; + typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList; +typedef QSIMPLEQ_HEAD(I2CPendingMasters, I2CPendingMaster) I2CPendingMasters; struct I2CBus { BusState qbus; I2CNodeList current_devs; + I2CPendingMasters pending_masters; uint8_t saved_address; bool broadcast; + + /* Set from slave currently mastering the bus. */ + QEMUBH *bh; }; I2CBus *i2c_init_bus(DeviceState *parent, const char *name); @@ -117,6 +129,8 @@ int i2c_start_send(I2CBus *bus, uint8_t address); void i2c_end_transfer(I2CBus *bus); void i2c_nack(I2CBus *bus); +void i2c_bus_master(I2CBus *bus, QEMUBH *bh); +void i2c_bus_release(I2CBus *bus); int i2c_send(I2CBus *bus, uint8_t data); uint8_t i2c_recv(I2CBus *bus); bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,