From nobody Thu Dec 18 08:10:09 2025 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C7E8ACA0EC7 for ; Mon, 11 Sep 2023 21:26:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240276AbjIKVR0 convert rfc822-to-8bit (ORCPT ); Mon, 11 Sep 2023 17:17:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235296AbjIKIZ3 (ORCPT ); Mon, 11 Sep 2023 04:25:29 -0400 Received: from ex01.ufhost.com (ex01.ufhost.com [61.152.239.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 16720E7 for ; Mon, 11 Sep 2023 01:25:23 -0700 (PDT) Received: from EXMBX166.cuchost.com (unknown [175.102.18.54]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "EXMBX166", Issuer "EXMBX166" (not verified)) by ex01.ufhost.com (Postfix) with ESMTP id E045E24E2C2; Mon, 11 Sep 2023 16:25:21 +0800 (CST) Received: from EXMBX066.cuchost.com (172.16.7.66) by EXMBX166.cuchost.com (172.16.6.76) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Mon, 11 Sep 2023 16:25:19 +0800 Received: from localhost.localdomain (202.188.176.82) by EXMBX066.cuchost.com (172.16.6.66) with Microsoft SMTP Server (TLS) id 15.0.1497.42; Mon, 11 Sep 2023 16:25:16 +0800 From: Joshua Yeong To: CC: , , "Joshua Yeong" Subject: [PATCH 1/1] i3c: Add fallback method for GETMXDS CCC Date: Mon, 11 Sep 2023 16:24:56 +0800 Message-ID: <20230911082456.23239-2-joshua.yeong@starfivetech.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230911082456.23239-1-joshua.yeong@starfivetech.com> References: <20230911082456.23239-1-joshua.yeong@starfivetech.com> MIME-Version: 1.0 X-Originating-IP: [202.188.176.82] X-ClientProxiedBy: EXCAS062.cuchost.com (172.16.6.22) To EXMBX066.cuchost.com (172.16.6.66) X-YovoleRuleAgent: yovoleflag Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Some I3C hardware will report error when incorrect length is received from device. GETMXDS CCC are availble in 2 formats; without turnaround time (for= mat 1) and with turnaround time (format 2). There is no mechanics to determine = which format is supported by device. In case sending GETMXDS CCC format 2 resulted failure, try sending GETMXDS CCC format 1 instead. Signed-off-by: Joshua Yeong --- drivers/i3c/master.c | 33 ++++++++++++++++++++++++++++----- include/linux/i3c/ccc.h | 17 +++++++++++++++-- 2 files changed, 43 insertions(+), 7 deletions(-) diff --git a/drivers/i3c/master.c b/drivers/i3c/master.c index 87283e4a4607..084f64bef155 100644 --- a/drivers/i3c/master.c +++ b/drivers/i3c/master.c @@ -1088,10 +1088,37 @@ static int i3c_master_getmxds_locked(struct i3c_mas= ter_controller *master, struct i3c_device_info *info) { struct i3c_ccc_getmxds *getmaxds; + struct i3c_ccc_getmxds_turnaround *getmaxds_ta; struct i3c_ccc_cmd_dest dest; struct i3c_ccc_cmd cmd; int ret; =20 + getmaxds_ta =3D i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, + sizeof(*getmaxds_ta)); + if (!getmaxds_ta) + return -ENOMEM; + + i3c_ccc_cmd_init(&cmd, true, I3C_CCC_GETMXDS, &dest, 1); + ret =3D i3c_master_send_ccc_cmd_locked(master, &cmd); + if (ret) { + goto alternative; + } + + if (dest.payload.len !=3D 2 && dest.payload.len !=3D 5) { + ret =3D -EIO; + goto out; + } + + info->max_read_ds =3D getmaxds_ta->maxrd; + info->max_write_ds =3D getmaxds_ta->maxwr; + if (dest.payload.len =3D=3D 5) + info->max_read_turnaround =3D getmaxds_ta->maxrdturn[0] | + ((u32)getmaxds_ta->maxrdturn[1] << 8) | + ((u32)getmaxds_ta->maxrdturn[2] << 16); + +alternative: + i3c_ccc_cmd_dest_cleanup(&dest); + getmaxds =3D i3c_ccc_cmd_dest_init(&dest, info->dyn_addr, sizeof(*getmaxds)); if (!getmaxds) @@ -1102,17 +1129,13 @@ static int i3c_master_getmxds_locked(struct i3c_mas= ter_controller *master, if (ret) goto out; =20 - if (dest.payload.len !=3D 2 && dest.payload.len !=3D 5) { + if (dest.payload.len !=3D 2) { ret =3D -EIO; goto out; } =20 info->max_read_ds =3D getmaxds->maxrd; info->max_write_ds =3D getmaxds->maxwr; - if (dest.payload.len =3D=3D 5) - info->max_read_turnaround =3D getmaxds->maxrdturn[0] | - ((u32)getmaxds->maxrdturn[1] << 8) | - ((u32)getmaxds->maxrdturn[2] << 16); =20 out: i3c_ccc_cmd_dest_cleanup(&dest); diff --git a/include/linux/i3c/ccc.h b/include/linux/i3c/ccc.h index ad59a4ae60d1..50ed41d4d5a1 100644 --- a/include/linux/i3c/ccc.h +++ b/include/linux/i3c/ccc.h @@ -269,14 +269,27 @@ enum i3c_tsco { #define I3C_CCC_MAX_SDR_FSCL(x) ((x) & I3C_CCC_MAX_SDR_FSCL_MASK) =20 /** - * struct i3c_ccc_getmxds - payload passed to GETMXDS CCC + * struct i3c_ccc_getmxds - payload passed to GETMXDS CCC without turnarou= nd + * (format 1) + * + * @maxwr: write limitations + * @maxrd: read limitations + */ +struct i3c_ccc_getmxds { + u8 maxwr; + u8 maxrd; +} __packed; + +/** + * struct i3c_ccc_getmxds_ta - payload passed to GETMXDS CCC with turnarou= nd + * (format 2) * * @maxwr: write limitations * @maxrd: read limitations * @maxrdturn: maximum read turn-around expressed micro-seconds and * little-endian formatted */ -struct i3c_ccc_getmxds { +struct i3c_ccc_getmxds_turnaround { u8 maxwr; u8 maxrd; u8 maxrdturn[3]; --=20 2.25.1