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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 070C7C4332F for ; Fri, 18 Nov 2022 22:08:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231293AbiKRWIn (ORCPT ); Fri, 18 Nov 2022 17:08:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35312 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231300AbiKRWI3 (ORCPT ); Fri, 18 Nov 2022 17:08:29 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D7E75583 for ; Fri, 18 Nov 2022 14:08:27 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id BDBE66277F for ; Fri, 18 Nov 2022 22:08:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2823C433D6; Fri, 18 Nov 2022 22:08:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668809306; bh=WOIrg5wuQ/eYm0RGCd9AzJ1SkNKh8ZHQZT887tkJBKc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fNBBXenbJghECcBwCW5qdTw6wAjvL7jduhxB8A2pkoJkVqOx+k4H0eQF6NFTLL/zd 4+9LFTWBy/O5uEij+YAWbX4zwZJ2kWLxFW+d2qtre2HJ+iodlZDdeLlL0U21qMSnuW 9fpgMsHpw4JfIflnf6kOpPcaRqJ+/sVorrV69gmEPKXIIl1R3S4ymIg9qJecIvPr7x byyskpfs7wToPH3S1FZRca/U922vgPqeVdxVe51FimFyoHBIf38xVdBswFZmW+vY3m mdjDDbOUlIC/y32WWVCNRASX3eKi3jh5y6/Q3bSLi9WsZRPioN2buxA0lISc2pNV4S u72xp+NuSjZLQ== From: Conor Dooley To: Conor Dooley , Jassi Brar Cc: Daire McNamara , linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] mailbox: mpfs: read the system controller's status Date: Fri, 18 Nov 2022 22:07:59 +0000 Message-Id: <20221118220758.1101409-3-conor@kernel.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20221118220758.1101409-1-conor@kernel.org> References: <20221118220758.1101409-1-conor@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Conor Dooley Some services explicitly return an error code in their response, but others rely on the system controller to set a status in its status register. The meaning of the bits varies based on what service is requested, so pass it back up to the driver that requested the service in the first place. The field in the message struct already existed, but was unused until now. If the system controller is busy, in which case we should never actually be in the interrupt handler, or if the service fails the mailbox itself should not be read. Callers should check the status before operating on the response. Fixes: 83d7b1560810 ("mbox: add polarfire soc system controller mailbox") Signed-off-by: Conor Dooley --- drivers/mailbox/mailbox-mpfs.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) diff --git a/drivers/mailbox/mailbox-mpfs.c b/drivers/mailbox/mailbox-mpfs.c index cfacb3f320a6..e9a72c5453e4 100644 --- a/drivers/mailbox/mailbox-mpfs.c +++ b/drivers/mailbox/mailbox-mpfs.c @@ -2,7 +2,7 @@ /* * Microchip PolarFire SoC (MPFS) system controller/mailbox controller driver * - * Copyright (c) 2020 Microchip Corporation. All rights reserved. + * Copyright (c) 2020-2022 Microchip Corporation. All rights reserved. * * Author: Conor Dooley * @@ -23,6 +23,8 @@ #define MAILBOX_REG_OFFSET 0x800u #define MSS_SYS_MAILBOX_DATA_OFFSET 0u #define SCB_MASK_WIDTH 16u +#define SCB_STATUS_SHIFT 16u +#define SCB_STATUS_MASK GENMASK(31, SCB_STATUS_SHIFT) /* SCBCTRL service control register */ @@ -130,13 +132,38 @@ static void mpfs_mbox_rx_data(struct mbox_chan *chan) struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv; struct mpfs_mss_response *response = mbox->response; u16 num_words = ALIGN((response->resp_size), (4)) / 4U; - u32 i; + u32 i, status; if (!response->resp_msg) { dev_err(mbox->dev, "failed to assign memory for response %d\n", -ENOMEM); return; } + /* + * The status is stored in bits 31:16 of the SERVICES_SR register. + * It is only valid when BUSY == 0. + * We should *never* get an interrupt while the controller is + * still in the busy state. If we do, something has gone badly + * wrong & the content of the mailbox would not be valid. + */ + if (mpfs_mbox_busy(mbox)) { + dev_err(mbox->dev, "got an interrupt but system controller is busy\n"); + response->resp_status = 0xDEAD; + return; + } + + status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET); + + /* + * If the status of the individual servers is non-zero, the service has + * failed. The contents of the mailbox at this point are not be valid, + * so don't bother reading them. Set the status so that the driver + * implementing the service can handle the result. + */ + response->resp_status = (status & SCB_STATUS_MASK); >> SCB_STATUS_SHIFT; + if (response->resp_status) + return; + if (!mpfs_mbox_busy(mbox)) { for (i = 0; i < num_words; i++) { response->resp_msg[i] = -- 2.37.2