From patchwork Fri Sep 24 11:08:38 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kelvin Cao X-Patchwork-Id: 12513985 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=-14.6 required=3.0 tests=BAYES_00, DATE_IN_FUTURE_06_12,DKIM_INVALID,DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham 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 EEACFC433F5 for ; Fri, 24 Sep 2021 04:15:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB4BF61267 for ; Fri, 24 Sep 2021 04:15:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240106AbhIXERW (ORCPT ); Fri, 24 Sep 2021 00:17:22 -0400 Received: from esa.microchip.iphmx.com ([68.232.154.123]:17497 "EHLO esa.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233203AbhIXERW (ORCPT ); Fri, 24 Sep 2021 00:17:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1632456949; x=1663992949; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=Irgi2+TJMQerZX7EqkPUuDWs1A7MVoqrPiYuyiRsMys=; b=rUqnFtMB/Zppw+qKAGthWARTU8ijcpBSKjN4PZOl8p9WNTJvA9k8NE4d kEXVifHu8VL8Es0wPXe9IJNG0tSeJmaCZJ+sDOMoP7081exFrXhTihsw7 E9WkynrzNdDVly4MFpYrdZyWJC9+wKcEJmo6BWajlxGLTdZ7YuF+lZR2x VWE1i1YmudnvT0w9NnIKRRMKnTK0z9133g/O5fpbtnfVpOIjs3l44X6/N Fc9ZP3gTVYlPt14yximE4KXQe6DlOfWR/nMMyQlH1xKYahdoXMIbl+TFO Mzi9SvONJ6kf5FflxvXpseLchjNGzJKJSpJ3tUeJkMDfht36a2obuEThd g==; IronPort-SDR: 7vdSxeWexCzp11lnwozW0HzV34fU91gbXGihiTjXL6sSzRQgedlOnaeKC8hwHkxDlIb6IEupQ4 /0DstvOdWgN/N2vug+2i+RSj8QwIwYHsvSCKqIezcw4Zgy694FdPWgq405AGH6dczLdTrqHAaP fqS0PBNWUfxNr3WHWr8GLPaGH5/ULbMTQZETOE1Jo2dVpUuB8usDYmxw4w/Znd2M5hot+bmsur XYoqFVzwcHDYDcMULHi9YOXUJdNNrWCJ7EF9j/I8rM/HNRoW5YWvYAATVH0WoH7BTLpdXNewht 4hX++wF3wv0HgEq51+Fvwu1R X-IronPort-AV: E=Sophos;i="5.85,318,1624345200"; d="scan'208";a="70411604" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 23 Sep 2021 21:15:49 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Thu, 23 Sep 2021 21:15:48 -0700 Received: from localhost (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2176.14 via Frontend Transport; Thu, 23 Sep 2021 21:15:48 -0700 From: To: , , , , CC: , Subject: [PATCH 1/5] PCI/switchtec: Error out MRPC execution when no GAS access Date: Fri, 24 Sep 2021 11:08:38 +0000 Message-ID: <20210924110842.6323-2-kelvin.cao@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210924110842.6323-1-kelvin.cao@microchip.com> References: <20210924110842.6323-1-kelvin.cao@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Kelvin Cao After a firmware hard reset, MRPC command executions, which are based on the PCI BAR (which Microchip refers to as GAS) read/write, will hang indefinitely. This is because after a reset, the host will fail all GAS reads (get all 1s), in which case the driver won't get a valid MRPC status. Add a read check to GAS access when a MRPC command execution doesn't response timely, error out if the check fails. Signed-off-by: Kelvin Cao --- drivers/pci/switch/switchtec.c | 59 ++++++++++++++++++++++++++++++---- 1 file changed, 52 insertions(+), 7 deletions(-) diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 0b301f8be9ed..092653487021 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -45,6 +45,7 @@ enum mrpc_state { MRPC_QUEUED, MRPC_RUNNING, MRPC_DONE, + MRPC_IO_ERROR, }; struct switchtec_user { @@ -66,6 +67,13 @@ struct switchtec_user { int event_cnt; }; +static int check_access(struct switchtec_dev *stdev) +{ + u32 device = ioread32(&stdev->mmio_sys_info->device_id); + + return stdev->pdev->device == device; +} + static struct switchtec_user *stuser_create(struct switchtec_dev *stdev) { struct switchtec_user *stuser; @@ -113,6 +121,7 @@ static void stuser_set_state(struct switchtec_user *stuser, [MRPC_QUEUED] = "QUEUED", [MRPC_RUNNING] = "RUNNING", [MRPC_DONE] = "DONE", + [MRPC_IO_ERROR] = "IO_ERROR", }; stuser->state = state; @@ -184,6 +193,21 @@ static int mrpc_queue_cmd(struct switchtec_user *stuser) return 0; } +static void mrpc_cleanup_cmd(struct switchtec_dev *stdev) +{ + /* requires the mrpc_mutex to already be held when called */ + struct switchtec_user *stuser = list_entry(stdev->mrpc_queue.next, + struct switchtec_user, list); + + stuser->cmd_done = true; + wake_up_interruptible(&stuser->cmd_comp); + list_del_init(&stuser->list); + stuser_put(stuser); + stdev->mrpc_busy = 0; + + mrpc_cmd_submit(stdev); +} + static void mrpc_complete_cmd(struct switchtec_dev *stdev) { /* requires the mrpc_mutex to already be held when called */ @@ -223,13 +247,7 @@ static void mrpc_complete_cmd(struct switchtec_dev *stdev) memcpy_fromio(stuser->data, &stdev->mmio_mrpc->output_data, stuser->read_len); out: - stuser->cmd_done = true; - wake_up_interruptible(&stuser->cmd_comp); - list_del_init(&stuser->list); - stuser_put(stuser); - stdev->mrpc_busy = 0; - - mrpc_cmd_submit(stdev); + mrpc_cleanup_cmd(stdev); } static void mrpc_event_work(struct work_struct *work) @@ -246,6 +264,23 @@ static void mrpc_event_work(struct work_struct *work) mutex_unlock(&stdev->mrpc_mutex); } +static void mrpc_error_complete_cmd(struct switchtec_dev *stdev) +{ + /* requires the mrpc_mutex to already be held when called */ + + struct switchtec_user *stuser; + + if (list_empty(&stdev->mrpc_queue)) + return; + + stuser = list_entry(stdev->mrpc_queue.next, + struct switchtec_user, list); + + stuser_set_state(stuser, MRPC_IO_ERROR); + + mrpc_cleanup_cmd(stdev); +} + static void mrpc_timeout_work(struct work_struct *work) { struct switchtec_dev *stdev; @@ -257,6 +292,11 @@ static void mrpc_timeout_work(struct work_struct *work) mutex_lock(&stdev->mrpc_mutex); + if (!check_access(stdev)) { + mrpc_error_complete_cmd(stdev); + goto out; + } + if (stdev->dma_mrpc) status = stdev->dma_mrpc->status; else @@ -544,6 +584,11 @@ static ssize_t switchtec_dev_read(struct file *filp, char __user *data, if (rc) return rc; + if (stuser->state == MRPC_IO_ERROR) { + mutex_unlock(&stdev->mrpc_mutex); + return -EIO; + } + if (stuser->state != MRPC_DONE) { mutex_unlock(&stdev->mrpc_mutex); return -EBADE;