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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 3A5D5C432C3 for ; Sat, 16 Nov 2019 03:47:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1D07220733 for ; Sat, 16 Nov 2019 03:47:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727517AbfKPDrm (ORCPT ); Fri, 15 Nov 2019 22:47:42 -0500 Received: from kvm5.telegraphics.com.au ([98.124.60.144]:35268 "EHLO kvm5.telegraphics.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727418AbfKPDrk (ORCPT ); Fri, 15 Nov 2019 22:47:40 -0500 Received: by kvm5.telegraphics.com.au (Postfix, from userid 502) id 99A542A721; Fri, 15 Nov 2019 22:47:39 -0500 (EST) To: "James E.J. Bottomley" , "Martin K. Petersen" Cc: "Michael Schmitz" , "Kars de Jong" , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Message-Id: <2bbb6359d542f5882be67c415ecc25ad2d9eeb5e.1573875417.git.fthain@telegraphics.com.au> From: Finn Thain Subject: [PATCH] esp_scsi: Clear Transfer Count registers before PIO transfers Date: Sat, 16 Nov 2019 14:36:57 +1100 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The zorro_esp driver uses both PIO and DMA transfers. If a failed DMA transfer happened to be followed by a PIO transfer, the TCLOW and TCMED registers would not get cleared. It is theoretically possible that the stale value from the transfer counter or the TCLOW/TCMED registers could then be used by the controller and the driver. Avoid that by clearing these registers before each PIO transfer. Cc: Michael Schmitz Cc: Kars de Jong Tested-by: Stan Johnson Signed-off-by: Finn Thain --- drivers/scsi/esp_scsi.c | 3 +++ drivers/scsi/mac_esp.c | 2 -- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/esp_scsi.c b/drivers/scsi/esp_scsi.c index bb88995a12c7..afbef83f5dd9 100644 --- a/drivers/scsi/esp_scsi.c +++ b/drivers/scsi/esp_scsi.c @@ -2835,6 +2835,9 @@ void esp_send_pio_cmd(struct esp *esp, u32 addr, u32 esp_count, cmd &= ~ESP_CMD_DMA; esp->send_cmd_error = 0; + esp_write8(0, ESP_TCLOW); + esp_write8(0, ESP_TCMED); + if (write) { u8 *dst = (u8 *)addr; u8 mask = ~(phase == ESP_MIP ? ESP_INTR_FDONE : ESP_INTR_BSERV); diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c index 1c78bc10c790..797579247e47 100644 --- a/drivers/scsi/mac_esp.c +++ b/drivers/scsi/mac_esp.c @@ -361,8 +361,6 @@ static int esp_mac_probe(struct platform_device *dev) esp->flags = ESP_FLAG_NO_DMA_MAP; if (mep->pdma_io == NULL) { printk(KERN_INFO PFX "using PIO for controller %d\n", dev->id); - esp_write8(0, ESP_TCLOW); - esp_write8(0, ESP_TCMED); esp->flags |= ESP_FLAG_DISABLE_SYNC; mac_esp_ops.send_dma_cmd = esp_send_pio_cmd; } else { -- 2.23.0