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[2620:137:e000::1:20]) by mx.google.com with ESMTP id v128-20020a626186000000b0064d32440768si4228379pfb.138.2023.06.05.11.02.58; Mon, 05 Jun 2023 11:03:13 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=fail header.i=@infineon.com header.s=IFXMAIL header.b=Kh7b07vr; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=infineon.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234593AbjFESA2 (ORCPT + 99 others); Mon, 5 Jun 2023 14:00:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60888 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231550AbjFESAN (ORCPT ); Mon, 5 Jun 2023 14:00:13 -0400 Received: from smtp14.infineon.com (smtp14.infineon.com [IPv6:2a00:18f0:1e00:4::6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2478F4; Mon, 5 Jun 2023 11:00:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=infineon.com; i=@infineon.com; q=dns/txt; s=IFXMAIL; t=1685988012; x=1717524012; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=hFaUtOwj7HlaUrYMRdzAtkuiOEy12Jko8agUx6FjxuM=; b=Kh7b07vrMVWbo3Ke+QyxpIODxw32fxvDzaHbUkNCDkvAgj0AyInaLGXE nvieU1jMBlYeOLv7gpVoC55VW5Gxso4MdPLgCH3kniJygdsGVIGInI2Q3 1fwr9c+r3xldgXMt3l4wGZu7+Ly/rmUqknJORJo1WYSP1FHs28GIgMLBN o=; X-IronPort-AV: E=McAfee;i="6600,9927,10732"; a="15904205" X-IronPort-AV: E=Sophos;i="6.00,218,1681164000"; d="scan'208";a="15904205" Received: from unknown (HELO MUCSE819.infineon.com) ([172.23.29.45]) by smtp14.infineon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jun 2023 20:00:10 +0200 Received: from KLUSE818.infineon.com (172.28.156.171) by MUCSE819.infineon.com (172.23.29.45) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Mon, 5 Jun 2023 20:00:09 +0200 Received: from ISCNPC0VBFBX.infineon.com (10.161.6.196) by KLUSE818.infineon.com (172.28.156.171) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.986.42; Mon, 5 Jun 2023 20:00:08 +0200 From: Alexander Steffen To: , , CC: Alexander Steffen Subject: [PATCH v2 3/4] tpm_tis: Use responseRetry to recover from data transfer errors Date: Mon, 5 Jun 2023 19:59:58 +0200 Message-ID: <20230605175959.2131-4-Alexander.Steffen@infineon.com> X-Mailer: git-send-email 2.28.0.windows.1 In-Reply-To: <20230605175959.2131-1-Alexander.Steffen@infineon.com> References: <20230605175959.2131-1-Alexander.Steffen@infineon.com> MIME-Version: 1.0 X-Originating-IP: [10.161.6.196] X-ClientProxiedBy: MUCSE804.infineon.com (172.23.29.30) To KLUSE818.infineon.com (172.28.156.171) X-Spam-Status: No, score=-7.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI,SPF_HELO_NONE, SPF_NONE,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1767886755653533995?= X-GMAIL-MSGID: =?utf-8?q?1767886755653533995?= TPM responses may become damaged during transmission, for example due to bit flips on the wire. Instead of aborting when detecting such issues, the responseRetry functionality can be used to make the TPM retransmit its response and receive it again without errors. Signed-off-by: Alexander Steffen --- drivers/char/tpm/tpm_tis_core.c | 40 ++++++++++++++++++++++++++------- drivers/char/tpm/tpm_tis_core.h | 1 + 2 files changed, 33 insertions(+), 8 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c index 5ddaf24518be..a08768e55803 100644 --- a/drivers/char/tpm/tpm_tis_core.c +++ b/drivers/char/tpm/tpm_tis_core.c @@ -345,11 +345,6 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) u32 expected; int rc; - if (count < TPM_HEADER_SIZE) { - size = -EIO; - goto out; - } - size = recv_data(chip, buf, TPM_HEADER_SIZE); /* read first 10 bytes, including tag, paramsize, and result */ if (size < TPM_HEADER_SIZE) { @@ -382,7 +377,7 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) goto out; } status = tpm_tis_status(chip); - if (status & TPM_STS_DATA_AVAIL) { /* retry? */ + if (status & TPM_STS_DATA_AVAIL) { dev_err(&chip->dev, "Error left over data\n"); size = -EIO; goto out; @@ -396,10 +391,39 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count) } out: - tpm_tis_ready(chip); return size; } +static int tpm_tis_recv_with_retries(struct tpm_chip *chip, u8 *buf, size_t count) +{ + struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev); + unsigned int try; + int rc = 0; + + if (count < TPM_HEADER_SIZE) { + rc = -EIO; + goto out; + } + + for (try = 0; try < TPM_RETRY; try++) { + rc = tpm_tis_recv(chip, buf, count); + + if (rc == -EIO) { + /* Data transfer errors, indicated by EIO, can be + * recovered by rereading the response. + */ + tpm_tis_write8(priv, TPM_STS(priv->locality), + TPM_STS_RESPONSE_RETRY); + } else { + break; + } + } + +out: + tpm_tis_ready(chip); + return rc; +} + /* * If interrupts are used (signaled by an irq set in the vendor structure) * tpm.c can skip polling for the data to be available as the interrupt is @@ -986,7 +1010,7 @@ static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value) static const struct tpm_class_ops tpm_tis = { .flags = TPM_OPS_AUTO_STARTUP, .status = tpm_tis_status, - .recv = tpm_tis_recv, + .recv = tpm_tis_recv_with_retries, .send = tpm_tis_send, .cancel = tpm_tis_ready, .update_timeouts = tpm_tis_update_timeouts, diff --git a/drivers/char/tpm/tpm_tis_core.h b/drivers/char/tpm/tpm_tis_core.h index e978f457fd4d..8458cd4a84ec 100644 --- a/drivers/char/tpm/tpm_tis_core.h +++ b/drivers/char/tpm/tpm_tis_core.h @@ -34,6 +34,7 @@ enum tis_status { TPM_STS_GO = 0x20, TPM_STS_DATA_AVAIL = 0x10, TPM_STS_DATA_EXPECT = 0x08, + TPM_STS_RESPONSE_RETRY = 0x02, TPM_STS_READ_ZERO = 0x23, /* bits that must be zero on read */ };