From patchwork Wed Mar 1 15:36:17 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Enric Balletbo i Serra X-Patchwork-Id: 9598627 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BD42760453 for ; Wed, 1 Mar 2017 15:36:38 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ADF1A27CF3 for ; Wed, 1 Mar 2017 15:36:38 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A0D8B2856B; Wed, 1 Mar 2017 15:36:38 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from lists.sourceforge.net (lists.sourceforge.net [216.34.181.88]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 26B4427CF3 for ; Wed, 1 Mar 2017 15:36:37 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=sfs-ml-2.v29.ch3.sourceforge.com) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1cj6Iu-0005zU-53; Wed, 01 Mar 2017 15:36:36 +0000 Received: from sog-mx-2.v43.ch3.sourceforge.com ([172.29.43.192] helo=mx.sourceforge.net) by sfs-ml-2.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1cj6It-0005zI-Ej for tpmdd-devel@lists.sourceforge.net; Wed, 01 Mar 2017 15:36:35 +0000 Received-SPF: pass (sog-mx-2.v43.ch3.sourceforge.com: domain of collabora.com designates 46.235.227.227 as permitted sender) client-ip=46.235.227.227; envelope-from=enric.balletbo@collabora.com; helo=bhuna.collabora.co.uk; Received: from bhuna.collabora.co.uk ([46.235.227.227]) by sog-mx-2.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1cj6Is-0004V6-9n for tpmdd-devel@lists.sourceforge.net; Wed, 01 Mar 2017 15:36:35 +0000 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id 8D496268562 From: Enric Balletbo i Serra To: Peter Huewe Date: Wed, 1 Mar 2017 16:36:17 +0100 Message-Id: <20170301153617.10106-1-enric.balletbo@collabora.com> X-Mailer: git-send-email 2.9.3 X-Headers-End: 1cj6Is-0004V6-9n Cc: Bryan Freed , tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, wsa@the-dreams.de Subject: [tpmdd-devel] [PATCH v2] tpm: Apply a sane minimum adapterlimit value for retransmission. X-BeenThere: tpmdd-devel@lists.sourceforge.net X-Mailman-Version: 2.1.9 Precedence: list List-Id: Tpm Device Driver maintainance List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: tpmdd-devel-bounces@lists.sourceforge.net X-Virus-Scanned: ClamAV using ClamSMTP From: Bryan Freed When the I2C Infineon part is attached to an I2C adapter that imposes a size limitation, large requests will fail with -EOPNOTSUPP. Retry them with a sane minimum size without re-issuing the 0x05 command as this appears to occasionally put the TPM in a bad state. Signed-off-by: Bryan Freed [rework the patch to adapt to the feedback received] Signed-off-by: Enric Balletbo i Serra --- This is a reworked version of the original patch based on the suggestion made by Wolfram Sang to simply fall back to a sane minimum when the maximum fails. Changes since v1: - Check the correct return value (-EOPNOTSUPP instead of -EINVAL) - Fall back len to I2C_SMBUS_BLOCK_MAX if fails. drivers/char/tpm/tpm_i2c_infineon.c | 45 +++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 19 deletions(-) diff --git a/drivers/char/tpm/tpm_i2c_infineon.c b/drivers/char/tpm/tpm_i2c_infineon.c index 62ee44e..88bf947 100644 --- a/drivers/char/tpm/tpm_i2c_infineon.c +++ b/drivers/char/tpm/tpm_i2c_infineon.c @@ -107,39 +107,27 @@ static int iic_tpm_read(u8 addr, u8 *buffer, size_t len) .len = len, .buf = buffer }; - struct i2c_msg msgs[] = {msg1, msg2}; int rc = 0; int count; + unsigned int adapterlimit = len; /* Lock the adapter for the duration of the whole sequence. */ if (!tpm_dev.client->adapter->algo->master_xfer) return -EOPNOTSUPP; i2c_lock_adapter(tpm_dev.client->adapter); - if (tpm_dev.chip_type == SLB9645) { - /* use a combined read for newer chips - * unfortunately the smbus functions are not suitable due to - * the 32 byte limit of the smbus. - * retries should usually not be needed, but are kept just to - * be on the safe side. - */ - for (count = 0; count < MAX_COUNT; count++) { - rc = __i2c_transfer(tpm_dev.client->adapter, msgs, 2); - if (rc > 0) - break; /* break here to skip sleep */ - usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI); - } - } else { + /* Expect to send one command message and one data message, but + * support looping over each or both if necessary. + */ + while (len > 0) { /* slb9635 protocol should work in all cases */ for (count = 0; count < MAX_COUNT; count++) { rc = __i2c_transfer(tpm_dev.client->adapter, &msg1, 1); if (rc > 0) - break; /* break here to skip sleep */ - + break; usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI); } - if (rc <= 0) goto out; @@ -148,11 +136,30 @@ static int iic_tpm_read(u8 addr, u8 *buffer, size_t len) * retrieving the data */ for (count = 0; count < MAX_COUNT; count++) { + unsigned int msglen = msg2.len = + min_t(unsigned int, adapterlimit, len); usleep_range(SLEEP_DURATION_LOW, SLEEP_DURATION_HI); rc = __i2c_transfer(tpm_dev.client->adapter, &msg2, 1); - if (rc > 0) + if (rc > 0) { + /* Since len is unsigned, make doubly sure we + * do not underflow it. + */ + if (msglen > len) + len = 0; + else + len -= msglen; + msg2.buf += msglen; break; + } + /* If the I2C adapter rejected the request (e.g when + * the quirk read_max_len < len) fall back to a sane + * minimum value and try again. + */ + if (rc == -EOPNOTSUPP) + adapterlimit = I2C_SMBUS_BLOCK_MAX; } + if (rc <= 0) + goto out; } out: