Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753808AbZIJUJp (ORCPT ); Thu, 10 Sep 2009 16:09:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753256AbZIJUJp (ORCPT ); Thu, 10 Sep 2009 16:09:45 -0400 Received: from e24smtp01.br.ibm.com ([32.104.18.85]:43062 "EHLO e24smtp01.br.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752320AbZIJUJo (ORCPT ); Thu, 10 Sep 2009 16:09:44 -0400 Subject: Re: [PATCH] tpm_tis: TPM_STS_DATA_EXPECT workaround From: Rajiv Andrade To: Daniel Walker Cc: Andy Isaacson , jmorris@namei.org, len.brown@intel.com, Alan Cox , Andy Isaacson , linux-kernel@vger.kernel.org, tpmdd-devel@lists.sourceforge.net, dds@google.com, Mimi Zohar , Shahbaz Khan , seiji.munetoh@gmail.com In-Reply-To: <1252612709.30578.219.camel@desktop> References: <1246410255-6839-1-git-send-email-adi@vmware.com> <1246410255-6839-6-git-send-email-adi@vmware.com> <20090701110136.576a1d14@lxorguk.ukuu.org.uk> <1246455920.9140.28.camel@blackbox> <20090720182732.GL6370@hexapodia.org> <1252609714.4837.87.camel@blackbox> <1252612471.4837.107.camel@blackbox> <1252612709.30578.219.camel@desktop> Content-Type: text/plain Date: Thu, 10 Sep 2009 17:09:35 -0300 Message-Id: <1252613375.4837.121.camel@blackbox> Mime-Version: 1.0 X-Mailer: Evolution 2.26.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2350 Lines: 62 Some newer Lenovo models are shipped with a TPM that doesn't seem to set the TPM_STS_DATA_EXPECT status bit when sending it a burst of data, so the code understands it as a failure and doesn't proceed sending the chip the intended data. In this patch we bypass this bit check in case the itpm module parameter was set. This patch is based on Andy Isaacson's one: http://marc.info/?l=linux-kernel&m=124650185023495&w=2 It was heavily discussed how should we deal with identifying the chip in kernel space, but the required patch to do so was NACK'd: http://marc.info/?l=linux-kernel&m=124650186423711&w=2 This way we let the user choose using this workaround or not based on his observations on this code behavior when trying to use the TPM. Fixed a checkpatch issue present on the previous patch, thanks to Daniel Walker. Signed-off-by: Rajiv Andrade --- diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c index aec1931..c9990db 100644 --- a/drivers/char/tpm/tpm_tis.c +++ b/drivers/char/tpm/tpm_tis.c @@ -257,6 +257,10 @@ out: return size; } +static int itpm; +module_param(itpm, bool, 0444); +MODULE_PARM_DESC(itpm, "Force iTPM workarounds (found on some Lenovo laptops)"); + /* * 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 @@ -293,7 +297,7 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len) wait_for_stat(chip, TPM_STS_VALID, chip->vendor.timeout_c, &chip->vendor.int_queue); status = tpm_tis_status(chip); - if ((status & TPM_STS_DATA_EXPECT) == 0) { + if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) { rc = -EIO; goto out_err; } @@ -467,6 +471,10 @@ static int tpm_tis_init(struct device *dev, resource_size_t start, "1.2 TPM (device-id 0x%X, rev-id %d)\n", vendor >> 16, ioread8(chip->vendor.iobase + TPM_RID(0))); + if (itpm) + dev_info(dev, "Intel iTPM workaround enabled\n"); + + /* Figure out the capabilities */ intfcaps = ioread32(chip->vendor.iobase + -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/