From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756810AbdLVSgX (ORCPT ); Fri, 22 Dec 2017 13:36:23 -0500 Received: from mga01.intel.com ([192.55.52.88]:45617 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756150AbdLVSgT (ORCPT ); Fri, 22 Dec 2017 13:36:19 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.45,442,1508828400"; d="scan'208";a="189083376" Date: Fri, 22 Dec 2017 20:36:15 +0200 From: Jarkko Sakkinen To: Javier Martinez Canillas Cc: linux-kernel@vger.kernel.org, James Ettle , Hans de Goede , Azhar Shaikh , Arnd Bergmann , Peter Huewe , Jason Gunthorpe , Greg Kroah-Hartman , linux-integrity@vger.kernel.org Subject: Re: [PATCH 4/4] tpm: only attempt to disable the LPC CLKRUN if is already enabled Message-ID: <20171222183615.ovfvf6jszsaontos@linux.intel.com> References: <20171220113538.16099-1-javierm@redhat.com> <20171220113538.16099-5-javierm@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171220113538.16099-5-javierm@redhat.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 20, 2017 at 12:35:38PM +0100, Javier Martinez Canillas wrote: > Commit 5e572cab92f0 ("tpm: Enable CLKRUN protocol for Braswell systems") > added logic in the TPM TIS driver to disable the Low Pin Count CLKRUN > signal during TPM transactions. > > Unfortunately this breaks other devices that are attached to the LPC bus > like for example PS/2 mouse and keyboards. > > One flaw with the logic is that it assumes that the CLKRUN is always > enabled, and so it unconditionally enables it after a TPM transaction. > > But it could be that the CLKRUN# signal was already disabled in the LPC > bus and so after the driver probes, CLKRUN_EN will remain enabled which > may break other devices that are attached to the LPC bus but don't have > support for the CLKRUN protocol. > > Fixes: 5e572cab92f0 ("tpm: Enable CLKRUN protocol for Braswell systems") > Signed-off-by: Javier Martinez Canillas > Tested-by: James Ettle > > --- > > This patch fixes the bug reported for the Fedora kernel [0] and the kernel > bugzilla [1]. The issue and the propossed solution were discussed in this > [2] thread. > > [0]: https://bugzilla.redhat.com/show_bug.cgi?id=1498987 > [1]: https://bugzilla.kernel.org/show_bug.cgi?id=197287 > [2]: https://patchwork.kernel.org/patch/10119417/ > > > drivers/char/tpm/tpm_tis.c | 2 +- > drivers/char/tpm/tpm_tis_core.c | 13 +++++++++++-- > 2 files changed, 12 insertions(+), 3 deletions(-) > > diff --git a/drivers/char/tpm/tpm_tis.c b/drivers/char/tpm/tpm_tis.c > index d0ad9a89b02b..c79193f6d092 100644 > --- a/drivers/char/tpm/tpm_tis.c > +++ b/drivers/char/tpm/tpm_tis.c > @@ -314,7 +314,7 @@ static int tpm_tis_plat_remove(struct platform_device *pdev) > tpm_chip_unregister(chip); > tpm_tis_remove(chip); > > - if (is_bsw()) > + if (is_bsw() && priv->ilb_base_addr) > iounmap(priv->ilb_base_addr); > > return 0; > diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c > index 534cd46fdfae..17fb9c600d0e 100644 > --- a/drivers/char/tpm/tpm_tis_core.c > +++ b/drivers/char/tpm/tpm_tis_core.c > @@ -742,7 +742,8 @@ static void tpm_tis_clkrun_enable(struct tpm_chip *chip, bool value) > struct tpm_tis_data *data = dev_get_drvdata(&chip->dev); > u32 clkrun_val; > > - if (!IS_ENABLED(CONFIG_X86) || !is_bsw()) > + if (!IS_ENABLED(CONFIG_X86) || !is_bsw() || > + !data->ilb_base_addr) > return; > > if (value) { > @@ -801,6 +802,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > u32 vendor; > u32 intfcaps; > u32 intmask; > + u32 clkrun_val; > u8 rid; > int rc, probe; > struct tpm_chip *chip; > @@ -826,6 +828,13 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > ILB_REMAP_SIZE); > if (!priv->ilb_base_addr) > return -ENOMEM; > + > + clkrun_val = ioread32(priv->ilb_base_addr + LPC_CNTRL_OFFSET); > + /* Check if CLKRUN# is already not enabled in the LPC bus */ > + if (!(clkrun_val & LPC_CLKRUN_EN)) { > + iounmap(priv->ilb_base_addr); > + priv->ilb_base_addr = NULL; > + } > } > > if (chip->ops->clk_enable != NULL) > @@ -935,7 +944,7 @@ int tpm_tis_core_init(struct device *dev, struct tpm_tis_data *priv, int irq, > if (chip->ops->clk_enable != NULL) > chip->ops->clk_enable(chip, false); > > - if (is_bsw()) > + if (is_bsw() && priv->ilb_base_addr) > iounmap(priv->ilb_base_addr); > > return rc; > -- > 2.14.3 > Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen /Jarkko