Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758152AbcJHMzB (ORCPT ); Sat, 8 Oct 2016 08:55:01 -0400 Received: from mga02.intel.com ([134.134.136.20]:40910 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756873AbcJHMxS (ORCPT ); Sat, 8 Oct 2016 08:53:18 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,460,1473145200"; d="scan'208";a="1042052407" Date: Sat, 8 Oct 2016 15:50:03 +0300 From: Jarkko Sakkinen To: Tomas Winkler Cc: tpmdd-devel@lists.sourceforge.net, Jason Gunthorpe , linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] tmp/tpm_crb: fix Intel PTT hw bug during idle state Message-ID: <20161008125003.GB10317@intel.com> References: <1475927979-23484-1-git-send-email-tomas.winkler@intel.com> <1475927979-23484-3-git-send-email-tomas.winkler@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1475927979-23484-3-git-send-email-tomas.winkler@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3725 Lines: 111 On Sat, Oct 08, 2016 at 02:59:37PM +0300, Tomas Winkler wrote: > From: "Winkler, Tomas" > > There is a HW bug in Skylake, Kabylake, and Broxton PCH Intel PTT device, > where most of the registers in the control area except START, REQUEST, > CANCEL, and LOC_CTRL lost retention when the device is in the idle state. > Hence we need to bring the device to ready state before accessing the other > registers. The fix brings device to ready state before trying to read > command and response buffer addresses in order to remap the for access. > > Signed-off-by: Tomas Winkler > --- > V2: cmd read need to be called also before crb_init as this will run > self test. > V3: resend. > V4: add Kabylake to the list of effected platforms > > drivers/char/tpm/tpm_crb.c | 47 ++++++++++++++++++++++++++++++++++++++-------- > 1 file changed, 39 insertions(+), 8 deletions(-) > > diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c > index 0f3b3f3d12d3..4eb96b85c653 100644 > --- a/drivers/char/tpm/tpm_crb.c > +++ b/drivers/char/tpm/tpm_crb.c > @@ -319,6 +319,7 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv, > struct list_head resources; > struct resource io_res; > struct device *dev = &device->dev; > + u32 pa_high, pa_low; > u64 cmd_pa; > u32 cmd_size; > u64 rsp_pa; > @@ -346,12 +347,27 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv, > if (IS_ERR(priv->cca)) > return PTR_ERR(priv->cca); > > - cmd_pa = ((u64) ioread32(&priv->cca->cmd_pa_high) << 32) | > - (u64) ioread32(&priv->cca->cmd_pa_low); > + /* > + * PTT HW bug w/a: wake up the device to access > + * possibly not retained registers. > + */ > + ret = crb_cmd_ready(dev, priv); > + if (ret) > + return ret; > + > + pa_high = ioread32(&priv->cca->cmd_pa_high); > + pa_low = ioread32(&priv->cca->cmd_pa_low); > + cmd_pa = ((u64)pa_high << 32) | pa_low; > cmd_size = ioread32(&priv->cca->cmd_size); > + > + dev_dbg(dev, "cmd_hi = %X cmd_low = %X cmd_size %X\n", > + pa_high, pa_low, cmd_size); > + > priv->cmd = crb_map_res(dev, priv, &io_res, cmd_pa, cmd_size); > - if (IS_ERR(priv->cmd)) > - return PTR_ERR(priv->cmd); > + if (IS_ERR(priv->cmd)) { > + ret = PTR_ERR(priv->cmd); > + goto out; > + } > > memcpy_fromio(&rsp_pa, &priv->cca->rsp_pa, 8); > rsp_pa = le64_to_cpu(rsp_pa); > @@ -359,7 +375,8 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv, > > if (cmd_pa != rsp_pa) { > priv->rsp = crb_map_res(dev, priv, &io_res, rsp_pa, rsp_size); > - return PTR_ERR_OR_ZERO(priv->rsp); > + ret = PTR_ERR_OR_ZERO(priv->rsp); > + goto out; > } > > /* According to the PTP specification, overlapping command and response > @@ -367,12 +384,18 @@ static int crb_map_io(struct acpi_device *device, struct crb_priv *priv, > */ > if (cmd_size != rsp_size) { > dev_err(dev, FW_BUG "overlapping command and response buffer sizes are not identical"); > - return -EINVAL; > + ret = -EINVAL; > + goto out; > } > + > priv->cmd_size = cmd_size; > > priv->rsp = priv->cmd; > - return 0; > + > +out: > + crb_go_idle(dev, priv); > + > + return ret; > } > > static int crb_acpi_add(struct acpi_device *device) > @@ -416,7 +439,15 @@ static int crb_acpi_add(struct acpi_device *device) > if (rc) > return rc; > > - return crb_init(device, priv); > + rc = crb_cmd_ready(dev, priv); > + if (rc) > + return rc; I cannot find any valid reason why crb_map_io calls crb_go_idle in the except in the case of a failure. This is something I complained earlier. A minor thing but the extra crb_cmd_ready is basically clutter to the initialization. /Jarkko