From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1765712AbcIOKwq (ORCPT ); Thu, 15 Sep 2016 06:52:46 -0400 Received: from mga02.intel.com ([134.134.136.20]:19713 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751070AbcIOKwo (ORCPT ); Thu, 15 Sep 2016 06:52:44 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.30,339,1470726000"; d="scan'208";a="8758591" Date: Thu, 15 Sep 2016 13:52:35 +0300 From: Jarkko Sakkinen To: Tomas Winkler Cc: tpmdd-devel@lists.sourceforge.net, Jason Gunthorpe , linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/4] tpm/tpm_crb: implement tpm crb idle state Message-ID: <20160915105235.GA22431@intel.com> References: <1473924458-29062-1-git-send-email-tomas.winkler@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1473924458-29062-1-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 On Thu, Sep 15, 2016 at 10:27:38AM +0300, Tomas Winkler wrote: > The register TPM_CRB_CTRL_REQ_x contains bits goIdle and cmdReady for > SW to indicate that the device can enter or should exit the idle state. > > The legacy ACPI-start (SMI + DMA) based devices do not support these > bits and the idle state management is not exposed to the host SW. > Thus, this functionality only is enabled only for a CRB start (MMIO) > based devices. > > Based on Jarkko Sakkinen > original patch: > 'tpm_crb: implement power tpm crb power management' > > To keep the implementation local to the hw we don't use wait_for_tpm_stat > for polling the TPM_CRB_CTRL_REQ. > > Signed-off-by: Tomas Winkler Reviewed-by: Jarkko Sakkinen Tested-by: Jarkko Sakkinen What about callback names? I've been thinking to name them simply as 'runtime_suspend' and 'runtime_resume'. I can do renaming. /Jarkko > --- > V2: do not export the functions via tpm ops > V3: fix lower case corruption; adjust function documentation > V4: comment on wait_for_tpm_stat. > > drivers/char/tpm/tpm_crb.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 69 insertions(+) > > diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c > index 6e9d1bca712f..b6923a8b3ff7 100644 > --- a/drivers/char/tpm/tpm_crb.c > +++ b/drivers/char/tpm/tpm_crb.c > @@ -83,6 +83,75 @@ struct crb_priv { > u32 cmd_size; > }; > > +/** > + * crb_go_idle - request tpm crb device to go the idle state > + * > + * @dev: crb device > + * @priv: crb private data > + * > + * Write CRB_CTRL_REQ_GO_IDLE to TPM_CRB_CTRL_REQ > + * The device should respond within TIMEOUT_C by clearing the bit. > + * Anyhow, we do not wait here as a consequent CMD_READY request > + * will be handled correctly even if idle was not completed. > + * > + * The function does nothing for devices with ACPI-start method. > + * > + * Return: 0 always > + */ > +static int __maybe_unused crb_go_idle(struct device *dev, struct crb_priv *priv) > +{ > + if (priv->flags & CRB_FL_ACPI_START) > + return 0; > + > + iowrite32(CRB_CTRL_REQ_GO_IDLE, &priv->cca->req); > + /* we don't really care when this settles */ > + > + return 0; > +} > + > +/** > + * crb_cmd_ready - request tpm crb device to enter ready state > + * > + * @dev: crb device > + * @priv: crb private data > + * > + * Write CRB_CTRL_REQ_CMD_READY to TPM_CRB_CTRL_REQ > + * and poll till the device acknowledge it by clearing the bit. > + * The device should respond within TIMEOUT_C. > + * > + * The function does nothing for devices with ACPI-start method > + * > + * Return: 0 on success -ETIME on timeout; > + */ > +static int __maybe_unused crb_cmd_ready(struct device *dev, > + struct crb_priv *priv) > +{ > + ktime_t stop, start; > + > + if (priv->flags & CRB_FL_ACPI_START) > + return 0; > + > + iowrite32(CRB_CTRL_REQ_CMD_READY, &priv->cca->req); > + > + start = ktime_get(); > + stop = ktime_add(start, ms_to_ktime(TPM2_TIMEOUT_C)); > + do { > + if (!(ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY)) { > + dev_dbg(dev, "cmdReady in %lld usecs\n", > + ktime_to_us(ktime_sub(ktime_get(), start))); > + return 0; > + } > + usleep_range(50, 100); > + } while (ktime_before(ktime_get(), stop)); > + > + if (ioread32(&priv->cca->req) & CRB_CTRL_REQ_CMD_READY) { > + dev_warn(dev, "cmdReady timed out\n"); > + return -ETIME; > + } > + > + return 0; > +} > + > static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume); > > static u8 crb_status(struct tpm_chip *chip) > -- > 2.7.4 >