linux-kernel - Re: [PATCH 4/4] tmp/tpm_crb: implement runtime pm for tpm

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Date:   Sat, 8 Oct 2016 15:47:08 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Tomas Winkler <tomas.winkler@...el.com>
Cc:     tpmdd-devel@...ts.sourceforge.net,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] tmp/tpm_crb: implement runtime pm for tpm_crb

On Sat, Oct 08, 2016 at 02:59:39PM +0300, Tomas Winkler wrote:
> From: "Winkler, Tomas" <tomas.winkler@...el.com>
> 
> Utilize runtime_pm for driving tpm crb idle states.
> The framework calls cmd_ready from the pm_runtime_resume handler
> and go idle from the pm_runtime_suspend handler.
> The TPM framework should wake the device before transmit and receive.
> In case the runtime_pm framework is not compiled in or enabled, the device
> will be in the permanent ready state.
> 
> Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>

I would rather want the fix as a separate patch to make review + testing
easier (without and with). Thanks.

/Jarkko

> ---
> V2: new in the series
> V3: resend
> V4: fix unbalanced runtime pm put and get
> 
>  drivers/char/tpm/tpm-interface.c |  5 +++++
>  drivers/char/tpm/tpm_crb.c       | 42 ++++++++++++++++++++++++++++++++++++----
>  2 files changed, 43 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 8de61876f633..7743e8a21b82 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -29,6 +29,7 @@
>  #include <linux/mutex.h>
>  #include <linux/spinlock.h>
>  #include <linux/freezer.h>
> +#include <linux/pm_runtime.h>
>  
>  #include "tpm.h"
>  #include "tpm_eventlog.h"
> @@ -356,6 +357,8 @@ ssize_t tpm_transmit(struct tpm_chip *chip, const u8 *buf, size_t bufsiz,
>  	if (!(flags & TPM_TRANSMIT_UNLOCKED))
>  		mutex_lock(&chip->tpm_mutex);
>  
> +	pm_runtime_get_sync(chip->dev.parent);
> +
>  	rc = chip->ops->send(chip, (u8 *) buf, count);
>  	if (rc < 0) {
>  		dev_err(&chip->dev,
> @@ -397,6 +400,8 @@ out_recv:
>  		dev_err(&chip->dev,
>  			"tpm_transmit: tpm_recv: error %zd\n", rc);
>  out:
> +	pm_runtime_put_sync(chip->dev.parent);
> +
>  	if (!(flags & TPM_TRANSMIT_UNLOCKED))
>  		mutex_unlock(&chip->tpm_mutex);
>  	return rc;
> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> index def50b7d47b2..eccd82af6215 100644
> --- a/drivers/char/tpm/tpm_crb.c
> +++ b/drivers/char/tpm/tpm_crb.c
> @@ -19,6 +19,7 @@
>  #include <linux/highmem.h>
>  #include <linux/rculist.h>
>  #include <linux/module.h>
> +#include <linux/pm_runtime.h>
>  #include "tpm.h"
>  
>  #define ACPI_SIG_TPM2 "TPM2"
> @@ -153,8 +154,6 @@ static int __maybe_unused crb_cmd_ready(struct device *dev,
>  	return 0;
>  }
>  
> -static SIMPLE_DEV_PM_OPS(crb_pm, tpm_pm_suspend, tpm_pm_resume);
> -
>  static u8 crb_status(struct tpm_chip *chip)
>  {
>  	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> @@ -437,11 +436,21 @@ static int crb_acpi_add(struct acpi_device *device)
>  	if (rc)
>  		return rc;
>  
> +	pm_runtime_get_noresume(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +
>  	rc = tpm_chip_register(chip);
> -	if (rc)
> +	if (rc) {
>  		crb_go_idle(dev, priv);
> +		pm_runtime_put_noidle(dev);
> +		pm_runtime_disable(dev);
> +		return rc;
> +	}
>  
> -	return rc;
> +	pm_runtime_put(dev);
> +
> +	return 0;
>  }
>  
>  static int crb_acpi_remove(struct acpi_device *device)
> @@ -451,9 +460,34 @@ static int crb_acpi_remove(struct acpi_device *device)
>  
>  	tpm_chip_unregister(chip);
>  
> +	pm_runtime_disable(dev);
> +
>  	return 0;
>  }
>  
> +#ifdef CONFIG_PM
> +static int crb_pm_runtime_suspend(struct device *dev)
> +{
> +	struct tpm_chip *chip = dev_get_drvdata(dev);
> +	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> +	return crb_go_idle(dev, priv);
> +}
> +
> +static int crb_pm_runtime_resume(struct device *dev)
> +{
> +	struct tpm_chip *chip = dev_get_drvdata(dev);
> +	struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> +
> +	return crb_cmd_ready(dev, priv);
> +}
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops crb_pm = {
> +	SET_SYSTEM_SLEEP_PM_OPS(tpm_pm_suspend, tpm_pm_resume)
> +	SET_RUNTIME_PM_OPS(crb_pm_runtime_suspend, crb_pm_runtime_resume, NULL)
> +};
> +
>  static struct acpi_device_id crb_device_ids[] = {
>  	{"MSFT0101", 0},
>  	{"", 0},
> -- 
> 2.7.4
>