linux-kernel - Re: [PATCH v2 2/2] crypto: sun4i-ss: enable pm

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Date:   Thu, 19 Sep 2019 18:55:59 +0200
From:   Maxime Ripard <mripard@...nel.org>
To:     Corentin Labbe <clabbe.montjoie@...il.com>
Cc:     davem@...emloft.net, herbert@...dor.apana.org.au, wens@...e.org,
        linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...glegroups.com
Subject: Re: [PATCH v2 2/2] crypto: sun4i-ss: enable pm_runtime

Hi,

On Thu, Sep 19, 2019 at 07:10:35AM +0200, Corentin Labbe wrote:
> This patch enables power management on the Security System.
>
> Signed-off-by: Corentin Labbe <clabbe.montjoie@...il.com>
> ---
>  drivers/crypto/sunxi-ss/sun4i-ss-cipher.c |  9 +++
>  drivers/crypto/sunxi-ss/sun4i-ss-core.c   | 94 +++++++++++++++++++----
>  drivers/crypto/sunxi-ss/sun4i-ss-hash.c   | 12 +++
>  drivers/crypto/sunxi-ss/sun4i-ss-prng.c   |  9 ++-
>  drivers/crypto/sunxi-ss/sun4i-ss.h        |  2 +
>  5 files changed, 110 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-cipher.c b/drivers/crypto/sunxi-ss/sun4i-ss-cipher.c
> index fa4b1b47822e..c9799cbe0530 100644
> --- a/drivers/crypto/sunxi-ss/sun4i-ss-cipher.c
> +++ b/drivers/crypto/sunxi-ss/sun4i-ss-cipher.c
> @@ -480,6 +480,7 @@ int sun4i_ss_cipher_init(struct crypto_tfm *tfm)
>  	struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
>  	struct sun4i_ss_alg_template *algt;
>  	const char *name = crypto_tfm_alg_name(tfm);
> +	int err;
>
>  	memset(op, 0, sizeof(struct sun4i_tfm_ctx));
>
> @@ -497,13 +498,21 @@ int sun4i_ss_cipher_init(struct crypto_tfm *tfm)
>  		return PTR_ERR(op->fallback_tfm);
>  	}
>
> +	err = pm_runtime_get_sync(op->ss->dev);
> +	if (err < 0)
> +		goto error_pm;
>  	return 0;

Newline here

> +error_pm:
> +	crypto_free_sync_skcipher(op->fallback_tfm);
> +	return err;
>  }
>
>  void sun4i_ss_cipher_exit(struct crypto_tfm *tfm)
>  {
>  	struct sun4i_tfm_ctx *op = crypto_tfm_ctx(tfm);
> +
>  	crypto_free_sync_skcipher(op->fallback_tfm);
> +	pm_runtime_put(op->ss->dev);
>  }
>
>  /* check and set the AES key, prepare the mode to be used */
> diff --git a/drivers/crypto/sunxi-ss/sun4i-ss-core.c b/drivers/crypto/sunxi-ss/sun4i-ss-core.c
> index 6c2db5d83b06..311c2653a9c3 100644
> --- a/drivers/crypto/sunxi-ss/sun4i-ss-core.c
> +++ b/drivers/crypto/sunxi-ss/sun4i-ss-core.c
> @@ -44,7 +44,8 @@ static struct sun4i_ss_alg_template ss_algs[] = {
>  				.cra_blocksize = MD5_HMAC_BLOCK_SIZE,
>  				.cra_ctxsize = sizeof(struct sun4i_req_ctx),
>  				.cra_module = THIS_MODULE,
> -				.cra_init = sun4i_hash_crainit
> +				.cra_init = sun4i_hash_crainit,
> +				.cra_exit = sun4i_hash_craexit

You should add a comma at the end to prevent having to modify it again

>  			}
>  		}
>  	}
> @@ -70,7 +71,8 @@ static struct sun4i_ss_alg_template ss_algs[] = {
>  				.cra_blocksize = SHA1_BLOCK_SIZE,
>  				.cra_ctxsize = sizeof(struct sun4i_req_ctx),
>  				.cra_module = THIS_MODULE,
> -				.cra_init = sun4i_hash_crainit
> +				.cra_init = sun4i_hash_crainit,
> +				.cra_exit = sun4i_hash_craexit

Ditto

>  			}
>  		}
>  	}
> @@ -262,6 +264,61 @@ static int sun4i_ss_enable(struct sun4i_ss_ctx *ss)
>  	return err;
>  }
>
> +/*
> + * Power management strategy: The device is suspended unless a TFM exists for
> + * one of the algorithms proposed by this driver.
> + */
> +#if defined(CONFIG_PM)
> +static int sun4i_ss_pm_suspend(struct device *dev)
> +{
> +	struct sun4i_ss_ctx *ss = dev_get_drvdata(dev);
> +
> +	sun4i_ss_disable(ss);
> +	return 0;
> +}
> +
> +static int sun4i_ss_pm_resume(struct device *dev)
> +{
> +	struct sun4i_ss_ctx *ss = dev_get_drvdata(dev);
> +
> +	return sun4i_ss_enable(ss);
> +}
> +#endif
> +

Why not just have the suspend and resume function and the enable /
disable functions merged together, you're not using them directy as
far as I can see.

> +const struct dev_pm_ops sun4i_ss_pm_ops = {
> +	SET_RUNTIME_PM_OPS(sun4i_ss_pm_suspend, sun4i_ss_pm_resume, NULL)
> +};
> +
> +/*
> + * When power management is enabled, this function enables the PM and set the
> + * device as suspended
> + * When power management is disabled, this function just enables the device
> + */
> +static int sun4i_ss_pm_init(struct sun4i_ss_ctx *ss)
> +{
> +	int err;
> +
> +	pm_runtime_use_autosuspend(ss->dev);
> +	pm_runtime_set_autosuspend_delay(ss->dev, 2000);
> +
> +	err = pm_runtime_set_suspended(ss->dev);
> +	if (err)
> +		return err;
> +	pm_runtime_enable(ss->dev);
> +#if !defined(CONFIG_PM)
> +	err = sun4i_ss_enable(ss);
> +#endif
> +	return err;
> +}

This looks nicer:
https://elixir.bootlin.com/linux/latest/source/drivers/spi/spi-sun4i.c#L492

Or, just make it depend on CONFIG_PM, we should probably do it anyway
at the ARCH level anyway.

Maxime

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