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Message-ID: <20170317190240.yn5ifl5ozvi2lxqf@intel.com>
Date: Fri, 17 Mar 2017 21:02:40 +0200
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: Nayna Jain <nayna@...ux.vnet.ibm.com>
Cc: tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de,
tpmdd@...horst.net, jgunthorpe@...idianresearch.com,
dan.morav@...oton.com, linux-security-module@...r.kernel.org,
linux-kernel@...r.kernel.org, "linux-4.8" <stable@...r.kernel.org>
Subject: Re: [PATCH 2/2] tpm: add sleep only for retry in
i2c_nuvoton_write_status()
On Fri, Mar 10, 2017 at 01:45:54PM -0500, Nayna Jain wrote:
> Currently, there is an unnecessary 1 msec delay added in
> i2c_nuvoton_write_status() for the successful case. This
> function is called multiple times during send() and recv(),
> which implies adding multiple extra delays for every TPM
> operation.
>
> This patch calls usleep_range() only if retry is to be done.
>
> Signed-off-by: Nayna Jain <nayna@...ux.vnet.ibm.com>
> Cc: stable@...r.kernel.org (linux-4.8)
> Reviewed-by: Mimi Zohar <zohar@...ux.vnet.ibm.com>
I applied this too.
/Jarkko
> ---
> drivers/char/tpm/tpm_i2c_nuvoton.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm_i2c_nuvoton.c b/drivers/char/tpm/tpm_i2c_nuvoton.c
> index 0c98c42..c642877 100644
> --- a/drivers/char/tpm/tpm_i2c_nuvoton.c
> +++ b/drivers/char/tpm/tpm_i2c_nuvoton.c
> @@ -124,8 +124,9 @@ static s32 i2c_nuvoton_write_status(struct i2c_client *client, u8 data)
> /* this causes the current command to be aborted */
> for (i = 0, status = -1; i < TPM_I2C_RETRY_COUNT && status < 0; i++) {
> status = i2c_nuvoton_write_buf(client, TPM_STS, 1, &data);
> - usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
> - + TPM_I2C_DELAY_RANGE);
> + if (status < 0)
> + usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
> + + TPM_I2C_DELAY_RANGE);
> }
> return status;
> }
> --
> 2.9.3
>
> --
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