Re: [tpmdd-devel] [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()

From: Jarkko Sakkinen
Date: Mon Mar 13 2017 - 14:26:24 EST


On Mon, Mar 13, 2017 at 10:54:22AM -0400, Mimi Zohar wrote:
> Hi Jarkko,
>
> On Fri, 2017-03-10 at 13:45 -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@xxxxxxxxxxxxxxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx (linux-4.8)
> > Reviewed-by: Mimi Zohar <zohar@xxxxxxxxxxxxxxxxxx>
>
> Either Reviewed-by/Acked-by is fine.
>
> Can you pick up this patch and replace the original version of "tpm:
> msleep() delays - replace with usleep_range()" with the one Nayna
> posted?
>
> Thanks!
>
> Mimi

Yes, sure. I'll try to get that done as soon as possible..

/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;
> > }
>
>