* [PATCH v1 1/2] tpm: msleep() delays - replace with usleep_range() in i2c nuvoton driver
@ 2017-03-10 18:15 Nayna Jain
2017-03-10 18:15 ` [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status() Nayna Jain
0 siblings, 1 reply; 9+ messages in thread
From: Nayna Jain @ 2017-03-10 18:15 UTC (permalink / raw)
To: zohar; +Cc: Nayna Jain, linux-4.8
Commit 500462a9de65 "timers: Switch to a non-cascading wheel" replaced
the 'classic' timer wheel, which aimed for near 'exact' expiry of the
timers. Their analysis was that the vast majority of timeout timers
are used as safeguards, not as real timers, and are cancelled or
rearmed before expiration. The only exception noted to this were
networking timers with a small expiry time.
Not included in the analysis was the TPM polling timer, which resulted
in a longer normal delay and, every so often, a very long delay. The
non-cascading wheel delay is based on CONFIG_HZ. For a description of
the different rings and their delays, refer to the comments in
kernel/time/timer.c.
Below are the delays given for rings 0 - 2, which explains the longer
"normal" delays and the very, long delays as seen on systems with
CONFIG_HZ 250.
* HZ 1000 steps
* Level Offset Granularity Range
* 0 0 1 ms 0 ms - 63 ms
* 1 64 8 ms 64 ms - 511 ms
* 2 128 64 ms 512 ms - 4095 ms (512ms - ~4s)
* HZ 250
* Level Offset Granularity Range
* 0 0 4 ms 0 ms - 255 ms
* 1 64 32 ms 256 ms - 2047 ms (256ms - ~2s)
* 2 128 256 ms 2048 ms - 16383 ms (~2s - ~16s)
Below is a comparison of extending the TPM with 1000 measurements,
using msleep() vs. usleep_delay() when configured for 1000 hz vs. 250
hz, before and after commit 500462a9de65.
linux-4.7 | msleep() usleep_range()
1000 hz: 0m44.628s | 1m34.497s 29.243s
250 hz: 1m28.510s | 4m49.269s 32.386s
linux-4.7 | min-max (msleep) min-max (usleep_range)
1000 hz: 0:017 - 2:760s | 0:015 - 3:967s 0:014 - 0:418s
250 hz: 0:028 - 1:954s | 0:040 - 4:096s 0:016 - 0:816s
This patch replaces the msleep() with usleep_range() calls in the
i2c nuvoton driver with a consistent max range value.
Cc: stable@vger.kernel.org ( linux-4.8)
Signed-of-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Reviewed-by: Nayna Jain <nayna@linux.vnet.ibm.com>
Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
---
Changelog v1:
- Included Jason's feedbacks related to #defines.
drivers/char/tpm/tpm_i2c_nuvoton.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/drivers/char/tpm/tpm_i2c_nuvoton.c b/drivers/char/tpm/tpm_i2c_nuvoton.c
index e3a9155..0c98c42 100644
--- a/drivers/char/tpm/tpm_i2c_nuvoton.c
+++ b/drivers/char/tpm/tpm_i2c_nuvoton.c
@@ -49,9 +49,10 @@
*/
#define TPM_I2C_MAX_BUF_SIZE 32
#define TPM_I2C_RETRY_COUNT 32
-#define TPM_I2C_BUS_DELAY 1 /* msec */
-#define TPM_I2C_RETRY_DELAY_SHORT 2 /* msec */
-#define TPM_I2C_RETRY_DELAY_LONG 10 /* msec */
+#define TPM_I2C_BUS_DELAY 1000 /* usec */
+#define TPM_I2C_RETRY_DELAY_SHORT (2 * 1000) /* usec */
+#define TPM_I2C_RETRY_DELAY_LONG (10 * 1000) /* usec */
+#define TPM_I2C_DELAY_RANGE 300 /* usec */
#define OF_IS_TPM2 ((void *)1)
#define I2C_IS_TPM2 1
@@ -123,7 +124,8 @@ 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);
- msleep(TPM_I2C_BUS_DELAY);
+ usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
+ + TPM_I2C_DELAY_RANGE);
}
return status;
}
@@ -160,7 +162,8 @@ static int i2c_nuvoton_get_burstcount(struct i2c_client *client,
burst_count = min_t(u8, TPM_I2C_MAX_BUF_SIZE, data);
break;
}
- msleep(TPM_I2C_BUS_DELAY);
+ usleep_range(TPM_I2C_BUS_DELAY, TPM_I2C_BUS_DELAY
+ + TPM_I2C_DELAY_RANGE);
} while (time_before(jiffies, stop));
return burst_count;
@@ -203,13 +206,17 @@ static int i2c_nuvoton_wait_for_stat(struct tpm_chip *chip, u8 mask, u8 value,
return 0;
/* use polling to wait for the event */
- ten_msec = jiffies + msecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
+ ten_msec = jiffies + usecs_to_jiffies(TPM_I2C_RETRY_DELAY_LONG);
stop = jiffies + timeout;
do {
if (time_before(jiffies, ten_msec))
- msleep(TPM_I2C_RETRY_DELAY_SHORT);
+ usleep_range(TPM_I2C_RETRY_DELAY_SHORT,
+ TPM_I2C_RETRY_DELAY_SHORT
+ + TPM_I2C_DELAY_RANGE);
else
- msleep(TPM_I2C_RETRY_DELAY_LONG);
+ usleep_range(TPM_I2C_RETRY_DELAY_LONG,
+ TPM_I2C_RETRY_DELAY_LONG
+ + TPM_I2C_DELAY_RANGE);
status_valid = i2c_nuvoton_check_status(chip, mask,
value);
if (status_valid)
--
2.9.3
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
2017-03-10 18:15 [PATCH v1 1/2] tpm: msleep() delays - replace with usleep_range() in i2c nuvoton driver Nayna Jain
@ 2017-03-10 18:15 ` Nayna Jain
0 siblings, 0 replies; 9+ messages in thread
From: Nayna Jain @ 2017-03-10 18:15 UTC (permalink / raw)
To: zohar; +Cc: Nayna Jain, linux-4.8
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.
Cc: stable@vger.kernel.org ( linux-4.8)
Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
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
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
2017-03-10 18:45 ` Nayna Jain
(?)
@ 2017-03-17 19:02 ` Jarkko Sakkinen
-1 siblings, 0 replies; 9+ messages in thread
From: Jarkko Sakkinen @ 2017-03-17 19:02 UTC (permalink / raw)
To: Nayna Jain
Cc: tpmdd-devel, peterhuewe, tpmdd, jgunthorpe, dan.morav,
linux-security-module, linux-kernel, linux-4.8
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@linux.vnet.ibm.com>
> Cc: stable@vger.kernel.org (linux-4.8)
> Reviewed-by: Mimi Zohar <zohar@linux.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
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
@ 2017-03-17 19:02 ` Jarkko Sakkinen
0 siblings, 0 replies; 9+ messages in thread
From: Jarkko Sakkinen @ 2017-03-17 19:02 UTC (permalink / raw)
To: linux-security-module
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@linux.vnet.ibm.com>
> Cc: stable at vger.kernel.org (linux-4.8)
> Reviewed-by: Mimi Zohar <zohar@linux.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
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
--
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
@ 2017-03-17 19:02 ` Jarkko Sakkinen
0 siblings, 0 replies; 9+ messages in thread
From: Jarkko Sakkinen @ 2017-03-17 19:02 UTC (permalink / raw)
To: Nayna Jain
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-4.8,
linux-security-module-u79uwXL29TY76Z2rM5mHXA,
tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f
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-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org (linux-4.8)
> Reviewed-by: Mimi Zohar <zohar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
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
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
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^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
[not found] ` <1489171554-6844-2-git-send-email-nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
@ 2017-03-13 14:54 ` Mimi Zohar
0 siblings, 0 replies; 9+ messages in thread
From: Mimi Zohar @ 2017-03-13 14:54 UTC (permalink / raw)
To: Jarkko Sakkinen
Cc: linux-security-module-u79uwXL29TY76Z2rM5mHXA,
tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f,
linux-kernel-u79uwXL29TY76Z2rM5mHXA, linux-4.8
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-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> Cc: stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org (linux-4.8)
> Reviewed-by: Mimi Zohar <zohar-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
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
> ---
> 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;
> }
------------------------------------------------------------------------------
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^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
2017-03-10 18:45 [PATCH v1 1/2] tpm: msleep() delays - replace with usleep_range() in i2c nuvoton driver Nayna Jain
2017-03-10 18:45 ` Nayna Jain
@ 2017-03-10 18:45 ` Nayna Jain
0 siblings, 0 replies; 9+ messages in thread
From: Nayna Jain @ 2017-03-10 18:45 UTC (permalink / raw)
To: tpmdd-devel
Cc: peterhuewe, tpmdd, jarkko.sakkinen, jgunthorpe, dan.morav,
linux-security-module, linux-kernel, Nayna Jain, linux-4.8
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@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org (linux-4.8)
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
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
^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
@ 2017-03-10 18:45 ` Nayna Jain
0 siblings, 0 replies; 9+ messages in thread
From: Nayna Jain @ 2017-03-10 18:45 UTC (permalink / raw)
To: linux-security-module
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@linux.vnet.ibm.com>
Cc: stable at vger.kernel.org (linux-4.8)
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
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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the body of a message to majordomo at vger.kernel.org
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^ permalink raw reply related [flat|nested] 9+ messages in thread
* [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status()
@ 2017-03-10 18:45 ` Nayna Jain
0 siblings, 0 replies; 9+ messages in thread
From: Nayna Jain @ 2017-03-10 18:45 UTC (permalink / raw)
To: tpmdd-devel
Cc: peterhuewe, tpmdd, jarkko.sakkinen, jgunthorpe, dan.morav,
linux-security-module, linux-kernel, Nayna Jain, linux-4.8
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@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org (linux-4.8)
Reviewed-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
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
^ permalink raw reply related [flat|nested] 9+ messages in thread
end of thread, other threads:[~2017-03-17 19:03 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2017-03-10 18:15 [PATCH v1 1/2] tpm: msleep() delays - replace with usleep_range() in i2c nuvoton driver Nayna Jain
2017-03-10 18:15 ` [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status() Nayna Jain
2017-03-10 18:45 [PATCH v1 1/2] tpm: msleep() delays - replace with usleep_range() in i2c nuvoton driver Nayna Jain
2017-03-10 18:45 ` [PATCH 2/2] tpm: add sleep only for retry in i2c_nuvoton_write_status() Nayna Jain
2017-03-10 18:45 ` Nayna Jain
2017-03-10 18:45 ` Nayna Jain
[not found] ` <1489171554-6844-2-git-send-email-nayna-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
2017-03-13 14:54 ` Mimi Zohar
2017-03-17 19:02 ` Jarkko Sakkinen
2017-03-17 19:02 ` Jarkko Sakkinen
2017-03-17 19:02 ` Jarkko Sakkinen
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