On 11/08/2013 12:49 PM, Aaron Lu wrote:
On 11/08/2013 05:10 PM, Arend van Spriel wrote:
On 11/08/2013 07:50 AM, Aaron Lu wrote:
On 11/07/2013 06:59 PM, Arend van Spriel wrote:
When the host->tuning_count is zero it means that the
If the tuning_count is zero, then the retuning timer shouldn't be
started in the first place and not possible to run code there. Or is the
tuning_count dynamically changed?
Actually, the sdhci_execute_tuning() must run once to do the initial
tuning procedure. This is mandatory for SDR104. However, *re*tuning is
not and a zero tuning_count disables it.
So the host in question doesn't need do retuning while in SDR104 mode?
It seems your host's retuning mode is mode_1.
The function is executed initially. The 'if' statement above the patched
'else' statement is actually responsible for programming the retuning
timer for the first time. However, it requires tuning_count to be
non-zero. The 'else' statement is actually for reloading the retuning
timer, which is not the case. Adding the non-zero check assures the
retuning timer is never started.
OK, I see.
The SDHCI_USING_RETUNING_TIMER flag is supposed to mean if the host is
currently using retuning timer to do retuning, it could also be used to
decide if retuning timer needs be re-programmed.
True. I can go for that approach.
Anyway, a host in retuning mode 1 does not have tuning_count set seems a
little odd to me...
Looking at sdhci.h it actually seems sdhci code is missing support for
the other modes:
unsigned int tuning_count; /* Timer count for re-tuning */
unsigned int tuning_mode; /* Re-tuning mode supported by host */
#define SDHCI_TUNING_MODE_1 0
struct timer_list tuning_timer; /* Timer for tuning */
At least the other modes are not defined here.
Regards,
Arend
Thanks,
Aaron
I guess the fact that this needs explaining indicates that the commit
message should be updated. I will send a V2 for this.
Regards,
Arend
Thanks,
Aaron
retuning is disabled. Doing a mod_timer() with a zero
tuning_count does something else.
Signed-off-by: Arend van Spriel <arend@xxxxxxxxxxxx>
---
drivers/mmc/host/sdhci.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7a7fb4f..9803e7a 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2007,7 +2007,8 @@ out:
} else {
host->flags &= ~SDHCI_NEEDS_RETUNING;
/* Reload the new initial value for timer */
- if (host->tuning_mode == SDHCI_TUNING_MODE_1)
+ if (host->tuning_count &&
+ host->tuning_mode == SDHCI_TUNING_MODE_1)
mod_timer(&host->tuning_timer, jiffies +
host->tuning_count * HZ);
}
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