Re: [PATCH v2 11/16] mmc: sdhci: Program a relatively accurate SW timeout value
On 19/02/18 11:24, Adrian Hunter wrote:
> On 05/02/18 14:50, Kishon Vijay Abraham I wrote:
>> sdhci has a 10 second timeout to catch devices that stop responding.
>> Instead of programming 10 second arbitrary value, calculate the total time
>> it would take for the entire transfer to happen and program the timeout
>> value accordingly.
>>
>> Signed-off-by: Kishon Vijay Abraham I
>> ---
>> drivers/mmc/host/sdhci.c | 46 +++---
>> drivers/mmc/host/sdhci.h | 10 ++
>> 2 files changed, 49 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 0489572d1892..d52f9e7eabe2 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -673,6 +673,37 @@ static void sdhci_adma_table_post(struct sdhci_host
>> *host,
>> }
>> }
>>
>> +static void sdhci_calc_sw_timeout(struct sdhci_host *host,
>> + struct mmc_command *cmd,
>> + unsigned int target_timeout)
>> +{
>> +struct mmc_data *data = cmd->data;
>> +struct mmc_host *mmc = host->mmc;
>> +unsigned long long transfer_time;
>> +struct mmc_ios *ios = &mmc->ios;
>> +unsigned char bus_width = ios->bus_width;
>> +unsigned int blksz;
>> +unsigned int freq;
>> +
>> +if (data) {
>> +blksz = data->blksz;
>> +freq = host->mmc->actual_clock ? host->mmc->actual_clock :
>> +host->clock;
>
> I think this can be:
>
> freq = host->mmc->actual_clock ? : host->clock;
>
>> +transfer_time = (unsigned long long)(blksz * NSEC_PER_SEC *
>> + (8 / bus_width)) / freq;
>
> You have got a 32-bit overflow here and a 64-bit division that can't always
> be done with '/'
>
>> +/* multiply by '2' to account for any unknowns */
>> +transfer_time = transfer_time * 2;
>
> transfer_time *= 2;
>
>> +/* calculate timeout for the entire data */
>> +host->data_timeout = (data->blocks * ((target_timeout *
>> + NSEC_PER_USEC) +
>> + transfer_time));
>> +} else {
>> +host->data_timeout = target_timeout * NSEC_PER_USEC;
>
> And another 32-bit overflow here
>
>> +}
>> +
>> +host->data_timeout += MMC_CMD_TRANSFER_TIME;
>> +}
>> +
>> static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command
>> *cmd)
>> {
>> u8 count;
>> @@ -742,6 +773,7 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host,
>> struct mmc_command *cmd)
>> host->hw_timeout_disabled = true;
>> }
>> }
>> +sdhci_calc_sw_timeout(host, cmd, target_timeout);
>>
>> return count;
>> }
>> @@ -1130,13 +1162,6 @@ void sdhci_send_command(struct sdhci_host *host,
>> struct mmc_command *cmd)
>> mdelay(1);
>> }
>>
>> -timeout = jiffies;
>> -if (!cmd->data && cmd->busy_timeout > 9000)
>> -timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
>> -else
>> -timeout += 10 * HZ;
>> -sdhci_mod_timer(host, cmd, timeout);
>> -
>> host->cmd = cmd;
>> if (sdhci_data_line_cmd(cmd)) {
>> WARN_ON(host->data_cmd);
>> @@ -1176,6 +1201,13 @@ void sdhci_send_command(struct sdhci_host *host,
>> struct mmc_command *cmd)
>> cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200)
>> flags |= SDHCI_CMD_DATA;
>>
>> +timeout = jiffies;
>> +if (sdhci_data_line_cmd(cmd))
>> +timeout += nsecs_to_jiffies(host->data_timeout);
>> +else
>> +timeout += 10 * HZ;
>> +sdhci_mod_timer(host, cmd, timeout);
>
> Here you probably want to avoid updating the timer if the mrq has already
> started using host->data_timeout.
>
>> +
>> sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
>> }
>> EXPORT_SYMBOL_GPL(sdhci_send_command);
>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>> index 3a967a56fcc3..b73577d77856 100644
>> --- a/drivers/mmc/host/sdhci.h
>> +++ b/drivers/mmc/host/sdhci.h
>> @@ -332,6 +332,14 @@ struct sdhci_adma2_64_desc {
>> /* Allow for a a command request and a data request at the same time */
>> #define SDHCI_MAX_MRQS 2
>>
>> +/*
>> + * 48bit command and 136 bit response in 400KHz clock should take 0.46ms.
>
> I am not sure the math is correct here. I would add the 64 clocks before
> the response also, and allow for 100 kHz clock.
>
> (48 + 64 + 136) * 100 us = 24.8 ms
No I am off by x10, sorry! I would still go for 10 ms.
>
> Given that you are looking at data block timeouts in excess of 700 ms, and
> anything up to 10% of that is relatively negligible, anything less that 70
> ms seems fine, so I would set 30 ms here as a round number.
>
>> + *
Re: [PATCH v2 11/16] mmc: sdhci: Program a relatively accurate SW timeout value
On 05/02/18 14:50, Kishon Vijay Abraham I wrote:
> sdhci has a 10 second timeout to catch devices that stop responding.
> Instead of programming 10 second arbitrary value, calculate the total time
> it would take for the entire transfer to happen and program the timeout
> value accordingly.
>
> Signed-off-by: Kishon Vijay Abraham I
> ---
> drivers/mmc/host/sdhci.c | 46 +++---
> drivers/mmc/host/sdhci.h | 10 ++
> 2 files changed, 49 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 0489572d1892..d52f9e7eabe2 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -673,6 +673,37 @@ static void sdhci_adma_table_post(struct sdhci_host
> *host,
> }
> }
>
> +static void sdhci_calc_sw_timeout(struct sdhci_host *host,
> + struct mmc_command *cmd,
> + unsigned int target_timeout)
> +{
> + struct mmc_data *data = cmd->data;
> + struct mmc_host *mmc = host->mmc;
> + unsigned long long transfer_time;
> + struct mmc_ios *ios = &mmc->ios;
> + unsigned char bus_width = ios->bus_width;
> + unsigned int blksz;
> + unsigned int freq;
> +
> + if (data) {
> + blksz = data->blksz;
> + freq = host->mmc->actual_clock ? host->mmc->actual_clock :
> + host->clock;
I think this can be:
freq = host->mmc->actual_clock ? : host->clock;
> + transfer_time = (unsigned long long)(blksz * NSEC_PER_SEC *
> + (8 / bus_width)) / freq;
You have got a 32-bit overflow here and a 64-bit division that can't always
be done with '/'
> + /* multiply by '2' to account for any unknowns */
> + transfer_time = transfer_time * 2;
transfer_time *= 2;
> + /* calculate timeout for the entire data */
> + host->data_timeout = (data->blocks * ((target_timeout *
> +NSEC_PER_USEC) +
> +transfer_time));
> + } else {
> + host->data_timeout = target_timeout * NSEC_PER_USEC;
And another 32-bit overflow here
> + }
> +
> + host->data_timeout += MMC_CMD_TRANSFER_TIME;
> +}
> +
> static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command
> *cmd)
> {
> u8 count;
> @@ -742,6 +773,7 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host,
> struct mmc_command *cmd)
> host->hw_timeout_disabled = true;
> }
> }
> + sdhci_calc_sw_timeout(host, cmd, target_timeout);
>
> return count;
> }
> @@ -1130,13 +1162,6 @@ void sdhci_send_command(struct sdhci_host *host,
> struct mmc_command *cmd)
> mdelay(1);
> }
>
> - timeout = jiffies;
> - if (!cmd->data && cmd->busy_timeout > 9000)
> - timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
> - else
> - timeout += 10 * HZ;
> - sdhci_mod_timer(host, cmd, timeout);
> -
> host->cmd = cmd;
> if (sdhci_data_line_cmd(cmd)) {
> WARN_ON(host->data_cmd);
> @@ -1176,6 +1201,13 @@ void sdhci_send_command(struct sdhci_host *host,
> struct mmc_command *cmd)
> cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200)
> flags |= SDHCI_CMD_DATA;
>
> + timeout = jiffies;
> + if (sdhci_data_line_cmd(cmd))
> + timeout += nsecs_to_jiffies(host->data_timeout);
> + else
> + timeout += 10 * HZ;
> + sdhci_mod_timer(host, cmd, timeout);
Here you probably want to avoid updating the timer if the mrq has already
started using host->data_timeout.
> +
> sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
> }
> EXPORT_SYMBOL_GPL(sdhci_send_command);
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 3a967a56fcc3..b73577d77856 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -332,6 +332,14 @@ struct sdhci_adma2_64_desc {
> /* Allow for a a command request and a data request at the same time */
> #define SDHCI_MAX_MRQS 2
>
> +/*
> + * 48bit command and 136 bit response in 400KHz clock should take 0.46ms.
I am not sure the math is correct here. I would add the 64 clocks before
the response also, and allow for 100 kHz clock.
(48 + 64 + 136) * 100 us = 24.8 ms
Given that you are looking at data block timeouts in excess of 700 ms, and
anything up to 10% of that is relatively negligible, anything less that 70
ms seems fine, so I would set 30 ms here as a round number.
> + * However since the start time of the command, the time between
> + * command and response, and the time between response and start of data is
> + * not known, set the command transfer time to 2ms.
> + */
Re: [PATCH v2 11/16] mmc: sdhci: Program a relatively accurate SW timeout value
On Monday 05 February 2018 06:20 PM, Kishon Vijay Abraham I wrote:
> sdhci has a 10 second timeout to catch devices that stop responding.
> Instead of programming 10 second arbitrary value, calculate the total time
> it would take for the entire transfer to happen and program the timeout
> value accordingly.
>
> Signed-off-by: Kishon Vijay Abraham I
> ---
> drivers/mmc/host/sdhci.c | 46 +++---
> drivers/mmc/host/sdhci.h | 10 ++
> 2 files changed, 49 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 0489572d1892..d52f9e7eabe2 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -673,6 +673,37 @@ static void sdhci_adma_table_post(struct sdhci_host
> *host,
> }
> }
>
> +static void sdhci_calc_sw_timeout(struct sdhci_host *host,
> + struct mmc_command *cmd,
> + unsigned int target_timeout)
> +{
> + struct mmc_data *data = cmd->data;
> + struct mmc_host *mmc = host->mmc;
> + unsigned long long transfer_time;
> + struct mmc_ios *ios = &mmc->ios;
> + unsigned char bus_width = ios->bus_width;
This should have been 1 << ios->bus_width.
-Kishon
[PATCH v2 11/16] mmc: sdhci: Program a relatively accurate SW timeout value
sdhci has a 10 second timeout to catch devices that stop responding.
Instead of programming 10 second arbitrary value, calculate the total time
it would take for the entire transfer to happen and program the timeout
value accordingly.
Signed-off-by: Kishon Vijay Abraham I
---
drivers/mmc/host/sdhci.c | 46 +++---
drivers/mmc/host/sdhci.h | 10 ++
2 files changed, 49 insertions(+), 7 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 0489572d1892..d52f9e7eabe2 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -673,6 +673,37 @@ static void sdhci_adma_table_post(struct sdhci_host *host,
}
}
+static void sdhci_calc_sw_timeout(struct sdhci_host *host,
+ struct mmc_command *cmd,
+ unsigned int target_timeout)
+{
+ struct mmc_data *data = cmd->data;
+ struct mmc_host *mmc = host->mmc;
+ unsigned long long transfer_time;
+ struct mmc_ios *ios = &mmc->ios;
+ unsigned char bus_width = ios->bus_width;
+ unsigned int blksz;
+ unsigned int freq;
+
+ if (data) {
+ blksz = data->blksz;
+ freq = host->mmc->actual_clock ? host->mmc->actual_clock :
+ host->clock;
+ transfer_time = (unsigned long long)(blksz * NSEC_PER_SEC *
+(8 / bus_width)) / freq;
+ /* multiply by '2' to account for any unknowns */
+ transfer_time = transfer_time * 2;
+ /* calculate timeout for the entire data */
+ host->data_timeout = (data->blocks * ((target_timeout *
+ NSEC_PER_USEC) +
+ transfer_time));
+ } else {
+ host->data_timeout = target_timeout * NSEC_PER_USEC;
+ }
+
+ host->data_timeout += MMC_CMD_TRANSFER_TIME;
+}
+
static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
{
u8 count;
@@ -742,6 +773,7 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host,
struct mmc_command *cmd)
host->hw_timeout_disabled = true;
}
}
+ sdhci_calc_sw_timeout(host, cmd, target_timeout);
return count;
}
@@ -1130,13 +1162,6 @@ void sdhci_send_command(struct sdhci_host *host, struct
mmc_command *cmd)
mdelay(1);
}
- timeout = jiffies;
- if (!cmd->data && cmd->busy_timeout > 9000)
- timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
- else
- timeout += 10 * HZ;
- sdhci_mod_timer(host, cmd, timeout);
-
host->cmd = cmd;
if (sdhci_data_line_cmd(cmd)) {
WARN_ON(host->data_cmd);
@@ -1176,6 +1201,13 @@ void sdhci_send_command(struct sdhci_host *host, struct
mmc_command *cmd)
cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200)
flags |= SDHCI_CMD_DATA;
+ timeout = jiffies;
+ if (sdhci_data_line_cmd(cmd))
+ timeout += nsecs_to_jiffies(host->data_timeout);
+ else
+ timeout += 10 * HZ;
+ sdhci_mod_timer(host, cmd, timeout);
+
sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
}
EXPORT_SYMBOL_GPL(sdhci_send_command);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 3a967a56fcc3..b73577d77856 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -332,6 +332,14 @@ struct sdhci_adma2_64_desc {
/* Allow for a a command request and a data request at the same time */
#define SDHCI_MAX_MRQS 2
+/*
+ * 48bit command and 136 bit response in 400KHz clock should take 0.46ms.
+ * However since the start time of the command, the time between
+ * command and response, and the time between response and start of data is
+ * not known, set the command transfer time to 2ms.
+ */
+#define MMC_CMD_TRANSFER_TIME (2 * NSEC_PER_MSEC) /* max 2 ms */
+
enum sdhci_cookie {
COOKIE_UNMAPPED,
COOKIE_PRE_MAPPED, /* mapped by sdhci_pre_req() */
@@ -554,6 +562,8 @@ struct sdhci_host {
/* Host SDMA buffer boundary. */
u32 sdma_boundary;
+ unsigned long long data_timeout;
+
unsigned long private[0] cacheline_aligned;
};
--
2.11.0
