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SubjectRe: [PATCH v3 07/11] mmc: sdhci: Program a relatively accurate SW timeout value
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On 20/03/18 11:48, Kishon Vijay Abraham I wrote:
> Hi Adrian,
>
> On Monday 19 March 2018 03:49 PM, Kishon Vijay Abraham I wrote:
>> Hi Adrian,
>>
>> On Monday 19 March 2018 03:30 PM, Adrian Hunter wrote:
>>> On 19/03/18 11:20, Kishon Vijay Abraham I wrote:
>>>> Hi Adrian,
>>>>
>>>> On Friday 16 March 2018 07:51 PM, Adrian Hunter wrote:
>>>>> On 16/03/18 08:29, Kishon Vijay Abraham I wrote:
>>>>>> Hi,
>>>>>>
>>>>>> On Thursday 15 March 2018 06:43 PM, Adrian Hunter wrote:
>>>>>>> On 07/03/18 15:20, 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 <kishon@ti.com>
>>>>>>>> ---
>>>>>>>> drivers/mmc/host/sdhci.c | 47 ++++++++++++++++++++++++++++++++++++++++-------
>>>>>>>> drivers/mmc/host/sdhci.h | 10 ++++++++++
>>>>>>>> 2 files changed, 50 insertions(+), 7 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>>>>>> index 1dd117cbeb6e..baab67bfa39b 100644
>>>>>>>> --- a/drivers/mmc/host/sdhci.c
>>>>>>>> +++ b/drivers/mmc/host/sdhci.c
>>>>>>>> @@ -709,6 +709,36 @@ static u32 sdhci_sdma_address(struct sdhci_host *host)
>>>>>>>> return sg_dma_address(host->data->sg);
>>>>>>>> }
>>>>>>>>
>>>>>>>> +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;
>>>>>>>> + u64 transfer_time;
>>>>>>>> + struct mmc_ios *ios = &mmc->ios;
>>>>>>>> + unsigned char bus_width = 1 << ios->bus_width;
>>>>>>>> + unsigned int blksz;
>>>>>>>> + unsigned int freq;
>>>>>>>> +
>>>>>>>> + if (data) {
>>>>>>>> + blksz = data->blksz;
>>>>>>>> + freq = host->mmc->actual_clock ? : host->clock;
>>>>>>>> + transfer_time = (u64)blksz * NSEC_PER_SEC * (8 / bus_width);
>>>>>>>> + do_div(transfer_time, 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));
>>>>>>>
>>>>>>> (target_timeout * NSEC_PER_USEC) might be 32-bit and therefore overflow
>>>>>>> for timeouts greater than about 4 seconds.
>>>>>>>
>>>>>>>> + } else {
>>>>>>>> + host->data_timeout = (u64)target_timeout * NSEC_PER_USEC;
>>>>>>>> + }
>>>>>>>> +
>>>>>>>> + host->data_timeout += MMC_CMD_TRANSFER_TIME;
>>>>>>>
>>>>>>> Need to allow for target_timeout == 0 so:
>>>>>>>
>>>>>>> if (host->data_timeout)
>>>>>>> host->data_timeout += MMC_CMD_TRANSFER_TIME;
>>>>>>>
>>>>>>>> +}
>>>>>>>> +
>>>>>>>> static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>>>>>>>> {
>>>>>>>> u8 count;
>>>>>>>> @@ -766,6 +796,7 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>>>>>>>> if (count >= 0xF)
>>>>>>>> break;
>>>>>>>> }
>>>>>>>> + sdhci_calc_sw_timeout(host, cmd, target_timeout);
>>>>>>>
>>>>>>> If you make the changes I suggest for patch 6, then this would
>>>>>>> move sdhci_calc_sw_timeout() into sdhci_set_timeout().
>>>>>>>
>>>>>>> I suggest you factor out the target_timeout calculation e.g.
>>>>>>>
>>>>>>> static unsigned int sdhci_target_timeout(struct sdhci_host *host,
>>>>>>> struct mmc_command *cmd,
>>>>>>> struct mmc_data *data)
>>>>>>> {
>>>>>>> unsigned int target_timeout;
>>>>>>>
>>>>>>> /* timeout in us */
>>>>>>> if (!data)
>>>>>>> target_timeout = cmd->busy_timeout * 1000;
>>>>>>> else {
>>>>>>> target_timeout = DIV_ROUND_UP(data->timeout_ns, 1000);
>>>>>>> if (host->clock && data->timeout_clks) {
>>>>>>> unsigned long long val;
>>>>>>>
>>>>>>> /*
>>>>>>> * data->timeout_clks is in units of clock cycles.
>>>>>>> * host->clock is in Hz. target_timeout is in us.
>>>>>>> * Hence, us = 1000000 * cycles / Hz. Round up.
>>>>>>> */
>>>>>>> val = 1000000ULL * data->timeout_clks;
>>>>>>> if (do_div(val, host->clock))
>>>>>>> target_timeout++;
>>>>>>> target_timeout += val;
>>>>>>> }
>>>>>>> }
>>>>>>>
>>>>>>> return target_timeout;
>>>>>>> }
>>>>>>>
>>>>>>> And call it from sdhci_calc_sw_timeout()
>>>>>>>
>>>>>>>>
>>>>>>>> return count;
>>>>>>>> }
>>>>>>>> @@ -1175,13 +1206,6 @@ 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->mrq, timeout);
>>>>>>>> -
>>>>>>>> host->cmd = cmd;
>>>>>>>> if (sdhci_data_line_cmd(cmd)) {
>>>>>>>> WARN_ON(host->data_cmd);
>>>>>>>> @@ -1221,6 +1245,15 @@ 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 (host->data_timeout > 0) {
>>>>>>>
>>>>>>> This can be just:
>>>>>>>
>>>>>>> if (host->data_timeout) {
>>>>>>>
>>>>>>>> + timeout += nsecs_to_jiffies(host->data_timeout);
>>>>>>>> + host->data_timeout = 0;
>>>>>>>
>>>>>>> It would be better to initialize host->data_timeout = 0 at the top of
>>>>>>> sdhci_prepare_data().
>>>>>>>
>>>>>>> Also still need:
>>>>>>>
>>>>>>> else if (!cmd->data && cmd->busy_timeout > 9000) {
>>>>>>> timeout += DIV_ROUND_UP(cmd->busy_timeout, 1000) * HZ + HZ;
>>>>>>
>>>>>> sdhci_calc_sw_timeout should have calculated the timeout for this case too no?
>>>>>
>>>>> Yes, but I was thinking you would only calculate when it was needed.
>>>>
>>>> I feel since we would have anyways calculated data_timeout, we should use that
>>>> instead unless you see a problem with that.
>>>
>>> I would prefer not to calculate data_timeout when a hardware timeout is
>>> being used.
>>>
>>
>> That differs from what I had thought. This patch tries to program a relatively
>> accurate SW timeout value (for data_timer) irrespective of whether hardware
>> timeout is used or not. This only tries to change the 10 Sec SW timeout value
>> programmed for all data transfer commands.
>
> IMHO since we calculate the worst case timeout value we should be using that
> for all cases where we are able to calculate the timeout value so that we don't
> give a too high or too low timeout value. Let me know If this sounds okay to you.

I don't want to do the calculation for drivers that don't need it.

How about the 3 patches attached
From 52d36e3bf42d189378603ecdad06ffda601cc545 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter@intel.com>
Date: Thu, 29 Mar 2018 16:04:14 +0300
Subject: [PATCH 1/3] mmc: sdhci: Add quirk to disable HW timeout

Add quirk to disable HW timeout if the requested timeout is more than the
maximum obtainable timeout.

Also, if the quirk is set and ->get_max_timeout_count() is not implemented,
max_busy_timeout is set to zero.

Based-on-patch-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/host/sdhci.c | 38 ++++++++++++++++++++++++++++++++++----
drivers/mmc/host/sdhci.h | 5 +++++
2 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 3bf6117ee879..5299ea6b5c9c 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -709,12 +709,15 @@ static u32 sdhci_sdma_address(struct sdhci_host *host)
return sg_dma_address(host->data->sg);
}

-static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
+static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd,
+ bool *too_big)
{
u8 count;
struct mmc_data *data = cmd->data;
unsigned target_timeout, current_timeout;

+ *too_big = true;
+
/*
* If the host controller provides us with an incorrect timeout
* value, just skip the check and use 0xE. The hardware may take
@@ -768,9 +771,12 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd)
}

if (count >= 0xF) {
- DBG("Too large timeout 0x%x requested for CMD%d!\n",
- count, cmd->opcode);
+ if (!(host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT))
+ DBG("Too large timeout 0x%x requested for CMD%d!\n",
+ count, cmd->opcode);
count = 0xE;
+ } else {
+ *too_big = false;
}

return count;
@@ -790,6 +796,16 @@ static void sdhci_set_transfer_irqs(struct sdhci_host *host)
sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
}

+static void sdhci_set_data_timeout_irq(struct sdhci_host *host, bool enable)
+{
+ if (enable)
+ host->ier |= SDHCI_INT_DATA_TIMEOUT;
+ else
+ host->ier &= ~SDHCI_INT_DATA_TIMEOUT;
+ sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+ sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+}
+
static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
{
u8 count;
@@ -797,7 +813,17 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
if (host->ops->set_timeout) {
host->ops->set_timeout(host, cmd);
} else {
- count = sdhci_calc_timeout(host, cmd);
+ bool too_big = false;
+
+ count = sdhci_calc_timeout(host, cmd, &too_big);
+
+ if (too_big &&
+ host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT) {
+ sdhci_set_data_timeout_irq(host, false);
+ } else if (!(host->ier & SDHCI_INT_DATA_TIMEOUT)) {
+ sdhci_set_data_timeout_irq(host, true);
+ }
+
sdhci_writeb(host, count, SDHCI_TIMEOUT_CONTROL);
}
}
@@ -3619,6 +3645,10 @@ int sdhci_setup_host(struct sdhci_host *host)
mmc->max_busy_timeout /= host->timeout_clk;
}

+ if (host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT &&
+ !host->ops->get_max_timeout_count)
+ mmc->max_busy_timeout = 0;
+
mmc->caps |= MMC_CAP_SDIO_IRQ | MMC_CAP_ERASE | MMC_CAP_CMD23;
mmc->caps2 |= MMC_CAP2_SDIO_IRQ_NOTHREAD;

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index c95b0a4a7594..f6555c0f4ad3 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -437,6 +437,11 @@ struct sdhci_host {
#define SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN (1<<15)
/* Controller has CRC in 136 bit Command Response */
#define SDHCI_QUIRK2_RSP_136_HAS_CRC (1<<16)
+/*
+ * Disable HW timeout if the requested timeout is more than the maximum
+ * obtainable timeout.
+ */
+#define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT (1<<17)

int irq; /* Device IRQ */
void __iomem *ioaddr; /* Mapped address */
--
1.9.1
From c73df33aa4549301e0b93424990dc16de2b14923 Mon Sep 17 00:00:00 2001
From: Adrian Hunter <adrian.hunter@intel.com>
Date: Wed, 4 Apr 2018 15:14:38 +0300
Subject: [PATCH 2/3] mmc: sdhci: Factor out target_timeout calculation

Factor out the target_timeout calculation so it can be re-used.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/host/sdhci.c | 48 ++++++++++++++++++++++++++++++------------------
1 file changed, 30 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 5299ea6b5c9c..7c0683b8baba 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -709,6 +709,35 @@ static u32 sdhci_sdma_address(struct sdhci_host *host)
return sg_dma_address(host->data->sg);
}

+static unsigned int sdhci_target_timeout(struct sdhci_host *host,
+ struct mmc_command *cmd,
+ struct mmc_data *data)
+{
+ unsigned int target_timeout;
+
+ /* timeout in us */
+ if (!data) {
+ target_timeout = cmd->busy_timeout * 1000;
+ } else {
+ target_timeout = DIV_ROUND_UP(data->timeout_ns, 1000);
+ if (host->clock && data->timeout_clks) {
+ unsigned long long val;
+
+ /*
+ * data->timeout_clks is in units of clock cycles.
+ * host->clock is in Hz. target_timeout is in us.
+ * Hence, us = 1000000 * cycles / Hz. Round up.
+ */
+ val = 1000000ULL * data->timeout_clks;
+ if (do_div(val, host->clock))
+ target_timeout++;
+ target_timeout += val;
+ }
+ }
+
+ return target_timeout;
+}
+
static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd,
bool *too_big)
{
@@ -732,24 +761,7 @@ static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd,
return 0xE;

/* timeout in us */
- if (!data)
- target_timeout = cmd->busy_timeout * 1000;
- else {
- target_timeout = DIV_ROUND_UP(data->timeout_ns, 1000);
- if (host->clock && data->timeout_clks) {
- unsigned long long val;
-
- /*
- * data->timeout_clks is in units of clock cycles.
- * host->clock is in Hz. target_timeout is in us.
- * Hence, us = 1000000 * cycles / Hz. Round up.
- */
- val = 1000000ULL * data->timeout_clks;
- if (do_div(val, host->clock))
- target_timeout++;
- target_timeout += val;
- }
- }
+ target_timeout = sdhci_target_timeout(host, cmd, data);

/*
* Figure out needed cycles.
--
1.9.1
From 0976d161bfb9c9a35c5176c8059c4ed9a985a0b2 Mon Sep 17 00:00:00 2001
From: Kishon Vijay Abraham I <kishon@ti.com>
Date: Wed, 7 Mar 2018 18:50:16 +0530
Subject: [PATCH 3/3] mmc: sdhci: Program a relatively accurate SW timeout
value

sdhci has a 10 second timeout to catch devices that stop responding.
In the case of quirk SDHCI_QUIRK2_DISABLE_HW_TIMEOUT, 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 <kishon@ti.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/host/sdhci.c | 36 ++++++++++++++++++++++++++++++++++++
drivers/mmc/host/sdhci.h | 10 ++++++++++
2 files changed, 46 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7c0683b8baba..d67ac1bf7caa 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -738,6 +738,39 @@ static unsigned int sdhci_target_timeout(struct sdhci_host *host,
return target_timeout;
}

+static void sdhci_calc_sw_timeout(struct sdhci_host *host,
+ struct mmc_command *cmd)
+{
+ struct mmc_data *data = cmd->data;
+ struct mmc_host *mmc = host->mmc;
+ struct mmc_ios *ios = &mmc->ios;
+ unsigned char bus_width = 1 << ios->bus_width;
+ unsigned int blksz;
+ unsigned int freq;
+ u64 target_timeout;
+ u64 transfer_time;
+
+ target_timeout = sdhci_target_timeout(host, cmd, data);
+ target_timeout *= NSEC_PER_USEC;
+
+ if (data) {
+ blksz = data->blksz;
+ freq = host->mmc->actual_clock ? : host->clock;
+ transfer_time = (u64)blksz * NSEC_PER_SEC * (8 / bus_width);
+ do_div(transfer_time, 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 +
+ transfer_time;
+ } else {
+ host->data_timeout = target_timeout;
+ }
+
+ if (host->data_timeout)
+ host->data_timeout += MMC_CMD_TRANSFER_TIME;
+}
+
static u8 sdhci_calc_timeout(struct sdhci_host *host, struct mmc_command *cmd,
bool *too_big)
{
@@ -831,6 +864,7 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)

if (too_big &&
host->quirks2 & SDHCI_QUIRK2_DISABLE_HW_TIMEOUT) {
+ sdhci_calc_sw_timeout(host, cmd);
sdhci_set_data_timeout_irq(host, false);
} else if (!(host->ier & SDHCI_INT_DATA_TIMEOUT)) {
sdhci_set_data_timeout_irq(host, true);
@@ -845,6 +879,8 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
u8 ctrl;
struct mmc_data *data = cmd->data;

+ host->data_timeout = 0;
+
if (sdhci_data_line_cmd(cmd))
sdhci_set_timeout(host, cmd);

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index f6555c0f4ad3..23966f887da6 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 100KHz clock could take upto 2.48ms.
+ * 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 10ms.
+ */
+#define MMC_CMD_TRANSFER_TIME (10 * NSEC_PER_MSEC) /* max 10 ms */
+
enum sdhci_cookie {
COOKIE_UNMAPPED,
COOKIE_PRE_MAPPED, /* mapped by sdhci_pre_req() */
@@ -555,6 +563,8 @@ struct sdhci_host {
/* Host SDMA buffer boundary. */
u32 sdma_boundary;

+ u64 data_timeout;
+
unsigned long private[0] ____cacheline_aligned;
};

--
1.9.1
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