Hi Adrian,
Thanks for the review.
Please find the inline comments.
Thanks,
Sajida
-----Original Message-----
From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Sent: Monday, January 3, 2022 3:20 PM
To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@xxxxxxxxxxx>; riteshh@xxxxxxxxxxxxxx; Asutosh Das (asd) <asutoshd@xxxxxxxxxxx>; ulf.hansson@xxxxxxxxxx; agross@xxxxxxxxxx; bjorn.andersson@xxxxxxxxxx; linux-mmc@xxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Cc: stummala@xxxxxxxxxxxxxx; vbadigan@xxxxxxxxxxxxxx; Ram Prakash Gupta (QUIC) <quic_rampraka@xxxxxxxxxxx>; Pradeep Pragallapati (QUIC) <quic_pragalla@xxxxxxxxxxx>; sartgarg@xxxxxxxxxxxxxx; nitirawa@xxxxxxxxxxxxxx; sayalil@xxxxxxxxxxxxxx
Subject: Re: [PATCH V2] mmc: debugfs: add error statistics
On 21/12/2021 09:16, Sajida Bhanu (Temp) (QUIC) wrote:
> Hi Adrian,
>
> Thanks for the review.
>
> Please find the inline comments.
I find the way the inline comments are done a bit difficult to follow, since what I wrote is not quoted, and what you wrote is quoted. Normally it is the other way around.
>
> Thanks,
> Sajida
>
> -----Original Message-----
> From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Sent: Wednesday, December 15, 2021 7:33 PM
> To: Sajida Bhanu (Temp) (QUIC) <quic_c_sbhanu@xxxxxxxxxxx>;
> riteshh@xxxxxxxxxxxxxx; Asutosh Das (asd) <asutoshd@xxxxxxxxxxx>;
> ulf.hansson@xxxxxxxxxx; agross@xxxxxxxxxx; bjorn.andersson@xxxxxxxxxx;
> linux-mmc@xxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> Cc: stummala@xxxxxxxxxxxxxx; vbadigan@xxxxxxxxxxxxxx; Ram Prakash
> Gupta (QUIC) <quic_rampraka@xxxxxxxxxxx>; Pradeep Pragallapati (QUIC)
> <quic_pragalla@xxxxxxxxxxx>; sartgarg@xxxxxxxxxxxxxx;
> nitirawa@xxxxxxxxxxxxxx; sayalil@xxxxxxxxxxxxxx
> Subject: Re: [PATCH V2] mmc: debugfs: add error statistics
>
> On 14/12/2021 16:41, Shaik Sajida Bhanu wrote:
>> Add debugfs entry to query eMMC and SD card errors statistics.
>> This feature is useful for debug and testing
>>
>> Signed-off-by: Shaik Sajida Bhanu <quic_c_sbhanu@xxxxxxxxxxx>
>> ---
>>
>> Changes since V1:
>> -Removed sysfs entry for eMMC and SD card error statistics and added
>> debugfs entry as suggested by Adrian Hunter and Ulf Hansson.
>
> Thanks for doing this.
>
>> ---
>> drivers/mmc/core/debugfs.c | 106 +++++++++++++++++++++++++++++++++++++++++++++
>> drivers/mmc/core/queue.c | 2 +
>> drivers/mmc/host/sdhci.c | 53 ++++++++++++++++++-----
>> include/linux/mmc/host.h | 37 ++++++++++++++++
>> 4 files changed, 186 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>> index 3fdbc80..40210c34 100644
>> --- a/drivers/mmc/core/debugfs.c
>> +++ b/drivers/mmc/core/debugfs.c
>> @@ -223,6 +223,107 @@ static int mmc_clock_opt_set(void *data, u64
>> val) DEFINE_DEBUGFS_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
>> "%llu\n");
>>
>> +static int mmc_err_state_get(void *data, u64 *val) {
>> + struct mmc_host *host = data;
>> +
>> + if (!host)
>> + return -EINVAL;
>> +
>> + *val = host->err_state ? 1 : 0;
>> +
>> + return 0;
>> +}
>> +
>> +static int mmc_err_state_clear(void *data, u64 val) {
>> + struct mmc_host *host = data;
>> +
>> + if (!host)
>> + return -EINVAL;
>> +
>> + host->err_state = false;
>
> Is there much reason to disable err stats from userspace?
>
>>>>>> Yes , while debugging we can go and check err_state , It is false means no errors happened in driver level and true means errors happened in driver level and then we can go and check err_stats[] to know more on error details like data CRC , command CRC etc.
That is not exectly how it is programmed. "err_state is false" means no errors have been recorded, not that no errors happended.
>>>>>> If user wants to explicitly clear then he can use this.
>
>> +
>> + return 0;
>> +}
>> +
>> +DEFINE_SIMPLE_ATTRIBUTE(mmc_err_state, mmc_err_state_get,
>> + mmc_err_state_clear, "%llu\n");
>> +
>> +static int mmc_err_stats_show(struct seq_file *file, void *data) {
>> + struct mmc_host *host = (struct mmc_host *)file->private;
>> +
>> + if (!host)
>> + return -EINVAL;
>
> I was thinking we needed a way to determine whether stats were being collected because not all drivers would support it at least initially e.g.
>
> if (!host->err_stats_enabled) {
> seq_printf(file, "Not supported by driver\n");
> return 0;
> }
>
>>>>>>>> You mean declare another variable (err_stats_enabled) and enable it in probe?
Yes, although it is not clear if this is the same as what you want from err_state, i.e. is err_state different from err_stats_enabled?
>>>>> Yes, err_state and err_stats_enabled both are different. err_state will be set if any errors happened in driver level.
err_stats_enabled will be set if err_stats feature enabled, if any vendor wants to use err_stats feature they will set this err_stats_enabled in their vendor specific file.
>
>> +
>> + seq_printf(file, "# Command Timeout Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_CMD_TIMEOUT]);
>
> Maybe put the descriptions in an array and iterate e.g.
>
> const char *desc[MMC_ERR_MAX] = {
> [MMC_ERR_CMD_TIMEOUT] = "Command Timeout Occurred",
> etc
> };
> int i;
>
> if (!host)
> return -EINVAL;
>
> for (i = 0; i < MMC_ERR_MAX; i++) {
> if (desc[i])
> seq_printf(file, "# %s:\t %d\n",
> desc[1], host->err_stats[i]);
> }
>
>>>>>>>> Sure
>
>> +
>> + seq_printf(file, "# Command CRC Errors Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_CMD_CRC]);
>> +
>> + seq_printf(file, "# Data Timeout Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_DAT_TIMEOUT]);
>> +
>> + seq_printf(file, "# Data CRC Errors Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_DAT_CRC]);
>> +
>> + seq_printf(file, "# Auto-Cmd Error Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_ADMA]);
>> +
>> + seq_printf(file, "# ADMA Error Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_ADMA]);
>> +
>> + seq_printf(file, "# Tuning Error Occurred:\t %d\n",
>> + host->err_stats[MMC_ERR_TUNING]);
>> +
>> + seq_printf(file, "# CMDQ RED Errors:\t\t %d\n",
>> + host->err_stats[MMC_ERR_CMDQ_RED]);
>> +
>> + seq_printf(file, "# CMDQ GCE Errors:\t\t %d\n",
>> + host->err_stats[MMC_ERR_CMDQ_GCE]);
>> +
>> + seq_printf(file, "# CMDQ ICCE Errors:\t\t %d\n",
>> + host->err_stats[MMC_ERR_CMDQ_ICCE]);
>> +
>> + seq_printf(file, "# Request Timedout:\t %d\n",
>> + host->err_stats[MMC_ERR_REQ_TIMEOUT]);
>> +
>> + seq_printf(file, "# CMDQ Request Timedout:\t %d\n",
>> + host->err_stats[MMC_ERR_CMDQ_REQ_TIMEOUT]);
>> +
>> + seq_printf(file, "# ICE Config Errors:\t\t %d\n",
>> + host->err_stats[MMC_ERR_ICE_CFG]);
>> +
>> + return 0;
>> +}
>> +
>> +static int mmc_err_stats_open(struct inode *inode, struct file
>> +*file) {
>> + return single_open(file, mmc_err_stats_show, inode->i_private); }
>> +
>> +static ssize_t mmc_err_stats_write(struct file *filp, const char __user *ubuf,
>> + size_t cnt, loff_t *ppos)
>> +{
>> + struct mmc_host *host = filp->f_mapping->host->i_private;
>> +
>> + if (!host)
>> + return -EINVAL;
>> +
>> + pr_debug("%s: Resetting MMC error statistics\n", __func__);
>> + memset(host->err_stats, 0, sizeof(host->err_stats));
>> +
>> + return cnt;
>> +}
>> +
>> +static const struct file_operations mmc_err_stats_fops = {
>> + .open = mmc_err_stats_open,
>> + .read = seq_read,
>> + .write = mmc_err_stats_write,
>> +};
>> +
>> void mmc_add_host_debugfs(struct mmc_host *host) {
>> struct dentry *root;
>> @@ -236,6 +337,11 @@ void mmc_add_host_debugfs(struct mmc_host *host)
>> debugfs_create_file_unsafe("clock", S_IRUSR | S_IWUSR, root, host,
>> &mmc_clock_fops);
>>
>> + debugfs_create_file("err_state", 0600, root, host,
>> + &mmc_err_state);
>> + debugfs_create_file("err_stats", 0600, root, host,
>> + &mmc_err_stats_fops);
>> +
>> #ifdef CONFIG_FAIL_MMC_REQUEST
>> if (fail_request)
>> setup_fault_attr(&fail_default_attr, fail_request); diff --git
>> a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c index
>> b15c034..5243929 100644
>> --- a/drivers/mmc/core/queue.c
>> +++ b/drivers/mmc/core/queue.c
>> @@ -100,6 +100,8 @@ static enum blk_eh_timer_return mmc_cqe_timed_out(struct request *req)
>> enum mmc_issue_type issue_type = mmc_issue_type(mq, req);
>> bool recovery_needed = false;
>>
>> + mmc_debugfs_err_stats_inc(host, MMC_ERR_CMDQ_REQ_TIMEOUT);
>> +
>> switch (issue_type) {
>> case MMC_ISSUE_ASYNC:
>> case MMC_ISSUE_DCMD:
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>
> I think the core changes should be a separate patch from sdhci.
> I would probably split into 4:
> mmc core
> mmc block driver
> cqhci driver
> sdhci driver
>
>>>>> Sure
>
>> index 07c6da1..d742051 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -113,6 +113,7 @@ void sdhci_dumpregs(struct sdhci_host *host)
>> if (host->ops->dump_vendor_regs)
>> host->ops->dump_vendor_regs(host);
>>
>> + mmc_debugfs_err_stats_enable(host->mmc);
>
> Why here and not in e.g. __sdhci_add_host() ?
>
>>>>> If any errors happened in driver level then we will call sdhci_dumpregs() right( err_state true means some errors happened in driver level ). So it is better to call mmc_debugfs_err_stats_enable() here.
Registers are not dumped for most errors. Please move this to __sdhci_add_host().
>>>> err_state is true means errors happened in driver level and for most of the errors we are dumping the registers, so I am thinking it is better to have this call in sdhci_dumpregs() only.
>
>> SDHCI_DUMP("============================================\n");
>> }
>> EXPORT_SYMBOL_GPL(sdhci_dumpregs);
>> @@ -3159,6 +3160,7 @@ static void sdhci_timeout_timer(struct timer_list *t)
>> spin_lock_irqsave(&host->lock, flags);
>>
>> if (host->cmd && !sdhci_data_line_cmd(host->cmd)) {
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_REQ_TIMEOUT);
>> pr_err("%s: Timeout waiting for hardware cmd interrupt.\n",
>> mmc_hostname(host->mmc));
>> sdhci_dumpregs(host);
>> @@ -3181,6 +3183,7 @@ static void sdhci_timeout_data_timer(struct
>> timer_list *t)
>>
>> if (host->data || host->data_cmd ||
>> (host->cmd && sdhci_data_line_cmd(host->cmd))) {
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_REQ_TIMEOUT);
>> pr_err("%s: Timeout waiting for hardware interrupt.\n",
>> mmc_hostname(host->mmc));
>> sdhci_dumpregs(host);
>> @@ -3240,11 +3243,15 @@ static void sdhci_cmd_irq(struct sdhci_host
>> *host, u32 intmask, u32 *intmask_p)
>>
>> if (intmask & (SDHCI_INT_TIMEOUT | SDHCI_INT_CRC |
>> SDHCI_INT_END_BIT | SDHCI_INT_INDEX)) {
>> - if (intmask & SDHCI_INT_TIMEOUT)
>> + if (intmask & SDHCI_INT_TIMEOUT) {
>> host->cmd->error = -ETIMEDOUT;
>> - else
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_CMD_TIMEOUT);
>> + } else {
>> host->cmd->error = -EILSEQ;
>> -
>> + if (host->cmd->opcode != MMC_SEND_TUNING_BLOCK ||
>> + host->cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200)
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_CMD_CRC);
>> + }
>> /* Treat data command CRC error the same as data CRC error */
>> if (host->cmd->data &&
>> (intmask & (SDHCI_INT_CRC | SDHCI_INT_TIMEOUT)) == @@ -3266,6
>> +3273,7 @@ static void sdhci_cmd_irq(struct sdhci_host *host, u32
>> +intmask, u32 *intmask_p)
>> -ETIMEDOUT :
>> -EILSEQ;
>>
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_AUTO_CMD);
>> if (sdhci_auto_cmd23(host, mrq)) {
>> mrq->sbc->error = err;
>> __sdhci_finish_mrq(host, mrq);
>> @@ -3342,6 +3350,7 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
>> if (intmask & SDHCI_INT_DATA_TIMEOUT) {
>> host->data_cmd = NULL;
>> data_cmd->error = -ETIMEDOUT;
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_CMD_TIMEOUT);
>> __sdhci_finish_mrq(host, data_cmd->mrq);
>> return;
>> }
>> @@ -3375,18 +3384,25 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
>> return;
>> }
>>
>> - if (intmask & SDHCI_INT_DATA_TIMEOUT)
>> + if (intmask & SDHCI_INT_DATA_TIMEOUT) {
>> host->data->error = -ETIMEDOUT;
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_DAT_TIMEOUT);
>> + }
>> else if (intmask & SDHCI_INT_DATA_END_BIT)
>> host->data->error = -EILSEQ;
>> else if ((intmask & SDHCI_INT_DATA_CRC) &&
>> SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND))
>> - != MMC_BUS_TEST_R)
>> + != MMC_BUS_TEST_R) {
>> host->data->error = -EILSEQ;
>> + if (host->cmd->opcode != MMC_SEND_TUNING_BLOCK ||
>> + host->cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200)
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_DAT_CRC);
>> + }
>> else if (intmask & SDHCI_INT_ADMA_ERROR) {
>> pr_err("%s: ADMA error: 0x%08x\n", mmc_hostname(host->mmc),
>> intmask);
>> sdhci_adma_show_error(host);
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_ADMA);
>> host->data->error = -EIO;
>> if (host->ops->adma_workaround)
>> host->ops->adma_workaround(host, intmask); @@ -3905,20 +3921,33
>> @@ bool sdhci_cqe_irq(struct sdhci_host *host, u32 intmask, int *cmd_error,
>> if (!host->cqe_on)
>> return false;
>>
>> - if (intmask & (SDHCI_INT_INDEX | SDHCI_INT_END_BIT | SDHCI_INT_CRC))
>> + if (intmask & (SDHCI_INT_INDEX | SDHCI_INT_END_BIT |
>> +SDHCI_INT_CRC)) {
>> *cmd_error = -EILSEQ;
>> - else if (intmask & SDHCI_INT_TIMEOUT)
>> + if (intmask & SDHCI_INT_CRC) {
>> + if (host->cmd->opcode != MMC_SEND_TUNING_BLOCK ||
>> + host->cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200)
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_CMD_CRC);
>> + }
>> + } else if (intmask & SDHCI_INT_TIMEOUT) {
>> *cmd_error = -ETIMEDOUT;
>> - else
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_CMD_TIMEOUT);
>> + } else
>> *cmd_error = 0;
>>
>> - if (intmask & (SDHCI_INT_DATA_END_BIT | SDHCI_INT_DATA_CRC))
>> + if (intmask & (SDHCI_INT_DATA_END_BIT | SDHCI_INT_DATA_CRC)) {
>> *data_error = -EILSEQ;
>> - else if (intmask & SDHCI_INT_DATA_TIMEOUT)
>> + if (intmask & SDHCI_INT_DATA_CRC) {
>> + if (host->cmd->opcode != MMC_SEND_TUNING_BLOCK ||
>> + host->cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200)
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_DAT_CRC);
>> + }
>> + } else if (intmask & SDHCI_INT_DATA_TIMEOUT) {
>> *data_error = -ETIMEDOUT;
>> - else if (intmask & SDHCI_INT_ADMA_ERROR)
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_DAT_TIMEOUT);
>> + } else if (intmask & SDHCI_INT_ADMA_ERROR) {
>> *data_error = -EIO;
>> - else
>> + mmc_debugfs_err_stats_inc(host->mmc, MMC_ERR_ADMA);
>> + } else
>> *data_error = 0;
>>
>> /* Clear selected interrupts. */
>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>> index 7afb57c..c263f8f 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -93,6 +93,23 @@ struct mmc_clk_phase_map {
>>
>> struct mmc_host;
>>
>> +enum mmc_err_stat {
>> + MMC_ERR_CMD_TIMEOUT,
>> + MMC_ERR_CMD_CRC,
>> + MMC_ERR_DAT_TIMEOUT,
>> + MMC_ERR_DAT_CRC,
>> + MMC_ERR_AUTO_CMD,
>> + MMC_ERR_ADMA,
>> + MMC_ERR_TUNING,
>> + MMC_ERR_CMDQ_RED,
>> + MMC_ERR_CMDQ_GCE,
>> + MMC_ERR_CMDQ_ICCE,
>> + MMC_ERR_REQ_TIMEOUT,
>> + MMC_ERR_CMDQ_REQ_TIMEOUT,
>> + MMC_ERR_ICE_CFG,
>> + MMC_ERR_MAX,
>> +};
>> +
>> struct mmc_host_ops {
>> /*
>> * It is optional for the host to implement pre_req and post_req in
>> @@ -500,6 +517,8 @@ struct mmc_host {
>>
>> /* Host Software Queue support */
>> bool hsq_enabled;
>> + u32 err_stats[MMC_ERR_MAX];
>
> If you make it u64 then we don't have to think about the value overflowing.
>
>>>> Sure
>
>> + bool err_state;
>>
>> unsigned long private[] ____cacheline_aligned;
>> };
>> @@ -635,6 +654,24 @@ static inline enum dma_data_direction mmc_get_dma_dir(struct mmc_data *data)
>> return data->flags & MMC_DATA_WRITE ? DMA_TO_DEVICE :
>> DMA_FROM_DEVICE; }
>>
>> +static inline void mmc_debugfs_err_stats_enable(struct mmc_host
>> +*mmc) {
>> + mmc->err_state = true;
>> +}
>> +
>> +static inline void mmc_debugfs_err_stats_inc(struct mmc_host *mmc,
>> + enum mmc_err_stat stat) {
>> +
>> + /*
>> + * Ignore the command timeout errors observed during
>> + * the card init as those are excepted.
>> + */
>> + if (!mmc->err_state)
>> + mmc->err_stats[MMC_ERR_CMD_TIMEOUT] = 0;
>
> This would be better handled in the card init code somewhere, not here.
>
>>>>> Sure.
>
>> +
>> + mmc->err_stats[stat] += 1;
>> +}
>> +
>> int mmc_send_tuning(struct mmc_host *host, u32 opcode, int
>> *cmd_error); int mmc_send_abort_tuning(struct mmc_host *host, u32
>> opcode); int mmc_get_ext_csd(struct mmc_card *card, u8
>> **new_ext_csd);
>>
>
