On 7/23/2013 1:54 PM, Seungwon Jeon wrote:
> On Sat, July 20, 2013, Sujit Reddy Thumma wrote:
>> On 7/19/2013 7:26 PM, Seungwon Jeon wrote:
>>> On Tue, July 09, 2013 Sujit Reddy Thumma wrote:
>>>> Currently, sending Task Management (TM) command to the card might
>>>> be broken in some scenarios as listed below:
>>>>
>>>> Problem: If there are more than 8 TM commands the implementation
>>>> returns error to the caller.
>>>> Fix: Wait for one of the slots to be emptied and send the command.
>>>>
>>>> Problem: Sometimes it is necessary for the caller to know the TM service
>>>> response code to determine the task status.
>>>> Fix: Propogate the service response to the caller.
>>>>
>>>> Problem: If the TM command times out no proper error recovery is
>>>> implemented.
>>>> Fix: Clear the command in the controller door-bell register, so that
>>>> further commands for the same slot don't fail.
>>>>
>>>> Problem: While preparing the TM command descriptor, the task tag used
>>>> should be unique across SCSI/NOP/QUERY/TM commands and not the
>>>> task tag of the command which the TM command is trying to manage.
>>>> Fix: Use a unique task tag instead of task tag of SCSI command.
>>>>
>>>> Problem: Since the TM command involves H/W communication, abruptly ending
>>>> the request on kill interrupt signal might cause h/w malfunction.
>>>> Fix: Wait for hardware completion interrupt with TASK_UNINTERRUPTIBLE
>>>> set.
>>>>
>>>> Signed-off-by: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
>>>> ---
>>>> drivers/scsi/ufs/ufshcd.c | 177 ++++++++++++++++++++++++++++++---------------
>>>> drivers/scsi/ufs/ufshcd.h | 8 ++-
>>>> 2 files changed, 126 insertions(+), 59 deletions(-)
>>>>
>>>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>>>> index af7d01d..a176421 100644
>>>> --- a/drivers/scsi/ufs/ufshcd.c
>>>> +++ b/drivers/scsi/ufs/ufshcd.c
>>>> @@ -53,6 +53,9 @@
>>>> /* Query request timeout */
>>>> #define QUERY_REQ_TIMEOUT 30 /* msec */
>>>>
>>>> +/* Task management command timeout */
>>>> +#define TM_CMD_TIMEOUT 100 /* msecs */
>>>> +
>>>> /* Expose the flag value from utp_upiu_query.value */
>>>> #define MASK_QUERY_UPIU_FLAG_LOC 0xFF
>>>>
>>>> @@ -190,13 +193,35 @@ ufshcd_get_tmr_ocs(struct utp_task_req_desc *task_req_descp)
>>>> /**
>>>> * ufshcd_get_tm_free_slot - get a free slot for task management request
>>>> * @hba: per adapter instance
>>>> + * @free_slot: pointer to variable with available slot value
>>>> *
>>>> - * Returns maximum number of task management request slots in case of
>>>> - * task management queue full or returns the free slot number
>>>> + * Get a free tag and lock it until ufshcd_put_tm_slot() is called.
>>>> + * Returns 0 if free slot is not available, else return 1 with tag value
>>>> + * in @free_slot.
>>>> */
>>>> -static inline int ufshcd_get_tm_free_slot(struct ufs_hba *hba)
>>>> +static bool ufshcd_get_tm_free_slot(struct ufs_hba *hba, int *free_slot)
>>>> +{
>>>> + int tag;
>>>> + bool ret = false;
>>>> +
>>>> + if (!free_slot)
>>>> + goto out;
>>>> +
>>>> + do {
>>>> + tag = find_first_zero_bit(&hba->tm_slots_in_use, hba->nutmrs);
>>>> + if (tag >= hba->nutmrs)
>>>> + goto out;
>>>> + } while (test_and_set_bit_lock(tag, &hba->tm_slots_in_use));
>>>> +
>>>> + *free_slot = tag;
>>>> + ret = true;
>>>> +out:
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static inline void ufshcd_put_tm_slot(struct ufs_hba *hba, int slot)
>>>> {
>>>> - return find_first_zero_bit(&hba->outstanding_tasks, hba->nutmrs);
>>>> + clear_bit_unlock(slot, &hba->tm_slots_in_use);
>>>> }
>>>>
>>>> /**
>>>> @@ -1778,10 +1803,11 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
>>>> * ufshcd_task_req_compl - handle task management request completion
>>>> * @hba: per adapter instance
>>>> * @index: index of the completed request
>>>> + * @resp: task management service response
>>>> *
>>>> - * Returns SUCCESS/FAILED
>>>> + * Returns non-zero value on error, zero on success
>>>> */
>>>> -static int ufshcd_task_req_compl(struct ufs_hba *hba, u32 index)
>>>> +static int ufshcd_task_req_compl(struct ufs_hba *hba, u32 index, u8 *resp)
>>>> {
>>>> struct utp_task_req_desc *task_req_descp;
>>>> struct utp_upiu_task_rsp *task_rsp_upiup;
>>>> @@ -1802,19 +1828,15 @@ static int ufshcd_task_req_compl(struct ufs_hba *hba, u32 index)
>>>> task_req_descp[index].task_rsp_upiu;
>>>> task_result = be32_to_cpu(task_rsp_upiup->header.dword_1);
>>>> task_result = ((task_result & MASK_TASK_RESPONSE) >> 8);
>>>> -
>>>> - if (task_result != UPIU_TASK_MANAGEMENT_FUNC_COMPL &&
>>>> - task_result != UPIU_TASK_MANAGEMENT_FUNC_SUCCEEDED)
>>>> - task_result = FAILED;
>>>> - else
>>>> - task_result = SUCCESS;
>>>> + if (resp)
>>>> + *resp = (u8)task_result;
>>>> } else {
>>>> - task_result = FAILED;
>>>> - dev_err(hba->dev,
>>>> - "trc: Invalid ocs = %x\n", ocs_value);
>>>> + dev_err(hba->dev, "%s: failed, ocs = 0x%x\n",
>>>> + __func__, ocs_value);
>>>> }
>>>> spin_unlock_irqrestore(hba->host->host_lock, flags);
>>>> - return task_result;
>>>> +
>>>> + return ocs_value;
>>>> }
>>>>
>>>> /**
>>>> @@ -2298,7 +2320,7 @@ static void ufshcd_tmc_handler(struct ufs_hba *hba)
>>>>
>>>> tm_doorbell = ufshcd_readl(hba, REG_UTP_TASK_REQ_DOOR_BELL);
>>>> hba->tm_condition = tm_doorbell ^ hba->outstanding_tasks;
>>>> - wake_up_interruptible(&hba->ufshcd_tm_wait_queue);
>>>> + wake_up(&hba->tm_wq);
>>>> }
>>>>
>>>> /**
>>>> @@ -2348,38 +2370,61 @@ static irqreturn_t ufshcd_intr(int irq, void *__hba)
>>>> return retval;
>>>> }
>>>>
>>>> +static int ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag)
>>>> +{
>>>> + int err = 0;
>>>> + u32 reg;
>>>> + u32 mask = 1 << tag;
>>>> + unsigned long flags;
>>>> +
>>>> + if (!test_bit(tag, &hba->outstanding_reqs))
>>>> + goto out;
>>>> +
>>>> + spin_lock_irqsave(hba->host->host_lock, flags);
>>>> + ufshcd_writel(hba, ~(1 << tag), REG_UTP_TASK_REQ_LIST_CLEAR);
>>>> + spin_unlock_irqrestore(hba->host->host_lock, flags);
>>>> +
>>>> + /* poll for max. 1 sec to clear door bell register by h/w */
>>>> + reg = ufshcd_wait_for_register(hba,
>>>> + REG_UTP_TASK_REQ_DOOR_BELL,
>>>> + mask, 0, 1000, 1000);
>>>> + if ((reg & mask) == mask)
>>>> + err = -ETIMEDOUT;
>>>> +out:
>>>> + return err;
>>>> +}
>>>> +
>>>> /**
>>>> * ufshcd_issue_tm_cmd - issues task management commands to controller
>>>> * @hba: per adapter instance
>>>> - * @lrbp: pointer to local reference block
>>>> + * @lun_id: LUN ID to which TM command is sent
>>>> + * @task_id: task ID to which the TM command is applicable
>>>> + * @tm_function: task management function opcode
>>>> + * @tm_response: task management service response return value
>>>> *
>>>> - * Returns SUCCESS/FAILED
>>>> + * Returns non-zero value on error, zero on success.
>>>> */
>>>> -static int
>>>> -ufshcd_issue_tm_cmd(struct ufs_hba *hba,
>>>> - struct ufshcd_lrb *lrbp,
>>>> - u8 tm_function)
>>>> +static int ufshcd_issue_tm_cmd(struct ufs_hba *hba, int lun_id, int task_id,
>>>> + u8 tm_function, u8 *tm_response)
>>>> {
>>>> struct utp_task_req_desc *task_req_descp;
>>>> struct utp_upiu_task_req *task_req_upiup;
>>>> struct Scsi_Host *host;
>>>> unsigned long flags;
>>>> - int free_slot = 0;
>>>> + int free_slot;
>>>> int err;
>>>> + int task_tag;
>>>>
>>>> host = hba->host;
>>>>
>>>> - spin_lock_irqsave(host->host_lock, flags);
>>>> -
>>>> - /* If task management queue is full */
>>>> - free_slot = ufshcd_get_tm_free_slot(hba);
>>>> - if (free_slot >= hba->nutmrs) {
>>>> - spin_unlock_irqrestore(host->host_lock, flags);
>>>> - dev_err(hba->dev, "Task management queue full\n");
>>>> - err = FAILED;
>>>> - goto out;
>>>> - }
>>>> + /*
>>>> + * Get free slot, sleep if slots are unavailable.
>>>> + * Even though we use wait_event() which sleeps indefinitely,
>>>> + * the maximum wait time is bounded by %TM_CMD_TIMEOUT.
>>>> + */
>>>> + wait_event(hba->tm_tag_wq, ufshcd_get_tm_free_slot(hba, &free_slot));
>>>>
>>>> + spin_lock_irqsave(host->host_lock, flags);
>>>> task_req_descp = hba->utmrdl_base_addr;
>>>> task_req_descp += free_slot;
>>>>
>>>> @@ -2391,18 +2436,15 @@ ufshcd_issue_tm_cmd(struct ufs_hba *hba,
>>>> /* Configure task request UPIU */
>>>> task_req_upiup =
>>>> (struct utp_upiu_task_req *) task_req_descp->task_req_upiu;
>>>> + task_tag = hba->nutrs + free_slot;
>>> Possible, did you intend 'hba->nutmrs', not 'hba->nutrs'?
>>> I think it's safer with hba->nutmrs if we can't sure that NUTRS is larger than NUTMRS.
>>
>> It should be hba->nutrs and not hba->nutmrs.
>>
>> The equation is -
>> 0 <= free_slot < hba->nutmrs
>> 0 <= transfer_req_task_id < hba->nutrs
>> hba->nutrs <= tm_req_task_id < hba->nutmrs + hba_nutrs
>>
>> Whatever be the values of NUTRS/NUTMRS the above gives a unique
>> task_id.
> Yes.
>
>>
>>
>>>
>>>> task_req_upiup->header.dword_0 =
>>>> UPIU_HEADER_DWORD(UPIU_TRANSACTION_TASK_REQ, 0,
>>>> - lrbp->lun, lrbp->task_tag);
>>>> + lun_id, task_tag);
>>>> task_req_upiup->header.dword_1 =
>>>> UPIU_HEADER_DWORD(0, tm_function, 0, 0);
>>>>
>>>> - task_req_upiup->input_param1 = lrbp->lun;
>>>> - task_req_upiup->input_param1 =
>>>> - cpu_to_be32(task_req_upiup->input_param1);
>>>> - task_req_upiup->input_param2 = lrbp->task_tag;
>>>> - task_req_upiup->input_param2 =
>>>> - cpu_to_be32(task_req_upiup->input_param2);
>>>> + task_req_upiup->input_param1 = cpu_to_be32(lun_id);
>>>> + task_req_upiup->input_param2 = cpu_to_be32(task_id);
>>>>
>>>> /* send command to the controller */
>>>> __set_bit(free_slot, &hba->outstanding_tasks);
>>>> @@ -2411,20 +2453,24 @@ ufshcd_issue_tm_cmd(struct ufs_hba *hba,
>>>> spin_unlock_irqrestore(host->host_lock, flags);
>>>>
>>>> /* wait until the task management command is completed */
>>>> - err =
>>>> - wait_event_interruptible_timeout(hba->ufshcd_tm_wait_queue,
>>>> - (test_bit(free_slot,
>>>> - &hba->tm_condition) != 0),
>>>> - 60 * HZ);
>>>> + err = wait_event_timeout(hba->tm_wq,
>>>> + test_bit(free_slot, &hba->tm_condition),
>>>> + msecs_to_jiffies(TM_CMD_TIMEOUT));
>>>> if (!err) {
>>>> - dev_err(hba->dev,
>>>> - "Task management command timed-out\n");
>>>> - err = FAILED;
>>>> - goto out;
>>>> + dev_err(hba->dev, "%s: task management cmd 0x%.2x timed-out\n",
>>>> + __func__, tm_function);
>>>> + if (ufshcd_clear_tm_cmd(hba, free_slot))
>>>> + dev_WARN(hba->dev, "%s: unable clear tm cmd (slot %d) after timeout\n",
>>>> + __func__, free_slot);
>>>> + err = -ETIMEDOUT;
>>>> + } else {
>>>> + err = ufshcd_task_req_compl(hba, free_slot, tm_response);
>>>> }
>>>> +
>>>> clear_bit(free_slot, &hba->tm_condition);
>>>> - err = ufshcd_task_req_compl(hba, free_slot);
>>>> -out:
>>>> + ufshcd_put_tm_slot(hba, free_slot);
>>>> + wake_up(&hba->tm_tag_wq);
>>>> +
>>>> return err;
>>>> }
>>>>
>>>> @@ -2441,14 +2487,22 @@ static int ufshcd_device_reset(struct scsi_cmnd *cmd)
>>>> unsigned int tag;
>>>> u32 pos;
>>>> int err;
>>>> + u8 resp;
>>>> + struct ufshcd_lrb *lrbp;
>>>>
>>>> host = cmd->device->host;
>>>> hba = shost_priv(host);
>>>> tag = cmd->request->tag;
>>>>
>>>> - err = ufshcd_issue_tm_cmd(hba, &hba->lrb[tag], UFS_LOGICAL_RESET);
>>>> - if (err == FAILED)
>>>> + lrbp = &hba->lrb[tag];
>>>> + err = ufshcd_issue_tm_cmd(hba, lrbp->lun, lrbp->task_tag,
>>> Argument 2nd, 3rd can be replaced by lrbp.
>>> Then, we can reduce the number of argument.
>>>
>>
>> TM issue command doesn't need to know about lrbp, It just need
>> LUN ID and task ID. This helps when we are not dealing with lrbp's
>> and just want to issue some other TM command.
>> I believe an extra argument is not so costly on the systems which
>> demand high performance UFS devices.
> Yes, you're right. only need LUN ID and task ID.
> It might be trivial. But 'lrbp' should be referred for getting these.
>
Whatever way the caller gets lun_id/task_id is not of a concern for
ufshcd_issue_tm_cmd().
I prefer this way even though lrbp is anyway needed to determine IDs.
--
Regards,
Sujit
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