> Hi,
>
> Sorry for the late response. I had a few days off.
>
> On Thu, July 11, 2013, Dolev Raviv wrote:
>> > On Tuesday, July 09, 2013, Sujit Reddy Thumma wrote:
>> >> From: Dolev Raviv <draviv@xxxxxxxxxxxxxx>
>> >> Allow UFS device to complete its initialization and accept
>> >> SCSI commands by setting fDeviceInit flag. The device may take
>> >> time for this operation and hence the host should poll until
>> >> fDeviceInit flag is toggled to zero. This step is mandated by
>> >> UFS device specification for device initialization completion.
>> >> Signed-off-by: Dolev Raviv <draviv@xxxxxxxxxxxxxx>
>> >> Signed-off-by: Sujit Reddy Thumma <sthumma@xxxxxxxxxxxxxx>
>> >> ---
>> >> drivers/scsi/ufs/ufs.h | 88 +++++++++++++-
>> >> drivers/scsi/ufs/ufshcd.c | 292
>> >> ++++++++++++++++++++++++++++++++++++++++++++-
>> >> drivers/scsi/ufs/ufshcd.h | 14 ++
>> >> drivers/scsi/ufs/ufshci.h | 2 +-
>> >> 4 files changed, 390 insertions(+), 6 deletions(-)
>> >> diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
>> >> index 14c0a4e..db5bde4 100644
>> >> --- a/drivers/scsi/ufs/ufs.h
>> >> +++ b/drivers/scsi/ufs/ufs.h
>> >> @@ -43,6 +43,8 @@
>> >> #define GENERAL_UPIU_REQUEST_SIZE 32
>> >> #define UPIU_HEADER_DATA_SEGMENT_MAX_SIZE ((ALIGNED_UPIU_SIZE) - \
>> >> (GENERAL_UPIU_REQUEST_SIZE))
>> >> +#define QUERY_OSF_SIZE ((GENERAL_UPIU_REQUEST_SIZE) - \
>> >> + (sizeof(struct utp_upiu_header)))
>> >> #define UPIU_HEADER_DWORD(byte3, byte2, byte1, byte0)\
>> >> cpu_to_be32((byte3 << 24) | (byte2 << 16) |\
>> >> @@ -68,7 +70,7 @@ enum {
>> >> UPIU_TRANSACTION_COMMAND = 0x01,
>> >> UPIU_TRANSACTION_DATA_OUT = 0x02,
>> >> UPIU_TRANSACTION_TASK_REQ = 0x04,
>> >> - UPIU_TRANSACTION_QUERY_REQ = 0x26,
>> >> + UPIU_TRANSACTION_QUERY_REQ = 0x16,
>> >> };
>> >> /* UTP UPIU Transaction Codes Target to Initiator */
>> >> @@ -97,8 +99,19 @@ enum {
>> >> UPIU_TASK_ATTR_ACA = 0x03,
>> >> };
>> >> -/* UTP QUERY Transaction Specific Fields OpCode */
>> >> +/* UPIU Query request function */
>> >> enum {
>> >> + UPIU_QUERY_FUNC_STANDARD_READ_REQUEST = 0x01,
>> >> + UPIU_QUERY_FUNC_STANDARD_WRITE_REQUEST = 0x81,
>> >> +};
>> >> +
>> >> +/* Flag idn for Query Requests*/
>> >> +enum flag_idn {
>> >> + QUERY_FLAG_IDN_FDEVICEINIT = 0x01,
>> >> +};
>> >> +
>> >> +/* UTP QUERY Transaction Specific Fields OpCode */
>> >> +enum query_opcode {
>> >> UPIU_QUERY_OPCODE_NOP = 0x0,
>> >> UPIU_QUERY_OPCODE_READ_DESC = 0x1,
>> >> UPIU_QUERY_OPCODE_WRITE_DESC = 0x2,
>> >> @@ -110,6 +123,21 @@ enum {
>> >> UPIU_QUERY_OPCODE_TOGGLE_FLAG = 0x8,
>> >> };
>> >> +/* Query response result code */
>> >> +enum {
>> >> + QUERY_RESULT_SUCCESS = 0x00,
>> >> + QUERY_RESULT_NOT_READABLE = 0xF6,
>> >> + QUERY_RESULT_NOT_WRITEABLE = 0xF7,
>> >> + QUERY_RESULT_ALREADY_WRITTEN = 0xF8,
>> >> + QUERY_RESULT_INVALID_LENGTH = 0xF9,
>> >> + QUERY_RESULT_INVALID_VALUE = 0xFA,
>> >> + QUERY_RESULT_INVALID_SELECTOR = 0xFB,
>> >> + QUERY_RESULT_INVALID_INDEX = 0xFC,
>> >> + QUERY_RESULT_INVALID_IDN = 0xFD,
>> >> + QUERY_RESULT_INVALID_OPCODE = 0xFE,
>> >> + QUERY_RESULT_GENERAL_FAILURE = 0xFF,
>> >> +};
>> >> +
>> >> /* UTP Transfer Request Command Type (CT) */
>> >> enum {
>> >> UPIU_COMMAND_SET_TYPE_SCSI = 0x0,
>> >> @@ -127,6 +155,7 @@ enum {
>> >> MASK_SCSI_STATUS = 0xFF,
>> >> MASK_TASK_RESPONSE = 0xFF00,
>> >> MASK_RSP_UPIU_RESULT = 0xFFFF,
>> >> + MASK_QUERY_DATA_SEG_LEN = 0xFFFF,
>> >> };
>> >> /* Task management service response */
>> >> @@ -160,13 +189,40 @@ struct utp_upiu_cmd {
>> >> };
>> >> /**
>> >> + * struct utp_upiu_query - upiu request buffer structure for
>> >> + * query request.
>> >> + * @opcode: command to perform B-0
>> >> + * @idn: a value that indicates the particular type of data B-1 + *
>> @index: Index to further identify data B-2
>> >> + * @selector: Index to further identify data B-3
>> >> + * @reserved_osf: spec reserved field B-4,5
>> >> + * @length: number of descriptor bytes to read/write B-6,7
>> >> + * @value: Attribute value to be written DW-5
>> >> + * @reserved: spec reserved DW-6,7
>> >> + */
>> >> +struct utp_upiu_query {
>> >> + u8 opcode;
>> >> + u8 idn;
>> >> + u8 index;
>> >> + u8 selector;
>> >> + u16 reserved_osf;
>> >> + u16 length;
>> >> + u32 value;
>> >> + u32 reserved[2];
>> >> +};
>> >> +
>> >> +/**
>> >> * struct utp_upiu_req - general upiu request structure
>> >> * @header:UPIU header structure DW-0 to DW-2
>> >> * @sc: fields structure for scsi command DW-3 to DW-7
>> >> + * @qr: fields structure for query request DW-3 to DW-7
>> >> */
>> >> struct utp_upiu_req {
>> >> struct utp_upiu_header header;
>> >> - struct utp_upiu_cmd sc;
>> >> + union {
>> >> + struct utp_upiu_cmd sc;
>> >> + struct utp_upiu_query qr;
>> >> + };
>> >> };
>> >> /**
>> >> @@ -187,10 +243,14 @@ struct utp_cmd_rsp {
>> >> * struct utp_upiu_rsp - general upiu response structure
>> >> * @header: UPIU header structure DW-0 to DW-2
>> >> * @sr: fields structure for scsi command DW-3 to DW-12
>> >> + * @qr: fields structure for query request DW-3 to DW-7
>> >> */
>> >> struct utp_upiu_rsp {
>> >> struct utp_upiu_header header;
>> >> - struct utp_cmd_rsp sr;
>> >> + union {
>> >> + struct utp_cmd_rsp sr;
>> >> + struct utp_upiu_query qr;
>> >> + };
>> >> };
>> >> /**
>> >> @@ -223,4 +283,24 @@ struct utp_upiu_task_rsp {
>> >> u32 reserved[3];
>> >> };
>> >> +/**
>> >> + * struct ufs_query_req - parameters for building a query request +
>> *
>> @query_func: UPIU header query function
>> >> + * @upiu_req: the query request data
>> >> + */
>> >> +struct ufs_query_req {
>> >> + u8 query_func;
>> >> + struct utp_upiu_query upiu_req;
>> >> +};
>> >> +
>> >> +/**
>> >> + * struct ufs_query_resp - UPIU QUERY
>> >> + * @response: device response code
>> >> + * @upiu_res: query response data
>> >> + */
>> >> +struct ufs_query_res {
>> >> + u8 response;
>> >> + struct utp_upiu_query upiu_res;
>> >> +};
>> >> +
>> >> #endif /* End of Header */
>> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index 3f482b6..96ccb28 100644
>> >> --- a/drivers/scsi/ufs/ufshcd.c
>> >> +++ b/drivers/scsi/ufs/ufshcd.c
>> >> @@ -48,6 +48,14 @@
>> >> /* Timeout after 30 msecs if NOP OUT hangs without response */
>> #define
>> NOP_OUT_TIMEOUT 30 /* msecs */
>> >> +/* Query request retries */
>> >> +#define QUERY_REQ_RETRIES 10
>> >> +/* Query request timeout */
>> >> +#define QUERY_REQ_TIMEOUT 30 /* msec */
>> >> +
>> >> +/* Expose the flag value from utp_upiu_query.value */
>> >> +#define MASK_QUERY_UPIU_FLAG_LOC 0xFF
>> >> +
>> >> enum {
>> >> UFSHCD_MAX_CHANNEL = 0,
>> >> UFSHCD_MAX_ID = 1,
>> >> @@ -348,6 +356,63 @@ static inline void ufshcd_copy_sense_data(struct
>> ufshcd_lrb *lrbp)
>> >> }
>> >> /**
>> >> + * ufshcd_query_to_cpu() - formats the buffer to native cpu endian +
>> *
>> @response: upiu query response to convert
>> >> + */
>> >> +static inline void ufshcd_query_to_cpu(struct utp_upiu_query
>> *response)
>> >> +{
>> >> + response->length = be16_to_cpu(response->length);
>> >> + response->value = be32_to_cpu(response->value);
>> >> +}
>> >> +
>> >> +/**
>> >> + * ufshcd_query_to_be() - formats the buffer to big endian
>> >> + * @request: upiu query request to convert
>> >> + */
>> >> +static inline void ufshcd_query_to_be(struct utp_upiu_query
>> *request) +{
>> >> + request->length = cpu_to_be16(request->length);
>> >> + request->value = cpu_to_be32(request->value);
>> >> +}
>> >> +
>> >> +/**
>> >> + * ufshcd_copy_query_response() - Copy the Query Response and the
>> data
>> + * descriptor
>> >> + * @hba: per adapter instance
>> >> + * @lrb - pointer to local reference block
>> >> + */
>> >> +static
>> >> +void ufshcd_copy_query_response(struct ufs_hba *hba, struct
>> ufshcd_lrb
>> *lrbp)
>> >> +{
>> >> + struct ufs_query_res *query_res = hba->dev_cmd.query.response; +
>> >> + /* Get the UPIU response */
>> >> + if (query_res) {
>> >> + query_res->response = ufshcd_get_rsp_upiu_result(
>> >> + lrbp->ucd_rsp_ptr) >> UPIU_RSP_CODE_OFFSET;
>> >> +
>> >> + memcpy(&query_res->upiu_res, &lrbp->ucd_rsp_ptr->qr,
>> >> + QUERY_OSF_SIZE);
>> >> + ufshcd_query_to_cpu(&query_res->upiu_res);
>> >> + }
>> >> +
>> >> + /* Get the descriptor */
>> >> + if (hba->dev_cmd.query.descriptor && lrbp->ucd_rsp_ptr->qr.opcode
>> ==
>> + UPIU_QUERY_OPCODE_READ_DESC) {
>> >> + u8 *descp = (u8 *)&lrbp->ucd_rsp_ptr +
>> >> + GENERAL_UPIU_REQUEST_SIZE;
>> >> + u16 len;
>> >> +
>> >> + /* data segment length */
>> >> + len = be32_to_cpu(lrbp->ucd_rsp_ptr->header.dword_2) &
>> >> + MASK_QUERY_DATA_SEG_LEN;
>> >> +
>> >> + memcpy(hba->dev_cmd.query.descriptor, descp,
>> >> + min_t(u16, len, UPIU_HEADER_DATA_SEGMENT_MAX_SIZE));
>> >> + }
>> >> +}
>> >> +
>> >> +/**
>> >> * ufshcd_hba_capabilities - Read controller capabilities
>> >> * @hba: per adapter instance
>> >> */
>> >> @@ -629,6 +694,46 @@ void ufshcd_prepare_utp_scsi_cmd_upiu(struct
>> ufshcd_lrb *lrbp, u32 upiu_flags)
>> >> (min_t(unsigned short, lrbp->cmd->cmd_len, MAX_CDB_SIZE)));
>> >> }
>> >> +/**
>> >> + * ufshcd_prepare_utp_query_req_upiu() - fills the
>> >> utp_transfer_req_desc,
>> >> + * for query requsts
>> >> + * @hba: UFS hba
>> >> + * @lrbp: local reference block pointer
>> >> + * @upiu_flags: flags
>> >> + */
>> >> +static void ufshcd_prepare_utp_query_req_upiu(struct ufs_hba *hba,
>> + struct ufshcd_lrb *lrbp,
>> >> + u32 upiu_flags)
>> >> +{
>> >> + struct utp_upiu_req *ucd_req_ptr = lrbp->ucd_req_ptr;
>> >> + u16 len = hba->dev_cmd.query.request->upiu_req.length;
>> >> + u8 *descp = (u8 *)lrbp->ucd_req_ptr + GENERAL_UPIU_REQUEST_SIZE; +
>> >> + /* Query request header */
>> >> + ucd_req_ptr->header.dword_0 = UPIU_HEADER_DWORD(
>> >> + UPIU_TRANSACTION_QUERY_REQ, upiu_flags,
>> >> + lrbp->lun, lrbp->task_tag);
>> >> + ucd_req_ptr->header.dword_1 = UPIU_HEADER_DWORD(
>> >> + 0, hba->dev_cmd.query.request->query_func, 0, 0);
>> >> +
>> >> + /* Data segment length */
>> >> + ucd_req_ptr->header.dword_2 = UPIU_HEADER_DWORD(
>> >> + 0, 0, len >> 8, (u8)len);
>> >> +
>> >> + /* Copy the Query Request buffer as is */
>> >> + memcpy(&lrbp->ucd_req_ptr->qr,
>> &hba->dev_cmd.query.request->upiu_req,
>> + QUERY_OSF_SIZE);
>> >> + ufshcd_query_to_be(&lrbp->ucd_req_ptr->qr);
>> >> +
>> >> + /* Copy the Descriptor */
>> >> + if ((hba->dev_cmd.query.descriptor != NULL) && (len > 0) &&
>> >> + (hba->dev_cmd.query.request->upiu_req.opcode ==
>> >> + UPIU_QUERY_OPCODE_WRITE_DESC)) {
>> >> + memcpy(descp, hba->dev_cmd.query.descriptor,
>> >> + min_t(u16, len, UPIU_HEADER_DATA_SEGMENT_MAX_SIZE));
>> >> + }
>> >> +}
>> >> +
>> >> static inline void ufshcd_prepare_utp_nop_upiu(struct ufshcd_lrb
>> *lrbp)
>> >> {
>> >> struct utp_upiu_req *ucd_req_ptr = lrbp->ucd_req_ptr;
>> >> @@ -663,7 +768,10 @@ static int ufshcd_compose_upiu(struct ufs_hba
>> *hba,
>> >> struct ufshcd_lrb *lrbp)
>> >> break;
>> >> case UTP_CMD_TYPE_DEV_MANAGE:
>> >> ufshcd_prepare_req_desc_hdr(lrbp, &upiu_flags, DMA_NONE);
>> >> - if (hba->dev_cmd.type == DEV_CMD_TYPE_NOP)
>> >> + if (hba->dev_cmd.type == DEV_CMD_TYPE_QUERY)
>> >> + ufshcd_prepare_utp_query_req_upiu(
>> >> + hba, lrbp, upiu_flags);
>> >> + else if (hba->dev_cmd.type == DEV_CMD_TYPE_NOP)
>> >> ufshcd_prepare_utp_nop_upiu(lrbp);
>> >> else
>> >> ret = -EINVAL;
>> >> @@ -831,6 +939,9 @@ ufshcd_dev_cmd_completion(struct ufs_hba *hba,
>> struct ufshcd_lrb *lrbp)
>> >> __func__, resp);
>> >> }
>> >> break;
>> >> + case UPIU_TRANSACTION_QUERY_RSP:
>> >> + ufshcd_copy_query_response(hba, lrbp);
>> >> + break;
>> >> case UPIU_TRANSACTION_REJECT_UPIU:
>> >> /* TODO: handle Reject UPIU Response */
>> >> err = -EPERM;
>> >> @@ -941,6 +1052,128 @@ out_put_tag:
>> >> }
>> >> /**
>> >> + * ufshcd_query_request() - API for issuing query request to the
>> device.
>> >> + * @hba: ufs driver context
>> >> + * @query: params for query request
>> >> + * @descriptor: buffer for sending/receiving descriptor
>> >> + * @retries: number of times to try executing the command
>> >> + *
>> >> + * All necessary fields for issuing a query and receiving its
>> response
>> + * are stored in the UFS hba struct. We can use this method since we
>> know
>> >> + * there is only one active query request or any device management
>> command
>> >> + * at all times.
>> >> + */
>> >> +static int ufshcd_send_query_request(struct ufs_hba *hba,
>> >> + struct ufs_query_req *query,
>> >> + u8 *descriptor,
>> >> + struct ufs_query_res *response)
>> >> +{
>> >> + int ret;
>> >> +
>> >> + BUG_ON(!hba);
>> >> + if (!query || !response) {
>> >> + dev_err(hba->dev,
>> >> + "%s: NULL pointer query = %p, response = %p\n",
>> >> + __func__, query, response);
>> >> + return -EINVAL;
>> >> + }
>> >> +
>> >> + mutex_lock(&hba->dev_cmd.lock);
>> >> + hba->dev_cmd.query.request = query;
>> >> + hba->dev_cmd.query.response = response;
>> >> + hba->dev_cmd.query.descriptor = descriptor;
>> >> +
>> >> + ret = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_QUERY,
>> >> + QUERY_REQ_TIMEOUT);
>> >> +
>> >> + hba->dev_cmd.query.request = NULL;
>> >> + hba->dev_cmd.query.response = NULL;
>> >> + hba->dev_cmd.query.descriptor = NULL;
>> >> + mutex_unlock(&hba->dev_cmd.lock);
>> >> +
>> >> + return ret;
>> >> +}
>> >> +
>> >> +/**
>> >> + * ufshcd_query_flag() - Helper function for composing flag query
>> requests
>> >> + * hba: per-adapter instance
>> >> + * query_opcode: flag query to perform
>> >> + * idn: flag idn to access
>> >> + * flag_res: the flag value after the query request completes
>> >> + *
>> >> + * Returns 0 for success, non-zero in case of failure
>> >> + */
>> >> +static int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode
>> opcode,
>> >> + enum flag_idn idn, bool *flag_res)
>> >> +{
>> >> + struct ufs_query_req *query;
>> >> + struct ufs_query_res *response;
>> >> + int err = -ENOMEM;
>> >> +
>> >> + query = kzalloc(sizeof(struct ufs_query_req), GFP_KERNEL);
>> >> + if (!query) {
>> >> + dev_err(hba->dev,
>> >> + "%s: Failed allocating ufs_query_req instance\n",
>> >> + __func__);
>> >> + goto out_no_mem;
>> >> + }
>> >> + response = kzalloc(sizeof(struct ufs_query_res), GFP_KERNEL); + if
>> (!response) {
>> >> + dev_err(hba->dev,
>> >> + "%s: Failed allocating ufs_query_res instance\n",
>> >> + __func__);
>> >> + goto out_free_query;
>> >> + }
>> > Can't stack local variable be permitted for query and response instead
>> of
>> > dynamic allocation?
>> It can, though I think it is safer this way. In addition, this code is
>> not
>> a bottle neck.
> Yes, once may not be a problem. But I am seeing this function is called
> from some loop routine.
> Could you explain the reason dynamic allocation is needed?
I don't like the idea of allocating it on stack, I suggest to statically
allocate it on the query struct. What do you think?
>
>> >> +
>> >> + switch (opcode) {
>> >> + case UPIU_QUERY_OPCODE_SET_FLAG:
>> >> + case UPIU_QUERY_OPCODE_CLEAR_FLAG:
>> >> + case UPIU_QUERY_OPCODE_TOGGLE_FLAG:
>> >> + query->query_func = UPIU_QUERY_FUNC_STANDARD_WRITE_REQUEST;
>> >> + break;
>> >> + case UPIU_QUERY_OPCODE_READ_FLAG:
>> >> + query->query_func = UPIU_QUERY_FUNC_STANDARD_READ_REQUEST;
>> >> + if (!flag_res) {
>> >> + /* No dummy reads */
>> >> + dev_err(hba->dev, "%s: Invalid argument for read request\n",
>> + __func__);
>> >> + err = -EINVAL;
>> >> + goto out;
>> >> + }
>> >> + break;
>> >> + default:
>> >> + dev_err(hba->dev,
>> >> + "%s: Expected query flag opcode but got = %d\n",
>> >> + __func__, opcode);
>> >> + err = -EINVAL;
>> >> + goto out;
>> >> + }
>> >> + query->upiu_req.opcode = opcode;
>> >> + query->upiu_req.idn = idn;
>> >> +
>> >> + /* Send query request */
>> >> + err = ufshcd_send_query_request(hba, query, NULL, response);
>> >> +
>> >> + if (err) {
>> >> + dev_err(hba->dev,
>> >> + "%s: Sending flag query for idn %d failed, err = %d\n",
>> >> + __func__, idn, err);
>> >> + goto out;
>> >> + }
>> >> +
>> >> + if (flag_res)
>> >> + *flag_res = (response->upiu_res.value &
>> >> + MASK_QUERY_UPIU_FLAG_LOC) & 0x1;
>> >> +
>> >> +out:
>> >> + kfree(response);
>> >> +out_free_query:
>> >> + kfree(query);
>> >> +out_no_mem:
>> >> + return err;
>> >> +}
>> >> +
>> >> +/**
>> >> * ufshcd_memory_alloc - allocate memory for host memory space data
>> >> structures
>> >> * @hba: per adapter instance
>> >> *
>> >> @@ -1110,6 +1343,59 @@ static int ufshcd_dme_link_startup(struct
>> ufs_hba
>> >> *hba)
>> >> }
>> >> /**
>> >> + * ufshcd_validate_device_init() - checks device readiness
>> >> + * hba: per-adapter instance
>> >> + *
>> >> + * Set fDeviceInit flag, than, query the flag until the device
>> clears the
>> >> + * flag.
>> >> + */
>> >> +static int ufshcd_validate_device_init(struct ufs_hba *hba)
>> > As standard description, this function is for initialization
>> completion.
>> How about ufshcd_complete_dev_init for function name?
>> You have a point.
>> >> +{
>> >> + int i, retries, err = 0;
>> >> + bool flag_res = 0;
>> >> +
>> >> + for (retries = QUERY_REQ_RETRIES; retries > 0; retries--) {
>> >> + /* Set the fDeviceIntit flag */
>> >> + err = ufshcd_query_flag(hba, UPIU_QUERY_OPCODE_SET_FLAG,
>> >> + QUERY_FLAG_IDN_FDEVICEINIT, &flag_res);
>> > There is no need to get flag_res in case set flag.
>> > Just passing NULL is good.
>> Consider the following scenario: a device is already fully initialized
>> when we init the driver, in this case setting the flag will return 0
>> since
>> no further initialization is required. This means we don't have to query
>> again or to poll for the fDeviceInit because we already now the
>> initialization is completed.
> It's not clear.
> I think it may be a broad interpretation.
> What's the meaning of returned flag_res?
> 1. original value
> 2. value which is applied by setting the fDeviceInit flag
> 3. value which is applied by setting the fDeviceInit flag and reset
>
> In this step, query is not for read-flag but for set-flag.
> Above all, spec. mentions polling the fDeviceInit using read-flag
> definitively.
After reading the spec, I agree, the statement is a little fuzzy. I will
change it to null and fix the code according.
>
>> >> + if (!err || err == -ETIMEDOUT)
>> >> + break;
>> >> + dev_dbg(hba->dev, "%s: error %d retrying\n", __func__, err); + }
>> >> + if (err) {
>> >> + dev_err(hba->dev,
>> >> + "%s setting fDeviceInit flag failed with error %d\n",
>> >> + __func__, err);
>> >> + goto out;
>> >> + }
>> >> +
>> >> + /* poll for max. 100 iterations for fDeviceInit flag to clear */
>> + for (i = 0; i < 100 && !err && flag_res; i++) {
>> > In first ufshcd_query_flag, if flag_res is updated with '0', this loop
>> can't be executed.
>> > Of course, we expect that flag_res has '1'.
>> In the described case above, this condition allows us to skip the
>> polling
>> process.
>>
>> >> + retries = QUERY_REQ_RETRIES;
>> >> + for (retries = QUERY_REQ_RETRIES; retries > 0; retries--) {
>> >> + err = ufshcd_query_flag(hba,
>> >> + UPIU_QUERY_OPCODE_READ_FLAG,
>> >> + QUERY_FLAG_IDN_FDEVICEINIT, &flag_res);
>> >> + if (!err || err == -ETIMEDOUT)
>> >> + break;
>> > Normally, ufshcd_query_flag returns '0' to err while flag is not being
>> cleared.
>> > If these routine is repeated, inner for-loop is just executed and go
>> to
>> outer loop.
>> > What is difference between two for-loop?
>> Your analysis was correct, each loop has a different responsibility. The
>> outer loop counts the poling retries, while the inner loop is
>> responsible
>> for passing the query request to the device without errors. So the inner
>> loop will execute more then once iff there was an error and the request
>> was not executed properly.
> I wonder that valid result comes after error is happened and retry is
> taken.
> Should we allow the retry in case errors?
Well, currently all other components, SCSI included, are retrying in case
of errors. I don't see a reason why this case should be different.
>
> Thanks,
> Seungwon Jeon
>
> --
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>
Thanks,
Dolev
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