[PATCH V1 8/8] scsi: ufs: Set fDeviceInit flag to initiate device initialization

[Dolev Raviv]

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>
Acked-by: Santosh Y <santoshsy@xxxxxxxxx>

--
Changes for V4:
- Add NULL pointer check
- Changed fix from v3 to bug on since hba can't be null
Changes for V3:
- Fix static checker error
Changes for V2:
- Add the query sending api via SCSI from the original query patch

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 086ff03..742363d 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -107,8 +107,13 @@ enum {
 	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 {
+enum query_opcode {
 	UPIU_QUERY_OPCODE_NOP		= 0x0,
 	UPIU_QUERY_OPCODE_READ_DESC	= 0x1,
 	UPIU_QUERY_OPCODE_WRITE_DESC	= 0x2,
@@ -208,6 +213,9 @@ struct utp_upiu_query {
 	u32 reserved[2];
 };
 
+/* Expose the flag value from utp_upiu_query.value */
+#define MASK_QUERY_UPIU_FLAG_LOC 0xFF
+
 /**
  * struct utp_upiu_req - general upiu request structure
  * @header:UPIU header structure DW-0 to DW-2
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 2db550b..e9dba33 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -50,6 +50,15 @@
 /* Reserved tag for internal commands */
 #define INTERNAL_CMD_TAG   0
 
+/* Query request standart retries */
+#define QUERY_REQ_RETRIES 10
+/* Query request standart timeout  in seconds */
+#define QUERY_REQ_TIMEOUT 5
+/* Send Query Requst with default parameters */
+#define send_query_request(ARG1, ARG2, ARG3, ARG4)	\
+	ufshcd_query_request(ARG1, ARG2, ARG3, ARG4,	\
+			QUERY_REQ_TIMEOUT, QUERY_REQ_RETRIES)
+
 enum {
 	UFSHCD_MAX_CHANNEL	= 0,
 	UFSHCD_MAX_ID		= 1,
@@ -862,6 +871,164 @@ out:
 }
 
 /**
+ *  ufshcd_query_request() - Entry point for issuing query request to a
+ *  ufs device.
+ *  @hba: ufs driver context
+ *  @query: params for query request
+ *  @descriptor: buffer for sending/receiving descriptor
+ *  @response: pointer to a buffer that will contain the response code and
+ *           response upiu
+ *  @timeout: time limit for the command in seconds
+ *  @retries: number of times to try executing the command
+ *
+ *  The query request is submitted to the same request queue as the rest of
+ *  the scsi commands passed to the UFS controller. In order to use this
+ *  queue, we need to receive a tag, same as all other commands. The tags
+ *  are issued from the block layer. To simulate a request from the block
+ *  layer, we use the same interface as the SCSI layer does when it issues
+ *  commands not generated by users. To distinguish a query request from
+ *  the SCSI commands, we use a vendor specific unused SCSI command
+ *  op-code. This op-code is not part of the SCSI command subset used in
+ *  UFS. In such way it is easy to check the command in the driver and
+ *  handle it appropriately.
+ *
+ *  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 at all times.
+ *
+ *  The request that will pass to the device is stored in "query" argument
+ *  passed to this function, while the "response" argument (which is output
+ *  field) will hold the query response from the device along with the
+ *  response code.
+ */
+int ufshcd_query_request(struct ufs_hba *hba,
+			struct ufs_query_req *query,
+			u8 *descriptor,
+			struct ufs_query_res *response,
+			int timeout,
+			int retries)
+{
+	struct scsi_device *sdev;
+	u8 cmd[UFS_QUERY_CMD_SIZE] = {0};
+	int result;
+	bool sdev_lookup = true;
+
+	BUG_ON(!hba);
+	if (!query || !response) {
+		dev_err(hba->dev,
+		"%s: NULL pointer hba = %p, query = %p response = %p\n",
+		__func__, hba, query, response);
+		return -EINVAL;
+	}
+
+	/*
+	 * A SCSI command structure is composed from opcode at the
+	 * begining and 0 at the end.
+	 */
+	cmd[0] = UFS_QUERY_RESERVED_SCSI_CMD;
+
+	/* extracting the SCSI Device */
+	sdev = scsi_device_lookup(hba->host, 0, 0, 0);
+	if (!sdev) {
+		/**
+		 * There are some Query Requests that are sent during device
+		 * initialization, this happens before the scsi device was
+		 * initialized. If there is no scsi device, we generate a
+		 * temporary device to allow the Query Request flow.
+		 */
+		sdev_lookup = false;
+		sdev = scsi_get_host_dev(hba->host);
+	}
+
+	if (!sdev) {
+		dev_err(hba->dev, "%s: Could not fetch scsi device\n",
+			__func__);
+		return -ENODEV;
+	}
+
+	mutex_lock(&hba->query.lock_ufs_query);
+	hba->query.request = query;
+	hba->query.descriptor = descriptor;
+	hba->query.response = response;
+
+	/* wait until request is completed */
+	result = scsi_execute(sdev, cmd, DMA_NONE, NULL, 0, NULL,
+				timeout, retries, 0, NULL);
+	if (result) {
+		dev_err(hba->dev,
+			"%s: Query with opcode 0x%x, failed with result %d\n",
+			__func__, query->upiu_req.opcode, result);
+		result = -EIO;
+	}
+
+	hba->query.request = NULL;
+	hba->query.descriptor = NULL;
+	hba->query.response = NULL;
+	mutex_unlock(&hba->query.lock_ufs_query);
+
+	/* Releasing scsi device resource */
+	if (sdev_lookup)
+		scsi_device_put(sdev);
+	else
+		scsi_free_host_dev(sdev);
+
+	return result;
+}
+
+/**
+ * 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
+ */
+int ufshcd_query_flag(struct ufs_hba *hba, enum query_opcode opcode,
+			enum flag_idn idn, bool *flag_res)
+{
+	struct ufs_query_req query = {0};
+	struct ufs_query_res response = {0};
+	int err;
+
+	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;
+		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 = 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:
+	return err;
+}
+
+/**
  * ufshcd_memory_alloc - allocate memory for host memory space data structures
  * @hba: per adapter instance
  *
@@ -1128,6 +1295,44 @@ out:
 }
 
 /**
+ * ufshcd_validate_device_init() - checks device readines
+ * hba: per-adapter instance
+ *
+ * Set fDeviceInit flag, than, query the flag untill the device clears the
+ * flag.
+ */
+static int ufshcd_validate_device_init(struct ufs_hba *hba)
+{
+	int i, err;
+	bool flag_res = 0;
+
+	err = ufshcd_query_flag(hba, UPIU_QUERY_OPCODE_SET_FLAG,
+				QUERY_FLAG_IDN_FDEVICEINIT, &flag_res);
+	if (err) {
+		dev_err(hba->dev,
+			"%s setting fDeviceInit flag failed with error %d\n",
+			__func__, err);
+		goto out;
+	}
+
+	for (i = 0; i < QUERY_REQ_RETRIES && !err && flag_res; i++) {
+		err = ufshcd_query_flag(hba, UPIU_QUERY_OPCODE_READ_FLAG,
+				QUERY_FLAG_IDN_FDEVICEINIT, &flag_res);
+	}
+	if (err)
+		dev_err(hba->dev,
+			"%s reading fDeviceInit flag failed with error %d\n",
+			__func__, err);
+	else if (flag_res)
+		dev_err(hba->dev,
+			"%s fDeviceInit was not cleared by the device\n",
+			__func__);
+
+out:
+	return err;
+}
+
+/**
  * ufshcd_make_hba_operational - Make UFS controller operational
  * @hba: per adapter instance
  *
@@ -1950,6 +2155,10 @@ static void ufshcd_async_scan(void *data, async_cookie_t cookie)
 	if (ret)
 		goto out;
 
+	ret = ufshcd_validate_device_init(hba);
+	if (ret)
+		goto out;
+
 	scsi_scan_host(hba->host);
 out:
 	return;
-- 
1.7.6

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