ufs: refactor query descriptor API support

Currently reading query descriptor is more tightened to each
descriptor type. This patch generalize the approach and allows
reading any parameter from any query descriptor.
Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/scsi/ufs/ufs.h

@@ -50,6 +50,8 @@
 			cpu_to_be32((byte3 << 24) | (byte2 << 16) |\
 			 (byte1 << 8) | (byte0))
 
+#define UFS_UPIU_MAX_GENERAL_LUN	8
+
 /*
  * UFS Protocol Information Unit related definitions
  */
@@ -129,10 +131,29 @@ enum desc_idn {
 	QUERY_DESC_IDN_RFU_1		= 0x6,
 	QUERY_DESC_IDN_GEOMETRY		= 0x7,
 	QUERY_DESC_IDN_POWER		= 0x8,
-	QUERY_DESC_IDN_RFU_2		= 0x9,
+	QUERY_DESC_IDN_MAX,
+};
+
+enum desc_header_offset {
+	QUERY_DESC_LENGTH_OFFSET	= 0x00,
+	QUERY_DESC_DESC_TYPE_OFFSET	= 0x01,
+};
+
+enum ufs_desc_max_size {
+	QUERY_DESC_DEVICE_MAX_SIZE		= 0x1F,
+	QUERY_DESC_CONFIGURAION_MAX_SIZE	= 0x90,
+	QUERY_DESC_UNIT_MAX_SIZE		= 0x23,
+	QUERY_DESC_INTERCONNECT_MAX_SIZE	= 0x06,
+	/*
+	 * Max. 126 UNICODE characters (2 bytes per character) plus 2 bytes
+	 * of descriptor header.
+	 */
+	QUERY_DESC_STRING_MAX_SIZE		= 0xFE,
+	QUERY_DESC_GEOMETRY_MAZ_SIZE		= 0x44,
+	QUERY_DESC_POWER_MAX_SIZE		= 0x62,
+	QUERY_DESC_RFU_MAX_SIZE			= 0x00,
 };
 
-#define UNIT_DESC_MAX_SIZE       0x22
 /* Unit descriptor parameters offsets in bytes*/
 enum unit_desc_param {
 	UNIT_DESC_PARAM_LEN			= 0x0,

drivers/scsi/ufs/ufshcd.c

@@ -78,6 +78,19 @@
 		_ret;                                                   \
 	})
 
+static u32 ufs_query_desc_max_size[] = {
+	QUERY_DESC_DEVICE_MAX_SIZE,
+	QUERY_DESC_CONFIGURAION_MAX_SIZE,
+	QUERY_DESC_UNIT_MAX_SIZE,
+	QUERY_DESC_RFU_MAX_SIZE,
+	QUERY_DESC_INTERCONNECT_MAX_SIZE,
+	QUERY_DESC_STRING_MAX_SIZE,
+	QUERY_DESC_RFU_MAX_SIZE,
+	QUERY_DESC_GEOMETRY_MAZ_SIZE,
+	QUERY_DESC_POWER_MAX_SIZE,
+	QUERY_DESC_RFU_MAX_SIZE,
+};
+
 enum {
 	UFSHCD_MAX_CHANNEL	= 0,
 	UFSHCD_MAX_ID		= 1,
@@ -124,8 +137,6 @@ static void ufshcd_tmc_handler(struct ufs_hba *hba);
 static void ufshcd_async_scan(void *data, async_cookie_t cookie);
 static int ufshcd_reset_and_restore(struct ufs_hba *hba);
 static int ufshcd_clear_tm_cmd(struct ufs_hba *hba, int tag);
-static int ufshcd_read_sdev_qdepth(struct ufs_hba *hba,
-					struct scsi_device *sdev);
 
 /*
  * ufshcd_wait_for_register - wait for register value to change
@@ -1392,6 +1403,115 @@ static int ufshcd_query_descriptor(struct ufs_hba *hba,
 	return err;
 }
 
+/**
+ * ufshcd_read_desc_param - read the specified descriptor parameter
+ * @hba: Pointer to adapter instance
+ * @desc_id: descriptor idn value
+ * @desc_index: descriptor index
+ * @param_offset: offset of the parameter to read
+ * @param_read_buf: pointer to buffer where parameter would be read
+ * @param_size: sizeof(param_read_buf)
+ *
+ * Return 0 in case of success, non-zero otherwise
+ */
+static int ufshcd_read_desc_param(struct ufs_hba *hba,
+				  enum desc_idn desc_id,
+				  int desc_index,
+				  u32 param_offset,
+				  u8 *param_read_buf,
+				  u32 param_size)
+{
+	int ret;
+	u8 *desc_buf;
+	u32 buff_len;
+	bool is_kmalloc = true;
+
+	/* safety checks */
+	if (desc_id >= QUERY_DESC_IDN_MAX)
+		return -EINVAL;
+
+	buff_len = ufs_query_desc_max_size[desc_id];
+	if ((param_offset + param_size) > buff_len)
+		return -EINVAL;
+
+	if (!param_offset && (param_size == buff_len)) {
+		/* memory space already available to hold full descriptor */
+		desc_buf = param_read_buf;
+		is_kmalloc = false;
+	} else {
+		/* allocate memory to hold full descriptor */
+		desc_buf = kmalloc(buff_len, GFP_KERNEL);
+		if (!desc_buf)
+			return -ENOMEM;
+	}
+
+	ret = ufshcd_query_descriptor(hba, UPIU_QUERY_OPCODE_READ_DESC,
+				      desc_id, desc_index, 0, desc_buf,
+				      &buff_len);
+
+	if (ret || (buff_len < ufs_query_desc_max_size[desc_id]) ||
+	    (desc_buf[QUERY_DESC_LENGTH_OFFSET] !=
+	     ufs_query_desc_max_size[desc_id])
+	    || (desc_buf[QUERY_DESC_DESC_TYPE_OFFSET] != desc_id)) {
+		dev_err(hba->dev, "%s: Failed reading descriptor. desc_id %d param_offset %d buff_len %d ret %d",
+			__func__, desc_id, param_offset, buff_len, ret);
+		if (!ret)
+			ret = -EINVAL;
+
+		goto out;
+	}
+
+	if (is_kmalloc)
+		memcpy(param_read_buf, &desc_buf[param_offset], param_size);
+out:
+	if (is_kmalloc)
+		kfree(desc_buf);
+	return ret;
+}
+
+static inline int ufshcd_read_desc(struct ufs_hba *hba,
+				   enum desc_idn desc_id,
+				   int desc_index,
+				   u8 *buf,
+				   u32 size)
+{
+	return ufshcd_read_desc_param(hba, desc_id, desc_index, 0, buf, size);
+}
+
+static inline int ufshcd_read_power_desc(struct ufs_hba *hba,
+					 u8 *buf,
+					 u32 size)
+{
+	return ufshcd_read_desc(hba, QUERY_DESC_IDN_POWER, 0, buf, size);
+}
+
+/**
+ * ufshcd_read_unit_desc_param - read the specified unit descriptor parameter
+ * @hba: Pointer to adapter instance
+ * @lun: lun id
+ * @param_offset: offset of the parameter to read
+ * @param_read_buf: pointer to buffer where parameter would be read
+ * @param_size: sizeof(param_read_buf)
+ *
+ * Return 0 in case of success, non-zero otherwise
+ */
+static inline int ufshcd_read_unit_desc_param(struct ufs_hba *hba,
+					      int lun,
+					      enum unit_desc_param param_offset,
+					      u8 *param_read_buf,
+					      u32 param_size)
+{
+	/*
+	 * Unit descriptors are only available for general purpose LUs (LUN id
+	 * from 0 to 7) and RPMB Well known LU.
+	 */
+	if (lun >= UFS_UPIU_MAX_GENERAL_LUN)
+		return -EOPNOTSUPP;
+
+	return ufshcd_read_desc_param(hba, QUERY_DESC_IDN_UNIT, lun,
+				      param_offset, param_read_buf, param_size);
+}
+
 /**
  * ufshcd_memory_alloc - allocate memory for host memory space data structures
  * @hba: per adapter instance
@@ -2011,7 +2131,8 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
 static int ufshcd_slave_alloc(struct scsi_device *sdev)
 {
 	struct ufs_hba *hba;
-	int lun_qdepth;
+	u8 lun_qdepth;
+	int ret;
 
 	hba = shost_priv(sdev->host);
 	sdev->tagged_supported = 1;
@@ -2026,8 +2147,12 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev)
 	/* REPORT SUPPORTED OPERATION CODES is not supported */
 	sdev->no_report_opcodes = 1;
 
-	lun_qdepth = ufshcd_read_sdev_qdepth(hba, sdev);
-	if (lun_qdepth <= 0)
+	ret = ufshcd_read_unit_desc_param(hba,
+					  sdev->lun,
+					  UNIT_DESC_PARAM_LU_Q_DEPTH,
+					  &lun_qdepth,
+					  sizeof(lun_qdepth));
+	if (!ret || !lun_qdepth)
 		/* eventually, we can figure out the real queue depth */
 		lun_qdepth = hba->nutrs;
 	else
@@ -3117,38 +3242,6 @@ static int ufshcd_eh_host_reset_handler(struct scsi_cmnd *cmd)
 	return err;
 }
 
-/**
- * ufshcd_read_sdev_qdepth - read the lun command queue depth
- * @hba: Pointer to adapter instance
- * @sdev: pointer to SCSI device
- *
- * Return in case of success the lun's queue depth else error.
- */
-static int ufshcd_read_sdev_qdepth(struct ufs_hba *hba,
-				struct scsi_device *sdev)
-{
-	int ret;
-	int buff_len = UNIT_DESC_MAX_SIZE;
-	u8 desc_buf[UNIT_DESC_MAX_SIZE];
-
-	ret = ufshcd_query_descriptor(hba, UPIU_QUERY_OPCODE_READ_DESC,
-			QUERY_DESC_IDN_UNIT, sdev->lun, 0, desc_buf, &buff_len);
-
-	if (ret || (buff_len < UNIT_DESC_PARAM_LU_Q_DEPTH)) {
-		dev_err(hba->dev,
-			"%s:Failed reading unit descriptor. len = %d ret = %d"
-			, __func__, buff_len, ret);
-		if (!ret)
-			ret = -EINVAL;
-
-		goto out;
-	}
-
-	ret = desc_buf[UNIT_DESC_PARAM_LU_Q_DEPTH] & 0xFF;
-out:
-	return ret;
-}
-
 /**
  * ufshcd_async_scan - asynchronous execution for link startup
  * @data: data pointer to pass to this function