scsi: ufs: Factor out ufshcd_read_desc_param

Since in UFS 2.1 specification some of the descriptor lengths differs
from 2.0 specification and some devices, which are reporting spec
version 2.0 have different descriptor lengths we can not rely on
hardcoded values taken from 2.0 specification. This patch introduces
reading these lengths per each device from descriptor headers at probe
time to ensure their correctness.

Signed-off-by: Michal' Potomski <[e-mail]>
Reviewed-by: Subhash Jadavani <[e-mail]>
Signed-off-by: Martin K. Petersen <[e-mail]>

drivers/scsi/ufs/ufs.h

···
 /* Descriptor idn for Query requests */
 enum desc_idn {
 	QUERY_DESC_IDN_DEVICE		= 0x0,
-	QUERY_DESC_IDN_CONFIGURAION	= 0x1,
+	QUERY_DESC_IDN_CONFIGURATION	= 0x1,
 	QUERY_DESC_IDN_UNIT		= 0x2,
 	QUERY_DESC_IDN_RFU_0		= 0x3,
 	QUERY_DESC_IDN_INTERCONNECT	= 0x4,
···
 	QUERY_DESC_DESC_TYPE_OFFSET	= 0x01,
 };
 
-enum ufs_desc_max_size {
-	QUERY_DESC_DEVICE_MAX_SIZE		= 0x40,
-	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_MAX_SIZE		= 0x44,
-	QUERY_DESC_POWER_MAX_SIZE		= 0x62,
-	QUERY_DESC_RFU_MAX_SIZE			= 0x00,
+enum ufs_desc_def_size {
+	QUERY_DESC_DEVICE_DEF_SIZE		= 0x40,
+	QUERY_DESC_CONFIGURATION_DEF_SIZE	= 0x90,
+	QUERY_DESC_UNIT_DEF_SIZE		= 0x23,
+	QUERY_DESC_INTERCONNECT_DEF_SIZE	= 0x06,
+	QUERY_DESC_GEOMETRY_DEF_SIZE		= 0x44,
+	QUERY_DESC_POWER_DEF_SIZE		= 0x62,
 };
 
 /* Unit descriptor parameters offsets in bytes*/

drivers/scsi/ufs/ufshcd.c

···
 #define ufshcd_hex_dump(prefix_str, buf, len) \
 print_hex_dump(KERN_ERR, prefix_str, DUMP_PREFIX_OFFSET, 16, 4, buf, len, false)
 
-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_MAX_SIZE,
-	QUERY_DESC_POWER_MAX_SIZE,
-	QUERY_DESC_RFU_MAX_SIZE,
-};
-
 enum {
 	UFSHCD_MAX_CHANNEL	= 0,
 	UFSHCD_MAX_ID		= 1,
···
 		goto out;
 	}
 
-	if (*buf_len <= QUERY_DESC_MIN_SIZE || *buf_len > QUERY_DESC_MAX_SIZE) {
+	if (*buf_len < QUERY_DESC_MIN_SIZE || *buf_len > QUERY_DESC_MAX_SIZE) {
 		dev_err(hba->dev, "%s: descriptor buffer size (%d) is out of range\n",
 				__func__, *buf_len);
 		err = -EINVAL;
···
 }
 
 /**
+ * ufshcd_read_desc_length - read the specified descriptor length from header
+ * @hba: Pointer to adapter instance
+ * @desc_id: descriptor idn value
+ * @desc_index: descriptor index
+ * @desc_length: pointer to variable to read the length of descriptor
+ *
+ * Return 0 in case of success, non-zero otherwise
+ */
+static int ufshcd_read_desc_length(struct ufs_hba *hba,
+	enum desc_idn desc_id,
+	int desc_index,
+	int *desc_length)
+{
+	int ret;
+	u8 header[QUERY_DESC_HDR_SIZE];
+	int header_len = QUERY_DESC_HDR_SIZE;
+
+	if (desc_id >= QUERY_DESC_IDN_MAX)
+		return -EINVAL;
+
+	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
+					desc_id, desc_index, 0, header,
+					&header_len);
+
+	if (ret) {
+		dev_err(hba->dev, "%s: Failed to get descriptor header id %d",
+			__func__, desc_id);
+		return ret;
+	} else if (desc_id != header[QUERY_DESC_DESC_TYPE_OFFSET]) {
+		dev_warn(hba->dev, "%s: descriptor header id %d and desc_id %d mismatch",
+			__func__, header[QUERY_DESC_DESC_TYPE_OFFSET],
+			desc_id);
+		ret = -EINVAL;
+	}
+
+	*desc_length = header[QUERY_DESC_LENGTH_OFFSET];
+	return ret;
+
+}
+
+/**
+ * ufshcd_map_desc_id_to_length - map descriptor IDN to its length
+ * @hba: Pointer to adapter instance
+ * @desc_id: descriptor idn value
+ * @desc_len: mapped desc length (out)
+ *
+ * Return 0 in case of success, non-zero otherwise
+ */
+int ufshcd_map_desc_id_to_length(struct ufs_hba *hba,
+	enum desc_idn desc_id, int *desc_len)
+{
+	switch (desc_id) {
+	case QUERY_DESC_IDN_DEVICE:
+		*desc_len = hba->desc_size.dev_desc;
+		break;
+	case QUERY_DESC_IDN_POWER:
+		*desc_len = hba->desc_size.pwr_desc;
+		break;
+	case QUERY_DESC_IDN_GEOMETRY:
+		*desc_len = hba->desc_size.geom_desc;
+		break;
+	case QUERY_DESC_IDN_CONFIGURATION:
+		*desc_len = hba->desc_size.conf_desc;
+		break;
+	case QUERY_DESC_IDN_UNIT:
+		*desc_len = hba->desc_size.unit_desc;
+		break;
+	case QUERY_DESC_IDN_INTERCONNECT:
+		*desc_len = hba->desc_size.interc_desc;
+		break;
+	case QUERY_DESC_IDN_STRING:
+		*desc_len = QUERY_DESC_MAX_SIZE;
+		break;
+	case QUERY_DESC_IDN_RFU_0:
+	case QUERY_DESC_IDN_RFU_1:
+		*desc_len = 0;
+		break;
+	default:
+		*desc_len = 0;
+		return -EINVAL;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(ufshcd_map_desc_id_to_length);
+
+/**
  * ufshcd_read_desc_param - read the specified descriptor parameter
  * @hba: Pointer to adapter instance
  * @desc_id: descriptor idn value
···
 static int ufshcd_read_desc_param(struct ufs_hba *hba,
 				  enum desc_idn desc_id,
 				  int desc_index,
-				  u32 param_offset,
+				  u8 param_offset,
 				  u8 *param_read_buf,
-				  u32 param_size)
+				  u8 param_size)
 {
 	int ret;
 	u8 *desc_buf;
-	u32 buff_len;
+	int buff_len;
 	bool is_kmalloc = true;
 
-	/* safety checks */
-	if (desc_id >= QUERY_DESC_IDN_MAX)
+	/* Safety check */
+	if (desc_id >= QUERY_DESC_IDN_MAX || !param_size)
 		return -EINVAL;
 
-	buff_len = ufs_query_desc_max_size[desc_id];
-	if ((param_offset + param_size) > buff_len)
-		return -EINVAL;
+	/* Get the max length of descriptor from structure filled up at probe
+	 * time.
+	 */
+	ret = ufshcd_map_desc_id_to_length(hba, desc_id, &buff_len);
 
-	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 */
+	/* Sanity checks */
+	if (ret || !buff_len) {
+		dev_err(hba->dev, "%s: Failed to get full descriptor length",
+			__func__);
+		return ret;
+	}
+
+	/* Check whether we need temp memory */
+	if (param_offset != 0 || param_size < buff_len) {
 		desc_buf = kmalloc(buff_len, GFP_KERNEL);
 		if (!desc_buf)
 			return -ENOMEM;
+	} else {
+		desc_buf = param_read_buf;
+		is_kmalloc = false;
 	}
 
+	/* Request for full descriptor */
 	ret = ufshcd_query_descriptor_retry(hba, UPIU_QUERY_OPCODE_READ_DESC,
-					desc_id, desc_index, 0, desc_buf,
-					&buff_len);
+					desc_id, desc_index, 0,
+					desc_buf, &buff_len);
 
 	if (ret) {
 		dev_err(hba->dev, "%s: Failed reading descriptor. desc_id %d, desc_index %d, param_offset %d, ret %d",
 			__func__, desc_id, desc_index, param_offset, ret);
-
 		goto out;
 	}
 
···
 		goto out;
 	}
 
-	/*
-	 * While reading variable size descriptors (like string descriptor),
-	 * some UFS devices may report the "LENGTH" (field in "Transaction
-	 * Specific fields" of Query Response UPIU) same as what was requested
-	 * in Query Request UPIU instead of reporting the actual size of the
-	 * variable size descriptor.
-	 * Although it's safe to ignore the "LENGTH" field for variable size
-	 * descriptors as we can always derive the length of the descriptor from
-	 * the descriptor header fields. Hence this change impose the length
-	 * match check only for fixed size descriptors (for which we always
-	 * request the correct size as part of Query Request UPIU).
-	 */
-	if ((desc_id != QUERY_DESC_IDN_STRING) &&
-	    (buff_len != desc_buf[QUERY_DESC_LENGTH_OFFSET])) {
-		dev_err(hba->dev, "%s: desc_buf length mismatch: buff_len %d, buff_len(desc_header) %d",
-			__func__, buff_len, desc_buf[QUERY_DESC_LENGTH_OFFSET]);
-		ret = -EINVAL;
-		goto out;
-	}
+	/* Check wherher we will not copy more data, than available */
+	if (is_kmalloc && param_size > buff_len)
+		param_size = buff_len;
 
 	if (is_kmalloc)
 		memcpy(param_read_buf, &desc_buf[param_offset], param_size);
···
 static void ufshcd_init_icc_levels(struct ufs_hba *hba)
 {
 	int ret;
-	int buff_len = QUERY_DESC_POWER_MAX_SIZE;
-	u8 desc_buf[QUERY_DESC_POWER_MAX_SIZE];
+	int buff_len = hba->desc_size.pwr_desc;
+	u8 desc_buf[hba->desc_size.pwr_desc];
 
 	ret = ufshcd_read_power_desc(hba, desc_buf, buff_len);
 	if (ret) {
···
 {
 	int err;
 	u8 model_index;
-	u8 str_desc_buf[QUERY_DESC_STRING_MAX_SIZE + 1] = {0};
-	u8 desc_buf[QUERY_DESC_DEVICE_MAX_SIZE];
+	u8 str_desc_buf[QUERY_DESC_MAX_SIZE + 1] = {0};
+	u8 desc_buf[hba->desc_size.dev_desc];
 
-	err = ufshcd_read_device_desc(hba, desc_buf,
-					QUERY_DESC_DEVICE_MAX_SIZE);
+	err = ufshcd_read_device_desc(hba, desc_buf, hba->desc_size.dev_desc);
 	if (err) {
 		dev_err(hba->dev, "%s: Failed reading Device Desc. err = %d\n",
 			__func__, err);
···
 	model_index = desc_buf[DEVICE_DESC_PARAM_PRDCT_NAME];
 
 	err = ufshcd_read_string_desc(hba, model_index, str_desc_buf,
-					QUERY_DESC_STRING_MAX_SIZE, ASCII_STD);
+				QUERY_DESC_MAX_SIZE, ASCII_STD);
 	if (err) {
 		dev_err(hba->dev, "%s: Failed reading Product Name. err = %d\n",
 			__func__, err);
 		goto out;
 	}
 
-	str_desc_buf[QUERY_DESC_STRING_MAX_SIZE] = '\0';
+	str_desc_buf[QUERY_DESC_MAX_SIZE] = '\0';
 	strlcpy(dev_desc->model, (str_desc_buf + QUERY_DESC_HDR_SIZE),
 		min_t(u8, str_desc_buf[QUERY_DESC_LENGTH_OFFSET],
 		      MAX_MODEL_LEN));
···
 	hba->req_abort_count = 0;
 }
 
+static void ufshcd_init_desc_sizes(struct ufs_hba *hba)
+{
+	int err;
+
+	err = ufshcd_read_desc_length(hba, QUERY_DESC_IDN_DEVICE, 0,
+		&hba->desc_size.dev_desc);
+	if (err)
+		hba->desc_size.dev_desc = QUERY_DESC_DEVICE_DEF_SIZE;
+
+	err = ufshcd_read_desc_length(hba, QUERY_DESC_IDN_POWER, 0,
+		&hba->desc_size.pwr_desc);
+	if (err)
+		hba->desc_size.pwr_desc = QUERY_DESC_POWER_DEF_SIZE;
+
+	err = ufshcd_read_desc_length(hba, QUERY_DESC_IDN_INTERCONNECT, 0,
+		&hba->desc_size.interc_desc);
+	if (err)
+		hba->desc_size.interc_desc = QUERY_DESC_INTERCONNECT_DEF_SIZE;
+
+	err = ufshcd_read_desc_length(hba, QUERY_DESC_IDN_CONFIGURATION, 0,
+		&hba->desc_size.conf_desc);
+	if (err)
+		hba->desc_size.conf_desc = QUERY_DESC_CONFIGURATION_DEF_SIZE;
+
+	err = ufshcd_read_desc_length(hba, QUERY_DESC_IDN_UNIT, 0,
+		&hba->desc_size.unit_desc);
+	if (err)
+		hba->desc_size.unit_desc = QUERY_DESC_UNIT_DEF_SIZE;
+
+	err = ufshcd_read_desc_length(hba, QUERY_DESC_IDN_GEOMETRY, 0,
+		&hba->desc_size.geom_desc);
+	if (err)
+		hba->desc_size.geom_desc = QUERY_DESC_GEOMETRY_DEF_SIZE;
+}
+
+static void ufshcd_def_desc_sizes(struct ufs_hba *hba)
+{
+	hba->desc_size.dev_desc = QUERY_DESC_DEVICE_DEF_SIZE;
+	hba->desc_size.pwr_desc = QUERY_DESC_POWER_DEF_SIZE;
+	hba->desc_size.interc_desc = QUERY_DESC_INTERCONNECT_DEF_SIZE;
+	hba->desc_size.conf_desc = QUERY_DESC_CONFIGURATION_DEF_SIZE;
+	hba->desc_size.unit_desc = QUERY_DESC_UNIT_DEF_SIZE;
+	hba->desc_size.geom_desc = QUERY_DESC_GEOMETRY_DEF_SIZE;
+}
+
 /**
  * ufshcd_probe_hba - probe hba to detect device and initialize
  * @hba: per-adapter instance
···
 	ret = ufshcd_complete_dev_init(hba);
 	if (ret)
 		goto out;
+
+	/* Init check for device descriptor sizes */
+	ufshcd_init_desc_sizes(hba);
 
 	ret = ufs_get_device_desc(hba, &card);
 	if (ret) {
···
 
 	/* set the state as operational after switching to desired gear */
 	hba->ufshcd_state = UFSHCD_STATE_OPERATIONAL;
+
 	/*
 	 * If we are in error handling context or in power management callbacks
 	 * context, no need to scan the host
···
 
 	hba->mmio_base = mmio_base;
 	hba->irq = irq;
+
+	/* Set descriptor lengths to specification defaults */
+	ufshcd_def_desc_sizes(hba);
 
 	err = ufshcd_hba_init(hba);
 	if (err)

drivers/scsi/ufs/ufshcd.h

···
 	struct ufs_query query;
 };
 
+struct ufs_desc_size {
+	int dev_desc;
+	int pwr_desc;
+	int geom_desc;
+	int interc_desc;
+	int unit_desc;
+	int conf_desc;
+};
+
 /**
  * struct ufs_clk_info - UFS clock related info
  * @list: list headed by hba->clk_list_head
···
  * @clk_list_head: UFS host controller clocks list node head
  * @pwr_info: holds current power mode
  * @max_pwr_info: keeps the device max valid pwm
+ * @desc_size: descriptor sizes reported by device
  * @urgent_bkops_lvl: keeps track of urgent bkops level for device
  * @is_urgent_bkops_lvl_checked: keeps track if the urgent bkops level for
  *  device is known or not.
···
 	bool is_urgent_bkops_lvl_checked;
 
 	struct rw_semaphore clk_scaling_lock;
+	struct ufs_desc_size desc_size;
 };
 
 /* Returns true if clocks can be gated. Otherwise false */
···
 	enum flag_idn idn, bool *flag_res);
 int ufshcd_hold(struct ufs_hba *hba, bool async);
 void ufshcd_release(struct ufs_hba *hba);
+
+int ufshcd_map_desc_id_to_length(struct ufs_hba *hba, enum desc_idn desc_id,
+	int *desc_length);
+
 u32 ufshcd_get_local_unipro_ver(struct ufs_hba *hba);
 
 /* Wrapper functions for safely calling variant operations */