ufs: introduce well known logical unit in ufs

UFS device may have standard LUs and LUN id could be from 0x00 to 0x7F.
UFS device specification use "Peripheral Device Addressing Format"
(SCSI SAM-5) for standard LUs.

UFS device may also have the Well Known LUs (also referred as W-LU) which
again could be from 0x00 to 0x7F. For W-LUs, UFS device specification only
allows the "Extended Addressing Format" (SCSI SAM-5) which means the W-LUNs
would start from 0xC100 onwards.

This means max. LUN number reported from UFS device could be 0xC17F hence
this patch advertise the "max_lun" as 0xC17F which will allow SCSI mid
layer to detect the W-LUs as well.

But once the W-LUs are detected, UFSHCD driver may get the commands with
SCSI LUN id upto 0xC17F but UPIU LUN id field is only 8-bit wide so it
requires the mapping of SCSI LUN id to UPIU LUN id. This patch also add
support for this mapping.

Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
Signed-off-by: Dolev Raviv <draviv@codeaurora.org>
Signed-off-by: Sujit Reddy Thumma <sthumma@codeaurora.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Author: Subhash Jadavani

drivers/scsi/ufs/ufs.h

@@ -49,9 +49,28 @@
 #define UPIU_HEADER_DWORD(byte3, byte2, byte1, byte0)\
 			cpu_to_be32((byte3 << 24) | (byte2 << 16) |\
 			 (byte1 << 8) | (byte0))
-
+/*
+ * UFS device may have standard LUs and LUN id could be from 0x00 to
+ * 0x7F. Standard LUs use "Peripheral Device Addressing Format".
+ * UFS device may also have the Well Known LUs (also referred as W-LU)
+ * which again could be from 0x00 to 0x7F. For W-LUs, device only use
+ * the "Extended Addressing Format" which means the W-LUNs would be
+ * from 0xc100 (SCSI_W_LUN_BASE) onwards.
+ * This means max. LUN number reported from UFS device could be 0xC17F.
+ */
+#define UFS_UPIU_MAX_UNIT_NUM_ID	0x7F
+#define UFS_MAX_LUNS		(SCSI_W_LUN_BASE + UFS_UPIU_MAX_UNIT_NUM_ID)
+#define UFS_UPIU_WLUN_ID	(1 << 7)
 #define UFS_UPIU_MAX_GENERAL_LUN	8
 
+/* Well known logical unit id in LUN field of UPIU */
+enum {
+	UFS_UPIU_REPORT_LUNS_WLUN	= 0x81,
+	UFS_UPIU_UFS_DEVICE_WLUN	= 0xD0,
+	UFS_UPIU_BOOT_WLUN		= 0xB0,
+	UFS_UPIU_RPMB_WLUN		= 0xC4,
+};
+
 /*
  * UFS Protocol Information Unit related definitions
  */

drivers/scsi/ufs/ufshcd.c

@@ -100,7 +100,6 @@ static u32 ufs_query_desc_max_size[] = {
 enum {
 	UFSHCD_MAX_CHANNEL	= 0,
 	UFSHCD_MAX_ID		= 1,
-	UFSHCD_MAX_LUNS		= 8,
 	UFSHCD_CMD_PER_LUN	= 32,
 	UFSHCD_CAN_QUEUE	= 32,
 };
@@ -901,6 +900,21 @@ static int ufshcd_compose_upiu(struct ufs_hba *hba, struct ufshcd_lrb *lrbp)
 	return ret;
 }
 
+/*
+ * ufshcd_scsi_to_upiu_lun - maps scsi LUN to UPIU LUN
+ * @scsi_lun: scsi LUN id
+ *
+ * Returns UPIU LUN id
+ */
+static inline u8 ufshcd_scsi_to_upiu_lun(unsigned int scsi_lun)
+{
+	if (scsi_is_wlun(scsi_lun))
+		return (scsi_lun & UFS_UPIU_MAX_UNIT_NUM_ID)
+			| UFS_UPIU_WLUN_ID;
+	else
+		return scsi_lun & UFS_UPIU_MAX_UNIT_NUM_ID;
+}
+
 /**
  * ufshcd_upiu_wlun_to_scsi_wlun - maps UPIU W-LUN id to SCSI W-LUN ID
  * @scsi_lun: UPIU W-LUN id
@@ -970,7 +984,7 @@ static int ufshcd_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *cmd)
 	lrbp->sense_bufflen = SCSI_SENSE_BUFFERSIZE;
 	lrbp->sense_buffer = cmd->sense_buffer;
 	lrbp->task_tag = tag;
-	lrbp->lun = cmd->device->lun;
+	lrbp->lun = ufshcd_scsi_to_upiu_lun(cmd->device->lun);
 	lrbp->intr_cmd = false;
 	lrbp->command_type = UTP_CMD_TYPE_SCSI;
 
@@ -1524,7 +1538,7 @@ static inline int ufshcd_read_unit_desc_param(struct ufs_hba *hba,
 	 * 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)
+	if (lun != UFS_UPIU_RPMB_WLUN && (lun >= UFS_UPIU_MAX_GENERAL_LUN))
 		return -EOPNOTSUPP;
 
 	return ufshcd_read_desc_param(hba, QUERY_DESC_IDN_UNIT, lun,
@@ -2154,6 +2168,44 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
 	return err;
 }
 
+/**
+ * ufshcd_set_queue_depth - set lun queue depth
+ * @sdev: pointer to SCSI device
+ *
+ * Read bLUQueueDepth value and activate scsi tagged command
+ * queueing. For WLUN, queue depth is set to 1. For best-effort
+ * cases (bLUQueueDepth = 0) the queue depth is set to a maximum
+ * value that host can queue.
+ */
+static void ufshcd_set_queue_depth(struct scsi_device *sdev)
+{
+	int ret = 0;
+	u8 lun_qdepth;
+	struct ufs_hba *hba;
+
+	hba = shost_priv(sdev->host);
+
+	lun_qdepth = hba->nutrs;
+	ret = ufshcd_read_unit_desc_param(hba,
+					  ufshcd_scsi_to_upiu_lun(sdev->lun),
+					  UNIT_DESC_PARAM_LU_Q_DEPTH,
+					  &lun_qdepth,
+					  sizeof(lun_qdepth));
+
+	/* Some WLUN doesn't support unit descriptor */
+	if (ret == -EOPNOTSUPP)
+		lun_qdepth = 1;
+	else if (!lun_qdepth)
+		/* eventually, we can figure out the real queue depth */
+		lun_qdepth = hba->nutrs;
+	else
+		lun_qdepth = min_t(int, lun_qdepth, hba->nutrs);
+
+	dev_dbg(hba->dev, "%s: activate tcq with queue depth %d\n",
+			__func__, lun_qdepth);
+	scsi_activate_tcq(sdev, lun_qdepth);
+}
+
 /**
  * ufshcd_slave_alloc - handle initial SCSI device configurations
  * @sdev: pointer to SCSI device
@@ -2163,8 +2215,6 @@ static int ufshcd_verify_dev_init(struct ufs_hba *hba)
 static int ufshcd_slave_alloc(struct scsi_device *sdev)
 {
 	struct ufs_hba *hba;
-	u8 lun_qdepth;
-	int ret;
 
 	hba = shost_priv(sdev->host);
 	sdev->tagged_supported = 1;
@@ -2179,20 +2229,8 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev)
 	/* REPORT SUPPORTED OPERATION CODES is not supported */
 	sdev->no_report_opcodes = 1;
 
-	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
-		lun_qdepth = min_t(int, lun_qdepth, hba->nutrs);
 
-	dev_dbg(hba->dev, "%s: activate tcq with queue depth %d\n",
-			__func__, lun_qdepth);
-	scsi_activate_tcq(sdev, lun_qdepth);
+	ufshcd_set_queue_depth(sdev);
 
 	return 0;
 }
@@ -2255,6 +2293,9 @@ static void ufshcd_slave_destroy(struct scsi_device *sdev)
 
 	hba = shost_priv(sdev->host);
 	scsi_deactivate_tcq(sdev, hba->nutrs);
+	/* Drop the reference as it won't be needed anymore */
+	if (ufshcd_scsi_to_upiu_lun(sdev->lun) == UFS_UPIU_UFS_DEVICE_WLUN)
+		hba->sdev_ufs_device = NULL;
 }
 
 /**
@@ -2972,7 +3013,10 @@ static int ufshcd_issue_tm_cmd(struct ufs_hba *hba, int lun_id, int task_id,
 					      lun_id, task_tag);
 	task_req_upiup->header.dword_1 =
 		UPIU_HEADER_DWORD(0, tm_function, 0, 0);
-
+	/*
+	 * The host shall provide the same value for LUN field in the basic
+	 * header and for Input Parameter.
+	 */
 	task_req_upiup->input_param1 = cpu_to_be32(lun_id);
 	task_req_upiup->input_param2 = cpu_to_be32(task_id);
 
@@ -4121,7 +4165,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem *mmio_base, unsigned int irq)
 	host->can_queue = hba->nutrs;
 	host->cmd_per_lun = hba->nutrs;
 	host->max_id = UFSHCD_MAX_ID;
-	host->max_lun = UFSHCD_MAX_LUNS;
+	host->max_lun = UFS_MAX_LUNS;
 	host->max_channel = UFSHCD_MAX_CHANNEL;
 	host->unique_id = host->host_no;
 	host->max_cmd_len = MAX_CDB_SIZE;

drivers/scsi/ufs/ufshcd.h

@@ -124,7 +124,7 @@ struct ufshcd_lrb {
 
 	int command_type;
 	int task_tag;
-	unsigned int lun;
+	u8 lun; /* UPIU LUN id field is only 8-bit wide */
 	bool intr_cmd;
 };