Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
 "This series has a huge amount of churn because it pulls in Mauro's doc
  update changing all our txt files to rst ones.

  Excluding that, we have the usual driver updates (qla2xxx, ufs, lpfc,
  zfcp, ibmvfc, pm80xx, aacraid), a treewide update for scnprintf and
  some other minor updates.

  The major core change is Hannes moving functions out of the aacraid
  driver and into the core"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (223 commits)
  scsi: aic7xxx: aic97xx: Remove FreeBSD-specific code
  scsi: ufs: Do not rely on prefetched data
  scsi: dc395x: remove dc395x_bios_param
  scsi: libiscsi: Fix error count for active session
  scsi: hpsa: correct race condition in offload enabled
  scsi: message: fusion: Replace zero-length array with flexible-array member
  scsi: qedi: Add PCI shutdown handler support
  scsi: qedi: Add MFW error recovery process
  scsi: ufs: Enable block layer runtime PM for well-known logical units
  scsi: ufs-qcom: Override devfreq parameters
  scsi: ufshcd: Let vendor override devfreq parameters
  scsi: ufshcd: Update the set frequency to devfreq
  scsi: ufs: Resume ufs host before accessing ufs device
  scsi: ufs-mediatek: customize the delay for enabling host
  scsi: ufs: make HCE polling more compact to improve initialization latency
  scsi: ufs: allow custom delay prior to host enabling
  scsi: ufs-mediatek: use common delay function
  scsi: ufs: introduce common and flexible delay function
  scsi: ufs: use an enum for host capabilities
  scsi: ufs: fix uninitialized tx_lanes in ufshcd_disable_tx_lcc()
  ...

1 files changed, 77 insertions, 0 deletions

diff --git a/Documentation/scsi/megaraid.rst b/Documentation/scsi/megaraid.rst
new file mode 100644
index 000000000000..22b75a86ba72
--- /dev/null
+++ b/Documentation/scsi/megaraid.rst
@@ -0,0 +1,77 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==========================
+Notes on Management Module
+==========================
+
+Overview
+--------
+
+Different classes of controllers from LSI Logic accept and respond to the
+user applications in a similar way. They understand the same firmware control
+commands. Furthermore, the applications also can treat different classes of
+the controllers uniformly. Hence it is logical to have a single module that
+interfaces with the applications on one side and all the low level drivers
+on the other.
+
+The advantages, though obvious, are listed for completeness:
+
+	i.	Avoid duplicate code from the low level drivers.
+	ii.	Unburden the low level drivers from having to export the
+		character node device and related handling.
+	iii.	Implement any policy mechanisms in one place.
+	iv.	Applications have to interface with only module instead of
+		multiple low level drivers.
+
+Currently this module (called Common Management Module) is used only to issue
+ioctl commands. But this module is envisioned to handle all user space level
+interactions. So any 'proc', 'sysfs' implementations will be localized in this
+common module.
+
+Credits
+-------
+
+::
+
+	"Shared code in a third module, a "library module", is an acceptable
+	solution. modprobe automatically loads dependent modules, so users
+	running "modprobe driver1" or "modprobe driver2" would automatically
+	load the shared library module."
+
+- Jeff Garzik (jgarzik@pobox.com), 02.25.2004 LKML
+
+::
+
+	"As Jeff hinted, if your userspace<->driver API is consistent between
+	your new MPT-based RAID controllers and your existing megaraid driver,
+	then perhaps you need a single small helper module (lsiioctl or some
+	better name), loaded by both mptraid and megaraid automatically, which
+	handles registering the /dev/megaraid node dynamically. In this case,
+	both mptraid and megaraid would register with lsiioctl for each
+	adapter discovered, and lsiioctl would essentially be a switch,
+	redirecting userspace tool ioctls to the appropriate driver."
+
+- Matt Domsch, (Matt_Domsch@dell.com), 02.25.2004 LKML
+
+Design
+------
+
+The Common Management Module is implemented in megaraid_mm.[ch] files. This
+module acts as a registry for low level hba drivers. The low level drivers
+(currently only megaraid) register each controller with the common module.
+
+The applications interface with the common module via the character device
+node exported by the module.
+
+The lower level drivers now understand only a new improved ioctl packet called
+uioc_t. The management module converts the older ioctl packets from the older
+applications into uioc_t. After driver handles the uioc_t, the common module
+will convert that back into the old format before returning to applications.
+
+As new applications evolve and replace the old ones, the old packet format
+will be retired.
+
+Common module dedicates one uioc_t packet to each controller registered. This
+can easily be more than one. But since megaraid is the only low level driver
+today, and it can handle only one ioctl, there is no reason to have more. But
+as new controller classes get added, this will be tuned appropriately.