aboutsummaryrefslogtreecommitdiff
path: root/Documentation/scsi/scsi-changer.rst
diff options
context:
space:
mode:
authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/scsi/scsi-changer.rst
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to '')
-rw-r--r--Documentation/scsi/scsi-changer.rst184
1 files changed, 184 insertions, 0 deletions
diff --git a/Documentation/scsi/scsi-changer.rst b/Documentation/scsi/scsi-changer.rst
new file mode 100644
index 000000000..ab60e7e61
--- /dev/null
+++ b/Documentation/scsi/scsi-changer.rst
@@ -0,0 +1,184 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+========================================
+README for the SCSI media changer driver
+========================================
+
+This is a driver for SCSI Medium Changer devices, which are listed
+with "Type: Medium Changer" in /proc/scsi/scsi.
+
+This is for *real* Jukeboxes. It is *not* supported to work with
+common small CD-ROM changers, neither one-lun-per-slot SCSI changers
+nor IDE drives.
+
+Userland tools available from here:
+ http://linux.bytesex.org/misc/changer.html
+
+
+General Information
+-------------------
+
+First some words about how changers work: A changer has 2 (possibly
+more) SCSI ID's. One for the changer device which controls the robot,
+and one for the device which actually reads and writes the data. The
+later may be anything, a MOD, a CD-ROM, a tape or whatever. For the
+changer device this is a "don't care", he *only* shuffles around the
+media, nothing else.
+
+
+The SCSI changer model is complex, compared to - for example - IDE-CD
+changers. But it allows to handle nearly all possible cases. It knows
+4 different types of changer elements:
+
+ =============== ==================================================
+ media transport this one shuffles around the media, i.e. the
+ transport arm. Also known as "picker".
+ storage a slot which can hold a media.
+ import/export the same as above, but is accessible from outside,
+ i.e. there the operator (you !) can use this to
+ fill in and remove media from the changer.
+ Sometimes named "mailslot".
+ data transfer this is the device which reads/writes, i.e. the
+ CD-ROM / Tape / whatever drive.
+ =============== ==================================================
+
+None of these is limited to one: A huge Jukebox could have slots for
+123 CD-ROM's, 5 CD-ROM readers (and therefore 6 SCSI ID's: the changer
+and each CD-ROM) and 2 transport arms. No problem to handle.
+
+
+How it is implemented
+---------------------
+
+I implemented the driver as character device driver with a NetBSD-like
+ioctl interface. Just grabbed NetBSD's header file and one of the
+other linux SCSI device drivers as starting point. The interface
+should be source code compatible with NetBSD. So if there is any
+software (anybody knows ???) which supports a BSDish changer driver,
+it should work with this driver too.
+
+Over time a few more ioctls where added, volume tag support for example
+wasn't covered by the NetBSD ioctl API.
+
+
+Current State
+-------------
+
+Support for more than one transport arm is not implemented yet (and
+nobody asked for it so far...).
+
+I test and use the driver myself with a 35 slot cdrom jukebox from
+Grundig. I got some reports telling it works ok with tape autoloaders
+(Exabyte, HP and DEC). Some People use this driver with amanda. It
+works fine with small (11 slots) and a huge (4 MOs, 88 slots)
+magneto-optical Jukebox. Probably with lots of other changers too, most
+(but not all :-) people mail me only if it does *not* work...
+
+I don't have any device lists, neither black-list nor white-list. Thus
+it is quite useless to ask me whenever a specific device is supported or
+not. In theory every changer device which supports the SCSI-2 media
+changer command set should work out-of-the-box with this driver. If it
+doesn't, it is a bug. Either within the driver or within the firmware
+of the changer device.
+
+
+Using it
+--------
+
+This is a character device with major number is 86, so use
+"mknod /dev/sch0 c 86 0" to create the special file for the driver.
+
+If the module finds the changer, it prints some messages about the
+device [ try "dmesg" if you don't see anything ] and should show up in
+/proc/devices. If not.... some changers use ID ? / LUN 0 for the
+device and ID ? / LUN 1 for the robot mechanism. But Linux does *not*
+look for LUNs other than 0 as default, because there are too many
+broken devices. So you can try:
+
+ 1) echo "scsi add-single-device 0 0 ID 1" > /proc/scsi/scsi
+ (replace ID with the SCSI-ID of the device)
+ 2) boot the kernel with "max_scsi_luns=1" on the command line
+ (append="max_scsi_luns=1" in lilo.conf should do the trick)
+
+
+Trouble?
+--------
+
+If you insmod the driver with "insmod debug=1", it will be verbose and
+prints a lot of stuff to the syslog. Compiling the kernel with
+CONFIG_SCSI_CONSTANTS=y improves the quality of the error messages a lot
+because the kernel will translate the error codes into human-readable
+strings then.
+
+You can display these messages with the dmesg command (or check the
+logfiles). If you email me some question because of a problem with the
+driver, please include these messages.
+
+
+Insmod options
+--------------
+
+debug=0/1
+ Enable debug messages (see above, default: 0).
+
+verbose=0/1
+ Be verbose (default: 1).
+
+init=0/1
+ Send INITIALIZE ELEMENT STATUS command to the changer
+ at insmod time (default: 1).
+
+timeout_init=<seconds>
+ timeout for the INITIALIZE ELEMENT STATUS command
+ (default: 3600).
+
+timeout_move=<seconds>
+ timeout for all other commands (default: 120).
+
+dt_id=<id1>,<id2>,... / dt_lun=<lun1>,<lun2>,...
+ These two allow to specify the SCSI ID and LUN for the data
+ transfer elements. You likely don't need this as the jukebox
+ should provide this information. But some devices don't ...
+
+vendor_firsts=, vendor_counts=, vendor_labels=
+ These insmod options can be used to tell the driver that there
+ are some vendor-specific element types. Grundig for example
+ does this. Some jukeboxes have a printer to label fresh burned
+ CDs, which is addressed as element 0xc000 (type 5). To tell the
+ driver about this vendor-specific element, use this::
+
+ $ insmod ch \
+ vendor_firsts=0xc000 \
+ vendor_counts=1 \
+ vendor_labels=printer
+
+ All three insmod options accept up to four comma-separated
+ values, this way you can configure the element types 5-8.
+ You likely need the SCSI specs for the device in question to
+ find the correct values as they are not covered by the SCSI-2
+ standard.
+
+
+Credits
+-------
+
+I wrote this driver using the famous mailing-patches-around-the-world
+method. With (more or less) help from:
+
+ - Daniel Moehwald <moehwald@hdg.de>
+ - Dane Jasper <dane@sonic.net>
+ - R. Scott Bailey <sbailey@dsddi.eds.com>
+ - Jonathan Corbet <corbet@lwn.net>
+
+Special thanks go to
+
+ - Martin Kuehne <martin.kuehne@bnbt.de>
+
+for a old, second-hand (but full functional) cdrom jukebox which I use
+to develop/test driver and tools now.
+
+Have fun,
+
+ Gerd
+
+Gerd Knorr <kraxel@bytesex.org>