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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/arm/omap
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
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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 'Documentation/arm/omap')
-rw-r--r--Documentation/arm/omap/dss.rst372
-rw-r--r--Documentation/arm/omap/index.rst12
-rw-r--r--Documentation/arm/omap/omap.rst18
-rw-r--r--Documentation/arm/omap/omap_pm.rst165
4 files changed, 567 insertions, 0 deletions
diff --git a/Documentation/arm/omap/dss.rst b/Documentation/arm/omap/dss.rst
new file mode 100644
index 000000000..a40c4d9c7
--- /dev/null
+++ b/Documentation/arm/omap/dss.rst
@@ -0,0 +1,372 @@
+=========================
+OMAP2/3 Display Subsystem
+=========================
+
+This is an almost total rewrite of the OMAP FB driver in drivers/video/omap
+(let's call it DSS1). The main differences between DSS1 and DSS2 are DSI,
+TV-out and multiple display support, but there are lots of small improvements
+also.
+
+The DSS2 driver (omapdss module) is in arch/arm/plat-omap/dss/, and the FB,
+panel and controller drivers are in drivers/video/omap2/. DSS1 and DSS2 live
+currently side by side, you can choose which one to use.
+
+Features
+--------
+
+Working and tested features include:
+
+- MIPI DPI (parallel) output
+- MIPI DSI output in command mode
+- MIPI DBI (RFBI) output
+- SDI output
+- TV output
+- All pieces can be compiled as a module or inside kernel
+- Use DISPC to update any of the outputs
+- Use CPU to update RFBI or DSI output
+- OMAP DISPC planes
+- RGB16, RGB24 packed, RGB24 unpacked
+- YUV2, UYVY
+- Scaling
+- Adjusting DSS FCK to find a good pixel clock
+- Use DSI DPLL to create DSS FCK
+
+Tested boards include:
+- OMAP3 SDP board
+- Beagle board
+- N810
+
+omapdss driver
+--------------
+
+The DSS driver does not itself have any support for Linux framebuffer, V4L or
+such like the current ones, but it has an internal kernel API that upper level
+drivers can use.
+
+The DSS driver models OMAP's overlays, overlay managers and displays in a
+flexible way to enable non-common multi-display configuration. In addition to
+modelling the hardware overlays, omapdss supports virtual overlays and overlay
+managers. These can be used when updating a display with CPU or system DMA.
+
+omapdss driver support for audio
+--------------------------------
+There exist several display technologies and standards that support audio as
+well. Hence, it is relevant to update the DSS device driver to provide an audio
+interface that may be used by an audio driver or any other driver interested in
+the functionality.
+
+The audio_enable function is intended to prepare the relevant
+IP for playback (e.g., enabling an audio FIFO, taking in/out of reset
+some IP, enabling companion chips, etc). It is intended to be called before
+audio_start. The audio_disable function performs the reverse operation and is
+intended to be called after audio_stop.
+
+While a given DSS device driver may support audio, it is possible that for
+certain configurations audio is not supported (e.g., an HDMI display using a
+VESA video timing). The audio_supported function is intended to query whether
+the current configuration of the display supports audio.
+
+The audio_config function is intended to configure all the relevant audio
+parameters of the display. In order to make the function independent of any
+specific DSS device driver, a struct omap_dss_audio is defined. Its purpose
+is to contain all the required parameters for audio configuration. At the
+moment, such structure contains pointers to IEC-60958 channel status word
+and CEA-861 audio infoframe structures. This should be enough to support
+HDMI and DisplayPort, as both are based on CEA-861 and IEC-60958.
+
+The audio_enable/disable, audio_config and audio_supported functions could be
+implemented as functions that may sleep. Hence, they should not be called
+while holding a spinlock or a readlock.
+
+The audio_start/audio_stop function is intended to effectively start/stop audio
+playback after the configuration has taken place. These functions are designed
+to be used in an atomic context. Hence, audio_start should return quickly and be
+called only after all the needed resources for audio playback (audio FIFOs,
+DMA channels, companion chips, etc) have been enabled to begin data transfers.
+audio_stop is designed to only stop the audio transfers. The resources used
+for playback are released using audio_disable.
+
+The enum omap_dss_audio_state may be used to help the implementations of
+the interface to keep track of the audio state. The initial state is _DISABLED;
+then, the state transitions to _CONFIGURED, and then, when it is ready to
+play audio, to _ENABLED. The state _PLAYING is used when the audio is being
+rendered.
+
+
+Panel and controller drivers
+----------------------------
+
+The drivers implement panel or controller specific functionality and are not
+usually visible to users except through omapfb driver. They register
+themselves to the DSS driver.
+
+omapfb driver
+-------------
+
+The omapfb driver implements arbitrary number of standard linux framebuffers.
+These framebuffers can be routed flexibly to any overlays, thus allowing very
+dynamic display architecture.
+
+The driver exports some omapfb specific ioctls, which are compatible with the
+ioctls in the old driver.
+
+The rest of the non standard features are exported via sysfs. Whether the final
+implementation will use sysfs, or ioctls, is still open.
+
+V4L2 drivers
+------------
+
+V4L2 is being implemented in TI.
+
+From omapdss point of view the V4L2 drivers should be similar to framebuffer
+driver.
+
+Architecture
+--------------------
+
+Some clarification what the different components do:
+
+ - Framebuffer is a memory area inside OMAP's SRAM/SDRAM that contains the
+ pixel data for the image. Framebuffer has width and height and color
+ depth.
+ - Overlay defines where the pixels are read from and where they go on the
+ screen. The overlay may be smaller than framebuffer, thus displaying only
+ part of the framebuffer. The position of the overlay may be changed if
+ the overlay is smaller than the display.
+ - Overlay manager combines the overlays in to one image and feeds them to
+ display.
+ - Display is the actual physical display device.
+
+A framebuffer can be connected to multiple overlays to show the same pixel data
+on all of the overlays. Note that in this case the overlay input sizes must be
+the same, but, in case of video overlays, the output size can be different. Any
+framebuffer can be connected to any overlay.
+
+An overlay can be connected to one overlay manager. Also DISPC overlays can be
+connected only to DISPC overlay managers, and virtual overlays can be only
+connected to virtual overlays.
+
+An overlay manager can be connected to one display. There are certain
+restrictions which kinds of displays an overlay manager can be connected:
+
+ - DISPC TV overlay manager can be only connected to TV display.
+ - Virtual overlay managers can only be connected to DBI or DSI displays.
+ - DISPC LCD overlay manager can be connected to all displays, except TV
+ display.
+
+Sysfs
+-----
+The sysfs interface is mainly used for testing. I don't think sysfs
+interface is the best for this in the final version, but I don't quite know
+what would be the best interfaces for these things.
+
+The sysfs interface is divided to two parts: DSS and FB.
+
+/sys/class/graphics/fb? directory:
+mirror 0=off, 1=on
+rotate Rotation 0-3 for 0, 90, 180, 270 degrees
+rotate_type 0 = DMA rotation, 1 = VRFB rotation
+overlays List of overlay numbers to which framebuffer pixels go
+phys_addr Physical address of the framebuffer
+virt_addr Virtual address of the framebuffer
+size Size of the framebuffer
+
+/sys/devices/platform/omapdss/overlay? directory:
+enabled 0=off, 1=on
+input_size width,height (ie. the framebuffer size)
+manager Destination overlay manager name
+name
+output_size width,height
+position x,y
+screen_width width
+global_alpha global alpha 0-255 0=transparent 255=opaque
+
+/sys/devices/platform/omapdss/manager? directory:
+display Destination display
+name
+alpha_blending_enabled 0=off, 1=on
+trans_key_enabled 0=off, 1=on
+trans_key_type gfx-destination, video-source
+trans_key_value transparency color key (RGB24)
+default_color default background color (RGB24)
+
+/sys/devices/platform/omapdss/display? directory:
+
+=============== =============================================================
+ctrl_name Controller name
+mirror 0=off, 1=on
+update_mode 0=off, 1=auto, 2=manual
+enabled 0=off, 1=on
+name
+rotate Rotation 0-3 for 0, 90, 180, 270 degrees
+timings Display timings (pixclock,xres/hfp/hbp/hsw,yres/vfp/vbp/vsw)
+ When writing, two special timings are accepted for tv-out:
+ "pal" and "ntsc"
+panel_name
+tear_elim Tearing elimination 0=off, 1=on
+output_type Output type (video encoder only): "composite" or "svideo"
+=============== =============================================================
+
+There are also some debugfs files at <debugfs>/omapdss/ which show information
+about clocks and registers.
+
+Examples
+--------
+
+The following definitions have been made for the examples below::
+
+ ovl0=/sys/devices/platform/omapdss/overlay0
+ ovl1=/sys/devices/platform/omapdss/overlay1
+ ovl2=/sys/devices/platform/omapdss/overlay2
+
+ mgr0=/sys/devices/platform/omapdss/manager0
+ mgr1=/sys/devices/platform/omapdss/manager1
+
+ lcd=/sys/devices/platform/omapdss/display0
+ dvi=/sys/devices/platform/omapdss/display1
+ tv=/sys/devices/platform/omapdss/display2
+
+ fb0=/sys/class/graphics/fb0
+ fb1=/sys/class/graphics/fb1
+ fb2=/sys/class/graphics/fb2
+
+Default setup on OMAP3 SDP
+--------------------------
+
+Here's the default setup on OMAP3 SDP board. All planes go to LCD. DVI
+and TV-out are not in use. The columns from left to right are:
+framebuffers, overlays, overlay managers, displays. Framebuffers are
+handled by omapfb, and the rest by the DSS::
+
+ FB0 --- GFX -\ DVI
+ FB1 --- VID1 --+- LCD ---- LCD
+ FB2 --- VID2 -/ TV ----- TV
+
+Example: Switch from LCD to DVI
+-------------------------------
+
+::
+
+ w=`cat $dvi/timings | cut -d "," -f 2 | cut -d "/" -f 1`
+ h=`cat $dvi/timings | cut -d "," -f 3 | cut -d "/" -f 1`
+
+ echo "0" > $lcd/enabled
+ echo "" > $mgr0/display
+ fbset -fb /dev/fb0 -xres $w -yres $h -vxres $w -vyres $h
+ # at this point you have to switch the dvi/lcd dip-switch from the omap board
+ echo "dvi" > $mgr0/display
+ echo "1" > $dvi/enabled
+
+After this the configuration looks like:::
+
+ FB0 --- GFX -\ -- DVI
+ FB1 --- VID1 --+- LCD -/ LCD
+ FB2 --- VID2 -/ TV ----- TV
+
+Example: Clone GFX overlay to LCD and TV
+----------------------------------------
+
+::
+
+ w=`cat $tv/timings | cut -d "," -f 2 | cut -d "/" -f 1`
+ h=`cat $tv/timings | cut -d "," -f 3 | cut -d "/" -f 1`
+
+ echo "0" > $ovl0/enabled
+ echo "0" > $ovl1/enabled
+
+ echo "" > $fb1/overlays
+ echo "0,1" > $fb0/overlays
+
+ echo "$w,$h" > $ovl1/output_size
+ echo "tv" > $ovl1/manager
+
+ echo "1" > $ovl0/enabled
+ echo "1" > $ovl1/enabled
+
+ echo "1" > $tv/enabled
+
+After this the configuration looks like (only relevant parts shown)::
+
+ FB0 +-- GFX ---- LCD ---- LCD
+ \- VID1 ---- TV ---- TV
+
+Misc notes
+----------
+
+OMAP FB allocates the framebuffer memory using the standard dma allocator. You
+can enable Contiguous Memory Allocator (CONFIG_CMA) to improve the dma
+allocator, and if CMA is enabled, you use "cma=" kernel parameter to increase
+the global memory area for CMA.
+
+Using DSI DPLL to generate pixel clock it is possible produce the pixel clock
+of 86.5MHz (max possible), and with that you get 1280x1024@57 output from DVI.
+
+Rotation and mirroring currently only supports RGB565 and RGB8888 modes. VRFB
+does not support mirroring.
+
+VRFB rotation requires much more memory than non-rotated framebuffer, so you
+probably need to increase your vram setting before using VRFB rotation. Also,
+many applications may not work with VRFB if they do not pay attention to all
+framebuffer parameters.
+
+Kernel boot arguments
+---------------------
+
+omapfb.mode=<display>:<mode>[,...]
+ - Default video mode for specified displays. For example,
+ "dvi:800x400MR-24@60". See drivers/video/modedb.c.
+ There are also two special modes: "pal" and "ntsc" that
+ can be used to tv out.
+
+omapfb.vram=<fbnum>:<size>[@<physaddr>][,...]
+ - VRAM allocated for a framebuffer. Normally omapfb allocates vram
+ depending on the display size. With this you can manually allocate
+ more or define the physical address of each framebuffer. For example,
+ "1:4M" to allocate 4M for fb1.
+
+omapfb.debug=<y|n>
+ - Enable debug printing. You have to have OMAPFB debug support enabled
+ in kernel config.
+
+omapfb.test=<y|n>
+ - Draw test pattern to framebuffer whenever framebuffer settings change.
+ You need to have OMAPFB debug support enabled in kernel config.
+
+omapfb.vrfb=<y|n>
+ - Use VRFB rotation for all framebuffers.
+
+omapfb.rotate=<angle>
+ - Default rotation applied to all framebuffers.
+ 0 - 0 degree rotation
+ 1 - 90 degree rotation
+ 2 - 180 degree rotation
+ 3 - 270 degree rotation
+
+omapfb.mirror=<y|n>
+ - Default mirror for all framebuffers. Only works with DMA rotation.
+
+omapdss.def_disp=<display>
+ - Name of default display, to which all overlays will be connected.
+ Common examples are "lcd" or "tv".
+
+omapdss.debug=<y|n>
+ - Enable debug printing. You have to have DSS debug support enabled in
+ kernel config.
+
+TODO
+----
+
+DSS locking
+
+Error checking
+
+- Lots of checks are missing or implemented just as BUG()
+
+System DMA update for DSI
+
+- Can be used for RGB16 and RGB24P modes. Probably not for RGB24U (how
+ to skip the empty byte?)
+
+OMAP1 support
+
+- Not sure if needed
diff --git a/Documentation/arm/omap/index.rst b/Documentation/arm/omap/index.rst
new file mode 100644
index 000000000..8b365b212
--- /dev/null
+++ b/Documentation/arm/omap/index.rst
@@ -0,0 +1,12 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=======
+TI OMAP
+=======
+
+.. toctree::
+ :maxdepth: 1
+
+ omap
+ omap_pm
+ dss
diff --git a/Documentation/arm/omap/omap.rst b/Documentation/arm/omap/omap.rst
new file mode 100644
index 000000000..f440c0f46
--- /dev/null
+++ b/Documentation/arm/omap/omap.rst
@@ -0,0 +1,18 @@
+============
+OMAP history
+============
+
+This file contains documentation for running mainline
+kernel on omaps.
+
+====== ======================================================
+KERNEL NEW DEPENDENCIES
+====== ======================================================
+v4.3+ Update is needed for custom .config files to make sure
+ CONFIG_REGULATOR_PBIAS is enabled for MMC1 to work
+ properly.
+
+v4.18+ Update is needed for custom .config files to make sure
+ CONFIG_MMC_SDHCI_OMAP is enabled for all MMC instances
+ to work in DRA7 and K2G based boards.
+====== ======================================================
diff --git a/Documentation/arm/omap/omap_pm.rst b/Documentation/arm/omap/omap_pm.rst
new file mode 100644
index 000000000..a335e4c8c
--- /dev/null
+++ b/Documentation/arm/omap/omap_pm.rst
@@ -0,0 +1,165 @@
+=====================
+The OMAP PM interface
+=====================
+
+This document describes the temporary OMAP PM interface. Driver
+authors use these functions to communicate minimum latency or
+throughput constraints to the kernel power management code.
+Over time, the intention is to merge features from the OMAP PM
+interface into the Linux PM QoS code.
+
+Drivers need to express PM parameters which:
+
+- support the range of power management parameters present in the TI SRF;
+
+- separate the drivers from the underlying PM parameter
+ implementation, whether it is the TI SRF or Linux PM QoS or Linux
+ latency framework or something else;
+
+- specify PM parameters in terms of fundamental units, such as
+ latency and throughput, rather than units which are specific to OMAP
+ or to particular OMAP variants;
+
+- allow drivers which are shared with other architectures (e.g.,
+ DaVinci) to add these constraints in a way which won't affect non-OMAP
+ systems,
+
+- can be implemented immediately with minimal disruption of other
+ architectures.
+
+
+This document proposes the OMAP PM interface, including the following
+five power management functions for driver code:
+
+1. Set the maximum MPU wakeup latency::
+
+ (*pdata->set_max_mpu_wakeup_lat)(struct device *dev, unsigned long t)
+
+2. Set the maximum device wakeup latency::
+
+ (*pdata->set_max_dev_wakeup_lat)(struct device *dev, unsigned long t)
+
+3. Set the maximum system DMA transfer start latency (CORE pwrdm)::
+
+ (*pdata->set_max_sdma_lat)(struct device *dev, long t)
+
+4. Set the minimum bus throughput needed by a device::
+
+ (*pdata->set_min_bus_tput)(struct device *dev, u8 agent_id, unsigned long r)
+
+5. Return the number of times the device has lost context::
+
+ (*pdata->get_dev_context_loss_count)(struct device *dev)
+
+
+Further documentation for all OMAP PM interface functions can be
+found in arch/arm/plat-omap/include/mach/omap-pm.h.
+
+
+The OMAP PM layer is intended to be temporary
+---------------------------------------------
+
+The intention is that eventually the Linux PM QoS layer should support
+the range of power management features present in OMAP3. As this
+happens, existing drivers using the OMAP PM interface can be modified
+to use the Linux PM QoS code; and the OMAP PM interface can disappear.
+
+
+Driver usage of the OMAP PM functions
+-------------------------------------
+
+As the 'pdata' in the above examples indicates, these functions are
+exposed to drivers through function pointers in driver .platform_data
+structures. The function pointers are initialized by the `board-*.c`
+files to point to the corresponding OMAP PM functions:
+
+- set_max_dev_wakeup_lat will point to
+ omap_pm_set_max_dev_wakeup_lat(), etc. Other architectures which do
+ not support these functions should leave these function pointers set
+ to NULL. Drivers should use the following idiom::
+
+ if (pdata->set_max_dev_wakeup_lat)
+ (*pdata->set_max_dev_wakeup_lat)(dev, t);
+
+The most common usage of these functions will probably be to specify
+the maximum time from when an interrupt occurs, to when the device
+becomes accessible. To accomplish this, driver writers should use the
+set_max_mpu_wakeup_lat() function to constrain the MPU wakeup
+latency, and the set_max_dev_wakeup_lat() function to constrain the
+device wakeup latency (from clk_enable() to accessibility). For
+example::
+
+ /* Limit MPU wakeup latency */
+ if (pdata->set_max_mpu_wakeup_lat)
+ (*pdata->set_max_mpu_wakeup_lat)(dev, tc);
+
+ /* Limit device powerdomain wakeup latency */
+ if (pdata->set_max_dev_wakeup_lat)
+ (*pdata->set_max_dev_wakeup_lat)(dev, td);
+
+ /* total wakeup latency in this example: (tc + td) */
+
+The PM parameters can be overwritten by calling the function again
+with the new value. The settings can be removed by calling the
+function with a t argument of -1 (except in the case of
+set_max_bus_tput(), which should be called with an r argument of 0).
+
+The fifth function above, omap_pm_get_dev_context_loss_count(),
+is intended as an optimization to allow drivers to determine whether the
+device has lost its internal context. If context has been lost, the
+driver must restore its internal context before proceeding.
+
+
+Other specialized interface functions
+-------------------------------------
+
+The five functions listed above are intended to be usable by any
+device driver. DSPBridge and CPUFreq have a few special requirements.
+DSPBridge expresses target DSP performance levels in terms of OPP IDs.
+CPUFreq expresses target MPU performance levels in terms of MPU
+frequency. The OMAP PM interface contains functions for these
+specialized cases to convert that input information (OPPs/MPU
+frequency) into the form that the underlying power management
+implementation needs:
+
+6. `(*pdata->dsp_get_opp_table)(void)`
+
+7. `(*pdata->dsp_set_min_opp)(u8 opp_id)`
+
+8. `(*pdata->dsp_get_opp)(void)`
+
+9. `(*pdata->cpu_get_freq_table)(void)`
+
+10. `(*pdata->cpu_set_freq)(unsigned long f)`
+
+11. `(*pdata->cpu_get_freq)(void)`
+
+Customizing OPP for platform
+============================
+Defining CONFIG_PM should enable OPP layer for the silicon
+and the registration of OPP table should take place automatically.
+However, in special cases, the default OPP table may need to be
+tweaked, for e.g.:
+
+ * enable default OPPs which are disabled by default, but which
+ could be enabled on a platform
+ * Disable an unsupported OPP on the platform
+ * Define and add a custom opp table entry
+ in these cases, the board file needs to do additional steps as follows:
+
+arch/arm/mach-omapx/board-xyz.c::
+
+ #include "pm.h"
+ ....
+ static void __init omap_xyz_init_irq(void)
+ {
+ ....
+ /* Initialize the default table */
+ omapx_opp_init();
+ /* Do customization to the defaults */
+ ....
+ }
+
+NOTE:
+ omapx_opp_init will be omap3_opp_init or as required
+ based on the omap family.