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-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
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diff --git a/Documentation/arm/omap/dss.rst b/Documentation/arm/omap/dss.rst
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+=========================
+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
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+.. 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
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+============
+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
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+=====================
+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.