Re: [PATCH v7 00/12] dmaengine/soc: Add Texas Instruments UDMA support

[Peter Ujfalusi <peter.ujfalusi@ti.com>]

On 09/12/2019 11.43, Peter Ujfalusi wrote:
> Hi,
> 
> Vinod, Nishanth, Tero, Santosh: the ti_sci patch in this series was sent
> upstream over a month ago:
> https://lore.kernel.org/lkml/20191025084715.25098-1-peter.ujfalusi@ti.com/
> 
> I'm still waiting on it's fate (Tero has given his r-b).
> The ti_sci patch did not made it to 5.5-rc1, but I included it in the series and
> let the maintainers decide if it can go via DMAengine for 5.6 or to later
> releases (5.6 probably for the ti_sci and 5.7 for the UDMA driver patch).
> 
> Changes since v6:
> (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=209455&state=*)
> 
> - UDMAP DMAengine driver:
>  - Squashed the split patches
>  - Squashed the early TX completion handling update
>    (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=210713&state=*)
>  - Hard reset fix for RX channels to avoid channel lockdown
>  - Correct completed descriptor's residue value

I got build failure with allmodconfig:

ERROR: "devm_ti_sci_get_of_resource" [drivers/soc/ti/k3-ringacc.ko]
undefined!
ERROR: "of_msi_get_domain" [drivers/soc/ti/k3-ringacc.ko] undefined!
ERROR: "devm_ti_sci_get_of_resource" [drivers/dma/ti/k3-udma.ko] undefined!
ERROR: "of_msi_get_domain" [drivers/dma/ti/k3-udma.ko] undefined!

They are because both devm_ti_sci_get_of_resource and of_msi_get_domain
is missing EXPORT_SYMBOL_GPL(), so they can not be used from modules.

There were patches in the past to add it for of_msi_get_domain:
https://lore.kernel.org/patchwork/patch/668123/
https://lore.kernel.org/patchwork/patch/716046/

I can not find a reason why these are not merged.
Matthias's patch looks to be the earlier one, is it OK if I resend it
within v8?

> Changes since v5:
> (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=201051&state=*)
> - Based on 5.4
> 
> - cppi5 header
>  - clear the bits before setting new value with '|='
> 
> - UDMAP DT bindings:
>  - valid compatibles as single enum list
> 
> - UDMAP DMAengine driver:
>  - Fix udma_is_chan_running()
>  - Use flags for acc32, burst support instead of a bool in udma_match_data
>    struct
>  - TDTYPE handling (teardown completion handling for j721e) is moved to separate
>    patch as the tisci core patch has not moved for over a month.
>    Both ti_sci and the iterative patch to udma is included in the series.
> 
> Changes since v4
> (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=196619&state=*)
> - Based on 5.4-rc7
> 
> - ringacc DT bindings:
>  - clarify the meaning of ti,sci-dev-id
> 
> - ringacc driver:
>  - Remove 'default y' from Kconfig
>  - Fix struct comments
>  - Move try_module_get() earlier in k3_ringacc_request_ring()
> 
> - PSI-L thread database:
>  - Add kernel style struct/enum documentation
>  - Add missing thread description for sa2ul second interface
>  - Change EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
> 
> - UDMAP DT bindings:
>  - move to dual license
>  - change compatible from const to enum
>  - items dropped for ti,sci-rm-ranges-*
>  - description text moved from literal block when it is sensible
>  - example fixed to compile cleanly
>   - added parent to provide correct address-cells
>   - navss is moved to simple-mfd from simple-bus
> 
> - UDMAP DMAengine driver:
>  - move fd_ring/r_ring under rflow
>  - get rid of unused iomem for rflows
>  - Remove 'default y' from Kconfig
>  - Use defines for rflow src/dst tag selection
>  - Merge the udma_ring_callback() and udma_tr_event_callback() to their
>    corresponding interrupt handler
>  - Create new defines for tx/rx channel's tisci valid parameter flags
>  - Remove re-initialization to 0 of tisci request struct members
>  - Make sure that vchan tasklets are also stopped when removing the module
>  - Additional checkpatch --strict fixes when it made sense
>   - make W=1 was clean
> 
> - UDMAP glue layer:
>  - Remove 'default y' from Kconfig
>  - commit message update for features needing the glue layer
> 
> Changes since v3
> (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=180679&state=*):
> - Based on 5.4-rc5
> - Fixed typos pointed out by Tero
> - Added reviewed-by tags from Tero
> 
> - ring accelerator driver
>  - TODO_GS is removed from the header
>  - pm_runtime removed as NAVSS and it's components are always on
>  - Check validity of Message mode setup (element size > 8 bytes must use proxy)
> 
> - cppi5 header
>  - add commit message
> 
> - UDMAP DT bindings
>  - Drop the psil-config node use on the remote PSI-L side and use only one cell
>    which is the remote threadID:
> 
>      dmas = <&main_udmap 0xc400>, <&main_udmap 0x4400>;
>      dma-names = "tx", "rx";
> 
>  - The PSI-L thread configuration description is moved to kernel as a new module:
>    k3-psil/k3-psil-am654/k3-psil-j721e
>  - ti,psil-base has been removed and moved to kernel
>  - removed the no longer needed dt-bindings/dma/k3-udma.h
>  - Convert the document to schema (yaml)
> 
> - NEW PSI-L endpoint configuration database
>  - a simple database holding the remote end's configuration needed for UDMAP
>    configuration. All previous parameters from DT has been moved here and merged
>    with the linux only tr mode channel flag.
>  - Client drivers can update the remote endpoint configuration as it can be
>    different based on system configuration and the endpoint itself is under the
>    control of the peripheral driver.
>  - database for am654 and j721e
> 
> - UDMAP DMAengine driver
>  - pm_runtime removed as NAVSS and it's components are always on
>  - rchan_oes_offset added to MSI dommain allocation
>  - Use the new PSI-L endpoint database for UDMAP configuration
>  - Support for waiting for PDMA teardown completion on j721e instead of
>    returning right away. depends on:
>    https://lkml.org/lkml/2019/10/25/189
>    Not included in this series, but it is in the branch I have prepared.
>  - psil-base is moved from DT to be part of udma_match_data
>  - tr_thread maps is removed and using the PSI-L endpoint configuration for it
> 
> - UDMAP glue layer
>  - pm_runtime removed as NAVSS and it's components are always on
>  - Use the new PSI-L endpoint database for UDMAP configuration
> 
> Changes since v2
> (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=152609&state=*)
> - Based on 5.4-rc1
> - Support for Flow only data transfer for the glue layer
> 
> - cppi5 header
>  - comments converted to kernel-doc style
>  - Remove the excessive WARN_ONs and rely on the user for sanity
>  - new macro for checking TearDown Completion Message
> 
> - ring accelerator driver
>  - fixed up th commit message (SoB, TI-SCI)
>  - fixed ring reset
>  - CONFIG_TI_K3_RINGACC_DEBUG is removed along with the dbg_write/read functions
>    and use dev_dbg()
>  - k3_ringacc_ring_dump() is moved to static
>  - step numbering removed from k3_ringacc_ring_reset_dma()
>  - Add clarification comment for shared ring usage in k3_ringacc_ring_cfg()
>  - Magic shift values in k3_ringacc_ring_cfg_proxy() got defined
>  - K3_RINGACC_RING_MODE_QM is removed as it is not supported
> 
> - UDMAP DT bindings
>  - Fix property prefixing: s/pdma,/ti,pdma-
>  - Add ti,notdpkt property to suppress teardown completion message on tchan
>  - example updated accordingly
> 
> - UDMAP DMAengine driver
>  - Change __raw_readl/writel to readl/writel
>  - Split up the udma_tisci_channel_config() into m2m, tx and rx tisci
>    configuration functions for clarity
>  - DT bindings change: s/pdma,/ti,pdma-
>  - Cleanup of udma_tx_status():
>   - residue calculation fix for m2m
>   - no need to read packet counter as it is not used
>   - peer byte counter only available in PDMAs
>   - Proper locking to avoid race with interrupt handler (polled m2m fix)
>  - Support for ti,notdpkt
>  - RFLOW management rework to support data movement without channel:
>   - the channel is not controlled by Linux but other core and we only have
>     rflows and rings to do the DMA transfers.
>     This mode is only supported by the Glue layer for now.
> 
> - UDMAP glue layer
>  - Debug print improvements
>  - Support for rflow/ring only data movement
> 
> Changes since v1
> (https://patchwork.kernel.org/project/linux-dmaengine/list/?series=114105&state=*)
> - Added support for j721e
> - Based on 5.3-rc2
> - dropped ti_sci API patch for RM management as it is already upstream
> - dropped dmadev_get_slave_channel() patch, using __dma_request_channel()
> - Added Rob's Reviewed-by to ringacc DT binding document patch
> - DT bindings changes:
>  - linux,udma-mode is gone, I have a simple lookup table in the driver to flag
>    TR channels.
>  - Support for j721e
> - Fix bug in of_node_put() handling in xlate function
> 
> Changes since RFC (https://patchwork.kernel.org/cover/10612465/):
> - Based on linux-next (20190506) which now have the ti_sci interrupt support
> - The series can be applied and the UDMA via DMAengine API will be functional
> - Included in the series: ti_sci Resource management API, cppi5 header and
>   driver for the ring accelerator.
> - The DMAengine core patches have been updated as per the review comments for
>   earlier submittion.
> - The DMAengine driver patch is artificially split up to 6 smaller patches
> 
> The k3-udma driver implements the Data Movement Architecture described in
> AM65x TRM (http://www.ti.com/lit/pdf/spruid7) and
> j721e TRM (http://www.ti.com/lit/pdf/spruil1)
> 
> This DMA architecture is a big departure from 'traditional' architecture where
> we had either EDMA or sDMA as system DMA.
> 
> Packet DMAs were used as dedicated DMAs to service only networking (Kesytone2)
> or USB (am335x) while other peripherals were serviced by EDMA.
> 
> In AM65x/j721e the UDMA (Unified DMA) is used for all data movment within the
> SoC, tasked to service all peripherals (UART, McSPI, McASP, networking, etc). 
> 
> The NAVSS/UDMA is built around CPPI5 (Communications Port Programming Interface)
> and it supports Packet mode (similar to CPPI4.1 in Keystone2 for networking) and
> TR mode (similar to EDMA descriptor).
> The data movement is done within a PSI-L fabric, peripherals (including the
> UDMA-P) are not addressed by their I/O register as with traditional DMAs but
> with their PSI-L thread ID.
> 
> In AM65x/j721e we have two main type of peripherals:
> Legacy: McASP, McSPI, UART, etc.
>  to provide connectivity they are serviced by PDMA (Peripheral DMA)
>  PDMA threads are locked to service a given peripheral, for example PSI-L thread
>  0x4400/0xc400 is to service McASP0 rx/tx.
>  The PDMa configuration can be done via the UDMA Real Time Peer registers.
> Native: Networking, security accelerator
>  these peripherals have native support for PSI-L.
> 
> To be able to use the DMA the following generic steps need to be taken:
> - configure a DMA channel (tchan for TX, rchan for RX)
>  - channel mode: Packet or TR mode
>  - for memcpy a tchan and rchan pair is used.
>  - for packet mode RX we also need to configure a receive flow to configure the
>    packet receiption
> - the source and destination threads must be paired
> - at minimum one pair of rings need to be configured:
>  - tx: transfer ring and transfer completion ring
>  - rx: free descriptor ring and receive ring
> - two interrupts: UDMA-P channel interrupt and ring interrupt for tc_ring/r_ring
>  - If the channel is in packet mode or configured to memcpy then we only need
>    one interrupt from the ring, events from UDMAP is not used.
> 
> When the channel setup is completed we only interract with the rings:
> - TX: push a descriptor to t_ring and wait for it to be pushed to the tc_ring by
>   the UDMA-P
> - RX: push a descriptor to the fd_ring and waith for UDMA-P to push it back to
>   the r_ring.
> 
> Since we have FIFOs in the DMA fabric (UDMA-P, PSI-L and PDMA) which was not the
> case in previous DMAs we need to report the amount of data held in these FIFOs
> to clients (delay calculation for ALSA, UART FIFO flush support).
> 
> Metadata support:
> DMAengine user driver was posted upstream based/tested on the v1 of the UDMA
> series: https://lkml.org/lkml/2019/6/28/20
> SA2UL is using the metadata DMAengine API.
> 
> Note on the last patch:
> In Keystone2 the networking had dedicated DMA (packet DMA) which is not the case
> anymore and the DMAengine API currently missing support for the features we
> would need to support networking, things like
> - support for receive descriptor 'classification'
>  - we need to support several receive queues for a channel.
>  - the queues are used for packet priority handling for example, but they can be
>    used to have pools of descriptors for different sizes.
> - out of order completion of descriptors on a channel
>  - when we have several queues to handle different priority packets the
>    descriptors will be completed 'out-of-order'
> - NAPI type of operation (polling instead of interrupt driven transfer)
>  - without this we can not sustain gigabit speeds and we need to support NAPI
>  - not to limit this to networking, but other high performance operations
> 
> It is my intention to work on these to be able to remove the 'glue' layer and
> switch to DMAengine API - or have an API aside of DMAengine to have generic way
> to support networking, but given how controversial and not trivial these changes
> are we need something to support networking.
> 
> The series (+DT patches to enabled DMA on AM65x and j721e) on top of 5.5-rc1 is
> available:
> https://github.com/omap-audio/linux-audio.git peter/udma/series_v7-5.5-rc1
> 
> Regards,
> Peter
> ---
> Grygorii Strashko (3):
>   bindings: soc: ti: add documentation for k3 ringacc
>   soc: ti: k3: add navss ringacc driver
>   dmaengine: ti: k3-udma: Add glue layer for non DMAengine users
> 
> Peter Ujfalusi (9):
>   dmaengine: doc: Add sections for per descriptor metadata support
>   dmaengine: Add metadata_ops for dma_async_tx_descriptor
>   dmaengine: Add support for reporting DMA cached data amount
>   dmaengine: ti: Add cppi5 header for K3 NAVSS/UDMA
>   dmaengine: ti: k3 PSI-L remote endpoint configuration
>   dt-bindings: dma: ti: Add document for K3 UDMA
>   dmaengine: ti: New driver for K3 UDMA
>   firmware: ti_sci: rm: Add support for tx_tdtype parameter for tx
>     channel
>   dmaengine: ti: k3-udma: Wait for peer teardown completion if supported
> 
>  .../devicetree/bindings/dma/ti/k3-udma.yaml   |  185 +
>  .../devicetree/bindings/soc/ti/k3-ringacc.txt |   59 +
>  Documentation/driver-api/dmaengine/client.rst |   75 +
>  .../driver-api/dmaengine/provider.rst         |   46 +
>  drivers/dma/dmaengine.c                       |   73 +
>  drivers/dma/dmaengine.h                       |    8 +
>  drivers/dma/ti/Kconfig                        |   24 +
>  drivers/dma/ti/Makefile                       |    3 +
>  drivers/dma/ti/k3-psil-am654.c                |  175 +
>  drivers/dma/ti/k3-psil-j721e.c                |  222 ++
>  drivers/dma/ti/k3-psil-priv.h                 |   39 +
>  drivers/dma/ti/k3-psil.c                      |   97 +
>  drivers/dma/ti/k3-udma-glue.c                 | 1198 ++++++
>  drivers/dma/ti/k3-udma-private.c              |  133 +
>  drivers/dma/ti/k3-udma.c                      | 3452 +++++++++++++++++
>  drivers/dma/ti/k3-udma.h                      |  151 +
>  drivers/firmware/ti_sci.c                     |    1 +
>  drivers/firmware/ti_sci.h                     |    7 +
>  drivers/soc/ti/Kconfig                        |   11 +
>  drivers/soc/ti/Makefile                       |    1 +
>  drivers/soc/ti/k3-ringacc.c                   | 1180 ++++++
>  include/linux/dma/k3-psil.h                   |   71 +
>  include/linux/dma/k3-udma-glue.h              |  134 +
>  include/linux/dma/ti-cppi5.h                  | 1061 +++++
>  include/linux/dmaengine.h                     |  110 +
>  include/linux/soc/ti/k3-ringacc.h             |  244 ++
>  include/linux/soc/ti/ti_sci_protocol.h        |    2 +
>  27 files changed, 8762 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/dma/ti/k3-udma.yaml
>  create mode 100644 Documentation/devicetree/bindings/soc/ti/k3-ringacc.txt
>  create mode 100644 drivers/dma/ti/k3-psil-am654.c
>  create mode 100644 drivers/dma/ti/k3-psil-j721e.c
>  create mode 100644 drivers/dma/ti/k3-psil-priv.h
>  create mode 100644 drivers/dma/ti/k3-psil.c
>  create mode 100644 drivers/dma/ti/k3-udma-glue.c
>  create mode 100644 drivers/dma/ti/k3-udma-private.c
>  create mode 100644 drivers/dma/ti/k3-udma.c
>  create mode 100644 drivers/dma/ti/k3-udma.h
>  create mode 100644 drivers/soc/ti/k3-ringacc.c
>  create mode 100644 include/linux/dma/k3-psil.h
>  create mode 100644 include/linux/dma/k3-udma-glue.h
>  create mode 100644 include/linux/dma/ti-cppi5.h
>  create mode 100644 include/linux/soc/ti/k3-ringacc.h
> 

- Péter

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