New remoteproc driver for TI PRU

[Roger Quadros]

+Suman & Tero

Hi David,

On 24/06/18 00:08, David Lechner wrote:
> 
> Date: Sat, 23 Jun 2018 15:43:59 -0500
> Subject: [PATCH 0/8] New remoteproc driver for TI PRU
> 
> This series adds a new remoteproc driver for the TI Programmable Runtime Unit
> (PRU) that is present in some TI Sitara processors. This code has been tested
> working on AM1808 (LEGO MINDSTORMS EV3) and AM3358 (BeagleBone Green).

This is great. We have been working on something similar and I think it would
be great if we can collaborate to get all our needs addressed.

Our primary requirement is that it should be possible for a user (e.g. kernel driver) to
- request a specific PRU core load a specific firmware blob and boot/stop the PRU.
- configure INTC interrupt mapping based on either resource table or DT
- use request_irq to request and use an interrupt.
- request access to DRAM/SRAM
- configure gpimode/miirt/xfr (CFG space)

The work is published here

PRUSS platform bus driver (platform resets & quirks)
https://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-linux-4.14.y/drivers/remoteproc/pruss_soc_bus.c

PRUSS core driver (resource management e.g. SRAM/DRAM for clients)
https://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-linux-4.14.y/drivers/remoteproc/pruss.c

PRU Rproc driver (PRU remoteproc driver)
https://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-linux-4.14.y/drivers/remoteproc/pru_rproc.c

INTC driver (irqchip support for INTC)
https://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-linux-4.14.y/drivers/remoteproc/pruss_intc.c

Please have a look at it. I think it addresses most if not all of what your series addresses.
Maybe Suman and you can decide which driver to start with and get the missing pieces addressed.

An example of a client driver
https://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-linux-4.14.y/drivers/net/ethernet/ti/prueth.c
and DT node for that
https://git.ti.com/ti-linux-kernel/ti-linux-kernel/blobs/ti-linux-4.14.y/arch/arm/boot/dts/am335x-icev2-prueth.dts#line25

> 
> There are a couple of quirks that had to be worked around in order to get this
> working. The PRU units have multiple memory maps. Notably, both the instruction
> RAM and data RAM are at address 0x0. This caused the da_to_va callback to not
> work because the same address could refer to two different locations. To work
> around this, the first two patches add a "map" parameter to the da_to_va
> callbacks so that we have an extra bit of information to make this distinction.
> 
> Also, on AM38xx we have to use pdata for accessing a reset since there is not
> a reset controller. There are several other devices doing this, so the seems
> the best way for now.
> 
> For anyone else who would like to test, I used the rpmsg-client-sample driver.
> Just enable it in your kernel config. Then grab the appropriate firmware[1]
> and put in in /lib/firmware/. Use sysfs to start and stop the PRU:
> 
>         echo start > /sys/class/remoteproc<n>/state
>         echo stop > /sys/class/remoteproc<n>/state
> 
> [1]: firmware downloads:
> 
> AM18XX: https://github.com/ev3dev/ev3dev-pru-firmware/releases/download/mainline-kernel-testing/AM18xx-PRU-rpmsg-client-sample.zip
> AM335X: https://github.com/ev3dev/ev3dev-pru-firmware/releases/download/mainline-kernel-testing/AM335x-PRU-rpmsg-client-sample.zip
> 
> David Lechner (8):
>   remoteproc: add map parameter to da_to_va
>   remoteproc: add page lookup for TI PRU to ELF loader
>   ARM: OMAP2+: add pdata quirks for PRUSS reset
>   dt-bindings: add bindings for TI PRU as remoteproc
>   remoteproc: new driver for TI PRU
>   ARM: davinci_all_defconfig: enable PRU remoteproc module
>   ARM: dts: da850: add node for PRUSS
>   ARM: dts: am33xx: add node for PRU remoteproc
> 
>  .../bindings/remoteproc/ti_pru_rproc.txt      |  51 ++
>  MAINTAINERS                                   |   5 +
>  arch/arm/boot/dts/am33xx.dtsi                 |   9 +
>  arch/arm/boot/dts/da850.dtsi                  |   8 +
>  arch/arm/configs/davinci_all_defconfig        |   2 +
>  arch/arm/mach-omap2/pdata-quirks.c            |   9 +
>  drivers/remoteproc/Kconfig                    |   7 +
>  drivers/remoteproc/Makefile                   |   1 +
>  drivers/remoteproc/imx_rproc.c                |   2 +-
>  drivers/remoteproc/keystone_remoteproc.c      |   3 +-
>  drivers/remoteproc/qcom_adsp_pil.c            |   2 +-
>  drivers/remoteproc/qcom_q6v5_pil.c            |   2 +-
>  drivers/remoteproc/qcom_wcnss.c               |   2 +-
>  drivers/remoteproc/remoteproc_core.c          |  10 +-
>  drivers/remoteproc/remoteproc_elf_loader.c    | 117 +++-
>  drivers/remoteproc/remoteproc_internal.h      |   2 +-
>  drivers/remoteproc/st_slim_rproc.c            |   2 +-
>  drivers/remoteproc/ti_pru_rproc.c             | 660 ++++++++++++++++++
>  drivers/remoteproc/wkup_m3_rproc.c            |   3 +-
>  include/linux/platform_data/ti-pruss.h        |  18 +
>  include/linux/remoteproc.h                    |   2 +-
>  include/uapi/linux/elf-em.h                   |   1 +
>  22 files changed, 899 insertions(+), 19 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/remoteproc/ti_pru_rproc.txt
>  create mode 100644 drivers/remoteproc/ti_pru_rproc.c
>  create mode 100644 include/linux/platform_data/ti-pruss.h
> 

-- 
cheers,
-roger

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