Message-ID: <2024071012-backpedal-punctured-5d7b@gregkh>
Date: Wed, 10 Jul 2024 16:11:40 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Vamsi Krishna Attunuru <vattunuru@...vell.com>
Cc: "arnd@...db.de" <arnd@...db.de>, Jerin Jacob <jerinj@...vell.com>,
	Srujana Challa <schalla@...vell.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [EXTERNAL] Re: [PATCH v10 1/1] misc: mrvl-cn10k-dpi: add Octeon
 CN10K DPI administrative driver

On Wed, Jul 10, 2024 at 01:48:40PM +0000, Vamsi Krishna Attunuru wrote:
> 
> 
> >-----Original Message-----
> >From: Greg KH <gregkh@...uxfoundation.org>
> >Sent: Wednesday, July 10, 2024 6:57 PM
> >To: Vamsi Krishna Attunuru <vattunuru@...vell.com>
> >Cc: arnd@...db.de; Jerin Jacob <jerinj@...vell.com>; Srujana Challa
> ><schalla@...vell.com>; linux-kernel@...r.kernel.org
> >Subject: Re: [EXTERNAL] Re: [PATCH v10 1/1] misc: mrvl-cn10k-dpi: add
> >Octeon CN10K DPI administrative driver
> >
> >On Wed, Jul 10, 2024 at 01: 19: 56PM +0000, Vamsi Krishna Attunuru wrote: > >
> >> >-----Original Message----- > >From: Greg KH
> ><gregkh@ linuxfoundation. org> > >Sent: Wednesday, July 10, 2024 6: 28 PM >
> >>To: Vamsi 
> >On Wed, Jul 10, 2024 at 01:19:56PM +0000, Vamsi Krishna Attunuru wrote:
> >>
> >>
> >> >-----Original Message-----
> >> >From: Greg KH <gregkh@...uxfoundation.org>
> >> >Sent: Wednesday, July 10, 2024 6:28 PM
> >> >To: Vamsi Krishna Attunuru <vattunuru@...vell.com>
> >> >Cc: arnd@...db.de; Jerin Jacob <jerinj@...vell.com>; Srujana Challa
> >> ><schalla@...vell.com>; linux-kernel@...r.kernel.org
> >> >Subject: [EXTERNAL] Re: [PATCH v10 1/1] misc: mrvl-cn10k-dpi: add
> >> >Octeon CN10K DPI administrative driver
> >> >
> >> >On Sat, Jul 06, 2024 at 08: 30: 09AM -0700, Vamsi Attunuru wrote: >
> >> >Adds a misc driver for Marvell CN10K DPI(DMA Engine) device's
> >> >physical > function which initializes DPI DMA hardware's global
> >> >configuration and > enables hardware mailbox On Sat, Jul 06, 2024 at
> >> >08:30:09AM -0700, Vamsi Attunuru wrote:
> >> >> Adds a misc driver for Marvell CN10K DPI(DMA Engine) device's
> >> >> physical function which initializes DPI DMA hardware's global
> >> >> configuration and enables hardware mailbox channels between
> >> >> physical function (PF) and it's virtual functions (VF). VF device
> >> >> drivers (User space drivers) use this hw mailbox to communicate any
> >> >> required device configuration on it's respective VF device.
> >> >> Accordingly, this DPI PF driver provisions the VF device resources.
> >> >>
> >> >> At the hardware level, the DPI physical function (PF) acts as a
> >> >> management interface to setup the VF device resources, VF devices
> >> >> are only provisioned to handle or control the actual DMA Engine's
> >> >> data transfer
> >> >capabilities.
> >> >>
> >> >> Signed-off-by: Vamsi Attunuru <vattunuru@...vell.com>
> >> >> Reviewed-by: Srujana Challa <schalla@...vell.com>
> >> >> ---
> >> >> Changes V9 -> V10
> >> >> - Added checks to ensure reserved fields are set to 0
> >> >>
> >> >> Changes V8 -> V9:
> >> >> - Addressed minor comments
> >> >>
> >> >> Changes V7 -> V8:
> >> >> - Used bit shift operations to access mbox msg fields
> >> >> - Removed bitfields in mailbox msg structure
> >> >>
> >> >> Changes V6 -> V7:
> >> >> - Updated documentation with required references
> >> >> - Addressed V6 review comments
> >> >>
> >> >> Changes V5 -> V6:
> >> >> - Updated documentation
> >> >> - Fixed data types in uapi file
> >> >>
> >> >> Changes V4 -> V5:
> >> >> - Fixed license and data types in uapi file
> >> >>
> >> >> Changes V3 -> V4:
> >> >> - Moved ioctl definations to .h file
> >> >> - Fixed structure alignements which are passed in ioctl
> >> >>
> >> >> Changes V2 -> V3:
> >> >> - Added ioctl operation to the fops
> >> >> - Used managed version of kzalloc & request_irq
> >> >> - Addressed miscellaneous comments
> >> >>
> >> >> Changes V1 -> V2:
> >> >> - Fixed return values and busy-wait loops
> >> >> - Merged .h file into .c file
> >> >> - Fixed directory structure
> >> >> - Removed module params
> >> >> - Registered the device as misc device
> >> >>
> >> >>  Documentation/misc-devices/index.rst          |   1 +
> >> >>  Documentation/misc-devices/mrvl_cn10k_dpi.rst |  52 ++
> >> >>  .../userspace-api/ioctl/ioctl-number.rst      |   1 +
> >> >>  MAINTAINERS                                   |   5 +
> >> >>  drivers/misc/Kconfig                          |  14 +
> >> >>  drivers/misc/Makefile                         |   1 +
> >> >>  drivers/misc/mrvl_cn10k_dpi.c                 | 676 ++++++++++++++++++
> >> >>  include/uapi/misc/mrvl_cn10k_dpi.h            |  39 +
> >> >>  8 files changed, 789 insertions(+)
> >> >>
> >> >> diff --git a/Documentation/misc-devices/index.rst
> >> >> b/Documentation/misc-devices/index.rst
> >> >> index 2d0ce9138588..8c5b226d8313 100644
> >> >> --- a/Documentation/misc-devices/index.rst
> >> >> +++ b/Documentation/misc-devices/index.rst
> >> >> @@ -21,6 +21,7 @@ fit into other categories.
> >> >>     isl29003
> >> >>     lis3lv02d
> >> >>     max6875
> >> >> +   mrvl_cn10k_dpi
> >> >>     oxsemi-tornado
> >> >>     pci-endpoint-test
> >> >>     spear-pcie-gadget
> >> >> diff --git a/Documentation/misc-devices/mrvl_cn10k_dpi.rst
> >> >> b/Documentation/misc-devices/mrvl_cn10k_dpi.rst
> >> >> new file mode 100644
> >> >> index 000000000000..a75e372723d8
> >> >> --- /dev/null
> >> >> +++ b/Documentation/misc-devices/mrvl_cn10k_dpi.rst
> >> >> @@ -0,0 +1,52 @@
> >> >> +.. SPDX-License-Identifier: GPL-2.0
> >> >> +
> >> >> +===============================================
> >> >> +Marvell CN10K DMA packet interface (DPI) driver
> >> >> +===============================================
> >> >> +
> >> >> +Overview
> >> >> +========
> >> >> +
> >> >> +DPI is a DMA packet interface hardware block in Marvell's CN10K silicon.
> >> >> +DPI hardware comprises a physical function (PF), its virtual
> >> >> +functions, mailbox logic, and a set of DMA engines & DMA command
> >> >queues.
> >> >> +
> >> >> +DPI PF function is an administrative function which services the
> >> >> +mailbox requests from its VF functions and provisions DMA engine
> >> >> +resources to it's VF functions.
> >> >> +
> >> >> +mrvl_cn10k_dpi.ko misc driver loads on DPI PF device and services
> >> >> +the mailbox commands submitted by the VF devices and accordingly
> >> >> +initializes the DMA engines and VF device's DMA command queues.
> >> >> +Also, driver creates /dev/mrvl-cn10k-dpi node to set DMA engine
> >> >> +and PEM (PCIe interface) port attributes like fifo length, molr, mps &
> >mrrs.
> >> >> +
> >> >> +DPI PF driver is just an administrative driver to setup its VF
> >> >> +device's queues and provisions the hardware resources, it cannot
> >> >> +initiate any DMA operations. Only VF devices are provisioned with
> >> >> +DMA
> >> >capabilities.
> >> >> +
> >> >> +Driver location
> >> >> +===============
> >> >> +
> >> >> +drivers/misc/mrvl_cn10k_dpi.c
> >> >> +
> >> >> +Driver IOCTLs
> >> >> +=============
> >> >> +
> >> >> +:c:macro::`DPI_MPS_MRRS_CFG`
> >> >> +ioctl that sets max payload size & max read request size
> >> >> +parameters of a pem port to which DMA engines are wired.
> >> >> +
> >> >> +
> >> >> +:c:macro::`DPI_ENGINE_CFG`
> >> >> +ioctl that sets DMA engine's fifo sizes & max outstanding load
> >> >> +request thresholds.
> >> >> +
> >> >> +User space code example
> >> >> +=======================
> >> >> +
> >> >> +DPI VF devices are probed and accessed from user space
> >> >> +applications using vfio-pci driver. Below is a sample dpi dma
> >> >> +application to demonstrate on how applications use mailbox and
> >> >> +ioctl services from DPI
> >> >PF kernel driver.
> >> >> +
> >> >> +https://urldefense.proofpoint.com/v2/url?u=https-
> >> <https://urldefense.proofpoint.com/v2/url?u=https-  >>
> >> >3A__github.com_Marve
> >> >> +llEmbeddedProcessors_dpi-2Dsample-
> >> >2Dapp&d=DwIBAg&c=nKjWec2b6R0mOyPaz7
> >> >>
> >>
> >>+xtfQ&r=WllrYaumVkxaWjgKto6E_rtDQshhIhik2jkvzFyRhW8&m=bFx_7eltw7
> >S
> >> >6zzVu
> >> >>
> >>
> >>+1LNEdtsbwwynJfAKTja649QUwGNU_y4uWqGoEZ4f7JluYLjX&s=wOMzADb
> >q
> >> >9f4xxz1Oug
> >> >> +-slj_xy4ZcbrnWfQJWeO0_ugA&e=
> >> >> diff --git a/Documentation/userspace-api/ioctl/ioctl-number.rst
> >> >> b/Documentation/userspace-api/ioctl/ioctl-number.rst
> >> >> index a141e8e65c5d..def539770439 100644
> >> >> --- a/Documentation/userspace-api/ioctl/ioctl-number.rst
> >> >> +++ b/Documentation/userspace-api/ioctl/ioctl-number.rst
> >> >> @@ -362,6 +362,7 @@ Code  Seq#    Include File
> >> >Comments
> >> >>  0xB6  all    linux/fpga-dfl.h
> >> >>  0xB7  all    uapi/linux/remoteproc_cdev.h                            <mailto:linux-
> >> >remoteproc@...r.kernel.org>
> >> >>  0xB7  all    uapi/linux/nsfs.h                                       <mailto:Andrei Vagin
> >> ><avagin@...nvz.org>>
> >> >> +0xB8  01-02  uapi/misc/mrvl_cn10k_dpi.h                              Marvell CN10K
> >DPI
> >> >driver
> >> >>  0xC0  00-0F  linux/usb/iowarrior.h  0xCA  00-0F  uapi/misc/cxl.h
> >> >> 0xCA  10-2F  uapi/misc/ocxl.h diff --git a/MAINTAINERS
> >> >> b/MAINTAINERS index aae88b7a6c32..2c17d651954a 100644
> >> >> --- a/MAINTAINERS
> >> >> +++ b/MAINTAINERS
> >> >> @@ -13477,6 +13477,11 @@ S:	Supported
> >> >>  F:	Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.yaml
> >> >>  F:	drivers/mmc/host/sdhci-xenon*
> >> >>
> >> >> +MARVELL OCTEON CN10K DPI DRIVER
> >> >> +M:	Vamsi Attunuru <vattunuru@...vell.com>
> >> >> +S:	Supported
> >> >> +F:	drivers/misc/mrvl_cn10k_dpi.c
> >> >> +
> >> >>  MATROX FRAMEBUFFER DRIVER
> >> >>  L:	linux-fbdev@...r.kernel.org
> >> >>  S:	Orphan
> >> >> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index
> >> >> faf983680040..965641017a62 100644
> >> >> --- a/drivers/misc/Kconfig
> >> >> +++ b/drivers/misc/Kconfig
> >> >> @@ -585,6 +585,20 @@ config NSM
> >> >>  	  To compile this driver as a module, choose M here.
> >> >>  	  The module will be called nsm.
> >> >>
> >> >> +config MARVELL_CN10K_DPI
> >> >> +	tristate "Octeon CN10K DPI driver"
> >> >> +	depends on ARM64 && PCI
> >> >
> >> >Why does ARM64 matter here?  I don't see any dependency required of it.
> >> >
> >> Thanks, Greg, for your time. This DPI device is an on-chip PCIe device
> >> and only present on Marvell's CN10K platforms(which are 64-bit ARM SoC
> >processors), so added those dependency.
> >
> >Then perhaps keep the ARM64 and add a COMPILE_TEST option as well so
> >that we can build this as part of normal testing?
> >
> >So that would be:
> >	depends on PCI && (ARM64 || COMPILE_TEST) right?
> >
> Yes, it makes sense to add. Can I send this fix as next version now so that it will show
> up in next release, please suggest.

Send it as a follow-on patch on top of my tree, doing what Arnd
suggested.

thanks,

greg k-h

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