Message-ID: <2024071053-mahogany-cavalier-6692@gregkh>
Date: Wed, 10 Jul 2024 15:27:08 +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 01:19:56PM +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-
> >3A__github.com_Marve
> >> +llEmbeddedProcessors_dpi-2Dsample-
> >2Dapp&d=DwIBAg&c=nKjWec2b6R0mOyPaz7
> >>
> >+xtfQ&r=WllrYaumVkxaWjgKto6E_rtDQshhIhik2jkvzFyRhW8&m=bFx_7eltw7S
> >6zzVu
> >>
> >+1LNEdtsbwwynJfAKTja649QUwGNU_y4uWqGoEZ4f7JluYLjX&s=wOMzADbq
> >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?

thanks,

greg k-h

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