Messages in this thread | ![/](/images/icornerl.gif) | | Date | Sat, 13 Apr 2024 07:47:36 +0200 | From | Greg KH <> | Subject | Re: [EXTERNAL] Re: [PATCH v5 1/1] misc: mrvl-cn10k-dpi: add Octeon CN10K DPI administrative driver |
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On Fri, Apr 12, 2024 at 04:19:58PM +0000, Vamsi Krishna Attunuru wrote: > > > > -----Original Message----- > > From: Greg KH <gregkh@linuxfoundation.org> > > Sent: Friday, April 12, 2024 9:05 PM > > To: Vamsi Krishna Attunuru <vattunuru@marvell.com> > > Cc: arnd@arndb.de; linux-kernel@vger.kernel.org > > Subject: Re: [EXTERNAL] Re: [PATCH v5 1/1] misc: mrvl-cn10k-dpi: add > > Octeon CN10K DPI administrative driver > > > > On Fri, Apr 12, 2024 at 01:56:36PM +0000, Vamsi Krishna Attunuru wrote: > > > > > > > > > > -----Original Message----- > > > > From: Greg KH <gregkh@linuxfoundation.org> > > > > Sent: Friday, April 12, 2024 5:57 PM > > > > To: Vamsi Krishna Attunuru <vattunuru@marvell.com> > > > > Cc: arnd@arndb.de; linux-kernel@vger.kernel.org > > > > Subject: [EXTERNAL] Re: [PATCH v5 1/1] misc: mrvl-cn10k-dpi: add > > > > Octeon CN10K DPI administrative driver > > > > > > > > Prioritize security for external emails: Confirm sender and content > > > > safety before clicking links or opening attachments > > > > > > > > -------------------------------------------------------------------- > > > > -- On Fri, Apr 12, 2024 at 05:10:05AM -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. > > > > > > > > No pointer to the userspace code that uses this? Why not? How are > > > > we supposed to be able to review this? > > > > > > Userspace code will use two functionalities (mailbox & ioctl) from > > > this driver. DPDK DMA driver uses the mailbox and the dpdk application > > > uses the ioctl to setup the device attributes. We are waiting for this > > > kernel driver get merged to update the corresponding support in DPDK > > driver and applications. I will provide the pointers to both the use cases in > > userspace code. > > > Meanwhile below is the current dpdk dma driver that uses sysfs based > > > scheme to convey mbox requests to the kernel DPI driver which gets > > replaced with hardware mailbox scheme once mrvl-cn10k-dpi kernel driver is > > merged. > > > https://urldefense.proofpoint.com/v2/url?u=https- > > 3A__github.com_DPDK_d > > > pdk_blob_main_drivers_common_cnxk_roc- > > 5Fdpi.c&d=DwIBAg&c=nKjWec2b6R0mO > > > > > yPaz7xtfQ&r=WllrYaumVkxaWjgKto6E_rtDQshhIhik2jkvzFyRhW8&m=o3EhoL > > s7dsod > > > -YHS438Wl2Pf_MKMBYegGSKteoX3qFTB0HV897ykpCVbTp- > > nmj4e&s=A6TJDFUtPm3ksJh > > > qop89CL8GgKj4sjkJIVi1-RdnUr8&e= > > > > So this is a DPDK thing? Ugh, do the networking people know about this? > > If not, why aren't they reviewing this? > > Actually, It's not networking related. Like the Linux kernel, DPDK also supports multiple subsystems like > network, scheduler, DMA, mempool etc. Regarding the usecases, the DPDK Marvell DMA/DPI VF driver > interacts(over hardware mailbox) with the mrvl-cn10k-dpi misc kernel driver(administrative driver) for setting > up the VF device resources.
So this is something that the PCI core should be concerned about then?
> DPDK is one example that uses this driver, there can be other userspace generic frameworks/applications > where the virtual functions are binded to userspace drivers and interact with physical/administrative function > driver running in the kernel.
Are there other devices/drivers that do this today in Linux? Why make a device-specific api for this common functionality?
thanks,
greg k-h
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