From: Mark Brown <broonie@kernel.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Takashi Iwai <tiwai@suse.de>,
Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>,
Ranjani Sridharan <ranjani.sridharan@linux.intel.com>,
Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
davem@davemloft.net, netdev@vger.kernel.org,
linux-rdma@vger.kernel.org, nhorman@redhat.com,
sassmann@redhat.com, Fred Oh <fred.oh@linux.intel.com>,
lee.jones@linaro.org
Subject: Re: [net-next v4 10/12] ASoC: SOF: Introduce descriptors for SOF client
Date: Tue, 30 Jun 2020 15:16:04 +0100 [thread overview]
Message-ID: <20200630141604.GJ5272@sirena.org.uk> (raw)
In-Reply-To: <20200630113245.GG25301@ziepe.ca>
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On Tue, Jun 30, 2020 at 08:32:45AM -0300, Jason Gunthorpe wrote:
> On Tue, Jun 30, 2020 at 11:31:41AM +0100, Mark Brown wrote:
> > On Mon, Jun 29, 2020 at 07:59:59PM -0300, Jason Gunthorpe wrote:
> > > > What are we supposed to do with things like PCI attached FPGAs and ASICs
> > > > in that case? They can have host visible devices with physical
> > > > resources like MMIO ranges and interrupts without those being split up
> > > > neatly as PCI subfunctions - the original use case for MFD was such
> > > > ASICs, there's a few PCI drivers in there now.
> > > Greg has been pretty clear that MFD shouldn't have been used on top of
> > > PCI drivers.
> > The proposed bus lacks resource handling, an equivalent of
> > platform_get_resource() and friends for example, which would be needed
> > for use with physical devices. Both that and the name suggest that it's
> > for virtual devices.
> Resource handling is only useful if the HW has a hard distinction
> between it's functional blocks. This scheme is intended for devices
> where that doesn't exist. The driver that attaches to the PCI device
> and creates the virtual devices is supposed to provide SW abstractions
> for the other drivers to sit on.
> I'm not sure why we are calling it virtual bus.
The abstraction that the PCI based MFDs (and FPGAs will be similar,
they're just dynamic MFDs to a good approximation) need is to pass
through MMIO regions, interrupts and so on which is exactly what the
platform bus offers. The hardware is basically someone taking a bunch
of IPs and shoving them behind the MMIO/interrupt regions of a PCI
device.
> > The reason the MFDs use platform devices is that they end up having to
> > have all the features of platform devices - originally people were
> > making virtual buses for them but the code duplication is real so
> > everyone (including Greg) decided to just use what was there already.
> Maybe Greg will explain why he didn't like the earlier version of that
> stuff that used MFD
AFAICT Greg is mostly concerned about the MFDs that aren't memory
mapped, though some of them do use the resource API to pass interrupts
through.
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next prev parent reply other threads:[~2020-06-30 14:16 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 7:02 [net-next v4 00/12][pull request] 100GbE Intel Wired LAN Driver Updates 2020-05-19 Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 01/12] Implementation of Virtual Bus Jeff Kirsher
2020-05-21 14:57 ` Parav Pandit
2020-05-21 17:43 ` gregkh
2020-05-21 20:10 ` Jason Gunthorpe
2020-05-20 7:02 ` [net-next v4 02/12] ice: Create and register virtual bus for RDMA Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 03/12] ice: Complete RDMA peer registration Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 04/12] ice: Support resource allocation requests Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 05/12] ice: Enable event notifications Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 06/12] ice: Allow reset operations Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 07/12] ice: Pass through communications to VF Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 08/12] i40e: Move client header location Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 09/12] i40e: Register a virtbus device to provide RDMA Jeff Kirsher
2020-05-20 7:02 ` [net-next v4 10/12] ASoC: SOF: Introduce descriptors for SOF client Jeff Kirsher
2020-05-20 7:20 ` Greg KH
2020-05-20 12:54 ` Jason Gunthorpe
2020-05-20 12:57 ` Jason Gunthorpe
2020-05-21 21:11 ` Ranjani Sridharan
2020-05-21 23:34 ` Jason Gunthorpe
2020-05-22 14:29 ` Pierre-Louis Bossart
2020-05-22 14:55 ` Jason Gunthorpe
2020-05-22 15:33 ` Pierre-Louis Bossart
2020-05-22 17:10 ` Jason Gunthorpe
2020-05-22 18:35 ` Pierre-Louis Bossart
2020-05-22 18:40 ` Jason Gunthorpe
2020-05-22 18:48 ` Pierre-Louis Bossart
2020-05-22 19:44 ` Jason Gunthorpe
2020-05-22 21:05 ` Pierre-Louis Bossart
2020-06-29 20:59 ` Mark Brown
2020-05-23 6:23 ` Greg KH
2020-05-23 19:41 ` Pierre-Louis Bossart
2020-05-24 6:35 ` Greg KH
2020-05-26 13:15 ` Pierre-Louis Bossart
2020-05-26 13:37 ` Takashi Iwai
2020-05-27 7:17 ` Greg KH
2020-05-27 14:05 ` Pierre-Louis Bossart
2020-06-29 20:33 ` Mark Brown
2020-06-29 22:59 ` Jason Gunthorpe
2020-06-29 23:13 ` Kirsher, Jeffrey T
2020-06-30 10:31 ` Mark Brown
2020-06-30 11:32 ` Jason Gunthorpe
2020-06-30 14:16 ` Mark Brown [this message]
2020-06-30 17:24 ` Ranjani Sridharan
2020-06-30 17:27 ` Jason Gunthorpe
2020-07-01 9:50 ` Mark Brown
2020-07-01 23:32 ` Jason Gunthorpe
2020-07-02 11:15 ` Mark Brown
2020-07-02 12:11 ` Jason Gunthorpe
2020-07-02 12:20 ` Mark Brown
2020-07-01 6:59 ` Greg KH
2020-07-02 13:43 ` Ranjani Sridharan
2020-07-06 23:02 ` Dan Williams
2020-07-07 14:16 ` Greg KH
2020-05-25 16:55 ` Jason Gunthorpe
2020-06-29 20:21 ` Mark Brown
2020-06-29 17:36 ` Mark Brown
2020-05-20 7:02 ` [net-next v4 11/12] ASoC: SOF: Create client driver for IPC test Jeff Kirsher
2020-05-20 7:22 ` Greg KH
2020-05-20 12:56 ` Jason Gunthorpe
2020-05-27 20:18 ` Ranjani Sridharan
2020-05-28 0:12 ` Jason Gunthorpe
2020-05-28 1:40 ` Ranjani Sridharan
2020-05-28 10:45 ` Greg KH
2020-06-29 20:37 ` Mark Brown
2020-05-20 7:02 ` [net-next v4 12/12] ASoC: SOF: ops: Add new op for client registration Jeff Kirsher
2020-05-20 7:23 ` Greg KH
2020-05-20 7:17 ` [net-next v4 00/12][pull request] 100GbE Intel Wired LAN Driver Updates 2020-05-19 Greg KH
2020-05-20 7:25 ` Kirsher, Jeffrey T
2020-05-20 9:08 ` Greg KH
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