From: Greg KH <gregkh@linuxfoundation.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: arnd@arndb.de, smohanad@codeaurora.org, jhugo@codeaurora.org,
kvalo@codeaurora.org, bjorn.andersson@linaro.org,
hemantk@codeaurora.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 02/16] bus: mhi: core: Add support for registering MHI controllers
Date: Thu, 13 Feb 2020 07:53:02 -0800 [thread overview]
Message-ID: <20200213155302.GA3635465@kroah.com> (raw)
In-Reply-To: <20200213154809.GA26953@mani>
On Thu, Feb 13, 2020 at 09:18:09PM +0530, Manivannan Sadhasivam wrote:
> Hi Greg,
>
> On Thu, Feb 13, 2020 at 07:34:18AM -0800, Greg KH wrote:
> > On Thu, Feb 13, 2020 at 08:50:13PM +0530, Manivannan Sadhasivam wrote:
> > > On Tue, Feb 11, 2020 at 11:20:55AM -0800, Greg KH wrote:
> > > > On Wed, Feb 12, 2020 at 12:11:30AM +0530, Manivannan Sadhasivam wrote:
> > > > > Hi Greg,
> > > > >
> > > > > On Thu, Feb 06, 2020 at 05:57:55PM +0100, Greg KH wrote:
> > > > > > On Fri, Jan 31, 2020 at 07:19:55PM +0530, Manivannan Sadhasivam wrote:
> > > > > > > --- /dev/null
> > > > > > > +++ b/drivers/bus/mhi/core/init.c
> > > > > > > @@ -0,0 +1,407 @@
> > > > > > > +// SPDX-License-Identifier: GPL-2.0
> > > > > > > +/*
> > > > > > > + * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
> > > > > > > + *
> > > > > > > + */
> > > > > > > +
> > > > > > > +#define dev_fmt(fmt) "MHI: " fmt
> > > > > >
> > > > > > This should not be needed, right? The bus/device name should give you
> > > > > > all you need here from what I can tell. So why is this needed?
> > > > > >
> > > > >
> > > > > The log will have only the device name as like PCI-E. But that won't specify
> > > > > where the error is coming from. Having "MHI" prefix helps the users to
> > > > > quickly identify that the error is coming from MHI stack.
> > > >
> > > > If the driver binds properly to the device, the name of the driver will
> > > > be there in the message, so I suggest using that please.
> > > >
> > > > No need for this prefix...
> > > >
> > >
> > > So the driver name will be in the log but that won't help identifying where
> > > the log is coming from. This is more important for MHI since it reuses the
> > > `struct device` of the transport device like PCI-E. For instance, below is
> > > the log without MHI prefix:
> > >
> > > [ 47.355582] ath11k_pci 0000:01:00.0: Requested to power on
> > > [ 47.355724] ath11k_pci 0000:01:00.0: Power on setup success
> > >
> > > As you can see, this gives the assumption that the log is coming from the
> > > ath11k_pci driver. But the reality is, it is coming from MHI bus.
> >
> > Then you should NOT be trying to "reuse" a struct device.
> >
> > > With the prefix added, we will get below:
> > >
> > > [ 47.355582] ath11k_pci 0000:01:00.0: MHI: Requested to power on
> > > [ 47.355724] ath11k_pci 0000:01:00.0: MHI: Power on setup success
> > >
> > > IMO, the prefix will give users a clear idea of logs and that will be very
> > > useful for debugging.
> > >
> > > Hope this clarifies.
> >
> > Don't try to reuse struct devices, if you are a bus, have your own
> > devices as that's the correct way to do things.
> >
>
> I assumed that the buses relying on a different physical interface for the
> actual communication can reuse the `struct device`. I can see that the MOXTET
> bus driver already doing it. It reuses the `struct device` of SPI.
How can you reuse anything?
> And this assumption has deep rooted in MHI bus design.
Maybe I do not understand what this is at all, but a device can only be
on one "bus" at a time. How is that being broken here?
thanks,
greg k-h
next prev parent reply other threads:[~2020-02-13 15:53 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-31 13:49 [PATCH v2 00/16] Add MHI bus support Manivannan Sadhasivam
2020-01-31 13:49 ` [PATCH v2 01/16] docs: Add documentation for MHI bus Manivannan Sadhasivam
2020-01-31 22:57 ` Jeffrey Hugo
2020-01-31 13:49 ` [PATCH v2 02/16] bus: mhi: core: Add support for registering MHI controllers Manivannan Sadhasivam
2020-02-06 16:56 ` Greg KH
2020-02-11 19:11 ` Manivannan Sadhasivam
2020-02-11 19:22 ` Greg KH
2020-02-13 15:22 ` Manivannan Sadhasivam
2020-02-06 16:57 ` Greg KH
2020-02-11 18:41 ` Manivannan Sadhasivam
2020-02-11 19:20 ` Greg KH
2020-02-13 15:20 ` Manivannan Sadhasivam
2020-02-13 15:34 ` Greg KH
2020-02-13 15:48 ` Manivannan Sadhasivam
2020-02-13 15:53 ` Greg KH [this message]
2020-02-14 16:41 ` Jeffrey Hugo
2020-02-17 5:27 ` Manivannan Sadhasivam
2020-02-17 11:45 ` Greg KH
2020-02-17 11:53 ` Manivannan Sadhasivam
2020-02-17 11:59 ` Greg KH
2020-02-17 13:04 ` Manivannan Sadhasivam
2020-02-17 14:15 ` Greg KH
2020-02-17 16:04 ` Arnd Bergmann
2020-02-17 16:32 ` Greg KH
2020-02-17 17:50 ` Manivannan Sadhasivam
2020-02-06 17:08 ` Jeffrey Hugo
2020-01-31 13:49 ` [PATCH v2 03/16] bus: mhi: core: Add support for registering MHI client drivers Manivannan Sadhasivam
2020-01-31 23:00 ` Jeffrey Hugo
2020-01-31 13:49 ` [PATCH v2 04/16] bus: mhi: core: Add support for creating and destroying MHI devices Manivannan Sadhasivam
2020-02-06 16:16 ` Jeffrey Hugo
2020-01-31 13:49 ` [PATCH v2 05/16] bus: mhi: core: Add support for ringing channel/event ring doorbells Manivannan Sadhasivam
2020-02-06 20:14 ` Jeffrey Hugo
2020-01-31 13:49 ` [PATCH v2 06/16] bus: mhi: core: Add support for PM state transitions Manivannan Sadhasivam
2020-02-06 20:15 ` Jeffrey Hugo
2020-01-31 13:50 ` [PATCH v2 07/16] bus: mhi: core: Add support for basic PM operations Manivannan Sadhasivam
2020-02-06 20:15 ` Jeffrey Hugo
2020-01-31 13:50 ` [PATCH v2 08/16] bus: mhi: core: Add support for downloading firmware over BHIe Manivannan Sadhasivam
2020-02-06 20:15 ` Jeffrey Hugo
2020-01-31 13:50 ` [PATCH v2 09/16] bus: mhi: core: Add support for downloading RDDM image during panic Manivannan Sadhasivam
2020-02-06 16:41 ` Jeffrey Hugo
2020-02-06 20:17 ` Jeffrey Hugo
2020-01-31 13:50 ` [PATCH v2 10/16] bus: mhi: core: Add support for processing events from client device Manivannan Sadhasivam
2020-02-06 20:16 ` Jeffrey Hugo
2020-01-31 13:50 ` [PATCH v2 11/16] bus: mhi: core: Add support for data transfer Manivannan Sadhasivam
2020-02-06 20:16 ` Jeffrey Hugo
2020-02-17 16:13 ` Arnd Bergmann
2020-02-17 16:47 ` Manivannan Sadhasivam
2020-02-18 5:51 ` Manivannan Sadhasivam
2020-02-18 14:34 ` Arnd Bergmann
2020-01-31 13:50 ` [PATCH v2 12/16] bus: mhi: core: Add uevent support for module autoloading Manivannan Sadhasivam
2020-02-06 20:16 ` Jeffrey Hugo
2020-01-31 13:50 ` [PATCH v2 13/16] MAINTAINERS: Add entry for MHI bus Manivannan Sadhasivam
2020-02-03 10:16 ` Andy Shevchenko
2020-02-04 7:05 ` Manivannan Sadhasivam
2020-01-31 13:50 ` [PATCH v2 14/16] net: qrtr: Add MHI transport layer Manivannan Sadhasivam
2020-02-03 18:12 ` Jakub Kicinski
2020-02-04 8:19 ` Manivannan Sadhasivam
2020-02-07 0:14 ` Chris Lew
2020-02-11 3:50 ` Manivannan Sadhasivam
2020-02-12 1:01 ` Chris Lew
2020-01-31 13:50 ` [PATCH v2 15/16] net: qrtr: Do not depend on ARCH_QCOM Manivannan Sadhasivam
2020-01-31 13:50 ` [PATCH v2 16/16] soc: qcom: Do not depend on ARCH_QCOM for QMI helpers Manivannan Sadhasivam
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