linux-kernel - Re: [PATCH 3/7] drivers: soc: xilinx: add check for platform

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Message-ID: <2023100223-trouble-conjoined-fb51@gregkh>
Date:   Mon, 2 Oct 2023 08:20:03 +0200
From:   Greg KH <gregkh@...uxfoundation.org>
To:     Michal Simek <michal.simek@....com>
Cc:     Jay Buddhabhatti <jay.buddhabhatti@....com>, tanmay.shah@....com,
        sai.krishna.potthuri@....com, nava.kishore.manne@....com,
        ben.levinsky@....com, dhaval.r.shah@....com, marex@...x.de,
        robh@...nel.org, arnd@...db.de, izhar.ameer.shaikh@....com,
        ruanjinjie@...wei.com, mathieu.poirier@...aro.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/7] drivers: soc: xilinx: add check for platform

On Mon, Oct 02, 2023 at 08:09:50AM +0200, Michal Simek wrote:
> 
> 
> On 9/30/23 09:17, Greg KH wrote:
> > On Fri, Sep 29, 2023 at 03:55:54AM -0700, Jay Buddhabhatti wrote:
> > > Some error event IDs for Versal and Versal NET are different.
> > > Both the platforms should access their respective error event
> > > IDs so use sub_family_code to check for platform and check
> > > error IDs for respective platforms. The family code is passed
> > > via platform data to avoid platform detection again.
> > > Platform data is setup when even driver is registered.
> > > 
> > > Signed-off-by: Jay Buddhabhatti <jay.buddhabhatti@....com>
> > > ---
> > >   drivers/firmware/xilinx/zynqmp.c        |  2 +-
> > >   drivers/soc/xilinx/xlnx_event_manager.c | 25 ++++++++++++++++++++-----
> > >   include/linux/firmware/xlnx-zynqmp.h    | 16 ++++++++++++----
> > >   3 files changed, 33 insertions(+), 10 deletions(-)
> > > 
> > > diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
> > > index 5f40288f69a9..6583efa9ac48 100644
> > > --- a/drivers/firmware/xilinx/zynqmp.c
> > > +++ b/drivers/firmware/xilinx/zynqmp.c
> > > @@ -2019,7 +2019,7 @@ static int zynqmp_firmware_probe(struct platform_device *pdev)
> > >   	np = of_find_compatible_node(NULL, NULL, "xlnx,versal");
> > >   	if (np) {
> > >   		em_dev = platform_device_register_data(&pdev->dev, "xlnx_event_manager",
> > > -						       -1, NULL, 0);
> > > +						       -1, &pm_sub_family_code, 4);
> > >   		if (IS_ERR(em_dev))
> > >   			dev_err_probe(&pdev->dev, PTR_ERR(em_dev), "EM register fail with error\n");
> > >   	}
> > > diff --git a/drivers/soc/xilinx/xlnx_event_manager.c b/drivers/soc/xilinx/xlnx_event_manager.c
> > > index 38cfc161a713..8074ded7b39c 100644
> > > --- a/drivers/soc/xilinx/xlnx_event_manager.c
> > > +++ b/drivers/soc/xilinx/xlnx_event_manager.c
> > > @@ -23,6 +23,7 @@ static DEFINE_PER_CPU_READ_MOSTLY(int, cpu_number1);
> > >   static int virq_sgi;
> > >   static int event_manager_availability = -EACCES;
> > > +static u32 pm_sub_family_code;
> > 
> > Why is this not a per-device variable?  Global variables like this for
> > drivers are almost always wrong.
> 
> Not sure I get what you mean by per-device. Can you please elaborate on it?

It should not be a global variable (i.e. the same for all devices in the
system.)

> This is the part of firmware infrastructure and there is only one instance
> of the driver in the system registered from firmware driver itself.

Then that should be fixed.

> If this should be done in a generic way then there are much more variables
> which should be moved to driver data not just this one.

Agreed, they should all be moved there.

thanks,

greg k-h