Re: [PATCH 2/4] fpga: dfl: move dfl_device_id to mod_devicetable.h

From: Xu Yilun <yilun.xu@intel.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Moritz Fischer <mdf@kernel.org>,
	linux-fpga@vger.kernel.org, Wu Hao <hao.wu@intel.com>,
	Matthew Gerlach <matthew.gerlach@linux.intel.com>,
	Russ Weight <russell.h.weight@intel.com>,
	Tom Rix <trix@redhat.com>,
	yilun.xu@intel.com
Subject: Re: [PATCH 2/4] fpga: dfl: move dfl_device_id to mod_devicetable.h
Date: Tue, 3 Nov 2020 16:54:27 +0800	[thread overview]
Message-ID: <20201103085427.GC10673@yilunxu-OptiPlex-7050> (raw)
In-Reply-To: <20201103074053.GC2500572@kroah.com>

On Tue, Nov 03, 2020 at 08:40:53AM +0100, Greg KH wrote:
> On Mon, Nov 02, 2020 at 11:21:02PM -0800, Moritz Fischer wrote:
> > From: Xu Yilun <yilun.xu@intel.com>
> > 
> > In order to support MODULE_DEVICE_TABLE() for dfl device driver, this
> > patch moves struct dfl_device_id to mod_devicetable.h
> > 
> > Some brief description for DFL (Device Feature List) is added to make
> > the DFL known to the whole kernel.
> > 
> > Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> > Signed-off-by: Wu Hao <hao.wu@intel.com>
> > Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> > Signed-off-by: Russ Weight <russell.h.weight@intel.com>
> > Reviewed-by: Tom Rix <trix@redhat.com>
> > Acked-by: Wu Hao <hao.wu@intel.com>
> > Signed-off-by: Moritz Fischer <mdf@kernel.org>
> > ---
> >  drivers/fpga/dfl.h              | 13 +------------
> >  include/linux/mod_devicetable.h | 24 ++++++++++++++++++++++++
> >  2 files changed, 25 insertions(+), 12 deletions(-)
> > 
> > diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> > index ac373b1fcff9..549c7900dcfd 100644
> > --- a/drivers/fpga/dfl.h
> > +++ b/drivers/fpga/dfl.h
> > @@ -22,6 +22,7 @@
> >  #include <linux/interrupt.h>
> >  #include <linux/iopoll.h>
> >  #include <linux/io-64-nonatomic-lo-hi.h>
> > +#include <linux/mod_devicetable.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/slab.h>
> >  #include <linux/uuid.h>
> > @@ -525,18 +526,6 @@ enum dfl_id_type {
> >  	DFL_ID_MAX,
> >  };
> >  
> > -/**
> > - * struct dfl_device_id -  dfl device identifier
> > - * @type: DFL FIU type of the device. See enum dfl_id_type.
> > - * @feature_id: feature identifier local to its DFL FIU type.
> > - * @driver_data: driver specific data.
> > - */
> > -struct dfl_device_id {
> > -	u16 type;
> > -	u16 feature_id;
> > -	unsigned long driver_data;
> > -};
> > -
> >  /**
> >   * struct dfl_device - represent an dfl device on dfl bus
> >   *
> > diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
> > index 5b08a473cdba..e4870e5d3ea8 100644
> > --- a/include/linux/mod_devicetable.h
> > +++ b/include/linux/mod_devicetable.h
> > @@ -838,4 +838,28 @@ struct mhi_device_id {
> >  	kernel_ulong_t driver_data;
> >  };
> >  
> > +/*
> > + * DFL (Device Feature List)
> > + *
> > + * DFL defines a linked list of feature headers within the device MMIO space to
> > + * provide an extensible way of adding features. Software can walk through these
> > + * predefined data structures to enumerate features. It is now used in the FPGA.
> > + * See Documentation/fpga/dfl.rst for more information.
> > + *
> > + * The dfl bus type is introduced to match the individual feature devices (dfl
> > + * devices) for specific dfl drivers.
> > + */
> > +
> > +/**
> > + * struct dfl_device_id -  dfl device identifier
> > + * @type: DFL FIU type of the device. See enum dfl_id_type.
> > + * @feature_id: feature identifier local to its DFL FIU type.
> > + * @driver_data: driver specific data.
> > + */
> > +struct dfl_device_id {
> > +	__u16 type;
> > +	__u16 feature_id;
> > +	unsigned long driver_data;
> 
> This is the wrong type for driver_data now that it goes to userspace :(
> 
> {sigh}

Thanks for the catching, I should change it to kernel_ulong_t.

Thanks,
Yilun