Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Fri, 9 Jun 2023 12:52:01 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     Sui Jingfeng <suijingfeng@loongson.cn>
Cc:     Sui Jingfeng <15330273260@189.cn>, Li Yi <liyi@loongson.cn>,
        linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        etnaviv@lists.freedesktop.org,
        Russell King <linux+etnaviv@armlinux.org.uk>,
        Bjorn Helgaas <bhelgaas@google.com>
Subject: Re: [PATCH v8 6/8] drm/etnaviv: add driver support for the PCI
 devices
Message-ID: <20230609175201.GA1253027@bhelgaas>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ec178d79-f96b-072e-aa1b-dd2bf7c9cdd0@loongson.cn>
Precedence: bulk

On Fri, Jun 09, 2023 at 09:37:02AM +0800, Sui Jingfeng wrote:
> On 2023/6/9 01:32, Bjorn Helgaas wrote:
> > On Wed, Jun 07, 2023 at 06:55:49PM +0800, Sui Jingfeng wrote:
> > > From: Sui Jingfeng <suijingfeng@loongson.cn>
> > > 
> > > This patch adds PCI driver support on top of what we already have. Take
> > > the GC1000 in LS7A1000/LS2K1000 as the first instance of the PCI device
> > > driver. There is only one GPU core for the GC1000 in the LS7A1000 and
> > > LS2K1000. Therefore, component frameworks can be avoided.

> > > +	{PCI_VENDOR_ID_LOONGSON, 0x7a15, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
> > > +	{PCI_VENDOR_ID_LOONGSON, 0x7a05, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
> >
> > PCI_VDEVICE()
> 
> This make it impossible to hook device-specific data in the future.
> 
> But currently there no device specific data associated with the
> 0x7a05 and 0x7a15,
> 
> so it's acceptable for now. Thanks.

Haha, ISTR having this conversation before, sorry for repeating it.

Indeed, it's fine as-is.  But PCI_VDEVICE() actually *does* allow for
vendor-specific data because it doesn't include the data element,
which defaults to zero if you don't specify it.

So for example, drivers/net/ethernet/realtek/r8169_main.c has this:

  { PCI_VDEVICE(REALTEK, 0x8129) },
  { PCI_VDEVICE(REALTEK, 0x8136), RTL_CFG_NO_GBIT },

where 0x8129 has no driver_data (it defaults to zero), but 0x8136
does.

Bjorn