From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [PATCH v3 02/12] eal/bus: introduce bus abstraction
Date: Tue, 20 Dec 2016 09:11:56 -0800
Message-ID: <20161220091156.4442cb07@xeon-e3>
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 <1481893853-31790-3-git-send-email-shreyansh.jain@nxp.com>
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Cc: Shreyansh Jain <shreyansh.jain@nxp.com>, dev@dpdk.org, David Marchand
 <david.marchand@6wind.com>, Thomas Monjalon <thomas.monjalon@6wind.com>,
 Ferruh Yigit <ferruh.yigit@intel.com>, jianbo.liu@linaro.org
To: Jan Blunck <jblunck@infradead.org>
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On Tue, 20 Dec 2016 14:17:14 +0100
Jan Blunck <jblunck@infradead.org> wrote:

> On Fri, Dec 16, 2016 at 2:10 PM, Shreyansh Jain <shreyansh.jain@nxp.com> wrote:
> > This patch introduces the rte_bus abstraction for devices and drivers in
> > EAL framework. The model is:
> >  - One or more buses are connected to a CPU (or core)
> >  - One or more devices are conneted to a Bus
> >  - Drivers are running instances which manage one or more devices
> >  - Bus is responsible for identifying devices (and interrupt propogation)
> >  - Driver is responsible for initializing the device
> >
> > This patch adds a 'rte_bus' class which rte_driver and rte_device refer.
> > This way, each device (rte_xxx_device) would have reference to the bus
> > it is based on. As well as, each driver (rte_xxx_driver) would have link
> > to the bus and devices on it for servicing.
> >
> >                                   __ rte_bus_list
> >                                  /
> >                      +----------'---+
> >                      |rte_bus       |
> >                      | driver_list------> List of rte_bus specific
> >                      | device_list----    devices
> >                      |              | `-> List of rte_bus associated
> >                      |              |     drivers
> >                      +--|------|----+
> >               _________/        \_________
> >     +--------/----+                     +-\---------------+
> >     |rte_device   |                     |rte_driver       |
> >     | rte_bus     |                     | rte_bus         |
> >     | rte_driver  |                     | ...             |
> >     | ...         |                     +---------...-----+
> >     |             |                               |||
> >     +---||--------+                               |||
> >         ||                                        |||
> >         | \                                        \\\
> >         |  \_____________                           \\\
> >         |                \                          |||
> >  +------|---------+ +----|----------+               |||
> >  |rte_pci_device  | |rte_xxx_device |               |||
> >  | ....           | | ....          |               |||
> >  +----------------+ +---------------+              / | \
> >                                                   /  |  \
> >                             _____________________/  /    \
> >                            /                    ___/      \
> >             +-------------'--+    +------------'---+    +--'------------+
> >             |rte_pci_driver  |    |rte_vdev_driver |    |rte_xxx_driver |
> >             | ....           |    | ....           |    | ....          |
> >             +----------------+    +----------------+    +---------------+
> >
> > This patch only enables the bus references on rte_driver and rte_driver.
> > EAL wide global device and driver list continue to exist until an instance
> > of bus is added in subsequent patches.
> >
> > This patch also introduces RTE_REGISTER_BUS macro on the lines of
> > RTE_PMD_REGISTER_XXX. Key difference is that the constructor priority has
> > been explicitly set to 101 so as to execute bus registration before PMD.
> >
> > Signed-off-by: Shreyansh Jain <shreyansh.jain@nxp.com>
> >

Ok, but let's keep this as bus type not bus. It gets really hard and complex
to enumerate all layers of PCI bus and bridges.