[dpdk-dev] [PATCH v3 02/12] eal/bus: introduce bus abstraction
Jan Blunck
jblunck at infradead.org
Wed Dec 21 16:38:42 CET 2016
On Tue, Dec 20, 2016 at 6:11 PM, Stephen Hemminger
<stephen at networkplumber.org> wrote:
> On Tue, 20 Dec 2016 14:17:14 +0100
> Jan Blunck <jblunck at infradead.org> wrote:
>
>> On Fri, Dec 16, 2016 at 2:10 PM, Shreyansh Jain <shreyansh.jain at 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 at 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.
As far as I understand it this isn't the intention to replicate the
hierarchy of buses we have in the kernel. The PCI bus in this case
becomes a list of PCI devices.
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