[dpdk-dev] [PATCH v6 0/8] Introducing EAL Bus-Device-Driver Model
Shreyansh Jain
shreyansh.jain at nxp.com
Tue Jan 17 06:09:03 CET 2017
On Monday 16 January 2017 11:57 PM, Stephen Hemminger wrote:
> On Mon, 16 Jan 2017 21:08:19 +0530
> Shreyansh Jain <shreyansh.jain at nxp.com> wrote:
>
>> Link to v5: [15]
>>
>> :: Introduction ::
>>
>> DPDK has been inherently a PCI inclined framework. Because of this, the
>> design of device tree (or list) within DPDK is also PCI inclined. A
>> non-PCI device doesn't have a way of being expressed without using hooks
>> started from EAL to PMD.
>>
>> (Check 'Version Changes' section for changes)
>>
>> :: Overview of the Proposed Changes ::
>>
>> Assuming the below graph for a computing node:
>>
>> device A1
>> |
>> +==.===='==============.============+ Bus A.
>> | `--> driver A11 \
>> device A2 `-> driver A12 \______
>> |CPU |
>> /`````
>> device B1 /
>> | /
>> +==.===='==============.============+ Bus B`
>> | `--> driver B11
>> device B2 `-> driver B12
>>
>>
>> - 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
>>
>> In [15], model assumes that rte_bus would be the base class using which
>> all the bus implementations would instantiate the objects. This patches
>> takes a much more basic approach, on the same lines of rte_device/
>> rte_driver and rte_pci_device/rte_pci_driver.
>> This is based on various review comments as well as offline (IRC)
>> discussions.
>>
>> - rte_bus is an abstract class which includes basic methods supported by
>> all buses.
>> - specific implementation, for example for PCI rte_pci_bus, would extend
>> this class to form their own buses, with their own bus specific device
>> and driver list.
>> -
>>
>> +-----------------+
>> |rte_pci_bus |
>> |+---------------+|
>> ||rte_bus ||
>> |+---------------+|
>> +-----------------+
>>
>> And example implementation would look like:
>>
>> .--------------->+-------------------+
>> | |rte_pci_bus |
>> | | +----------------+|
>> | | |rte_bus <------.
>> | | | name || |
>> | | | scan || |
>> | | | probe || |
>> | | | attach || |
>> | | | detach || |
>> | | +----------------+| |
>> | | pci_driver_list | |
>> | .-------------->pci_device_list | |
>> | | | ... | |
>> | | +-------------------+ |
>> | | |
>> | +-------------------+ |
>> | |rte_pci_device | |
>> '----bus | |
>> | +----------------+| |
>> | |rte_device || |
>> | | bus --------------------------------'
>> | | ... ||
>> | +----------------+|
>> | ... |
>> +-------------------+
>>
>>
>> :: Brief about Patch Layout ::
>>
>> 0001~0002: Introducing the basic Bus model and associated test case
>> 0003 : Split the PCI match into a separate function
>> 0004~0005: Introduce bus->scan APIs and integrate with EAL
>> 0006 : Update the Bus and PCI test cases for scanning/probing
>> 0007 : Enable PCI bus and remove code for direct PCI scan/probe from
>> EAL
>> 0008 : Add device hotplugging over the bus and introduce PCI helpers
>>
>>
>> :: Pending Changes/Caveats ::
>>
>> 1. This patchset only moves the PCI into a bus. And, that movement is also
>> currently part of the EAL (lib/librte_eal/linux)
>> Eventual aim is the PCI bus reside in driver/bus/pci
>>
>> 2. Though the implementation for bus is common for Linux and BSD, the PCI
>> bus implementation has been done/tested only for Linux.
>>
>> 3. RTE_REGISTER_BUS has been declared with contructor priority of 101
>> It is important that Bus is registered *before* drivers are registered.
>> Only way I could find to assure that was via
>> __attribute(contructor(priority)) of GCC. I am not sure how it would
>> behave on other compilers. Any suggestions?
>> - One suggestion from David Marchand was to use global bus object
>> handles, which I have not implemented for now. If that is common
>> choice, I will change in v3.
>>
>> :: ToDo list ::
>>
>> - Bump to librte_eal version
>> - Documentation continues to have references to some _old_ PCI symbols
>>
>> :: References ::
>>
>> [1] http://dpdk.org/ml/archives/dev/2016-November/050186.html
>> [2] http://dpdk.org/ml/archives/dev/2016-November/050622.html
>> [3] http://dpdk.org/ml/archives/dev/2016-November/050416.html
>> [4] http://dpdk.org/ml/archives/dev/2016-November/050567.html
>> [5] http://dpdk.org/ml/archives/dev/2016-November/050628.html
>> [6] http://dpdk.org/ml/archives/dev/2016-November/050415.html
>> [7] http://dpdk.org/ml/archives/dev/2016-November/050443.html
>> [8] http://dpdk.org/ml/archives/dev/2016-November/050624.html
>> [9] http://dpdk.org/ml/archives/dev/2016-November/050296.html
>> [10] http://dpdk.org/ml/archives/dev/2016-December/051349.html
>> [12] http://dpdk.org/ml/archives/dev/2016-December/052092.html
>> [13] http://dpdk.org/ml/archives/dev/2016-December/052381.html
>> [14] http://dpdk.org/ml/archives/dev/2016-December/053302.html
>> [15] http://dpdk.org/ml/archives/dev/2016-December/053315.html
>>
>> :: Version Changes ::
>> v6:
>> - Rearchitecture to bring bus object parallel to rte_device/driver
>> This majorly includes:
>> -- rte_pci_bus class and pci_bus as its object for PCI
>> -- bus->attach/detach (hotplugging)
>> -- removing bus->match as that is local to an implementation
>> - rename symbols rte_eal_bus_* to rte_bus_*
>> - restructuring patches (order) for simplicity
>> - update to test_pci
>>
>> v5:
>> - Fix checkpatch error in Patch 0003
>>
>> v4:
>> - rebase over master (eac901ce)
>> - Fix a bug in test_bus while setup and cleanup
>> - rename rte_eal_get_bus to rte_eal_bus_get
>> - Add helper (iterator) macros for easy bus,device,driver traversal
>> - removed 0001 patch as it is already merged in master
>> - fix missing rte_eal_bus_insert_device symbol in map file
>>
>> v3:
>> - rebase over master (c431384c8f)
>> - revert patch 0001 changes for checkpatch (container_of macro)
>> - qat/rte_qat_cryptodev update for rte_driver->probe
>> - test_pci update for using a test_pci_bus for verification
>> - some bug fixes based on internal testing.
>> -- rte_eal_dev_attach not handling devargs
>> -- blacklisting not working
>>
>> v2:
>> - No more bus->probe()
>> Now, rte_eal_bus_probe() calls rte_driver->probe based on match output
>> - new functions, rte_eal_pci_probe and rte_eal_pci_remove have been
>> added as glue code between PCI PMDs and PCI Bus
>> `-> PMDs are updated to use these new functions as callbacks for
>> rte_driver
>> - 'default' keyword has been removed from match and scan
>> - Fix for incorrect changes in mlx* and nicvf*
>> - Checkpatch fixes
>> - Some variable checks have been removed from internal functions;
>> functions which are externally visible continue to have such checks
>> - Some rearrangement of patches:
>> -- changes to drivers have been separated from EAL changes (but this
>> does make PCI PMDs non-working for a particular patch)
>>
>> Shreyansh Jain (8):
>> eal/bus: introduce bus abstraction
>> test: add basic bus infrastructure tests
>> pci: split match and probe function
>> eal/bus: support for scanning of bus
>> eal: introduce bus scan and probe in EAL
>> test: update bus and pci unit test cases
>> eal: enable PCI bus
>> eal: enable hotplugging of devices on bus
>>
>> app/test/Makefile | 2 +-
>> app/test/test.h | 2 +
>> app/test/test_bus.c | 686 ++++++++++++++++++++++++
>> app/test/test_pci.c | 164 ++++--
>> lib/librte_eal/bsdapp/eal/Makefile | 1 +
>> lib/librte_eal/bsdapp/eal/eal.c | 13 +-
>> lib/librte_eal/bsdapp/eal/eal_pci.c | 13 +
>> lib/librte_eal/bsdapp/eal/rte_eal_version.map | 15 +-
>> lib/librte_eal/common/Makefile | 2 +-
>> lib/librte_eal/common/eal_common_bus.c | 140 +++++
>> lib/librte_eal/common/eal_common_dev.c | 56 +-
>> lib/librte_eal/common/eal_common_pci.c | 330 ++++++++----
>> lib/librte_eal/common/eal_private.h | 10 -
>> lib/librte_eal/common/include/rte_bus.h | 206 +++++++
>> lib/librte_eal/common/include/rte_dev.h | 1 +
>> lib/librte_eal/common/include/rte_pci.h | 161 +++++-
>> lib/librte_eal/linuxapp/eal/Makefile | 1 +
>> lib/librte_eal/linuxapp/eal/eal.c | 13 +-
>> lib/librte_eal/linuxapp/eal/eal_pci.c | 53 +-
>> lib/librte_eal/linuxapp/eal/rte_eal_version.map | 15 +-
>> 20 files changed, 1646 insertions(+), 238 deletions(-)
>> create mode 100644 app/test/test_bus.c
>> create mode 100644 lib/librte_eal/common/eal_common_bus.c
>> create mode 100644 lib/librte_eal/common/include/rte_bus.h
>>
>
>
> All this is excellent, but doesn't go far enough to break the assumptions
> of 'struct eth_driver'
>
That is true. But, this is the first step of many steps. Next would be:
- unlinking eth_device from pci_device (already upstream by Jan)
- unlinking eth_driver from pci_driver dependency
- Same steps for cryptodev (I will pick this next)
- moving buses to drivers/bus
And some more minor changes making PCI just one bus exposing services;
eth_device/eth_driver being just a type of device provided by DPDK
without any linkage to bus actual device belongs to.
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