Subject: Re: [PATCH v8 00/45] powerpc/powernv: PCI hotplug support

From: Alexey Kardashevskiy <[email-masked]>
Date: Wed, 13 Apr 2016 19:14:59 +1000

On 04/13/2016 05:42 PM, Gavin Shan wrote:
> On Wed, Apr 13, 2016 at 05:28:15PM +1000, Alexey Kardashevskiy wrote:
>> On 02/17/2016 02:43 PM, Gavin Shan wrote:
>>> This series of patches rebases on powerpc/next branch, plus below additional
>>> patches:
>>>
>>>     <This series of patches>
>>>     <Followup 3 patches from Gavin on SRIOV EEH, which aren't posted>
>>>     https://patchwork.ozlabs.org/patch/581315/	(PATCH[1/9] Richard's SRIOV EEH)
>>>     https://patchwork.ozlabs.org/patch/582639/	(PATCH[1/1] Gavin's EEH fix)
>>>     https://patchwork.ozlabs.org/patch/582093/	(PATCH[1/1] Gavin's EEH fix)
>>>     https://patchwork.ozlabs.org/patch/580626/	(PATCH[1/4] Gavin's PCI fix)
>>>     https://patchwork.ozlabs.org/patch/580153/	(PATCH[1/1] Andrew's EEH minor fix)
>>>     https://patchwork.ozlabs.org/patch/566827/	(PATCH[1/1] Russell's P5IOC2 removal)
>>>     https://patchwork.ozlabs.org/patch/534154/	(PATCH[1/7] Richard's SRIOV rework)
>>>     commit 388f7b1 ("Linux 4.5-rc3")
>>>
>>> The series of patches intend to support PCI slot for PowerPC PowerNV platform,
>>> which is running on top of skiboot firmware. The patchset requires corresponding
>>> changes from skiboot firmware, which is sent to [email-masked]
>>> for review. The PCI slots are exposed by skiboot with device node properties,
>>> and kernel utilizes those properties to populated PCI slots accordingly.
>>>
>>> The original PCI infrastructure on PowerNV platform can't support hotplug
>>> because the PE is assigned during PHB fixup time, which is called for once
>>> during system boot time. For this, the PCI infrastructure on PowerNV platform
>>> has been reworked for a lot. After that, the PE and its corresponding resources
>>> (IODT, M32DT, M64 segments, DMA32 and bypass window) are assigned upon updating
>>> PCI bridge's resources, which might decide PE# assigned to the PE (e.g. M64
>>> resources, on P8 strictly speaking). Each PE will maintain a reference count,
>>> which is (number of child PCI devices + 1). That indicates when last child PCI
>>> device leaves the PE, the PE and its included resources will be relased and put
>>> back into free pool again. With this design, the PE will be released when EEH PE
>>> is released. PATCH[1 - 23] are related to this part.
>>>
>>>  From skiboot perspective, PCI slot is providing (hot/fundamental/complete)
>>> resets to EEH. The kernel gets to know if skiboot supports various reset on one
>>> particular PCI slot through device-tree node. If it does, EEH will utilize the
>>> functionality provided by skiboot. Besides, the device-tree nodes have to change
>>> in order to support PCI hotplug. For example, when one PCI adapter inserted to
>>> one slot, its device-tree node should be added to the system dynamically. Conversely,
>>> the device-tree node should be removed from the system when the PCI adapter is going
>>> to be offline. Since pci_dn and eeh_dev have same life cyle as PCI device nodes,
>>> they should be added/removed accordingly during PCI hotplug. PATCH[24 - 39] are
>>> doing the related work.
>>>
>>> The OF driver is changed to support unflattening FDT blob for sub-stree, which
>>> is covered by PATCH[40 - 44].
>>>
>>> The last one, PATCH[45], is the standalone PCI hotplug driver for PowerPC PowerNV
>>> platform.
>>>
>>> =======
>>> Testing
>>> =======
>>> 1. Unplug adapters behind non-empty slot, then plug them.
>>>
>>>     1.1 Check status
>>>     # cat /sys/bus/pci/slots/C10/address
>>>     0003:09:00
>>>     # cat /sys/bus/pci/slots/C10/adapter
>>>     1
>>>     # cat /sys/bus/pci/slots/C10/power
>>>     1
>>>     # lspci
>>>     0003:09:00.0 Ethernet controller: \
>>>     Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
>>>     0003:09:00.1 Ethernet controller: \
>>>     Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
>>>     0003:09:00.2 Ethernet controller: \
>>>     Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
>>>     0003:09:00.3 Ethernet controller: \
>>>     Broadcom Corporation NetXtreme BCM5719 Gigabit Ethernet PCIe (rev 01)
>>>     # lspci -t
>>>     # lspci -t
>>>     -+-[0003:00]---00.0-[01-13]----00.0-[02-13]--+-01.0-[03]----00.0
>>>      |                                           +-08.0-[04-08]--
>>>      |                                           +-09.0-[09]--+-00.0
>>>      |                                           |            +-00.1
>>>      |                                           |            +-00.2
>>>      |                                           |            \-00.3
>>>      |                                           +-10.0-[0a-0e]--
>>>      |                                           \-11.0-[0f-13]--
>>>
>>>     1.2 Unplug adapter 0003:09.00.x
>>>     # echo 0 > /sys/bus/pci/slots/C10/power
>>>     # lspci -t
>>>     -+-[0003:00]---00.0-[01-13]----00.0-[02-13]--+-01.0-[03]----00.0
>>>      |                                           +-08.0-[04-08]--
>>>      |                                           +-09.0-[09]--
>>>      |                                           +-10.0-[0a-0e]--
>>>      |                                           \-11.0-[0f-13]--
>>>
>>>     1.3 Plug adapter 0003:09.00.x
>>>     # echo 1 > /sys/bus/pci/slots/C10/power
>>
>>
>> Do I understand correctly that the adapter was not physically moved in/out of
>> the slot between 1.2 and 1.3?
>>
>
> Correct.

This is not right then... Someone should try it, on both P7 and P8.

>
>>
>>
>>>     # lspci -t
>>>     -+-[0003:00]---00.0-[01-13]----00.0-[02-13]--+-01.0-[03]----00.0
>>>      |                                           +-08.0-[04-08]--
>>>      |                                           +-09.0-[09]--+-00.0
>>>      |                                           |            +-00.1
>>>      |                                           |            +-00.2
>>>      |                                           |            \-00.3
>>>      |                                           +-10.0-[0a-0e]--
>>>      |                                           \-11.0-[0f-13]--
>>>
>>>
>>>     1.4 Inject EEH error to adapter 0003:09:00.x, which is recovered.
>>
>> I am confused - why is this needed to test hotplug?
>>
>
> Without the series, the EEH reset is always done by kenrel. With the
> series applied, the EEH reset could be done in skiboot.

Why exactly cannot EEH reset changes go to a smaller separate patchset 
(before hotplug)?

> That's the
> major change introduced by the series from EEH's perspective. Also,
> the EEH code was touched.
>
>>>     # cat /sys/bus/pci/devices/0003:09:00.0/eeh_pe_config_addr
>>>     0x1
>>>     # echo 1:0:4:0:0 > /sys/kernel/debug/powerpc/PCI0003/err_injct
>>>     # lspci -ns 0003:09:00.0
>>>     # dmesg | grep EEH
>>>     EEH: Frozen PHB#3-PE#1 detected
>>>     EEH: PE location: U78C9.001.WZS00CF-P1-C10, PHB location: N/A
>>>     EEH: Detected PCI bus error on PHB#3-PE#1
>>>     EEH: This PCI device has failed 1 times in the last hour
>>>     EEH: Notify device drivers to shutdown
>>>     EEH: Collect temporary log
>>>     EEH: Reset without hotplug activity
>>>     EEH: Notify device drivers the completion of reset
>>>     EEH: Notify device driver to resume
>>>
>>> 2. Plug adapter and then unplug it. This requires hack in skiboot
>>>     to skip probing the adapters behind the target (C12 in the
>>>     testing) for once.
>>>
>>>     2.1 Check status
>>>     # cat /sys/bus/pci/slots/C12/address
>>>     0001:06
>>>     # cat /sys/bus/pci/slots/C12/power
>>>     0
>>>     # cat /sys/bus/pci/slots/C12/adapter
>>>     1
>>>     # lspci -t
>>>     +-[0001:00]---00.0-[01-0a]----00.0-[02-0a]--+-01.0-[03-04]----00.0-[04]----00.0
>>>                                                 +-08.0-[05]----00.0
>>>                                                 \-09.0-[06-0a]--
>>>
>>>     2.2 Plug adapter 0001:06:00.x
>>>     # echo 1 > /sys/bus/pci/slots/C12/power
>>>     # lspci -t
>>>     +-[0001:00]---00.0-[01-0a]----00.0-[02-0a]--+-01.0-[03-04]----00.0-[04]----00.0
>>>                                                 +-08.0-[05]----00.0
>>>                                                 \-09.0-[06-0a]--+-00.0
>>>                                                                 \-00.1
>>>     # lspci
>>>     0001:06:00.0 Ethernet controller: \
>>>     Broadcom Corporation NetXtreme II BCM57810 10 Gigabit Ethernet (rev 10)
>>>     0001:06:00.1 Ethernet controller: \
>>>     Broadcom Corporation NetXtreme II BCM57810 10 Gigabit Ethernet (rev 10)
>>>
>>>     2.3 Inject EEH error to adapter 0001:06:00.x, which is recovered
>>>     # cat /sys/bus/pci/devices/0001:06:00.0/eeh_pe_config_addr
>>>     0x2
>>>     # echo 2:0:4:0:0 > /sys/kernel/debug/powerpc/PCI0001/err_injct
>>>     # dmesg | grep EEH
>>>     EEH: Frozen PHB#1-PE#2 detected
>>>     EEH: PE location: U78C9.001.WZS00CF-P1-C12, PHB location: N/A
>>>     EEH: Detected PCI bus error on PHB#1-PE#2
>>>     EEH: This PCI device has failed 1 times in the last hour
>>>     EEH: Notify device drivers to shutdown
>>>     EEH: Collect temporary log
>>>     EEH: Reset without hotplug activity
>>>     EEH: Notify device drivers the completion of reset
>>>     EEH: Notify device driver to resume
>>>
>>>     2.4 Unplug adapter 0001:06:00.x
>>>     # echo 0 > /sys/bus/pci/slots/C12/power
>>>     # lspci -t
>>>     +-[0001:00]---00.0-[01-0a]----00.0-[02-0a]--+-01.0-[03-04]----00.0-[04]----00.0
>>>                                                 +-08.0-[05]----00.0
>>>                                                 \-09.0-[06-0a]--
>>>
>>> =========
>>> Changelog
>>> =========
>>> v8:
>>>     * Rebased to linux-powerpc next branch.
>>>     * Resolve comments from Alexey and Daniel on PCI part
>>>     * Resolve comments from Rob on fdt.c
>>>     * Retested (refer to the "Testing section")
>>> v7:
>>>     * Reworked revision to some extent.
>>>     * Rebased to powerpc/next repository.
>>>     * Reorder/split/merge/drop according - Alexey.
>>>     * Defined macros and use array to track IO/M32/M64/DMA32 segments - Alexey.
>>>     * Merged 3 files to one for the hotplug driver - Alexey.
>>>     * As part of OPAL API, defined macros for PCI slot power state, hotplug
>>>       message type. Defined macros for PCI slot power confirmed state in
>>>       hotplug driver.
>>>     * Misc comments from Alexey.
>>>     * Reworked unflatten_dt_node() to avoid recursive function calls.
>>>     * Use EXPORT_SYMBOL_GPL() and document function's input/output - Rob/Frank.
>>> v6:
>>>     * Patch reorder, split, squash - Alexey.
>>>     * Minor coding style - Alexey.
>>>     * Better function names for pcibios_{add,remove}_pci_devices - Bjorn
>>>     * Replace pr_warn() with dev_warn() in PowerNV hotplug driver - Bjorn
>>>     * Concurrent depth as parameter passed to __unflatten_dt_node() - Grant / Alexey
>>>     * Replace overlay with of_changeset - Grant
>>> v5:
>>>     * Rebased to 4.1.rc6 and some unmerged patches as below:
>>>       Alexey's DDW patchset (v11);
>>>       Gavin's EEH error injection support (in mpe's next branch);
>>>       Richard's EEH cleanup patches (in mpe's next branch);
>>>       Richard's EEH support for VF (v7);
>>>       Gavin's misc EEH fixes for 4.2;
>>>     * The revision bases on skiboot corresponding patches (v7):
>>>       https://patchwork.ozlabs.org/patch/480437/
>>>     * Utilize OF overlay to update device-tree with help of newly introduced
>>>       OPAL API opal_get_overlay_dt().
>>>     * Split patches for easy review according to aik's comments.
>>>     * Fix coding style from checkpatchc.pl as pointed by aik.
>>>     * Code cleanup and misc fixup according to aik's input.
>>> v4:
>>>     * Rebased to 4.1.RC1
>>>     * Added API to unflatten FDT blob to device node sub-tree, which is attached
>>>       the indicated parent device node. The original mechanism based on formatted
>>>       string stream has been dropped.
>>>     * The PATCH[v3 09/21] ("powerpc/eeh: Delay probing EEH device during hotplug")
>>>       was picked up sent to linux-ppc@ separately for review as Richard's "VF EEH
>>>       Support" depends on that.
>>> v3:
>>>     * Rebased to 4.1.RC0
>>>     * PowerNV PCI infrasturcture is total refactored in order to support PCI
>>>       hotplug. The PowerNV hotplug driver is also reworked a lot because of
>>>       the changes in skiboot in order to support PCI hotplug.
>>>
>>> Gavin Shan (45):
>>>    PCI: Add pcibios_setup_bridge()
>>>    powerpc/pci: Override pcibios_setup_bridge()
>>>    powerpc/pci: Cleanup on struct pci_controller_ops
>>>    powerpc/powernv: Cleanup on pci_controller_ops instances
>>>    powerpc/powernv: Drop phb->bdfn_to_pe()
>>>    powerpc/powernv: Reorder fields in struct pnv_phb
>>>    powerpc/powernv: Rename PE# fields in struct pnv_phb
>>>    powerpc/powernv: Fix initial IO and M32 segmap
>>>    powerpc/powernv: Simplify pnv_ioda_setup_pe_seg()
>>>    powerpc/powernv: IO and M32 mapping based on PCI device resources
>>>    powerpc/powernv: Track M64 segment consumption
>>>    powerpc/powernv: Rename M64 related functions
>>>    powerpc/powernv/ioda1: M64 support on P7IOC
>>>    powerpc/powernv/ioda1: Rename pnv_pci_ioda_setup_dma_pe()
>>>    powerpc/powernv/ioda1: Introduce PNV_IODA1_DMA32_SEGSIZE
>>>    powerpc/powernv: Remove DMA32 PE list
>>>    powerpc/powernv/ioda1: Improve DMA32 segment track
>>>    powerpc/powernv: Increase PE# capacity
>>>    powerpc/powernv: Use PE instead of number during setup and release
>>>    powerpc/powernv: Allocate PE# in reverse order
>>>    powerpc/powernv: Create PEs at PCI hot plugging time
>>>    powerpc/powernv/ioda1: Support releasing IODA1 TCE table
>>>    powerpc/powernv: Dynamically release PEs
>>>    powerpc/pci: Rename pcibios_{add,remove}_pci_devices()
>>>    powerpc/pci: Rename pcibios_find_pci_bus()
>>>    powerpc/pci: Move pci_find_bus_by_node() around
>>>    powerpc/pci: Export pci_add_device_node_info()
>>>    powerpc/pci: Introduce pci_remove_device_node_info()
>>>    powerpc/pci: Export pci_traverse_device_nodes()
>>>    powerpc/pci: Delay populating pdn
>>>    powerpc/pci: Don't scan empty slot
>>>    powerpc/pci: Update bridge windows on PCI plug
>>>    powerpc/powernv: Simplify pnv_eeh_reset()
>>>    powerpc/powernv: Exclude root bus in pnv_pci_reset_secondary_bus()
>>>    powerpc/powernv: Fundamental reset in pnv_pci_reset_secondary_bus()
>>>    powerpc/powernv: Support PCI slot ID
>>>    powerpc/powernv: Use firmware PCI slot reset infrastructure
>>>    powerpc/powernv: Functions to get/set PCI slot status
>>>    powerpc/powernv: Select OF_DYNAMIC
>>>    drivers/of: Split unflatten_dt_node()
>>>    drivers/of: Avoid recursively calling unflatten_dt_node()
>>>    drivers/of: Rename unflatten_dt_node()
>>>    drivers/of: Specify parent node in of_fdt_unflatten_tree()
>>>    drivers/of: Return allocated memory from of_fdt_unflatten_tree()
>>>    PCI/hotplug: PowerPC PowerNV PCI hotplug driver
>>>
>>>   arch/powerpc/include/asm/eeh.h                 |    2 +-
>>>   arch/powerpc/include/asm/opal-api.h            |   17 +-
>>>   arch/powerpc/include/asm/opal.h                |    8 +-
>>>   arch/powerpc/include/asm/pci-bridge.h          |   25 +-
>>>   arch/powerpc/include/asm/pnv-pci.h             |    7 +
>>>   arch/powerpc/include/asm/ppc-pci.h             |    8 +-
>>>   arch/powerpc/kernel/eeh_dev.c                  |   17 +-
>>>   arch/powerpc/kernel/eeh_driver.c               |   12 +-
>>>   arch/powerpc/kernel/pci-common.c               |   16 +-
>>>   arch/powerpc/kernel/pci-hotplug.c              |   47 +-
>>>   arch/powerpc/kernel/pci_dn.c                   |   89 +-
>>>   arch/powerpc/platforms/maple/pci.c             |   34 +-
>>>   arch/powerpc/platforms/pasemi/pci.c            |    3 -
>>>   arch/powerpc/platforms/powermac/pci.c          |   38 +-
>>>   arch/powerpc/platforms/powernv/Kconfig         |    1 +
>>>   arch/powerpc/platforms/powernv/eeh-powernv.c   |  179 ++--
>>>   arch/powerpc/platforms/powernv/opal-wrappers.S |    4 +
>>>   arch/powerpc/platforms/powernv/pci-ioda.c      | 1243 +++++++++++++++---------
>>>   arch/powerpc/platforms/powernv/pci.c           |   92 +-
>>>   arch/powerpc/platforms/powernv/pci.h           |   60 +-
>>>   arch/powerpc/platforms/pseries/msi.c           |    4 +-
>>>   arch/powerpc/platforms/pseries/pci_dlpar.c     |   32 -
>>>   arch/powerpc/platforms/pseries/setup.c         |    8 +-
>>>   drivers/gpu/drm/tilcdc/tilcdc_slave_compat.c   |    2 +-
>>>   drivers/of/fdt.c                               |  372 ++++---
>>>   drivers/of/unittest.c                          |    2 +-
>>>   drivers/pci/hotplug/Kconfig                    |   12 +
>>>   drivers/pci/hotplug/Makefile                   |    3 +
>>>   drivers/pci/hotplug/pnv_php.c                  |  870 +++++++++++++++++
>>>   drivers/pci/hotplug/rpadlpar_core.c            |    8 +-
>>>   drivers/pci/hotplug/rpaphp_core.c              |    4 +-
>>>   drivers/pci/hotplug/rpaphp_pci.c               |    4 +-
>>>   drivers/pci/setup-bus.c                        |    5 +
>>>   include/linux/of_fdt.h                         |    5 +-
>>>   include/linux/pci.h                            |    1 +
>>>   35 files changed, 2360 insertions(+), 874 deletions(-)
>>>   create mode 100644 drivers/pci/hotplug/pnv_php.c
>>>
>>
>>
>> --
>> Alexey
>>
>

-- 
Alexey