skiboot-5.7-rc1 release notes

Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

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+.. _skiboot-5.7-rc1:
+
+skiboot-5.7-rc1
+===============
+
+skiboot v5.7-rc1 was released on Monday July 3rd 2017. It is the first
+release candidate of skiboot 5.7, which will become the new stable release
+of skiboot following the 5.6 release, first released 24th May 2017.
+
+skiboot v5.7-rc1 contains all bug fixes as of :ref:`skiboot-5.4.6`
+and :ref:`skiboot-5.1.19` (the currently maintained stable releases). We
+do not currently expect to do any 5.6.x stable releases.
+
+For how the skiboot stable releases work, see :ref:`stable-rules` for details.
+
+The current plan is to cut the final 5.7 by July 12th, with skiboot 5.7
+being for all POWER8 and POWER9 platforms in op-build v1.18 (Due July 12th).
+This is a short cycle as this release is mainly targetted towards POWER9
+bringup efforts.
+
+This is the second release using the new regular six week release cycle,
+similar to op-build, but slightly offset to allow for a short stabilisation
+period. Expected release dates and contents are tracked using GitHub milestone
+and issues: https://github.com/open-power/skiboot/milestones
+
+Over skiboot-5.6, we have the following changes:
+
+New Features
+------------
+
+New features in this release for POWER9 systems:
+
+- In Memory Counters (IMC) (See :ref:`imc` for details)
+- phb4: Activate shared PCI slot on witherspoon (see :ref:`Shared Slot <shared-slot-rn>`)
+- phb4 capi (i.e. CAPI2): Enable capi mode for PHB4 (see :ref:`CAPI on PHB4 <capi2-rn>`)
+
+New feature for IBM FSP based systems:
+
+- fsp/tpo: Provide support for disabling TPO alarm
+
+  This patch adds support for disabling a preconfigured
+  Timed-Power-On(TPO) alarm on FSP based systems. Presently once a TPO alarm
+  is configured from the kernel it will be triggered even if its
+  subsequently disabled.
+
+  With this patch a TPO alarm can be disabled by passing
+  y_m_d==hr_min==0 to fsp_opal_tpo_write(). A branch is added to the
+  function to handle this case by sending FSP_CMD_TPO_DISABLE message to
+  the FSP instead of usual FSP_CMD_TPO_WRITE message. The kernel is
+  expected to call opal_tpo_write() with y_m_d==hr_min==0 to request
+  opal to disable TPO alarm.
+
+POWER9
+------
+
+Development on POWER9 systems continues in earnest.
+
+This release includes the first support for POWER9 DD2 chips. Future releases
+will likely contain more bug fixes, this release has booted on real hardware.
+
+- hdata: Reserve Trace Areas
+
+  When hostboot is configured to setup in memory tracing it will reserve
+  some memory for use by the hardware tracing facility. We need to mark
+  these areas as off limits to the operating system and firmware.
+- hdata: Make out-of-range idata print at PR_DEBUG
+
+  Some fields just aren't populated on some systems.
+
+- hdata: Ignore unnamed memory reservations.
+
+  Hostboot should name any and all memory reservations that it provides.
+  Currently some hostboots export a broken reservation covering the first
+  256MB of memory and this causes the system to crash at boot due to an
+  invalid free because this overlaps with the static "ibm,os-reserve"
+  region (which covers the first 768MB of memory).
+
+  According to the hostboot team unnamed reservations are invalid and can
+  be ignored.
+
+- hdata: Check the Host I2C devices array version
+
+  Currently this is not populated on FSP machines which causes some
+  obnoxious errors to appear in the boot log. We also only want to
+  parse version 1 of this structure since future versions will completely
+  change the array item format.
+
+- Ensure P9 DD1 workarounds apply only to Nimbus
+
+  The workarounds for P9 DD1 are only needed for Nimbus. P9 Cumulus will
+  be DD1 but don't need these same workarounds.
+
+  This patch ensures the P9 DD1 workarounds only apply to Nimbus. It
+  also renames some things to make clear what's what.
+
+- cpu: Cleanup AMR and IAMR when re-initializing CPUs
+
+  There's a bug in current Linux kernels leaving crap in those registers
+  accross kexec and not sanitizing them on boot. This breaks kexec under
+  some circumstances (such as booting a hash kernel from a radix one
+  on P9 DD2.0).
+
+  The long term fix is in Linux, but this workaround is a reasonable
+  way of "sanitizing" those SPRs when Linux calls opal_reinit_cpus()
+  and shouldn't have adverse effects.
+
+  We could also use that same mechanism to cleanup other things as
+  well such as restoring some other SPRs to their default value in
+  the future.
+
+- Set POWER9 RPR SPR to 0x00000103070F1F3F.  Same value as P8.
+
+  Without this, thread priorities inside a core don't work.
+
+- cpu: Support setting HID[RADIX] and set it by default on P9
+
+  This adds new opal_reinit_cpus() flags to setup radix or hash
+  mode in HID[8] on POWER9.
+
+  By default HID[8] will be set. On P9 DD1.0, Linux will change
+  it as needed. On P9 DD2.0 hash works in radix mode (radix is
+  really "dual" mode) so KVM won't break and existing kernels
+  will work.
+
+  Newer kernels built for hash will call this to clear the HID bit
+  and thus get the full size of the TLB as an optimization.
+
+- Add "cleanup_global_tlb" for P9 and later
+
+  Uses broadcast TLBIE's to cleanup the TLB on all cores and on
+  the nest MMU
+
+- xive: DD2.0 updates
+
+  Add support for StoreEOI, fix StoreEOI MMIO offset in ESB page,
+  and other cleanups
+
+- Update default TSCR value for P9 as recommended by HW folk.
+
+- xive: Fix initialisation of xive_cpu_state struct
+
+  When using XIVE emulation with DEBUG=1, we run into crashes in log_add()
+  due to the xive_cpu_state->log_pos being uninitialised (and thus, with
+  DEBUG enabled, initialised to the poison value of 0x99999999).
+
+OCC/Power Management
+^^^^^^^^^^^^^^^^^^^^
+
+With this release, it's possible to boot POWER9 systems with the OCC
+enabled and change CPU frequencies. Doing so does require other firmware
+components to also support this (otherwise the frequency will not be set).
+
+- occ: Skip setting cores to nominal frequency in P9
+
+  In P9, once OCC is up, it is supposed to setup the cores to nominal
+  frequency. So skip this step in OPAL.
+- occ: Fix Pstate ordering for P9
+
+  In P9 the pstate values are positive. They are continuous set of
+  unsigned integers [0 to +N] where Pmax is 0 and Pmin is N. The
+  linear ordering of pstates for P9 has changed compared to P8.
+  P8 has neagtive pstate values advertised as [0 to -N] where Pmax
+  is 0 and Pmin is -N. This patch adds helper routines to abstract
+  pstate comparison with pmax and adds sanity pstate limit checks.
+  This patch also fixes pstate arithmetic by using labs().
+- p8-i2c: occ: Add support for OCC to use I2C engines
+
+  This patch adds support to share the I2C engines with host and OCC.
+  OCC uses I2C engines to read DIMM temperatures and to communicate with
+  GPU. OCC Flag register is used for locking between host and OCC. Host
+  requests for the bus by setting a bit in OCC Flag register. OCC sends
+  an interrupt to indicate the change in ownership.
+
+opal-prd/PRD
+^^^^^^^^^^^^
+
+- opal-prd: Handle SBE passthrough message passing
+
+  This patch adds support to send SBE pass through command to HBRT.
+- SBE: Add passthrough command support
+
+  SBE sends passthrough command. We have to capture this interrupt and
+  send event to HBRT via opal-prd (user space daemon).
+- opal-prd: hook up reset_pm_complex
+
+  This change provides the facility to invoke HBRT's reset_pm_complex, in
+  the same manner is done with process_occ_reset previously.
+
+  We add a control command for `opal-prd pm-complex reset`, which is just
+  an alias for occ_reset at this stage.
+
+- prd: Implement firmware side of opaque PRD channel
+
+  This change introduces the firmware side of the opaque HBRT <--> OPAL
+  message channel. We define a base message format to be shared with HBRT
+  (in include/prd-fw-msg.h), and allow firmware requests and responses to
+  be sent over this channel.
+
+  We don't currently have any notifications defined, so have nothing to do
+  for firmware_notify() at this stage.
+
+- opal-prd: Add firmware_request & firmware_notify implementations
+
+  This change adds the implementation of firmware_request() and
+  firmware_notify(). To do this, we need to add a message queue, so that
+  we can properly handle out-of-order messages coming from firmware.
+
+- opal-prd: Add support for variable-sized messages
+
+  With the introductuion of the opaque firmware channel, we want to
+  support variable-sized messages. Rather than expecting to read an
+  entire 'struct opal_prd_msg' in one read() call, we can split this
+  over mutiple reads, potentially expanding our message buffer.
+
+- opal-prd: Sync hostboot interfaces with HBRT
+
+  This change adds new callbacks defined for p9, and the base thunks for
+  the added calls.
+
+- opal-prd: interpret log level prefixes from HBRT
+
+  Interpret the (optional) \*_MRK log prefixes on HBRT messages, and set
+  the syslog log priority to suit.
+
+- opal-prd: Add occ reset to usage text
+- opal-prd: allow different chips for occ control actions
+
+  The `occ reset` and `occ error` actions can both take a chip id
+  argument, but we're currently just using zero. This change changes the
+  control message format to pass the chip ID from the control process to
+  the opal-prd daemon.
+
+
+PCI/PHB4
+^^^^^^^^
+
+- phb4: Fix number of index bits in IODA tables
+
+  On PHB4 the number of index bits in the IODA table address register
+  was bumped to 10 bits to accomodate for 1024 MSIs and 1024 TVEs (DD2).
+
+  However our macro only defined the field to be 9 bits, thus causing
+  "interesting" behaviours on some systems.
+
+- phb4: Harden init with bad PHBs
+
+  Currently if we read all 1's from the EEH or IRQ capabilities, we end
+  up train wrecking on some other random code (eg. an assert() in xive).
+
+  This hardens the PHB4 code to look for these bad reads and more
+  gracefully fails the init for that PHB alone.  This allows the rest of
+  the system to boot and ignore those bad PHBs.
+
+- phb4 capi (i.e. CAPI2): Handle HMI events
+
+  Find the CAPP on the chip associated with the HMI event for PHB4.
+  The recovery mode (re-initialization of the capp, resume of functional
+  operations) is only available with P9 DD2. A new patch will be provided
+  to support this feature.
+
+.. _capi2-rn:
+
+- phb4 capi (i.e. CAPI2): Enable capi mode for PHB4
+
+  Enable the Coherently attached processor interface. The PHB is used as
+  a CAPI interface.
+  CAPI Adapters can be connected to either PEC0 or PEC2. Single port
+  CAPI adapter can be connected to either PEC0 or PEC2, but Dual-Port
+  Adapter can be only connected to PEC2
+  * CAPP0 attached to PHB0(PEC0 - single port)
+  * CAPP1 attached to PHB3(PEC2 - single or dual port)
+
+- hw/phb4: Rework phb4_get_presence_state()
+
+  There are two issues in current implementation: It should return errcode
+  visibile to Linux, which has prefix OPAL_*. The code isn't very obvious.
+
+  This returns OPAL_HARDWARE when the PHB is broken. Otherwise, OPAL_SUCCESS
+  is always returned. In the mean while, It refactors the code to make it
+  obvious: OPAL_PCI_SLOT_PRESENT is returned when the presence signal (low active)
+  or PCIe link is active. Otherwise, OPAL_PCI_SLOT_EMPTY is returned.
+
+- phb4: Error injection for config space
+
+  Implement CFG (config space) error injection.
+
+  This works the same as PHB3.  MMIO and DMA error injection require a
+  rewrite, so they're unsupported for now.
+
+  While it's not feature complete, this at least provides an easy way to
+  inject an error that will trigger EEH.
+
+- phb4: Error clear implementation
+- phb4: Mask link down errors during reset
+
+  During a hot reset the PCI link will drop, so we need to mask link down
+  events to prevent unnecessary errors.
+- phb4: Implement root port initialization
+
+  phb4_root_port_init() was a NOP before, so fix that.
+- phb4: Complete reset implementation
+
+  This implements complete reset (creset) functionality for POWER9 DD1.
+
+  Only partially tested and contends with some DD1 errata, but it's a start.
+
+.. _shared-slot-rn:
+
+- phb4: Activate shared PCI slot on witherspoon
+
+  Witherspoon systems come with a 'shared' PCI slot: physically, it
+  looks like a x16 slot, but it's actually two x8 slots connected to two
+  PHBs of two different chips. Taking advantage of it requires some
+  logic on the PCI adapter. Only the Mellanox CX5 adapter is known to
+  support it at the time of this writing.
+
+  This patch enables support for the shared slot on witherspoon if a x16
+  adapter is detected. Each x8 slot has a presence bit, so both bits
+  need to be set for the activation to take place. Slot sharing is
+  activated through a gpio.
+
+  Note that there's no easy way to be sure that the card is indeed a
+  shared-slot compatible PCI adapter and not a normal x16 card. Plugging
+  a normal x16 adapter on the shared slot should be avoided on
+  witherspoon, as the link won't train on the second slot, resulting in
+  a timeout and a longer boot time. Only the first slot is usable and
+  the x16 adapter will end up using only half the lines.
+
+  If the PCI card plugged on the physical slot is only x8 (or less),
+  then the presence bit of the second slot is not set, so this patch
+  does nothing. The x8 (or less) adapter should work like on any other
+  physical slot.
+
+- phb4: Block D-state power management on direct slots
+
+  As current revisions of PHB4 don't properly handle the resulting
+  L1 link transition.
+
+- phb4: Call pci config filters
+
+- phb4: Mask out write-1-to-clear registers in RC cfg
+
+  The root complex config space only supports 4-byte accesses. Thus, when
+  the client requests a smaller size write, we do a read-modify-write to
+  the register.
+
+  However, some register have bits defined as "write 1 to clear".
+
+  If we do a RMW cycles on such a register and such bits are 1 in the
+  part that the client doesn't intend to modify, we will accidentally
+  write back those 1's and clear the corresponding bit.
+
+  This avoids it by masking out those magic bits from the "old" value
+  read from the register.
+
+- phb4: Properly mask out link down errors during reset
+- phb3/4: Silence a useless warning
+
+  PHB's don't have base location codes on non-FSP systems and it's
+  normal.
+
+- phb4: Workaround bug in spec 053
+
+  Wait for DLP PGRESET to clear *after* lifting the PCIe core reset
+
+- phb4: DD2.0 updates
+
+  Support StoreEOI, full complements of PEs (twice as big TVT)
+  and other updates.
+
+  Also renumber init steps to match spec 063
+
+
+NPU2
+^^^^
+
+Note that currently NPU2 support is limited to POWER9 DD1 hardware.
+
+- platforms/astbmc/witherspoon.c: Add NPU2 slot mappings
+
+  For NVLink2 to function PCIe devices need to be associated with the right
+  NVLinks. This association is supposed to be passed down to Skiboot via HDAT but
+  those fields are still not correctly filled out. To work around this we add slot
+  tables for the NVLinks similar to what we have for P8+.
+
+- hw/npu2.c: Fix device aperture calculation
+
+  The POWER9 NPU2 implements an address compression scheme to compress 56-bit P9
+  physical addresses to 47-bit GPU addresses. System software needs to know both
+  addresses, unfortunately the calculation of the compressed address was
+  incorrect. Fix it here.
+
+- hw/npu2.c: Change MCD BAR allocation order
+
+  MCD BARs need to be correctly aligned to the size of the region. As GPU
+  memory is allocated from the top of memory down we should start allocating
+  from the highest GPU memory address to the lowest to ensure correct
+  alignment.
+
+- NPU2: Add flag to nvlink config space indicating DL reset state
+
+  Device drivers need to be able to determine if the DL is out of reset or
+  not so they can safely probe to see if links have already been trained.
+  This patch adds a flag to the vendor specific config space indicating if
+  the DL is out of reset.
+
+- hw/npu2.c: Hardcode MSR_SF when setting up npu XTS contexts
+
+  We don't support anything other than 64-bit mode for address translations so we
+  can safely hardcode it.
+
+- hw/npu2-hw-procedures.c: Add nvram option to override zcal calculations
+
+  In some rare cases the zcal state machine may fail and flag an error. According
+  to hardware designers it is sometimes ok to ignore this failure and use nominal
+  values for the calculations. In this case we add a nvram variable
+  (nv_zcal_override) which will cause skiboot to ignore the failure and use the
+  nominal value specified in nvram.
+- npu2: Fix npu2_{read,write}_4b()
+
+  When writing or reading 4-byte values, we need to use the upper half of
+  the 64-bit SCOM register.
+
+  Fix npu2_{read,write}_4b() and their callers to use uint32_t, and
+  appropriately shift the value being written or returned.
+
+
+- hw/npu2.c: Fix opal_npu_map_lpar to search for existing BDF
+- hw/npu2-hw-procedures.c: Fix running of zcal procedure
+
+    The zcal procedure should only be run once per obus (ie. once per group of 3
+    links). Clean up the code and fix the potential buffer overflow due to a typo.
+    Also updates the zcal settings to their proper values.
+- hw/npu2.c: Add memory coherence directory programming
+
+  The memory coherence directory (MCD) needs to know which system memory addresses
+  belong to the GPU. This amounts to setting a BAR and a size in the MCD to cover
+  the addresses assigned to each of the GPUs. To ease assignment we assume GPUs
+  are assigned memory in a contiguous block per chip.
+
+
+pflash/libflash
+---------------
+
+- libflash/libffs: Zero checksum words
+
+  On writing ffs entries to flash libffs doesn't zero checksum words
+  before calculating the checksum across the entire structure. This causes
+  an inaccurate calculation of the checksum as it may calculate a checksum
+  on non-zero checksum bytes.
+
+- libffs: Fix ffs_lookup_part() return value
+
+  It would return success when the part wasn't found
+- libflash/libffs: Correctly update the actual size of the partition
+
+  libffs has been updating FFS partition information in the wrong place
+  which leads to incomplete erases and corruption.
+- libflash: Initialise entries list earlier
+
+  In the bail-out path we call ffs_close() to tear down the partially
+  initialised ffs_handle. ffs_close() expects the entries list to be
+  initialised so we need to do that earlier to prevent a null pointer
+  dereference.
+
+mbox-flash
+----------
+
+mbox-flash is the emerging standard way of talking to host PNOR flash
+on POWER9 systems.
+
+- libflash/mbox-flash: Implement MARK_WRITE_ERASED mbox call
+
+  Version two of the mbox-flash protocol defines a new command:
+  MARK_WRITE_ERASED.
+
+  This command provides a simple way to mark a region of flash as all 0xff
+  without the need to go and write all 0xff. This is an optimisation as
+  there is no need for an erase before a write, it is the responsibility of
+  the BMC to deal with the flash correctly, however in v1 it was ambiguous
+  what a client should do if the flash should be erased but not actually
+  written to. This allows of a optimal path to resolve this problem.
+
+- libflash/mbox-flash: Update to V2 of the protocol
+
+  Updated version 2 of the protocol can be found at:
+  https://github.com/openbmc/mboxbridge/blob/master/Documentation/mbox_protocol.md
+
+  This commit changes mbox-flash such that it will preferentially talk
+  version 2 to any capable daemon but still remain capable of talking to
+  v1 daemons.
+
+  Version two changes some of the command definitions for increased
+  consistency and usability.
+  Version two includes more attention bits - these are now dealt with at a
+  simple level.
+- libflash/mbox-flash: Implement MARK_WRITE_ERASED mbox call
+
+  Version two of the mbox-flash protocol defines a new command:
+  MARK_WRITE_ERASED.
+
+  This command provides a simple way to mark a region of flash as all 0xff
+  without the need to go and write all 0xff. This is an optimisation as
+  there is no need for an erase before a write, it is the responsibility of
+  the BMC to deal with the flash correctly, however in v1 it was ambiguous
+  what a client should do if the flash should be erased but not actually
+  written to. This allows of a optimal path to resolve this problem.
+
+- libflash/mbox-flash: Update to V2 of the protocol
+
+  Updated version 2 of the protocol can be found at:
+  https://github.com/openbmc/mboxbridge/blob/master/Documentation/mbox_protocol.md
+
+  This commit changes mbox-flash such that it will preferentially talk
+  version 2 to any capable daemon but still remain capable of talking to
+  v1 daemons.
+
+  Version two changes some of the command definitions for increased
+  consistency and usability.
+  Version two includes more attention bits - these are now dealt with at a
+  simple level.
+
+- hw/lpc-mbox: Use message registers for interrupts
+
+  Currently the BMC raises the interrupt using the BMC control register.
+  It does so on all accesses to the 16 'data' registers meaning that when
+  the BMC only wants to set the ATTN (on which we have interrupts enabled)
+  bit we will also get a control register based interrupt.
+
+  The solution here is to mask that interrupt permanantly and enable
+  interrupts on the protocol defined 'response' data byte.
+
+General fixes
+-------------
+
+- Reduce log level on non-error log messages
+
+  90% of what we print isn't useful to a normal user. This
+  dramatically reduces the amount of messages printed by
+  OPAL in normal circumstances.
+
+- init: Silence messages and call ourselves "OPAL"
+- psi: Switch to ESB mode later
+
+  There's an errata, if we switch to ESB mode before setting up
+  the various ESB mode related registers, a pending interrupts
+  can go wrong.
+
+- lpc: Enable "new" SerIRQ mode
+- hw/ipmi/ipmi-sel: missing newline in prlog warning
+
+- p8-i2c OCC lock: fix locking in p9_i2c_bus_owner_change
+- Convert important polling loops to spin at lowest SMT priority
+
+  The pattern of calling cpu_relax() inside a polling loop does
+  not suit the powerpc SMT priority instructions. Prefrred is to
+  set a low priority then spin until break condition is reached,
+  then restore priority.
+
+- Improve cpu_idle when PM is disabled
+
+  Split cpu_idle() into cpu_idle_delay() and cpu_idle_job() rather than
+  requesting the idle type as a function argument. Have those functions
+  provide a default polling (non-PM) implentation which spin at the
+  lowest SMT priority.
+
+- core/fdt: Always add a reserve map
+
+  Currently we skip adding the reserved ranges block to the generated
+  FDT blob if we are excluding the root node. This can result in a DTB
+  that dtc will barf on because the reserved memory ranges overlap with
+  the start of the dt_struct block. As an example: ::
+
+    $ fdtdump broken.dtb -d
+    /dts-v1/;
+    // magic:               0xd00dfeed
+    // totalsize:           0x7f3 (2035)
+    // off_dt_struct:       0x30  <----\
+    // off_dt_strings:      0x7b8       | this is bad!
+    // off_mem_rsvmap:      0x30  <----/
+    // version:             17
+    // last_comp_version:   16
+    // boot_cpuid_phys:     0x0
+    // size_dt_strings:     0x3b
+    // size_dt_struct:      0x788
+
+    /memreserve/ 0x100000000 0x300000004;
+    /memreserve/ 0x3300000001 0x169626d2c;
+    /memreserve/ 0x706369652d736c6f 0x7473000000000003;
+            *continues*
+
+  With this patch: ::
+
+    $ fdtdump working.dtb -d
+    /dts-v1/;
+    // magic:               0xd00dfeed
+    // totalsize:           0x803 (2051)
+    // off_dt_struct:       0x40
+    // off_dt_strings:      0x7c8
+    // off_mem_rsvmap:      0x30
+    // version:             17
+    // last_comp_version:   16
+    // boot_cpuid_phys:     0x0
+    // size_dt_strings:     0x3b
+    // size_dt_struct:      0x788
+
+    // 0040: tag: 0x00000001 (FDT_BEGIN_NODE)
+    / {
+    // 0048: tag: 0x00000003 (FDT_PROP)
+    // 07fb: string: phandle
+    // 0054: value
+        phandle = <0x00000001>;
+            *continues*
+
+- hw/lpc-mbox: Use message registers for interrupts
+
+  Currently the BMC raises the interrupt using the BMC control register.
+  It does so on all accesses to the 16 'data' registers meaning that when
+  the BMC only wants to set the ATTN (on which we have interrupts enabled)
+  bit we will also get a control register based interrupt.
+
+  The solution here is to mask that interrupt permanantly and enable
+  interrupts on the protocol defined 'response' data byte.
+
+
+PCI
+---
+- pci: Wait 20ms before checking presence detect on PCIe
+
+  As the PHB presence logic has a debounce timer that can take
+  a while to settle.
+
+- phb3+iov: Fixup support for config space filters
+
+  The filter should be called before the HW access and its
+  return value control whether to perform the access or not
+- core/pci: Use PCI slot's power facality in pci_enable_bridge()
+
+  The current implmentation has incorrect assumptions: there is
+  always a PCI slot associated with root port and PCIe switch
+  downstream port and all of them are capable to change its
+  power state by register PCICAP_EXP_SLOTCTL. Firstly, there
+  might not a PCI slot associated with the root port or PCIe
+  switch downstream port. Secondly, the power isn't controlled
+  by standard config register (PCICAP_EXP_SLOTCTL). There are
+  I2C slave devices used to control the power states on Tuleta.
+
+  In order to use the PCI slot's methods to manage the power
+  states, this does:
+
+  * Introduce PCI_SLOT_FLAG_ENFORCE, indicates the request operation
+    is enforced to be applied.
+  * pci_enable_bridge() is split into 3 functions: pci_bridge_power_on()
+    to power it on; pci_enable_bridge() as a place holder and
+    pci_bridge_wait_link() to wait the downstream link to come up.
+  * In pci_bridge_power_on(), the PCI slot's specific power management
+    methods are used if there is a PCI slot associated with the PCIe
+    switch downstream port or root port.
+- platforms/astbmc/slots.c: Allow comparison of bus numbers when matching slots
+
+  When matching devices on multiple down stream PLX busses we need to compare more
+  than just the device-id of the PCIe BDFN, so increase the mask to do so.
+
+Tests and simulators
+--------------------
+
+- boot-tests: add OpenBMC support
+- boot_test.sh: Add SMC BMC support
+
+  Your BMC needs a special debug image flashed to use this, the exact
+  image and methods aren't something I can publish here, but if you work
+  for IBM or SMC you can find out from the right sources.
+
+  A few things are needed to move around to be able to flash to a SMC BMC.
+
+  For a start, the SSH daemon will only accept connections after a special
+  incantation (which I also can't share), but you should put that in the
+  ~/.skiboot_boot_tests file along with some other default login information
+  we don't publicise too broadly (because Security Through Obscurity is
+  *obviously* a good idea....)
+
+  We also can't just directly "ssh /bin/true", we need an expect script,
+  and we can't scp, but we can anonymous rsync!
+
+  You also need a pflash binary to copy over.
+- hdata_to_dt: Add PVR overrides to the usage text
+- mambo: Add a reservation for the initramfs
+
+  On most systems the initramfs is loaded inside the part of memory
+  reserved for the OS [0x0-0x30000000] and skiboot will never touch it.
+  On mambo it's loaded at 0x80000000 and if you're unlucky skiboot can
+  allocate over the top of it and corrupt the initramfs blob.
+
+  There might be the downside that the kernel cannot re-use the initramfs
+  memory since it's marked as reserved, but the kernel might also free it
+  anyway.
+- mambo: Update P9 PVR to reflect Scale out 24 core chips
+
+  The P9 PVR bits 48:51 don't indicate a revision but instead different
+  configurations.  From BookIV we have:
+
+  ==== ===================
+  Bits Configuration
+  ==== ===================
+     0 Scale out 12 cores
+     1 Scale out 24 cores
+     2 Scale up 12 cores
+     3 Scale up 24 cores
+  ==== ===================
+
+  Skiboot will mostly the use "Scale out 24 core" configuration
+  (ie. SMT4 not SMT8) so reflect this in mambo.
+- core: Move enable_mambo_console() into chip initialisation
+
+  Rather than having a wart in main_cpu_entry() that initialises the mambo
+  console, we can move it into init_chips() which is where we discover that we're
+  on mambo.
+
+- mambo: Create multiple chips when we have multiple CPUs
+
+  Currently when we boot mambo with multiple CPUs, we create multiple CPU nodes in
+  the device tree, and each claims to be on a separate chip.
+
+  However we don't create multiple xscom nodes, which means skiboot only knows
+  about a single chip, and all CPUs end up on it. At the moment mambo is not able
+  to create multiple xscom controllers. We can create fake ones, just by faking
+  the device tree up, but that seems uglier than this solution.
+
+  So create a mambo-chip for each CPU other than 0, to tell skiboot we want a
+  separate chip created. This then enables Linux to see multiple chips: ::
+
+      smp: Brought up 2 nodes, 2 CPUs
+      numa: Node 0 CPUs: 0
+      numa: Node 1 CPUs: 1
+
+- chip: Add support for discovering chips on mambo
+
+  Currently the only way for skiboot to discover chips is by looking for xscom
+  nodes. But on mambo it's currently not possible to create multiple xscom nodes,
+  which means we can only simulate a single chip system.
+
+  However it seems we can fairly cleanly add support for a special mambo chip
+  node, and use that to instantiate multiple chips.
+
+  Add a check in init_chip() that we're not clobbering an already initialised
+  chip, now that we have two places that initialise chips.
+- mambo: Make xscom claim to be DD 2.0
+
+  In the mambo tcl we set the CPU version to DD 2.0, because mambo is not
+  bug compatible with DD 1.
+
+  But in xscom_read_cfam_chipid() we have a hard coded value, to work
+  around the lack of the f000f register, which claims to be P9 DD 1.0.
+
+  This doesn't seem to cause crashes or anything, but at boot we do see: ::
+
+      [    0.003893084,5] XSCOM: chip 0x0 at 0x1a0000000000 [P9N DD1.0]
+
+  So fix it to claim that the xscom is also DD 2.0 to match the CPU.
+
+- mambo: Match whole string when looking up symbols with linsym/skisym
+
+  linsym/skisym use a regex to match the symbol name, and accepts a
+  partial match against the entry in the symbol map, which can lead to
+  somewhat confusing results, eg: ::
+
+      systemsim % linsym early_setup
+      0xc000000000027890
+      systemsim % linsym early_setup$
+      0xc000000000aa8054
+      systemsim % linsym early_setup_secondary
+      0xc000000000027890
+
+  I don't think that's the behaviour we want, so append a $ to the name so
+  that the symbol has to match against the whole entry, eg: ::
+
+      systemsim % linsym early_setup
+      0xc000000000aa8054
+
+- Disable nap on P8 Mambo, public release has bugs
+- mambo: Allow loading multiple CPIOs
+
+  Currently we have support for loading a single CPIO and telling Linux to
+  use it as the initrd. But the Linux code actually supports having
+  multiple CPIOs contiguously in memory, between initrd-start and end, and
+  will unpack them all in order. That is a really nice feature as it means
+  you can have a base CPIO with your root filesystem, and then tack on
+  others as you need for various tests etc.
+
+  So expand the logic to handle SKIBOOT_INITRD, and treat it as a comma
+  separated list of CPIOs to load. I chose comma as it's fairly rare in
+  filenames, but we could make it space, colon, whatever. Or we could add
+  a new environment variable entirely. The code also supports trimming
+  whitespace from the values, so you can have "cpio1, cpio2".
+- hdata/test: Add memory reservations to hdata_to_dt
+
+  Currently memory reservations are parsed, but since they are not
+  processed until mem_region_init() they don't appear in the output
+  device tree blob. Several bugs have been found with memory reservations
+  so we want them to be part of the test output.
+
+  Add them and clean up several usages of printf() since we want only the
+  dtb to appear in standard out.
+
+IBM FSP systems
+---------------
+
+- FSP/CONSOLE: Fix possible NULL dereference
+- platforms/ibm-fsp/firenze: Fix PCI slot power-off pattern
+
+  When powering off the PCI slot, the corresponding bits should
+  be set to 0bxx00xx00 instead of 0bxx11xx11. Otherwise, the
+  specified PCI slot can't be put into power-off state. Fortunately,
+  it didn't introduce any side-effects so far.
+- FSP/CONSOLE: Workaround for unresponsive ipmi daemon
+
+  We use TCE mapped area to write data to console. Console header
+  (fsp_serbuf_hdr) is modified by both FSP and OPAL (OPAL updates
+  next_in pointer in fsp_serbuf_hdr and FSP updates next_out pointer).
+
+  Kernel makes opal_console_write() OPAL call to write data to console.
+  OPAL write data to TCE mapped area and sends MBOX command to FSP.
+  If our console becomes full and we have data to write to console,
+  we keep on waiting until FSP reads data.
+
+  In some corner cases, where FSP is active but not responding to
+  console MBOX message (due to buggy IPMI) and we have heavy console
+  write happening from kernel, then eventually our console buffer
+  becomes full. At this point OPAL starts sending OPAL_BUSY_EVENT to
+  kernel. Kernel will keep on retrying. This is creating kernel soft
+  lockups. In some extreme case when every CPU is trying to write to
+  console, user will not be able to ssh and thinks system is hang.
+
+  If we reset FSP or restart IPMI daemon on FSP, system recovers and
+  everything becomes normal.
+
+  This patch adds workaround to above issue by returning OPAL_HARDWARE
+  when cosole is full. Side effect of this patch is, we may endup dropping
+  latest console data. But better to drop console data than system hang.
+
+- FSP: Set status field in response message for timed out message
+
+  For timed out FSP messages, we set message status as "fsp_msg_timeout".
+  But most FSP driver users (like surviellance) are ignoring this field.
+  They always look for FSP returned status value in callback function
+  (second byte in word1). So we endup treating timed out message as success
+  response from FSP.
+
+  Sample output: ::
+
+    [69902.432509048,7] SURV: Sending the heartbeat command to FSP
+    [70023.226860117,4] FSP: Response from FSP timed out, word0 = d66a00d7, word1 = 0 state: 3
+    ....
+    [70023.226901445,7] SURV: Received heartbeat acknowledge from FSP
+    [70023.226903251,3] FSP: fsp_trigger_reset() entry
+
+  Here SURV code thought it got valid response from FSP. But actually we didn't
+  receive response from FSP.
+
+  This patch fixes above issue by updating status field in response structure.
+
+- FSP: Improve timeout message
+
+- FSP/RTC: Fix possible FSP R/R issue in rtc write path
+- hw/fsp/rtc: read/write cached rtc tod on fsp hir.
+
+  Currently fsp-rtc reads/writes the cached RTC TOD on an fsp
+  reset. Use latest fsp_in_rr() function to properly read the cached rtc
+  value when fsp reset initiated by the hir.
+
+  Below is the kernel trace when we set hw clock, when hir process starts. ::
+
+    [ 1727.775824] NMI watchdog: BUG: soft lockup - CPU#57 stuck for 23s! [hwclock:7688]
+    [ 1727.775856] Modules linked in: vmx_crypto ibmpowernv ipmi_powernv uio_pdrv_genirq ipmi_devintf powernv_op_panel uio ipmi_msghandler powernv_rng leds_powernv ip_tables x_tables autofs4 ses enclosure scsi_transport_sas crc32c_vpmsum lpfc ipr tg3 scsi_transport_fc
+    [ 1727.775883] CPU: 57 PID: 7688 Comm: hwclock Not tainted 4.10.0-14-generic #16-Ubuntu
+    [ 1727.775883] task: c000000fdfdc8400 task.stack: c000000fdfef4000
+    [ 1727.775884] NIP: c00000000090540c LR: c0000000000846f4 CTR: 000000003006dd70
+    [ 1727.775885] REGS: c000000fdfef79a0 TRAP: 0901   Not tainted  (4.10.0-14-generic)
+    [ 1727.775886] MSR: 9000000000009033 <SF,HV,EE,ME,IR,DR,RI,LE>
+    [ 1727.775889]   CR: 28024442  XER: 20000000
+    [ 1727.775890] CFAR: c00000000008472c SOFTE: 1
+                   GPR00: 0000000030005128 c000000fdfef7c20 c00000000144c900 fffffffffffffff4
+                   GPR04: 0000000028024442 c00000000090540c 9000000000009033 0000000000000000
+                   GPR08: 0000000000000000 0000000031fc4000 c000000000084710 9000000000001003
+                   GPR12: c0000000000846e8 c00000000fba0100
+    [ 1727.775897] NIP [c00000000090540c] opal_set_rtc_time+0x4c/0xb0
+    [ 1727.775899] LR [c0000000000846f4] opal_return+0xc/0x48
+    [ 1727.775899] Call Trace:
+    [ 1727.775900] [c000000fdfef7c20] [c00000000090540c] opal_set_rtc_time+0x4c/0xb0 (unreliable)
+    [ 1727.775901] [c000000fdfef7c60] [c000000000900828] rtc_set_time+0xb8/0x1b0
+    [ 1727.775903] [c000000fdfef7ca0] [c000000000902364] rtc_dev_ioctl+0x454/0x630
+    [ 1727.775904] [c000000fdfef7d40] [c00000000035b1f4] do_vfs_ioctl+0xd4/0x8c0
+    [ 1727.775906] [c000000fdfef7de0] [c00000000035bab4] SyS_ioctl+0xd4/0xf0
+    [ 1727.775907] [c000000fdfef7e30] [c00000000000b184] system_call+0x38/0xe0
+    [ 1727.775908] Instruction dump:
+    [ 1727.775909] f821ffc1 39200000 7c832378 91210028 38a10020 39200000 38810028 f9210020
+    [ 1727.775911] 4bfffe6d e8810020 80610028 4b77f61d <60000000> 7c7f1b78 3860000a 2fbffff4
+
+  This is found when executing the testcase
+  https://github.com/open-power/op-test-framework/blob/master/testcases/fspresetReload.py
+
+  With this fix ran fsp hir torture testcase in the above test
+  which is working fine.
+- occ: Set return variable to correct value
+
+  When entering this section of code rc will be zero. If fsp_mkmsg() fails
+  the code responsible for printing an error message won't be set.
+  Resetting rc should allow for the error case to trigger if fsp_mkmsg
+  fails.
+- capp: Fix hang when CAPP microcode LID is missing on FSP machine
+
+  When the LID is absent, we fail early with an error from
+  start_preload_resource. In that case, capp_ucode_info.load_result
+  isn't set properly causing a subsequent capp_lid_download() to
+  call wait_for_resource_loaded() on something that isn't being
+  loaded, thus hanging.
+
+- FSP: Add check to detect FSP R/R inside fsp_sync_msg()
+
+  OPAL sends MBOX message to FSP and updates message state from fsp_msg_queued
+  -> fsp_msg_sent. fsp_sync_msg() queues message and waits until we get response
+  from FSP. During FSP R/R we move outstanding MBOX messages from msgq to rr_queue
+  including inflight message (fsp_reset_cmdclass()). But we are not resetting
+  inflight message state.
+
+  In extreme croner case where we sent message to FSP via fsp_sync_msg() path
+  and FSP R/R happens before getting respose from FSP, then we will endup waiting
+  in fsp_sync_msg() until everything becomes normal.
+
+  This patch adds fsp_in_rr() check to fsp_sync_msg() and return error to caller
+    if FSP is in R/R.
+- FSP: Add check to detect FSP R/R inside fsp_sync_msg()
+
+  OPAL sends MBOX message to FSP and updates message state from fsp_msg_queued
+  -> fsp_msg_sent. fsp_sync_msg() queues message and waits until we get response
+  from FSP. During FSP R/R we move outstanding MBOX messages from msgq to rr_queue
+  including inflight message (fsp_reset_cmdclass()). But we are not resetting
+  inflight message state.
+
+  In extreme croner case where we sent message to FSP via fsp_sync_msg() path
+  and FSP R/R happens before getting respose from FSP, then we will endup waiting
+  in fsp_sync_msg() until everything becomes normal.
+
+  This patch adds fsp_in_rr() check to fsp_sync_msg() and return error to caller
+    if FSP is in R/R.
+- capp: Fix hang when CAPP microcode LID is missing on FSP machine
+
+  When the LID is absent, we fail early with an error from
+  start_preload_resource. In that case, capp_ucode_info.load_result
+  isn't set properly causing a subsequent capp_lid_download() to
+  call wait_for_resource_loaded() on something that isn't being
+  loaded, thus hanging.
+- FSP/CONSOLE: Do not free fsp_msg in error path
+
+  as we reuse same msg to send next output message.
+
+- platform/zz: Acknowledge OCC_LOAD mbox message in ZZ
+
+  In P9 FSP box, OCC image is pre-loaded. So do not handle the load
+  command and send SUCCESS to FSP on recieving OCC_LOAD mbox message.
+
+- FSP/RTC: Improve error log
+
+astbmc systems
+--------------
+
+- platforms/astbmc: Don't validate model on palmetto
+
+  The platform isn't compatible with palmetto until the root device-tree
+  node's "model" property is NULL or "palmetto". However, we could have
+  "TN71-BP012" for the property on palmetto. ::
+
+       linux# cat /proc/device-tree/model
+       TN71-BP012
+
+  This skips the validation on root device-tree node's "model" property
+  on palmetto, meaning we check the "compatible" property only.
+
+