mbox series

[v4,00/25] Add support for OpenCAPI Persistent Memory devices

Message ID 20200327071202.2159885-1-alastair@d-silva.org (mailing list archive)
Headers show
Series Add support for OpenCAPI Persistent Memory devices | expand

Message

Alastair D'Silva March 27, 2020, 7:11 a.m. UTC
This series adds support for OpenCAPI Persistent Memory devices on bare metal (arch/powernv), exposing them as nvdimms so that we can make use of the existing infrastructure. There already exists a driver for the same devices abstracted through PowerVM (arch/pseries): arch/powerpc/platforms/pseries/papr_scm.c

These devices are connected via OpenCAPI, and present as LPC (lowest coherence point) memory to the system, practically, that means that memory on these cards could be treated as conventional, cache-coherent memory.

Since the devices are connected via OpenCAPI, they are not enumerated via ACPI. Instead, OpenCAPI links present as pseudo-PCI bridges, with devices below them.

This series introduces a driver that exposes the memory on these cards as nvdimms, with each card getting it's own bus. This is somewhat complicated by the fact that the cards do not have out of band persistent storage for metadata, so 1 SECTION_SIZE's (see SPARSEMEM) worth of storage is carved out of the top of the card storage to implement the ndctl_config_* calls.

The driver is not responsible for configuring the NPU (NVLink Processing Unit) BARs to map the LPC memory from the card into the system's physical address space, instead, it requests this to be done via OPAL calls (typically implemented by Skiboot).

The series is structured as follows:
 - Required infrastructure changes & cleanup
 - A minimal driver implementation
 - Implementing additional features within the driver

Changelog:
V4:
  - Rebase on next-20200320
  - Bump copyright to 2020
  - Ensure all uapi headers use C89 compatible comments (missed ocxlpmem.h)
  - Move the driver back to drivers/nvdimm/ocxl, after confirmation
    that this location is desirable
  - Rename ocxl.c to ocxlpmem.c (+ support files)
  - Rename all ocxl_pmem to ocxlpmem
  - Address checkpatch --strict issues
  - "powerpc/powernv: Add OPAL calls for LPC memory alloc/release"
	- Pass base address as __be64
  - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
	- Address checkpatch spacing warnings
	- Reword blurb
	- Reword size description for ocxl_link_add_lpc_mem()
	- Add an early exit in ocxl_link_lpc_release() to avoid triggering
	  bogus warnings if called after ocxl_link_lpc_map() fails
  - "powerpc/powernv: Add OPAL calls for LPC memory alloc/release"
	- Reword blurb
  - "powerpc/powernv: Map & release OpenCAPI LPC memory"
	- Reword blurb
  - Move minor_idr init from file_init() to ocxlpmem_init() (fixes runtime error
    in "nvdimm: Add driver for OpenCAPI Persistent Memory")
  - Wrap long lines
  - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
	- Remove '+ 1' workround from serial number->cookie assignment
	- Drop out of memory message for ocxlpmem in probe()
	- Fix leaks of ocxlpmem & ocxlpmem->ocxl_fn in probe()
	- remove struct ocxlpmem_function0, it didn't value add
	- factor out err_unregistered label in probe
	- Address more checkpatch warnings
	- get/put the pci dev on probe/free
	- Drop ocxlpmem_ prefix from static functions
	- Propogate errors up from called functions in probe()
	- Set MODULE_LICENSE to GPLv2
	- Add myself as module author
	- Call nvdimm_bus_unregister() in remove() to release references
	- Don't call devm_memunmap on metadata_address, the release handler on
	 the device already deals with this
  - "nvdimm/ocxl: Read the capability registers & wait for device ready"
	- Fix mask for read_latency
	- Fold in is_usable logic into timeout to remove error message race
	- propogate bad rc from read_device_metadata
  - "nvdimm/ocxl: Add register addresses & status values to the header"
	- Add comments for register abbreviations where names have been
	  expanded
	- Add missing status for blocked on background task
	- Alias defines for firmware update status to show that the duplication
	  of values is intentional
  - "nvdimm/ocxl: Register a character device for userspace to interact with"
	- Add lock around minors IDR, delete the cdev before device_unregister
	- Propogate errors up from called functions in probe()
  - "nvdimm/ocxl: Add support for Admin commands"
	- Fix typo in setup_command_data error message, and drop 'ocxl' from it
	- Drop vestigial CHI read from admin_command_request
	- Change command ID mismatch message to dev_err, and return an error
	- Use jiffies to implement admin_command_complete_timeout()
	- Flesh out blurb
	- Create a wrapper to issue the command & wait for timeout
  - "nvdimm/ocxl: Add support for near storage commands"
	- dropped (will submit with the patches for nvdimm overwrite)
  - "nvdimm/ocxl: Implement the Read Error Log command"
	- Remove stray blank line
	- change misplaced goto to an early exit in read_error_log
	- Inline error_log_offset_0x08
	- Read WWID data as LE rather than host endian
	- Move the include of nvdimm/ocxlpmem.h to ocxl.c
	- Add padding after fwrevision in struct ioctl_ocxl_pmem_error_log
	- Register IOCTL magic
	- Coerce pointers to __u64 in IOCTLs
  - "nvdimm/ocxl: Add controller dump IOCTLs"
	- Coerce pointers to __u64 in IOCTLs
	- Document expected IOCTL usage in blurb
	- Add missing rc check
	- Only populate up to the number of bytes returned by the card,
	  and return this length to the caller
	- Add missing header check
  - "nvdimm/ocxl: Add an IOCTL to report controller statistics"
	- Update to match the latest version of the spec
	- Verify that parametr block IDs & lengths match what we expect
	- Use defines for offsets
  - "nvdimm/ocxl: Forward events to userspace"
	- Don't enable NSCRA doorbell
	- return -EBUSY if the event context is already used
	- return -ENODEV if IRQs cannot be mapped
	- Tag IRQ pointers with __iomem
	- Drop ocxlpmem_ prefix from static functions
	- Propogate error from eventfd_ctx_fdget
	- Fix error check in copy_to_user
	- Drop GLOBAL_MMIO_CHI_NSCRA (this should be in the overwrite patch)
	- Drop unused irq_pgmap
	- Don't redef BIT_ULL
  - "nvdimm/ocxl: Add debug IOCTLs"
	- Eliminate clearing loop (now done in admin_command_execute()
	- Drop dummy IOCTLs if CONFIG_OCXL_PMEM_DEBUG is not set
	- Group debug IOCTLs together & comment that they may not be available
  - "nvdimm/ocxl: Expose SMART data via ndctl"
	- Drop 'rc = 0; goto out;'
	- Propogate errors from ndctl_smart()
  - "nvdimm/ocxl: Expose the serial number in sysfs" & "nvdimm/ocxl: Expose the firmware version in sysfs"
	- Squash these 2 patches together
	- Expose data as a DIMM attribute rather than an ocxlpmem
	  attribute
  - "nvdimm/ocxl: Add an IOCTL to request controller health & perf data"
	- Reword blurb
  - "nvdimm/ocxl: Implement the heartbeat command"
	- Propogate rc in probe()

V3:
  - Rebase against next/next-20200220
  - Move driver to arch/powerpc/platforms/powernv, we now expect this
    driver to go upstream via the powerpc tree
  - "nvdimm/ocxl: Implement the Read Error Log command"
	- Fix bad header path
  - "nvdimm/ocxl: Read the capability registers & wait for device ready"
	- Fix overlapping masks between readiness_timeout & memory_available_timeout
  - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
	- Address minor review comments from Jonathan Cameron
	- Remove attributes
	- Default to module if building LIBNVDIMM
	- Propogate errors up from called functions in probe()
  - "nvdimm/ocxl: Expose SMART data via ndctl"
	- Pack attributes in struct
	- Support different size SMART buffers for compatibility with newer
	  ndctls that may want more SMART attribs than we provide
	- Rework to to use ND_CMD_CALL instead of ND_CMD_SMART
  - drop "ocxl: Free detached contexts in ocxl_context_detach_all()"
  - "powerpc: Map & release OpenCAPI LPC memory"
	- Remove 'extern'
	- Only available with CONFIG_MEMORY_HOTPLUG_SPARSE
  - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
	- Address minor review comments from Jonathan Cameron
  - "ocxl: Add functions to map/unmap LPC memory"
	- Split detected memory message into a separate patch
	- Address minor review comments from Jonathan Cameron
	- Add a comment explaining why unmap_lpc_mem is in deconfigure_afu
  - "nvdimm/ocxl: Add support for Admin commands"
	- use sizeof(u64) rather than 0x08 when iterating u64s
  - "nvdimm/ocxl: Implement the heartbeat command"
	- Fix typo in blurb
  - Address kernel doc issues
  - Ensure all uapi headers use C89 compatible comments
  - Drop patches for firmware update & overwrite, these will be
    submitted later once patches are available for ndctl
  - Rename SCM to OpenCAPI Persistent Memory

V2:
  - "powerpc: Map & release OpenCAPI LPC memory"
      - Fix #if -> #ifdef
      - use pci_dev_id to get the bdfn
      - use __be64 to hold be data
      - indent check_hotplug_memory_addressable correctly 
      - Remove export of check_hotplug_memory_addressable
  - "ocxl: Conditionally bind SCM devices to the generic OCXL driver"
      - Improve patch description and remove redundant default
  - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
      - Mark a few funcs as static as identified by the 0day bot
      - Add OCXL dependancies to OCXL_SCM
      - Use memcpy_mcsafe in scm_ndctl_config_read
      - Rename scm_foo_offset_0x00 to scm_foo_header_parse & add docs
      - Name DIMM attribs "ocxl" rather than "scm"
      - Split out into base + many feature patches
  - "powerpc: Enable OpenCAPI Storage Class Memory driver on bare metal"
      - Build DEV_DAX & friends as modules
  - "ocxl: Conditionally bind SCM devices to the generic OCXL driver"
      - Patch dropped (easy enough to maintain this out of tree for development)
  - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
      - Add a warning if an unmatched lpc_release is called
  - "ocxl: Add functions to map/unmap LPC memory"
      - Use EXPORT_SYMBOL_GPL


Alastair D'Silva (25):
  powerpc/powernv: Add OPAL calls for LPC memory alloc/release
  mm/memory_hotplug: Allow check_hotplug_memory_addressable to be called
    from drivers
  powerpc/powernv: Map & release OpenCAPI LPC memory
  ocxl: Remove unnecessary externs
  ocxl: Address kernel doc errors & warnings
  ocxl: Tally up the LPC memory on a link & allow it to be mapped
  ocxl: Add functions to map/unmap LPC memory
  ocxl: Emit a log message showing how much LPC memory was detected
  ocxl: Save the device serial number in ocxl_fn
  nvdimm: Add driver for OpenCAPI Persistent Memory
  powerpc: Enable the OpenCAPI Persistent Memory driver for
    powernv_defconfig
  nvdimm/ocxl: Add register addresses & status values to the header
  nvdimm/ocxl: Read the capability registers & wait for device ready
  nvdimm/ocxl: Add support for Admin commands
  nvdimm/ocxl: Register a character device for userspace to interact
    with
  nvdimm/ocxl: Implement the Read Error Log command
  nvdimm/ocxl: Add controller dump IOCTLs
  nvdimm/ocxl: Add an IOCTL to report controller statistics
  nvdimm/ocxl: Forward events to userspace
  nvdimm/ocxl: Add an IOCTL to request controller health & perf data
  nvdimm/ocxl: Implement the heartbeat command
  nvdimm/ocxl: Add debug IOCTLs
  nvdimm/ocxl: Expose SMART data via ndctl
  nvdimm/ocxl: Expose the serial number & firmware version in sysfs
  MAINTAINERS: Add myself & nvdimm/ocxl to ocxl

 .../userspace-api/ioctl/ioctl-number.rst      |    1 +
 MAINTAINERS                                   |    3 +
 arch/powerpc/configs/powernv_defconfig        |    5 +
 arch/powerpc/include/asm/opal-api.h           |    2 +
 arch/powerpc/include/asm/opal.h               |    2 +
 arch/powerpc/include/asm/pnv-ocxl.h           |   42 +-
 arch/powerpc/platforms/powernv/ocxl.c         |   43 +
 arch/powerpc/platforms/powernv/opal-call.c    |    2 +
 drivers/misc/ocxl/config.c                    |   74 +-
 drivers/misc/ocxl/core.c                      |   61 +
 drivers/misc/ocxl/link.c                      |   60 +
 drivers/misc/ocxl/ocxl_internal.h             |   45 +-
 drivers/nvdimm/Kconfig                        |    2 +
 drivers/nvdimm/Makefile                       |    1 +
 drivers/nvdimm/ocxl/Kconfig                   |   21 +
 drivers/nvdimm/ocxl/Makefile                  |    7 +
 drivers/nvdimm/ocxl/main.c                    | 1975 +++++++++++++++++
 drivers/nvdimm/ocxl/ocxlpmem.h                |  197 ++
 drivers/nvdimm/ocxl/ocxlpmem_internal.c       |  280 +++
 include/linux/memory_hotplug.h                |    5 +
 include/misc/ocxl.h                           |  122 +-
 include/uapi/linux/ndctl.h                    |    1 +
 include/uapi/nvdimm/ocxlpmem.h                |  127 ++
 mm/memory_hotplug.c                           |    4 +-
 24 files changed, 2983 insertions(+), 99 deletions(-)
 create mode 100644 drivers/nvdimm/ocxl/Kconfig
 create mode 100644 drivers/nvdimm/ocxl/Makefile
 create mode 100644 drivers/nvdimm/ocxl/main.c
 create mode 100644 drivers/nvdimm/ocxl/ocxlpmem.h
 create mode 100644 drivers/nvdimm/ocxl/ocxlpmem_internal.c
 create mode 100644 include/uapi/nvdimm/ocxlpmem.h

Comments

Dan Williams April 1, 2020, 8:47 a.m. UTC | #1
On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@d-silva.org> wrote:
>
> This series adds support for OpenCAPI Persistent Memory devices on bare metal (arch/powernv), exposing them as nvdimms so that we can make use of the existing infrastructure. There already exists a driver for the same devices abstracted through PowerVM (arch/pseries): arch/powerpc/platforms/pseries/papr_scm.c
>
> These devices are connected via OpenCAPI, and present as LPC (lowest coherence point) memory to the system, practically, that means that memory on these cards could be treated as conventional, cache-coherent memory.
>
> Since the devices are connected via OpenCAPI, they are not enumerated via ACPI. Instead, OpenCAPI links present as pseudo-PCI bridges, with devices below them.
>
> This series introduces a driver that exposes the memory on these cards as nvdimms, with each card getting it's own bus. This is somewhat complicated by the fact that the cards do not have out of band persistent storage for metadata, so 1 SECTION_SIZE's (see SPARSEMEM) worth of storage is carved out of the top of the card storage to implement the ndctl_config_* calls.

Is it really tied to section-size? Can't that change based on the
configured page-size? It's not clear to me why that would be the
choice, but I'll dig into the implementation.

> The driver is not responsible for configuring the NPU (NVLink Processing Unit) BARs to map the LPC memory from the card into the system's physical address space, instead, it requests this to be done via OPAL calls (typically implemented by Skiboot).

Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
platform firmware services? What's Skiboot?

>
> The series is structured as follows:
>  - Required infrastructure changes & cleanup
>  - A minimal driver implementation
>  - Implementing additional features within the driver

Thanks for the intro and the changelog!

>
> Changelog:
> V4:
>   - Rebase on next-20200320

Do you have dependencies on other material that's in -next? Otherwise
-next is only a viable development baseline if you are going to merge
through Andrew's tree.

>   - Bump copyright to 2020
>   - Ensure all uapi headers use C89 compatible comments (missed ocxlpmem.h)
>   - Move the driver back to drivers/nvdimm/ocxl, after confirmation
>     that this location is desirable
>   - Rename ocxl.c to ocxlpmem.c (+ support files)
>   - Rename all ocxl_pmem to ocxlpmem
>   - Address checkpatch --strict issues
>   - "powerpc/powernv: Add OPAL calls for LPC memory alloc/release"
>         - Pass base address as __be64
>   - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
>         - Address checkpatch spacing warnings
>         - Reword blurb
>         - Reword size description for ocxl_link_add_lpc_mem()
>         - Add an early exit in ocxl_link_lpc_release() to avoid triggering
>           bogus warnings if called after ocxl_link_lpc_map() fails
>   - "powerpc/powernv: Add OPAL calls for LPC memory alloc/release"
>         - Reword blurb
>   - "powerpc/powernv: Map & release OpenCAPI LPC memory"
>         - Reword blurb
>   - Move minor_idr init from file_init() to ocxlpmem_init() (fixes runtime error
>     in "nvdimm: Add driver for OpenCAPI Persistent Memory")
>   - Wrap long lines
>   - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
>         - Remove '+ 1' workround from serial number->cookie assignment
>         - Drop out of memory message for ocxlpmem in probe()
>         - Fix leaks of ocxlpmem & ocxlpmem->ocxl_fn in probe()
>         - remove struct ocxlpmem_function0, it didn't value add
>         - factor out err_unregistered label in probe
>         - Address more checkpatch warnings
>         - get/put the pci dev on probe/free
>         - Drop ocxlpmem_ prefix from static functions
>         - Propogate errors up from called functions in probe()
>         - Set MODULE_LICENSE to GPLv2
>         - Add myself as module author
>         - Call nvdimm_bus_unregister() in remove() to release references
>         - Don't call devm_memunmap on metadata_address, the release handler on
>          the device already deals with this
>   - "nvdimm/ocxl: Read the capability registers & wait for device ready"
>         - Fix mask for read_latency
>         - Fold in is_usable logic into timeout to remove error message race
>         - propogate bad rc from read_device_metadata
>   - "nvdimm/ocxl: Add register addresses & status values to the header"
>         - Add comments for register abbreviations where names have been
>           expanded
>         - Add missing status for blocked on background task
>         - Alias defines for firmware update status to show that the duplication
>           of values is intentional
>   - "nvdimm/ocxl: Register a character device for userspace to interact with"
>         - Add lock around minors IDR, delete the cdev before device_unregister
>         - Propogate errors up from called functions in probe()
>   - "nvdimm/ocxl: Add support for Admin commands"
>         - Fix typo in setup_command_data error message, and drop 'ocxl' from it
>         - Drop vestigial CHI read from admin_command_request
>         - Change command ID mismatch message to dev_err, and return an error
>         - Use jiffies to implement admin_command_complete_timeout()
>         - Flesh out blurb
>         - Create a wrapper to issue the command & wait for timeout
>   - "nvdimm/ocxl: Add support for near storage commands"
>         - dropped (will submit with the patches for nvdimm overwrite)
>   - "nvdimm/ocxl: Implement the Read Error Log command"
>         - Remove stray blank line
>         - change misplaced goto to an early exit in read_error_log
>         - Inline error_log_offset_0x08
>         - Read WWID data as LE rather than host endian
>         - Move the include of nvdimm/ocxlpmem.h to ocxl.c
>         - Add padding after fwrevision in struct ioctl_ocxl_pmem_error_log
>         - Register IOCTL magic
>         - Coerce pointers to __u64 in IOCTLs
>   - "nvdimm/ocxl: Add controller dump IOCTLs"
>         - Coerce pointers to __u64 in IOCTLs
>         - Document expected IOCTL usage in blurb
>         - Add missing rc check
>         - Only populate up to the number of bytes returned by the card,
>           and return this length to the caller
>         - Add missing header check
>   - "nvdimm/ocxl: Add an IOCTL to report controller statistics"
>         - Update to match the latest version of the spec
>         - Verify that parametr block IDs & lengths match what we expect
>         - Use defines for offsets
>   - "nvdimm/ocxl: Forward events to userspace"
>         - Don't enable NSCRA doorbell
>         - return -EBUSY if the event context is already used
>         - return -ENODEV if IRQs cannot be mapped
>         - Tag IRQ pointers with __iomem
>         - Drop ocxlpmem_ prefix from static functions
>         - Propogate error from eventfd_ctx_fdget
>         - Fix error check in copy_to_user
>         - Drop GLOBAL_MMIO_CHI_NSCRA (this should be in the overwrite patch)
>         - Drop unused irq_pgmap
>         - Don't redef BIT_ULL
>   - "nvdimm/ocxl: Add debug IOCTLs"
>         - Eliminate clearing loop (now done in admin_command_execute()
>         - Drop dummy IOCTLs if CONFIG_OCXL_PMEM_DEBUG is not set
>         - Group debug IOCTLs together & comment that they may not be available
>   - "nvdimm/ocxl: Expose SMART data via ndctl"
>         - Drop 'rc = 0; goto out;'
>         - Propogate errors from ndctl_smart()
>   - "nvdimm/ocxl: Expose the serial number in sysfs" & "nvdimm/ocxl: Expose the firmware version in sysfs"
>         - Squash these 2 patches together
>         - Expose data as a DIMM attribute rather than an ocxlpmem
>           attribute
>   - "nvdimm/ocxl: Add an IOCTL to request controller health & perf data"
>         - Reword blurb
>   - "nvdimm/ocxl: Implement the heartbeat command"
>         - Propogate rc in probe()
>
> V3:
>   - Rebase against next/next-20200220
>   - Move driver to arch/powerpc/platforms/powernv, we now expect this
>     driver to go upstream via the powerpc tree
>   - "nvdimm/ocxl: Implement the Read Error Log command"
>         - Fix bad header path
>   - "nvdimm/ocxl: Read the capability registers & wait for device ready"
>         - Fix overlapping masks between readiness_timeout & memory_available_timeout
>   - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
>         - Address minor review comments from Jonathan Cameron
>         - Remove attributes
>         - Default to module if building LIBNVDIMM
>         - Propogate errors up from called functions in probe()
>   - "nvdimm/ocxl: Expose SMART data via ndctl"
>         - Pack attributes in struct
>         - Support different size SMART buffers for compatibility with newer
>           ndctls that may want more SMART attribs than we provide
>         - Rework to to use ND_CMD_CALL instead of ND_CMD_SMART
>   - drop "ocxl: Free detached contexts in ocxl_context_detach_all()"
>   - "powerpc: Map & release OpenCAPI LPC memory"
>         - Remove 'extern'
>         - Only available with CONFIG_MEMORY_HOTPLUG_SPARSE
>   - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
>         - Address minor review comments from Jonathan Cameron
>   - "ocxl: Add functions to map/unmap LPC memory"
>         - Split detected memory message into a separate patch
>         - Address minor review comments from Jonathan Cameron
>         - Add a comment explaining why unmap_lpc_mem is in deconfigure_afu
>   - "nvdimm/ocxl: Add support for Admin commands"
>         - use sizeof(u64) rather than 0x08 when iterating u64s
>   - "nvdimm/ocxl: Implement the heartbeat command"
>         - Fix typo in blurb
>   - Address kernel doc issues
>   - Ensure all uapi headers use C89 compatible comments
>   - Drop patches for firmware update & overwrite, these will be
>     submitted later once patches are available for ndctl
>   - Rename SCM to OpenCAPI Persistent Memory
>
> V2:
>   - "powerpc: Map & release OpenCAPI LPC memory"
>       - Fix #if -> #ifdef
>       - use pci_dev_id to get the bdfn
>       - use __be64 to hold be data
>       - indent check_hotplug_memory_addressable correctly
>       - Remove export of check_hotplug_memory_addressable
>   - "ocxl: Conditionally bind SCM devices to the generic OCXL driver"
>       - Improve patch description and remove redundant default
>   - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
>       - Mark a few funcs as static as identified by the 0day bot
>       - Add OCXL dependancies to OCXL_SCM
>       - Use memcpy_mcsafe in scm_ndctl_config_read
>       - Rename scm_foo_offset_0x00 to scm_foo_header_parse & add docs
>       - Name DIMM attribs "ocxl" rather than "scm"
>       - Split out into base + many feature patches
>   - "powerpc: Enable OpenCAPI Storage Class Memory driver on bare metal"
>       - Build DEV_DAX & friends as modules
>   - "ocxl: Conditionally bind SCM devices to the generic OCXL driver"
>       - Patch dropped (easy enough to maintain this out of tree for development)
>   - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
>       - Add a warning if an unmatched lpc_release is called
>   - "ocxl: Add functions to map/unmap LPC memory"
>       - Use EXPORT_SYMBOL_GPL
>
>
> Alastair D'Silva (25):
>   powerpc/powernv: Add OPAL calls for LPC memory alloc/release
>   mm/memory_hotplug: Allow check_hotplug_memory_addressable to be called
>     from drivers
>   powerpc/powernv: Map & release OpenCAPI LPC memory
>   ocxl: Remove unnecessary externs
>   ocxl: Address kernel doc errors & warnings
>   ocxl: Tally up the LPC memory on a link & allow it to be mapped
>   ocxl: Add functions to map/unmap LPC memory
>   ocxl: Emit a log message showing how much LPC memory was detected
>   ocxl: Save the device serial number in ocxl_fn
>   nvdimm: Add driver for OpenCAPI Persistent Memory
>   powerpc: Enable the OpenCAPI Persistent Memory driver for
>     powernv_defconfig
>   nvdimm/ocxl: Add register addresses & status values to the header
>   nvdimm/ocxl: Read the capability registers & wait for device ready
>   nvdimm/ocxl: Add support for Admin commands
>   nvdimm/ocxl: Register a character device for userspace to interact
>     with
>   nvdimm/ocxl: Implement the Read Error Log command
>   nvdimm/ocxl: Add controller dump IOCTLs
>   nvdimm/ocxl: Add an IOCTL to report controller statistics
>   nvdimm/ocxl: Forward events to userspace
>   nvdimm/ocxl: Add an IOCTL to request controller health & perf data
>   nvdimm/ocxl: Implement the heartbeat command
>   nvdimm/ocxl: Add debug IOCTLs
>   nvdimm/ocxl: Expose SMART data via ndctl
>   nvdimm/ocxl: Expose the serial number & firmware version in sysfs
>   MAINTAINERS: Add myself & nvdimm/ocxl to ocxl
>
>  .../userspace-api/ioctl/ioctl-number.rst      |    1 +
>  MAINTAINERS                                   |    3 +
>  arch/powerpc/configs/powernv_defconfig        |    5 +
>  arch/powerpc/include/asm/opal-api.h           |    2 +
>  arch/powerpc/include/asm/opal.h               |    2 +
>  arch/powerpc/include/asm/pnv-ocxl.h           |   42 +-
>  arch/powerpc/platforms/powernv/ocxl.c         |   43 +
>  arch/powerpc/platforms/powernv/opal-call.c    |    2 +
>  drivers/misc/ocxl/config.c                    |   74 +-
>  drivers/misc/ocxl/core.c                      |   61 +
>  drivers/misc/ocxl/link.c                      |   60 +
>  drivers/misc/ocxl/ocxl_internal.h             |   45 +-
>  drivers/nvdimm/Kconfig                        |    2 +
>  drivers/nvdimm/Makefile                       |    1 +
>  drivers/nvdimm/ocxl/Kconfig                   |   21 +
>  drivers/nvdimm/ocxl/Makefile                  |    7 +
>  drivers/nvdimm/ocxl/main.c                    | 1975 +++++++++++++++++
>  drivers/nvdimm/ocxl/ocxlpmem.h                |  197 ++
>  drivers/nvdimm/ocxl/ocxlpmem_internal.c       |  280 +++
>  include/linux/memory_hotplug.h                |    5 +
>  include/misc/ocxl.h                           |  122 +-
>  include/uapi/linux/ndctl.h                    |    1 +
>  include/uapi/nvdimm/ocxlpmem.h                |  127 ++
>  mm/memory_hotplug.c                           |    4 +-
>  24 files changed, 2983 insertions(+), 99 deletions(-)
>  create mode 100644 drivers/nvdimm/ocxl/Kconfig
>  create mode 100644 drivers/nvdimm/ocxl/Makefile
>  create mode 100644 drivers/nvdimm/ocxl/main.c
>  create mode 100644 drivers/nvdimm/ocxl/ocxlpmem.h
>  create mode 100644 drivers/nvdimm/ocxl/ocxlpmem_internal.c
>  create mode 100644 include/uapi/nvdimm/ocxlpmem.h
>
> --
> 2.24.1
>
Alastair D'Silva April 1, 2020, 10:44 p.m. UTC | #2
> -----Original Message-----
> From: Dan Williams <dan.j.williams@intel.com>
> Sent: Wednesday, 1 April 2020 7:48 PM
> To: Alastair D'Silva <alastair@d-silva.org>
> Cc: Aneesh Kumar K . V <aneesh.kumar@linux.ibm.com>; Oliver O'Halloran
> <oohall@gmail.com>; Benjamin Herrenschmidt
> <benh@kernel.crashing.org>; Paul Mackerras <paulus@samba.org>; Michael
> Ellerman <mpe@ellerman.id.au>; Frederic Barrat <fbarrat@linux.ibm.com>;
> Andrew Donnellan <ajd@linux.ibm.com>; Arnd Bergmann
> <arnd@arndb.de>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>;
> Vishal Verma <vishal.l.verma@intel.com>; Dave Jiang
> <dave.jiang@intel.com>; Ira Weiny <ira.weiny@intel.com>; Andrew Morton
> <akpm@linux-foundation.org>; Mauro Carvalho Chehab
> <mchehab+samsung@kernel.org>; David S. Miller <davem@davemloft.net>;
> Rob Herring <robh@kernel.org>; Anton Blanchard <anton@ozlabs.org>;
> Krzysztof Kozlowski <krzk@kernel.org>; Mahesh Salgaonkar
> <mahesh@linux.vnet.ibm.com>; Madhavan Srinivasan
> <maddy@linux.vnet.ibm.com>; C├ędric Le Goater <clg@kaod.org>; Anju T
> Sudhakar <anju@linux.vnet.ibm.com>; Hari Bathini
> <hbathini@linux.ibm.com>; Thomas Gleixner <tglx@linutronix.de>; Greg
> Kurz <groug@kaod.org>; Nicholas Piggin <npiggin@gmail.com>; Masahiro
> Yamada <yamada.masahiro@socionext.com>; Alexey Kardashevskiy
> <aik@ozlabs.ru>; Linux Kernel Mailing List <linux-kernel@vger.kernel.org>;
> linuxppc-dev <linuxppc-dev@lists.ozlabs.org>; linux-nvdimm <linux-
> nvdimm@lists.01.org>; Linux MM <linux-mm@kvack.org>
> Subject: Re: [PATCH v4 00/25] Add support for OpenCAPI Persistent Memory
> devices
> 
> On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@d-silva.org>
> wrote:
> >
> > This series adds support for OpenCAPI Persistent Memory devices on
> > bare metal (arch/powernv), exposing them as nvdimms so that we can
> > make use of the existing infrastructure. There already exists a driver
> > for the same devices abstracted through PowerVM (arch/pseries):
> > arch/powerpc/platforms/pseries/papr_scm.c
> >
> > These devices are connected via OpenCAPI, and present as LPC (lowest
> coherence point) memory to the system, practically, that means that
> memory on these cards could be treated as conventional, cache-coherent
> memory.
> >
> > Since the devices are connected via OpenCAPI, they are not enumerated
> via ACPI. Instead, OpenCAPI links present as pseudo-PCI bridges, with
> devices below them.
> >
> > This series introduces a driver that exposes the memory on these cards as
> nvdimms, with each card getting it's own bus. This is somewhat complicated
> by the fact that the cards do not have out of band persistent storage for
> metadata, so 1 SECTION_SIZE's (see SPARSEMEM) worth of storage is carved
> out of the top of the card storage to implement the ndctl_config_* calls.
> 
> Is it really tied to section-size? Can't that change based on the configured
> page-size? It's not clear to me why that would be the choice, but I'll dig into
> the implementation.
> 

I had tried using PAGE_SIZE, but ran into problems carving off just 1 page and handing it to the kernel, while leaving the rest as pmem. That was a while ago though, so maybe I should retry it.

> > The driver is not responsible for configuring the NPU (NVLink Processing
> Unit) BARs to map the LPC memory from the card into the system's physical
> address space, instead, it requests this to be done via OPAL calls (typically
> implemented by Skiboot).
> 
> Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
> platform firmware services? What's Skiboot?
> 

Yes, OPAL is the interface to firmware for POWER. Skiboot is the open-source (and only) implementation of OPAL.

> >
> > The series is structured as follows:
> >  - Required infrastructure changes & cleanup
> >  - A minimal driver implementation
> >  - Implementing additional features within the driver
> 
> Thanks for the intro and the changelog!
> 
> >
> > Changelog:
> > V4:
> >   - Rebase on next-20200320
> 
> Do you have dependencies on other material that's in -next? Otherwise -
> next is only a viable development baseline if you are going to merge through
> Andrew's tree.
> 
> >   - Bump copyright to 2020
> >   - Ensure all uapi headers use C89 compatible comments (missed
> ocxlpmem.h)
> >   - Move the driver back to drivers/nvdimm/ocxl, after confirmation
> >     that this location is desirable
> >   - Rename ocxl.c to ocxlpmem.c (+ support files)
> >   - Rename all ocxl_pmem to ocxlpmem
> >   - Address checkpatch --strict issues
> >   - "powerpc/powernv: Add OPAL calls for LPC memory alloc/release"
> >         - Pass base address as __be64
> >   - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
> >         - Address checkpatch spacing warnings
> >         - Reword blurb
> >         - Reword size description for ocxl_link_add_lpc_mem()
> >         - Add an early exit in ocxl_link_lpc_release() to avoid triggering
> >           bogus warnings if called after ocxl_link_lpc_map() fails
> >   - "powerpc/powernv: Add OPAL calls for LPC memory alloc/release"
> >         - Reword blurb
> >   - "powerpc/powernv: Map & release OpenCAPI LPC memory"
> >         - Reword blurb
> >   - Move minor_idr init from file_init() to ocxlpmem_init() (fixes runtime
> error
> >     in "nvdimm: Add driver for OpenCAPI Persistent Memory")
> >   - Wrap long lines
> >   - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
> >         - Remove '+ 1' workround from serial number->cookie assignment
> >         - Drop out of memory message for ocxlpmem in probe()
> >         - Fix leaks of ocxlpmem & ocxlpmem->ocxl_fn in probe()
> >         - remove struct ocxlpmem_function0, it didn't value add
> >         - factor out err_unregistered label in probe
> >         - Address more checkpatch warnings
> >         - get/put the pci dev on probe/free
> >         - Drop ocxlpmem_ prefix from static functions
> >         - Propogate errors up from called functions in probe()
> >         - Set MODULE_LICENSE to GPLv2
> >         - Add myself as module author
> >         - Call nvdimm_bus_unregister() in remove() to release references
> >         - Don't call devm_memunmap on metadata_address, the release
> handler on
> >          the device already deals with this
> >   - "nvdimm/ocxl: Read the capability registers & wait for device ready"
> >         - Fix mask for read_latency
> >         - Fold in is_usable logic into timeout to remove error message race
> >         - propogate bad rc from read_device_metadata
> >   - "nvdimm/ocxl: Add register addresses & status values to the header"
> >         - Add comments for register abbreviations where names have been
> >           expanded
> >         - Add missing status for blocked on background task
> >         - Alias defines for firmware update status to show that the duplication
> >           of values is intentional
> >   - "nvdimm/ocxl: Register a character device for userspace to interact with"
> >         - Add lock around minors IDR, delete the cdev before
> device_unregister
> >         - Propogate errors up from called functions in probe()
> >   - "nvdimm/ocxl: Add support for Admin commands"
> >         - Fix typo in setup_command_data error message, and drop 'ocxl' from
> it
> >         - Drop vestigial CHI read from admin_command_request
> >         - Change command ID mismatch message to dev_err, and return an
> error
> >         - Use jiffies to implement admin_command_complete_timeout()
> >         - Flesh out blurb
> >         - Create a wrapper to issue the command & wait for timeout
> >   - "nvdimm/ocxl: Add support for near storage commands"
> >         - dropped (will submit with the patches for nvdimm overwrite)
> >   - "nvdimm/ocxl: Implement the Read Error Log command"
> >         - Remove stray blank line
> >         - change misplaced goto to an early exit in read_error_log
> >         - Inline error_log_offset_0x08
> >         - Read WWID data as LE rather than host endian
> >         - Move the include of nvdimm/ocxlpmem.h to ocxl.c
> >         - Add padding after fwrevision in struct ioctl_ocxl_pmem_error_log
> >         - Register IOCTL magic
> >         - Coerce pointers to __u64 in IOCTLs
> >   - "nvdimm/ocxl: Add controller dump IOCTLs"
> >         - Coerce pointers to __u64 in IOCTLs
> >         - Document expected IOCTL usage in blurb
> >         - Add missing rc check
> >         - Only populate up to the number of bytes returned by the card,
> >           and return this length to the caller
> >         - Add missing header check
> >   - "nvdimm/ocxl: Add an IOCTL to report controller statistics"
> >         - Update to match the latest version of the spec
> >         - Verify that parametr block IDs & lengths match what we expect
> >         - Use defines for offsets
> >   - "nvdimm/ocxl: Forward events to userspace"
> >         - Don't enable NSCRA doorbell
> >         - return -EBUSY if the event context is already used
> >         - return -ENODEV if IRQs cannot be mapped
> >         - Tag IRQ pointers with __iomem
> >         - Drop ocxlpmem_ prefix from static functions
> >         - Propogate error from eventfd_ctx_fdget
> >         - Fix error check in copy_to_user
> >         - Drop GLOBAL_MMIO_CHI_NSCRA (this should be in the overwrite
> patch)
> >         - Drop unused irq_pgmap
> >         - Don't redef BIT_ULL
> >   - "nvdimm/ocxl: Add debug IOCTLs"
> >         - Eliminate clearing loop (now done in admin_command_execute()
> >         - Drop dummy IOCTLs if CONFIG_OCXL_PMEM_DEBUG is not set
> >         - Group debug IOCTLs together & comment that they may not be
> available
> >   - "nvdimm/ocxl: Expose SMART data via ndctl"
> >         - Drop 'rc = 0; goto out;'
> >         - Propogate errors from ndctl_smart()
> >   - "nvdimm/ocxl: Expose the serial number in sysfs" & "nvdimm/ocxl:
> Expose the firmware version in sysfs"
> >         - Squash these 2 patches together
> >         - Expose data as a DIMM attribute rather than an ocxlpmem
> >           attribute
> >   - "nvdimm/ocxl: Add an IOCTL to request controller health & perf data"
> >         - Reword blurb
> >   - "nvdimm/ocxl: Implement the heartbeat command"
> >         - Propogate rc in probe()
> >
> > V3:
> >   - Rebase against next/next-20200220
> >   - Move driver to arch/powerpc/platforms/powernv, we now expect this
> >     driver to go upstream via the powerpc tree
> >   - "nvdimm/ocxl: Implement the Read Error Log command"
> >         - Fix bad header path
> >   - "nvdimm/ocxl: Read the capability registers & wait for device ready"
> >         - Fix overlapping masks between readiness_timeout &
> memory_available_timeout
> >   - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
> >         - Address minor review comments from Jonathan Cameron
> >         - Remove attributes
> >         - Default to module if building LIBNVDIMM
> >         - Propogate errors up from called functions in probe()
> >   - "nvdimm/ocxl: Expose SMART data via ndctl"
> >         - Pack attributes in struct
> >         - Support different size SMART buffers for compatibility with newer
> >           ndctls that may want more SMART attribs than we provide
> >         - Rework to to use ND_CMD_CALL instead of ND_CMD_SMART
> >   - drop "ocxl: Free detached contexts in ocxl_context_detach_all()"
> >   - "powerpc: Map & release OpenCAPI LPC memory"
> >         - Remove 'extern'
> >         - Only available with CONFIG_MEMORY_HOTPLUG_SPARSE
> >   - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
> >         - Address minor review comments from Jonathan Cameron
> >   - "ocxl: Add functions to map/unmap LPC memory"
> >         - Split detected memory message into a separate patch
> >         - Address minor review comments from Jonathan Cameron
> >         - Add a comment explaining why unmap_lpc_mem is in
> deconfigure_afu
> >   - "nvdimm/ocxl: Add support for Admin commands"
> >         - use sizeof(u64) rather than 0x08 when iterating u64s
> >   - "nvdimm/ocxl: Implement the heartbeat command"
> >         - Fix typo in blurb
> >   - Address kernel doc issues
> >   - Ensure all uapi headers use C89 compatible comments
> >   - Drop patches for firmware update & overwrite, these will be
> >     submitted later once patches are available for ndctl
> >   - Rename SCM to OpenCAPI Persistent Memory
> >
> > V2:
> >   - "powerpc: Map & release OpenCAPI LPC memory"
> >       - Fix #if -> #ifdef
> >       - use pci_dev_id to get the bdfn
> >       - use __be64 to hold be data
> >       - indent check_hotplug_memory_addressable correctly
> >       - Remove export of check_hotplug_memory_addressable
> >   - "ocxl: Conditionally bind SCM devices to the generic OCXL driver"
> >       - Improve patch description and remove redundant default
> >   - "nvdimm: Add driver for OpenCAPI Storage Class Memory"
> >       - Mark a few funcs as static as identified by the 0day bot
> >       - Add OCXL dependancies to OCXL_SCM
> >       - Use memcpy_mcsafe in scm_ndctl_config_read
> >       - Rename scm_foo_offset_0x00 to scm_foo_header_parse & add docs
> >       - Name DIMM attribs "ocxl" rather than "scm"
> >       - Split out into base + many feature patches
> >   - "powerpc: Enable OpenCAPI Storage Class Memory driver on bare
> metal"
> >       - Build DEV_DAX & friends as modules
> >   - "ocxl: Conditionally bind SCM devices to the generic OCXL driver"
> >       - Patch dropped (easy enough to maintain this out of tree for
> development)
> >   - "ocxl: Tally up the LPC memory on a link & allow it to be mapped"
> >       - Add a warning if an unmatched lpc_release is called
> >   - "ocxl: Add functions to map/unmap LPC memory"
> >       - Use EXPORT_SYMBOL_GPL
> >
> >
> > Alastair D'Silva (25):
> >   powerpc/powernv: Add OPAL calls for LPC memory alloc/release
> >   mm/memory_hotplug: Allow check_hotplug_memory_addressable to be
> called
> >     from drivers
> >   powerpc/powernv: Map & release OpenCAPI LPC memory
> >   ocxl: Remove unnecessary externs
> >   ocxl: Address kernel doc errors & warnings
> >   ocxl: Tally up the LPC memory on a link & allow it to be mapped
> >   ocxl: Add functions to map/unmap LPC memory
> >   ocxl: Emit a log message showing how much LPC memory was detected
> >   ocxl: Save the device serial number in ocxl_fn
> >   nvdimm: Add driver for OpenCAPI Persistent Memory
> >   powerpc: Enable the OpenCAPI Persistent Memory driver for
> >     powernv_defconfig
> >   nvdimm/ocxl: Add register addresses & status values to the header
> >   nvdimm/ocxl: Read the capability registers & wait for device ready
> >   nvdimm/ocxl: Add support for Admin commands
> >   nvdimm/ocxl: Register a character device for userspace to interact
> >     with
> >   nvdimm/ocxl: Implement the Read Error Log command
> >   nvdimm/ocxl: Add controller dump IOCTLs
> >   nvdimm/ocxl: Add an IOCTL to report controller statistics
> >   nvdimm/ocxl: Forward events to userspace
> >   nvdimm/ocxl: Add an IOCTL to request controller health & perf data
> >   nvdimm/ocxl: Implement the heartbeat command
> >   nvdimm/ocxl: Add debug IOCTLs
> >   nvdimm/ocxl: Expose SMART data via ndctl
> >   nvdimm/ocxl: Expose the serial number & firmware version in sysfs
> >   MAINTAINERS: Add myself & nvdimm/ocxl to ocxl
> >
> >  .../userspace-api/ioctl/ioctl-number.rst      |    1 +
> >  MAINTAINERS                                   |    3 +
> >  arch/powerpc/configs/powernv_defconfig        |    5 +
> >  arch/powerpc/include/asm/opal-api.h           |    2 +
> >  arch/powerpc/include/asm/opal.h               |    2 +
> >  arch/powerpc/include/asm/pnv-ocxl.h           |   42 +-
> >  arch/powerpc/platforms/powernv/ocxl.c         |   43 +
> >  arch/powerpc/platforms/powernv/opal-call.c    |    2 +
> >  drivers/misc/ocxl/config.c                    |   74 +-
> >  drivers/misc/ocxl/core.c                      |   61 +
> >  drivers/misc/ocxl/link.c                      |   60 +
> >  drivers/misc/ocxl/ocxl_internal.h             |   45 +-
> >  drivers/nvdimm/Kconfig                        |    2 +
> >  drivers/nvdimm/Makefile                       |    1 +
> >  drivers/nvdimm/ocxl/Kconfig                   |   21 +
> >  drivers/nvdimm/ocxl/Makefile                  |    7 +
> >  drivers/nvdimm/ocxl/main.c                    | 1975 +++++++++++++++++
> >  drivers/nvdimm/ocxl/ocxlpmem.h                |  197 ++
> >  drivers/nvdimm/ocxl/ocxlpmem_internal.c       |  280 +++
> >  include/linux/memory_hotplug.h                |    5 +
> >  include/misc/ocxl.h                           |  122 +-
> >  include/uapi/linux/ndctl.h                    |    1 +
> >  include/uapi/nvdimm/ocxlpmem.h                |  127 ++
> >  mm/memory_hotplug.c                           |    4 +-
> >  24 files changed, 2983 insertions(+), 99 deletions(-)  create mode
> > 100644 drivers/nvdimm/ocxl/Kconfig  create mode 100644
> > drivers/nvdimm/ocxl/Makefile  create mode 100644
> > drivers/nvdimm/ocxl/main.c  create mode 100644
> > drivers/nvdimm/ocxl/ocxlpmem.h  create mode 100644
> > drivers/nvdimm/ocxl/ocxlpmem_internal.c
> >  create mode 100644 include/uapi/nvdimm/ocxlpmem.h
> >
> > --
> > 2.24.1
> >
Michael Ellerman April 2, 2020, 3:42 a.m. UTC | #3
"Alastair D'Silva" <alastair@d-silva.org> writes:
>> -----Original Message-----
>> From: Dan Williams <dan.j.williams@intel.com>
>> 
>> On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@d-silva.org>
>> wrote:
>> >
>> > This series adds support for OpenCAPI Persistent Memory devices on
>> > bare metal (arch/powernv), exposing them as nvdimms so that we can
>> > make use of the existing infrastructure. There already exists a driver
>> > for the same devices abstracted through PowerVM (arch/pseries):
>> > arch/powerpc/platforms/pseries/papr_scm.c
>> >
>> > These devices are connected via OpenCAPI, and present as LPC (lowest
>> coherence point) memory to the system, practically, that means that
>> memory on these cards could be treated as conventional, cache-coherent
>> memory.
>> >
>> > Since the devices are connected via OpenCAPI, they are not enumerated
>> via ACPI. Instead, OpenCAPI links present as pseudo-PCI bridges, with
>> devices below them.
>> >
>> > This series introduces a driver that exposes the memory on these cards as
>> nvdimms, with each card getting it's own bus. This is somewhat complicated
>> by the fact that the cards do not have out of band persistent storage for
>> metadata, so 1 SECTION_SIZE's (see SPARSEMEM) worth of storage is carved
>> out of the top of the card storage to implement the ndctl_config_* calls.
>> 
>> Is it really tied to section-size? Can't that change based on the configured
>> page-size? It's not clear to me why that would be the choice, but I'll dig into
>> the implementation.
>> 
>
> I had tried using PAGE_SIZE, but ran into problems carving off just 1 page and handing it to the kernel, while leaving the rest as pmem. That was a while ago though, so maybe I should retry it.
>
>> > The driver is not responsible for configuring the NPU (NVLink Processing
>> Unit) BARs to map the LPC memory from the card into the system's physical
>> address space, instead, it requests this to be done via OPAL calls (typically
>> implemented by Skiboot).
>> 
>> Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
>> platform firmware services? What's Skiboot?
>> 
>
> Yes, OPAL is the interface to firmware for POWER. Skiboot is the open-source (and only) implementation of OPAL.

  https://github.com/open-power/skiboot

In particular the tokens for calls are defined here:

  https://github.com/open-power/skiboot/blob/master/include/opal-api.h#L220

And you can grep for the token to find the implementation:

  https://github.com/open-power/skiboot/blob/master/hw/npu2-opencapi.c#L2328


cheers
Oliver O'Halloran April 2, 2020, 3:50 a.m. UTC | #4
On Thu, Apr 2, 2020 at 2:42 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
>
> "Alastair D'Silva" <alastair@d-silva.org> writes:
> >> -----Original Message-----
> >> From: Dan Williams <dan.j.williams@intel.com>
> >>
> >> On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@d-silva.org>
> >> wrote:
> >> >
> >> > *snip*
> >> Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
> >> platform firmware services? What's Skiboot?
> >>
> >
> > Yes, OPAL is the interface to firmware for POWER. Skiboot is the open-source (and only) implementation of OPAL.
>
>   https://github.com/open-power/skiboot
>
> In particular the tokens for calls are defined here:
>
>   https://github.com/open-power/skiboot/blob/master/include/opal-api.h#L220
>
> And you can grep for the token to find the implementation:
>
>   https://github.com/open-power/skiboot/blob/master/hw/npu2-opencapi.c#L2328

I'm not sure I'd encourage anyone to read npu2-opencapi.c. I find it
hard enough to follow even with access to the workbooks.

There's an OPAL call API reference here:
http://open-power.github.io/skiboot/doc/opal-api/index.html

Oliver
Michael Ellerman April 2, 2020, 10:06 a.m. UTC | #5
"Oliver O'Halloran" <oohall@gmail.com> writes:
> On Thu, Apr 2, 2020 at 2:42 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
>> "Alastair D'Silva" <alastair@d-silva.org> writes:
>> >> -----Original Message-----
>> >> From: Dan Williams <dan.j.williams@intel.com>
>> >>
>> >> On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@d-silva.org>
>> >> wrote:
>> >> >
>> >> > *snip*
>> >> Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
>> >> platform firmware services? What's Skiboot?
>> >
>> > Yes, OPAL is the interface to firmware for POWER. Skiboot is the open-source (and only) implementation of OPAL.
>>
>>   https://github.com/open-power/skiboot
>>
>> In particular the tokens for calls are defined here:
>>
>>   https://github.com/open-power/skiboot/blob/master/include/opal-api.h#L220
>>
>> And you can grep for the token to find the implementation:
>>
>>   https://github.com/open-power/skiboot/blob/master/hw/npu2-opencapi.c#L2328
>
> I'm not sure I'd encourage anyone to read npu2-opencapi.c. I find it
> hard enough to follow even with access to the workbooks.

Compared to certain firmwares that run on certain other platforms it's
actually pretty readable code ;)

> There's an OPAL call API reference here:
> http://open-power.github.io/skiboot/doc/opal-api/index.html

Even better.

cheers
Greg Kurz April 2, 2020, 11:10 a.m. UTC | #6
On Thu, 02 Apr 2020 21:06:01 +1100
Michael Ellerman <mpe@ellerman.id.au> wrote:

> "Oliver O'Halloran" <oohall@gmail.com> writes:
> > On Thu, Apr 2, 2020 at 2:42 PM Michael Ellerman <mpe@ellerman.id.au> wrote:
> >> "Alastair D'Silva" <alastair@d-silva.org> writes:
> >> >> -----Original Message-----
> >> >> From: Dan Williams <dan.j.williams@intel.com>
> >> >>
> >> >> On Sun, Mar 29, 2020 at 10:23 PM Alastair D'Silva <alastair@d-silva.org>
> >> >> wrote:
> >> >> >
> >> >> > *snip*
> >> >> Are OPAL calls similar to ACPI DSMs? I.e. methods for the OS to invoke
> >> >> platform firmware services? What's Skiboot?
> >> >
> >> > Yes, OPAL is the interface to firmware for POWER. Skiboot is the open-source (and only) implementation of OPAL.
> >>
> >>   https://github.com/open-power/skiboot
> >>
> >> In particular the tokens for calls are defined here:
> >>
> >>   https://github.com/open-power/skiboot/blob/master/include/opal-api.h#L220
> >>
> >> And you can grep for the token to find the implementation:
> >>
> >>   https://github.com/open-power/skiboot/blob/master/hw/npu2-opencapi.c#L2328
> >
> > I'm not sure I'd encourage anyone to read npu2-opencapi.c. I find it
> > hard enough to follow even with access to the workbooks.
> 
> Compared to certain firmwares that run on certain other platforms it's
> actually pretty readable code ;)
> 

Forth rocks ! ;-)

> > There's an OPAL call API reference here:
> > http://open-power.github.io/skiboot/doc/opal-api/index.html
> 
> Even better.
> 
> cheers