New subject: [PATCH v8 08/12] device core: Introduce DMA range map, supplanting dma_pfn_offset

15 Jul 2020


      Patchset Summary:
  Enhance a PCIe host controller driver.  Because of its unusual design
  we are foced to change dev->dma_pfn_offset into a more general role
  allowing multiple offsets.  See the 'v1' notes below for more info.
v8:
  Commit: "device core: Introduce DMA range map, supplanting ..."
  -- To satisfy a specific m68 compile configuration, I moved the 'struct
     bus_dma_region; definition out of #ifdef CONFIG_HAS_DMA and also defined
     three inline functions for !CONFIG_HAS_DMA (kernel test robot).
  -- The sunXi drivers -- suc4i_csi, sun6i_csi, cedrus_hw -- set
     a pfn_offset outside of_dma_configure() but the code offers no 
     insight on the size of the translation window.  V7 had me using
     SIZE_MAX as the size.  I have since contacted the sunXi maintainer and
     he said that using a size of SZ_4G would cover sunXi configurations.
v7:
  Commit: "device core: Introduce DMA range map, supplanting ..."
  -- remove second kcalloc/copy in device.c (AndyS)
  -- use PTR_ERR_OR_ZERO() and PHYS_PFN() (AndyS)
  -- indentation, sizeof(struct ...) => sizeof(*r) (AndyS)
  -- add pfn.h definitions: PFN_DMA_ADDR(), DMA_ADDR_PFN() (AndyS)
  -- Fixed compile error in "sun6i_csi.c" (kernel test robot)
  Commit "ata: ahci_brcm: Fix use of BCM7216 reset controller"
  -- correct name of function in the commit msg (SergeiS)
v6:
  Commit "device core: Introduce DMA range map":
  -- of_dma_get_range() now takes a single argument and returns either
     NULL, a valid map, or an ERR_PTR. (Robin)
  -- offsets are no longer a PFN value but an actual address. (Robin)
  -- the bus_dma_region struct stores the range size instead of
     the cpu_end and pci_end values. (Robin)
  -- devices that were setting a single offset with no boundaries
     have been modified to have boundaries; in a few places
     where this informatino was unavilable a /* FIXME: ... */
     comment was added. (Robin)
  -- dma_attach_offset_range() can be called when an offset
     map already exists; if it's range is already present
     nothing is done and success is returned. (Robin)
  All commits:
  -- Man name/style/corrections/etc changed (Bjorn)
  -- rebase to Torvalds master
v5:
  Commit "device core: Introduce multiple dma pfn offsets"
  -- in of/address.c: "map_size = 0" => "*map_size = 0"
  -- use kcalloc instead of kzalloc (AndyS)
  -- use PHYS_ADDR_MAX instead of "~(phys_addr_t)0"
  Commit "PCI: brcmstb: Set internal memory viewport sizes"
  -- now gives error on missing dma-ranges property.
  Commit "dt-bindings: PCI: Add bindings for more Brcmstb chips"
  -- removed "Allof:" from brcm,scb-sizes definition (RobH)
  All Commits:
  -- indentation style, use max chars 100 (AndyS)
  -- rebased to torvalds master
v4:
  Commit "device core: Introduce multiple dma pfn offsets"
  -- of_dma_get_range() does not take a dev param but instead
     takes two "out" params: map and map_size.  We do this so
     that the code that parses dma-ranges is separate from
     the code that modifies 'dev'.   (Nicolas)
  -- the separate case of having a single pfn offset has
     been removed and is now processed by going through the
     map array. (Nicolas)
  -- move attach_uniform_dma_pfn_offset() from of/address.c to
     dma/mapping.c so that it does not depend on CONFIG_OF. (Nicolas)
  -- devm_kcalloc => devm_kzalloc (DanC)
  -- add/fix assignment to dev->dma_pfn_offset_map for func
     attach_uniform_dma_pfn_offset() (DanC, Nicolas)
  -- s/struct dma_pfn_offset_region/struct bus_dma_region/ (Nicolas)
  -- s/attach_uniform_dma_pfn_offset/dma_attach_uniform_pfn_offset/
  -- s/attach_dma_pfn_offset_map/dma_attach_pfn_offset_map/
  -- More use of PFN_{PHYS,DOWN,UP}. (AndyS)
  Commit "of: Include a dev param in of_dma_get_range()"
  -- this commit was sqaushed with "device core: Introduce ..."
v3:
  Commit "device core: Introduce multiple dma pfn offsets"
  Commit "arm: dma-mapping: Invoke dma offset func if needed"
  -- The above two commits have been squashed.  More importantly,
     the code has been modified so that the functionality for
     multiple pfn offsets subsumes the use of dev->dma_pfn_offset.
     In fact, dma_pfn_offset is removed and supplanted by
     dma_pfn_offset_map, which is a pointer to an array.  The
     more common case of a uniform offset is now handled as
     a map with a single entry, while cases requiring multiple
     pfn offsets use a map with multiple entries.  Code paths
     that used to do this:
dev->dma_pfn_offset = mydrivers_pfn_offset;
have been changed to do this:
attach_uniform_dma_pfn_offset(dev, pfn_offset);
Commit "dt-bindings: PCI: Add bindings for more Brcmstb chips"
  -- Add if/then clause for required props: resets, reset-names (RobH)
  -- Change compatible list from const to enum (RobH)
  -- Change list of u32-tuples to u64 (RobH)
Commit "of: Include a dev param in of_dma_get_range()"
  -- modify of/unittests.c to add NULL param in of_dma_get_range() call.
Commit "device core: Add ability to handle multiple dma offsets"
  -- align comment in device.h (AndyS).
  -- s/cpu_beg/cpu_start/ and s/dma_beg/dma_start/ in struct
     dma_pfn_offset_region (AndyS).
v2:
Commit: "device core: Add ability to handle multiple dma offsets"
  o Added helper func attach_dma_pfn_offset_map() in address.c (Chistoph)
  o Helpers funcs added to __phys_to_dma() & __dma_to_phys() (Christoph)
  o Added warning when multiple offsets are needed and !DMA_PFN_OFFSET_MAP
  o dev->dma_pfn_map => dev->dma_pfn_offset_map
  o s/frm/from/ for dma_pfn_offset_frm_{phys,dma}_addr() (Christoph)
  o In device.h: s/const void */const struct dma_pfn_offset_region */
  o removed 'unlikely' from unlikely(dev->dma_pfn_offset_map) since
    guarded by CONFIG_DMA_PFN_OFFSET_MAP (Christoph)
  o Since dev->dma_pfn_offset is copied in usb/core/{usb,message}.c, now
    dev->dma_pfn_offset_map is copied as well.
  o Merged two of the DMA commits into one (Christoph).
Commit "arm: dma-mapping: Invoke dma offset func if needed":
  o Use helper functions instead of #if CONFIG_DMA_PFN_OFFSET
Other commits' changes:
  o Removed need for carrying of_id var in priv (Nicolas)
  o Commit message rewordings (Bjorn)
  o Commit log messages filled to 75 chars (Bjorn)
  o devm_reset_control_get_shared())
    => devm_reset_control_get_optional_shared (Philipp)
  o Add call to reset_control_assert() in PCIe remove routines (Philipp)
v1:
This patchset expands the usefulness of the Broadcom Settop Box PCIe
controller by building upon the PCIe driver used currently by the
Raspbery Pi.  Other forms of this patchset were submitted by me years
ago and not accepted; the major sticking point was the code required
for the DMA remapping needed for the PCIe driver to work [1].
There have been many changes to the DMA and OF subsystems since that
time, making a cleaner and less intrusive patchset possible.  This
patchset implements a generalization of "dev->dma_pfn_offset", except
that instead of a single scalar offset it provides for multiple
offsets via a function which depends upon the "dma-ranges" property of
the PCIe host controller.  This is required for proper functionality
of the BrcmSTB PCIe controller and possibly some other devices.
[1] https://lore.kernel.org/linux-arm-kernel/1516058925-46522-5-git-send-email-j...
Jim Quinlan (12):
  PCI: brcmstb: PCIE_BRCMSTB depends on ARCH_BRCMSTB
  ata: ahci_brcm: Fix use of BCM7216 reset controller
  dt-bindings: PCI: Add bindings for more Brcmstb chips
  PCI: brcmstb: Add bcm7278 register info
  PCI: brcmstb: Add suspend and resume pm_ops
  PCI: brcmstb: Add bcm7278 PERST# support
  PCI: brcmstb: Add control of rescal reset
  device core: Introduce DMA range map, supplanting dma_pfn_offset
  PCI: brcmstb: Set additional internal memory DMA viewport sizes
  PCI: brcmstb: Accommodate MSI for older chips
  PCI: brcmstb: Set bus max burst size by chip type
  PCI: brcmstb: Add bcm7211, bcm7216, bcm7445, bcm7278 to match list
.../bindings/pci/brcm,stb-pcie.yaml           |  56 ++-
 arch/arm/include/asm/dma-mapping.h            |   9 +-
 arch/arm/mach-keystone/keystone.c             |  17 +-
 arch/sh/drivers/pci/pcie-sh7786.c             |   9 +-
 arch/sh/kernel/dma-coherent.c                 |  16 +-
 arch/x86/pci/sta2x11-fixup.c                  |   7 +-
 drivers/acpi/arm64/iort.c                     |   5 +-
 drivers/ata/ahci_brcm.c                       |  11 +-
 drivers/gpu/drm/sun4i/sun4i_backend.c         |   5 +-
 drivers/iommu/io-pgtable-arm.c                |   2 +-
 .../platform/sunxi/sun4i-csi/sun4i_csi.c      |   5 +-
 .../platform/sunxi/sun6i-csi/sun6i_csi.c      |   4 +-
 drivers/of/address.c                          |  95 ++--
 drivers/of/device.c                           |  47 +-
 drivers/of/of_private.h                       |   9 +-
 drivers/of/unittest.c                         |  35 +-
 drivers/pci/controller/Kconfig                |   3 +-
 drivers/pci/controller/pcie-brcmstb.c         | 408 +++++++++++++++---
 drivers/remoteproc/remoteproc_core.c          |   2 +-
 .../staging/media/sunxi/cedrus/cedrus_hw.c    |   7 +-
 drivers/usb/core/message.c                    |   4 +-
 drivers/usb/core/usb.c                        |   2 +-
 include/linux/device.h                        |   4 +-
 include/linux/dma-direct.h                    |  10 +-
 include/linux/dma-mapping.h                   |  43 ++
 include/linux/pfn.h                           |   2 +
 kernel/dma/coherent.c                         |  10 +-
 kernel/dma/mapping.c                          |  53 +++
 28 files changed, 683 insertions(+), 197 deletions(-)
-- 
2.17.1

[PATCH v8 00/12] PCI: brcmstb: enable PCIe for STB chips