[U-Boot] [PATCH v2 00/71] dm: Add support for a 'live' device tree

Simon Glass sjg at chromium.org
Wed May 10 14:20:39 UTC 2017


(this is series 2 of 3 for live tree support - the final series will
fully convert a real board and provide size comparisons)

So far U-Boot uses a 'flat' device tree, which means that it is decoded
on the fly as needed. This uses the libfdt library and avoids needing
extra memory for additional tables.

For some time there has been discussion about moving U-Boot to use a
'live' tree, where the device tree is decoded at start-up into a set of
hierarchical structures with pointers.

The advantages are:

- It is somewhat faster to access (in particular scanning and looking for a
    parent)
- It permits the device tree to be changed at run-time (this is not
    recommended with the flat device tree since devices store the offset
    of their device tree node and updating the tree may invalidate that).
    Enabling this feature could be useful for overlays, for example.
- It allows nodes to be referenced by a single pointer, instead of the
    current device tree pointer plus offset

The disadvantages are:

- It requires more memory
- It takes (a little) time to build the live tree
- It adds more complexity under the hood, including an additional
    abstraction layer

This series is an attempt to introduce a useful live tree feature into
U-Boot. There are many options and trade-offs. This series is the
culmination of quite a bit of thought and experimentation.

The approach used in this series is:

- Before relocation the flat tree is used, to avoid extra memory usage
and time. In general, there is not much access before relocation since
most drivers are not started up. So there is little benefit in having a
live tree

- After relocation the live tree is built. At this point the CPU should be
running quickly and there is plenty of memory. All available devices will
be bound so the overhead of building the live tree may be outweighed by
its greater efficiency.

As a simplification, this series supports only one tree or the other. When
the live tree is active, the flat tree cannot be used. That makes it easy
to know the current state and avoids confusion over mixing offset and node
pointers.

Some drivers will need to be used both before and after relocation. This
means that they must support both the flat and the live tree. To support
this, the concept of a node 'reference' is defined. A reference can hold
either a node offset (for the flat tree) or a node pointer (for the live
tree). This allows drivers to access values from the tree regardless of
which tree is in use.

In addition, since most device tree access happens in the context of a
device (struct udevice), a new 'dev_read' layer is provided to read device
tree configuration associated with a device. This encapsulates the details
of exactly how this information is read.

I have taken the view that code compatibility with Linux is desirable. So
the of_access.c file brings in code from Linux with very little
modification. As new access methods are needed we should be able to bring
in more code and avoid writing it ourselves in U-Boot.

Conversion of drivers and subsystems to support the live tree (as well as
flat tree) is fairly easy. Patch are included to add support to subsystems
for which tests exist, to ensure that 'make tests' still passes.

Future work will enable the live device tree on a real board and include
code size comparisons.

For now here is a code size comparison for firefly (within inlining of
ofnode which I intend to implement):

arm: (for 1/1 boards) all +268.0 bss -24.0 data -4.0 spl/u-boot-spl:all +240.0 spl/u-boot-spl:text +240.0 text +296.0
     firefly-rk3288 : all +268 bss -24 data -4 spl/u-boot-spl:all +240 spl/u-boot-spl:text +240 text +296
        u-boot: add: 18/-4, grow: 2/-22 bytes: 764/-490 (274)
          function                                   old     new   delta
          gpio_request_tail                            -     132    +132
          ofnode_parse_phandle_with_args               -      66     +66
          uclass_find_device_by_ofnode                 -      64     +64
          ofnode_pre_reloc                             -      64     +64
          ofnode_read_string                           -      52     +52
          fdt_support_default_count_cells              -      52     +52
          ofnode_read_u32                              -      48     +48
          gpio_request_by_name                        32      72     +40
          ofnode_read_size                             -      34     +34
          uclass_get_device_by_ofnode                  -      28     +28
          ofnode_read_u32_array                        -      28     +28
          ofnode_read_bool                             -      26     +26
          ofnode_read_prop                             -      24     +24
          ofnode_get_addr_size                         -      24     +24
          ofnode_read_u32_default                      -      22     +22
          ofnode_find_subnode                          -      18     +18
          ofnode_next_subnode                          -      14     +14
          ofnode_first_subnode                         -      14     +14
          ofnode_get_name                              -      12     +12
          dm_init_and_scan                            42      44      +2
          uclass_get_device_by_phandle               106     104      -2
          spi_child_post_bind                         32      30      -2
          i2c_child_post_bind                         32      30      -2
          spi_post_probe                              36      32      -4
          spi_flash_scan                             520     516      -4
          serial_init                                212     208      -4
          i2c_post_probe                              48      44      -4
          clk_fixed_rate_ofdata_to_platdata           36      32      -4
          act8846_bind                                48      44      -4
          simple_bus_post_bind                        60      52      -8
          lists_bind_fdt                             240     232      -8
          i2c_chip_ofdata_to_platdata                 64      56      -8
          clk_get_by_index                           108     100      -8
          usb_child_post_bind                         92      80     -12
          regmap_init_mem                            228     216     -12
          fixed_regulator_ofdata_to_platdata         108      96     -12
          pmic_bind_children                         158     144     -14
          spi_slave_ofdata_to_platdata               256     240     -16
          pinconfig_post_bind                        136     116     -20
          led_gpio_bind                              108      88     -20
          regulator_post_bind                        148     124     -24
          gpio_request_by_name_nodev                  28       -     -28
          fdtdec_get_uint                             30       -     -30
          regulator_pre_probe                        220     184     -36
          of_bus_default_count_cells                  52       -     -52
          _gpio_request_by_name_nodev                152       -    -152
        spl-u-boot-spl: add: 8/-1, grow: 1/-5 bytes: 300/-56 (244)
          function                                   old     new   delta
          ofnode_parse_phandle_with_args               -      66     +66
          uclass_find_device_by_ofnode                 -      64     +64
          ofnode_read_u32                              -      48     +48
          ofnode_read_size                             -      34     +34
          uclass_get_device_by_ofnode                  -      28     +28
          ofnode_read_prop                             -      24     +24
          ofnode_read_u32_default                      -      22     +22
          ofnode_get_name                              -      12     +12
          dm_init_and_scan                            42      44      +2
          dm_scan_fdt_node                            96      94      -2
          clk_fixed_rate_ofdata_to_platdata           36      32      -4
          lists_bind_fdt                             224     216      -8
          clk_get_by_index                           108     100      -8
          regmap_init_mem                            220     208     -12
          device_bind                                 22       -     -22
(no errors to report)


Changes in v2:
- Rewrite based on testing and refining the v1 series
- Convert various subsystems to enable sandbox tests to pass

Simon Glass (71):
  dm: core: Set return value first in lists_bind_fdt()
  Update WARN_ON() to return a value
  dm: core: Add livetree definitions
  dm: core: Add livetree access functions
  dm: Add a function to create a 'live' device tree
  dm: Build a live tree after relocation
  dm: core: Rename of_device_is_compatible()
  dm: core: Add operations on device tree references
  dm: core: Add livetree address functions
  fdt: Update fdt_get_base_address() to use const
  dm: core: Add address operations on device tree references
  dm: core: Add a place to put extra device-tree reading functions
  dm: core: Add device-based 'read' functions to access DT
  dm: core: Implement live tree 'read' functions
  dm: core: Allow binding a device from a live tree
  dm: core: Update lists_bind_fdt() to use ofnode
  dm: core: Update device_bind_driver_to_node() to use ofnode
  dm: core: Scan the live tree when setting up driver model
  dm: core: Add a way to find a device by ofnode
  dm: regmap: Add support for livetree
  dm: simple-bus: Add support for livetree
  dm: core: Update uclass_find_device_by_phandle() for livetree
  sandbox: Add a way to reset sandbox state for tests
  dm: test: Move test running code into a separate function
  dm: test: Show the test filename when running
  dm: test: Add support for running tests with livetree
  dm: core: Run tests with both livetree and flat tree
  dm: gpio: Refactor to prepare for live tree support
  dm: gpio: Drop blank line in gpio_xlate_offs_flags() comment
  dm: gpio: sandbox: Use dev_read...() functions to access DT
  dm: gpio: Add live tree support
  cros_ec: Fix debug() statement in ec_command_inptr()
  cros_ec: Convert to support live tree
  sandbox: Add a new sandbox_flattree board
  test: Update 'make test' to run more tests
  fdt: Rename a few functions in fdt_support
  dm: Add more livetree helpers and definitions
  string: Add strchrnul()
  string: Add strcspn()
  dm: i2c: Convert uclass to livetree
  dm: pmic: Convert uclass to livetree
  sandbox: pmic: Convert pmic emulator to support livetree
  dm: regulator: Convert regulator uclass to support livetree
  dm: regulator: Update fixed regulator to support livetree.
  dm: mmc: Convert uclass to livetree
  dm: adc: Convert uclass to livetree
  dm: usb: Convert uclass to livetree
  sandbox: usb: Convert emulators to livetree
  clk: Modify xlate() method for livetree
  dm: clk: Update uclass to support livetree
  dm: clk: fixed: Update to support livetree
  dm: test: Separate out the bus DT offset test
  dm: test: Disable the fdt_offset test with livetree
  dm: phy: Update tests to use ut_asserteq()
  dm: mailbox: Update uclass to support livetree
  dm: phy: Update uclass to support livetree
  sandbox: phy: Update driver for livetree
  dm: power-domain: Update uclass to support livetree
  dm: reset: Update uclass to support livetree
  dm: pci: Update uclass to support livetree
  dm: Update the I2C eeprom driver for livetree
  cros_ec: Update the cros_ec keyboard driver to livetree
  dm: spi: Convert uclass to livetree
  dm: sandbox: i2c: Drop fdtdec.h header
  dm: sandbox: i2c_rtc: Drop fdtdec.h header
  dm: spi-flash: Convert uclass to livetree
  dm: sandbox: spi: Convert driver to support livetree
  dm: sandbox: sysreset: Convert driver to livetree
  dm: test: Fix nit with position of backslash
  dm: gpio: power: Convert pm8916 drivers to livetree
  sandbox: Move to use live tree

 arch/arm/cpu/armv8/fsl-layerscape/fdt.c          |   4 +-
 arch/arm/mach-tegra/tegra186/nvtboot_mem.c       |   4 +-
 arch/sandbox/cpu/state.c                         |  14 +-
 arch/sandbox/include/asm/state.h                 |   7 +
 board/qualcomm/dragonboard410c/dragonboard410c.c |  12 +-
 board/samsung/common/board.c                     |   4 +-
 board/samsung/common/exynos5-dt.c                |   2 +-
 board/sandbox/MAINTAINERS                        |   7 +
 common/board_r.c                                 |  12 +
 common/fdt_support.c                             |  28 +-
 configs/sandbox_defconfig                        |   1 +
 configs/sandbox_flattree_defconfig               | 179 ++++++
 drivers/adc/adc-uclass.c                         |  14 +-
 drivers/clk/at91/pmc.c                           |   4 +-
 drivers/clk/at91/pmc.h                           |   2 +-
 drivers/clk/clk-uclass.c                         |  14 +-
 drivers/clk/clk_fixed_rate.c                     |   5 +-
 drivers/clk/clk_stm32f7.c                        |   3 +-
 drivers/core/Kconfig                             |   4 +
 drivers/core/Makefile                            |   5 +
 drivers/core/device.c                            |  20 +-
 drivers/core/lists.c                             |  29 +-
 drivers/core/of_access.c                         | 736 +++++++++++++++++++++++
 drivers/core/of_addr.c                           | 359 +++++++++++
 drivers/core/of_extra.c                          |  37 ++
 drivers/core/ofnode.c                            | 579 ++++++++++++++++++
 drivers/core/read.c                              | 140 +++++
 drivers/core/regmap.c                            |  37 +-
 drivers/core/root.c                              |  60 +-
 drivers/core/simple-bus.c                        |   3 +-
 drivers/core/uclass.c                            |  42 +-
 drivers/cpu/cpu-uclass.c                         |   6 +-
 drivers/firmware/psci.c                          |   4 +-
 drivers/gpio/74x164_gpio.c                       |   2 +-
 drivers/gpio/gpio-uclass.c                       |  82 +--
 drivers/gpio/pca953x_gpio.c                      |   2 +-
 drivers/gpio/pm8916_gpio.c                       |   8 +-
 drivers/gpio/sandbox.c                           |  12 +-
 drivers/gpio/sunxi_gpio.c                        |   2 +-
 drivers/gpio/tegra186_gpio.c                     |   2 +-
 drivers/gpio/tegra_gpio.c                        |   2 +-
 drivers/i2c/i2c-uclass.c                         |  28 +-
 drivers/i2c/muxes/i2c-mux-uclass.c               |  11 +-
 drivers/i2c/mxc_i2c.c                            |  12 +-
 drivers/i2c/sandbox_i2c.c                        |   1 -
 drivers/input/cros_ec_keyb.c                     |  24 +-
 drivers/input/key_matrix.c                       |  19 +-
 drivers/input/tegra-kbc.c                        |   3 +-
 drivers/led/led_gpio.c                           |  13 +-
 drivers/mailbox/mailbox-uclass.c                 |  20 +-
 drivers/mailbox/tegra-hsp.c                      |   2 +-
 drivers/misc/cros_ec.c                           |  36 +-
 drivers/misc/cros_ec_sandbox.c                   |  23 +-
 drivers/misc/i2c_eeprom_emul.c                   |   7 +-
 drivers/misc/tegra186_bpmp.c                     |   6 +-
 drivers/misc/tegra_car.c                         |   4 +-
 drivers/mmc/fsl_esdhc.c                          |   6 +-
 drivers/mmc/mmc-uclass.c                         |   3 +-
 drivers/mmc/s5p_sdhci.c                          |   8 +-
 drivers/mmc/xenon_sdhci.c                        |   2 +-
 drivers/mtd/altera_qspi.c                        |   2 +-
 drivers/mtd/cfi_flash.c                          |   2 +-
 drivers/mtd/nand/sunxi_nand.c                    |   2 +-
 drivers/mtd/nand/tegra_nand.c                    |   4 +-
 drivers/mtd/pic32_flash.c                        |   2 +-
 drivers/mtd/spi/sandbox.c                        |   6 +-
 drivers/mtd/spi/spi_flash.c                      |   7 +-
 drivers/net/altera_tse.c                         |   2 +-
 drivers/net/cpsw-common.c                        |   4 +-
 drivers/net/keystone_net.c                       |   6 +-
 drivers/net/mvneta.c                             |   2 +-
 drivers/net/pic32_eth.c                          |   3 +-
 drivers/pci/pci-uclass.c                         |  26 +-
 drivers/phy/marvell/comphy_core.c                |   4 +-
 drivers/phy/phy-uclass.c                         |  21 +-
 drivers/phy/sandbox-phy.c                        |   3 +-
 drivers/pinctrl/pinctrl-uclass.c                 |  15 +-
 drivers/power/domain/power-domain-uclass.c       |  19 +-
 drivers/power/pmic/act8846.c                     |   8 +-
 drivers/power/pmic/i2c_pmic_emul.c               |   6 +-
 drivers/power/pmic/lp873x.c                      |  12 +-
 drivers/power/pmic/max77686.c                    |   8 +-
 drivers/power/pmic/palmas.c                      |  16 +-
 drivers/power/pmic/pfuze100.c                    |   8 +-
 drivers/power/pmic/pm8916.c                      |   2 +-
 drivers/power/pmic/pmic-uclass.c                 |  22 +-
 drivers/power/pmic/rk808.c                       |   8 +-
 drivers/power/pmic/s5m8767.c                     |   7 +-
 drivers/power/pmic/sandbox.c                     |   2 +-
 drivers/power/pmic/tps65090.c                    |   8 +-
 drivers/power/regulator/fixed.c                  |  17 +-
 drivers/power/regulator/regulator-uclass.c       |  39 +-
 drivers/reset/reset-uclass.c                     |  21 +-
 drivers/rtc/i2c_rtc_emul.c                       |   1 -
 drivers/serial/serial-uclass.c                   |   3 +-
 drivers/sound/max98095.c                         |   2 +
 drivers/sound/wm8994.c                           |   2 +-
 drivers/spi/pic32_spi.c                          |   2 +-
 drivers/spi/spi-uclass.c                         |  31 +-
 drivers/sysreset/sysreset_sandbox.c              |   2 +-
 drivers/timer/timer-uclass.c                     |   3 +-
 drivers/usb/emul/sandbox_flash.c                 |   4 +-
 drivers/usb/emul/sandbox_hub.c                   |   3 +-
 drivers/usb/host/ehci-marvell.c                  |   2 +-
 drivers/usb/host/ehci-tegra.c                    |   7 +-
 drivers/usb/host/ehci-vf.c                       |   5 +-
 drivers/usb/host/usb-uclass.c                    |   8 +-
 drivers/usb/host/xhci-rockchip.c                 |   2 +-
 drivers/usb/musb-new/ti-musb.c                   |   2 +-
 dts/Kconfig                                      |  11 +
 include/asm-generic/global_data.h                |   3 +
 include/asm-generic/gpio.h                       |  17 +-
 include/clk-uclass.h                             |   5 +-
 include/cros_ec.h                                |   8 +-
 include/dm.h                                     |   2 +
 include/dm/device-internal.h                     |  10 +-
 include/dm/device.h                              |   4 +-
 include/dm/lists.h                               |   9 +-
 include/dm/of.h                                  | 139 +++++
 include/dm/of_access.h                           | 347 +++++++++++
 include/dm/of_addr.h                             |  64 ++
 include/dm/of_extra.h                            |  46 ++
 include/dm/ofnode.h                              | 487 ++++++++++++++-
 include/dm/read.h                                | 439 ++++++++++++++
 include/dm/root.h                                |   3 +-
 include/dm/test.h                                |   2 +
 include/dm/uclass-internal.h                     |  16 +
 include/dm/uclass.h                              |  16 +
 include/fdt_support.h                            |   6 +-
 include/fdtdec.h                                 |  34 --
 include/generic-phy.h                            |   3 +-
 include/i2c.h                                    |   3 +-
 include/key_matrix.h                             |   3 +-
 include/linux/compat.h                           |   8 +-
 include/linux/string.h                           |  28 +
 include/mailbox-uclass.h                         |   2 +-
 include/of_live.h                                |  24 +
 include/power-domain-uclass.h                    |   2 +-
 include/power/pmic.h                             |   2 +-
 include/reset-uclass.h                           |   4 +-
 include/spi.h                                    |   2 +-
 include/test/test.h                              |   4 +
 include/test/ut.h                                |   2 +-
 lib/Makefile                                     |   1 +
 lib/fdtdec.c                                     |  33 +-
 lib/of_live.c                                    | 333 ++++++++++
 lib/string.c                                     |  32 +
 test/dm/bus.c                                    |  16 +-
 test/dm/phy.c                                    |  15 +-
 test/dm/test-fdt.c                               |   3 +-
 test/dm/test-main.c                              | 105 +++-
 test/run                                         |   8 +-
 152 files changed, 4749 insertions(+), 662 deletions(-)
 create mode 100644 configs/sandbox_flattree_defconfig
 create mode 100644 drivers/core/of_access.c
 create mode 100644 drivers/core/of_addr.c
 create mode 100644 drivers/core/of_extra.c
 create mode 100644 drivers/core/ofnode.c
 create mode 100644 drivers/core/read.c
 create mode 100644 include/dm/of.h
 create mode 100644 include/dm/of_access.h
 create mode 100644 include/dm/of_addr.h
 create mode 100644 include/dm/of_extra.h
 create mode 100644 include/dm/read.h
 create mode 100644 include/of_live.h
 create mode 100644 lib/of_live.c

-- 
2.13.0.rc2.291.g57267f2277-goog



More information about the U-Boot mailing list