[U-Boot] [PATCH v2 00/55] RFC: dm: rockchip: Add support for compiled-in platform data

Simon Glass sjg at chromium.org
Mon Jun 13 07:32:41 CEST 2016


Note: This v2 series has some minor updates and improvements, mostly as new
patches in the series.

This series provides a way to compile in the contents of a device tree as C
code into U-Boot, implementing an idea that Tom Rini came up with. It is
intended to deal with extremely tight environments where there is not enough
space for the ~3KB device tree code overhead. Examples include SPL where
there is only 16KB of available RAM yet a full MMC stack is required.

To provide a reasonable test environment, SPL support is added to sandbox,
through a new 'sandbox_spl' target. A new tool 'dtoc' converts device tree
data to C code (and structure definitions).

To check its effectiveness for a real application, the v2 series includes
support for enabling of-platdata for a rockchip board (firefly-rk3288). The
results are as follows:

                          Code       Data      u-boot-spl.bin size
of-platdata disabled      23159	     1624      28864
of-platdata enabled       19093      2616      21761

Overall the saving is 7103 bytes, about 7KB. Approximately 4KB of this comes
from removing the device tree data from SPL although this is offset by
the size of the of-platdata itself (around 1KB). On top of this effective
3KB reduction, another ~3KB reduction comes from dropping libfdt and a
further 1KB from dropping unused setup and driver-model code.

Clearly this approach does have value. Looked at with a favourable light it
provides the best of both worlds: configuration using standard device tree
bindings without the run-time overhead.

Looking under the hood shows a less rosy picture. Effectively we end up
with a new set of C structures which must be handled by the driver. This
series suggests a suitable approach for dealing with this (see of-plat.txt)
which is workable. However there are a number of serious caveats. See that
file for details.

If this feature makes it to mainline it should be used sparingly. Rockchip
is to some extent an unusual case: lots of features, no MMC stack available
to SPL from the internal ROM* and a very limited maximum SPL size. Most SoCs
will not benefit from this.

However, for an SoC with very small SRAM where only a few drivers are needed
in SPL (such as serial and MMC) then of-platdata could provide a useful
benefit, without a significant increase in complexity.

More work is needed before this feature is ready for use, but this series
contains enough to attract initial comments and testing. It is available at
u-boot-dm/dt-working.

* Note that the rockchip internal ROM does include an MMC stack but it only
permits loading of data in its own format, outside control of U-Boot.

Changes in v2:
- Add a comment to the effect that 64-bit machines are not supported
- Add support for rockchip
- Various minor enhancements to the v1 implementation

Simon Glass (55):
  sandbox: Don't print a warning for CONFIG_I2C_COMPAT
  README: Remove CONFIG_SYS_MALLOC_F_LEN comment
  spl: Drop include of i2c.h
  Makefile: Allow the SPL final link rule to be overridden
  sandbox: Allow chaining from SPL to U-Boot proper
  sandbox: Support building an SPL image
  sandbox: Correct header file order in cpu.c
  sandbox: Add some missing headers in cpu.c
  sandbox: Don't use PCI in SPL
  sandbox: Don't include the main loop in SPL
  sandbox: Add basic SPL implementation
  sandbox: Don't use IDE and iotrace in SPL
  sandbox: serial: Don't sync video in SPL
  sandbox: Add a new sandbox_spl board
  sandbox: Add a test device that uses of-platdata
  dm: spl: Don't set up device tree with of-platdata
  dm: Makefile: Build of-platdata before SPL
  dm: core: Don't use device tree with of-platdata
  dm: regmap: Add a dummy implementation for of-platdata
  dm: syscon: Add support for of-platdata
  dm: sandbox: Add a simple driver to test of-platdata
  dm: Add a header that provides access to the of-platdata structs
  dm: clk: Add support for of-platdata
  dm: serial: Add support for of-platdata
  dm: Don't include fdtdec functions when of-platdata is enabled
  dm: Add an option to enable the of-platdata feature
  dm: Add a README for of-platdata
  dm: Add a library to provide simple device-tree access
  dm: Add a tool to generate C code from a device tree
  dm: Makefile: Build of-platdata files when the feature is enabled
  dm: Add a more efficient libfdt library
  Only build the libfdt python module if 'swig' is available
  tiny-printf: Support assert()
  dm: spl: Bind in all devices in SPL with of-platdata
  dm: core: Rename DM_NAME_ALLOCED to DM_FLAG_NAME_ALLOCED
  dtoc: Ignore the u-boot,dm-pre-reloc property
  dm: Don't attach the device tree to SPL with of-platdata
  dm: core: Expand platdata for of-platdata devices
  dm: core: Move regmap allocation into a separate function
  dm: core: Add an implementation of regmap_init_mem_platdata()
  dm: serial: ns16550: Update to support of-platdata
  rockchip: serial: Add an of-platdata driver for rockchip
  rockchip: Update the sdram-channel property to support of-platdata
  rockchip: mmc: Move all DT decoding to ofdata_to_platdata()
  rockchip: mmc: Update the driver to support of-platdata
  rockchip: clk: Move all DT decoding to ofdata_to_platdata()
  rockchip: clk: Update the rk3288 driver to support of-platdata
  rockchip: pinctrl: Update the rk3288 driver to support of-platdata
  rockchip: Move the MMC setup check earlier
  rockchip: Don't use spl_boot_device() with of-platdata
  rockchip: syscon: Update to work with of-platdata
  rockchip: sdram: Move all DT decoding to ofdata_to_platdata()
  rockchip: sdram: Update the driver to support of-platdata
  rockchip: Use of-platdata for firefly-rk3288
  dm: Update the of-platdata README for the new features

 Makefile                                      |   5 +-
 README                                        |   3 -
 arch/arm/dts/rk3288-firefly.dts               |   3 +-
 arch/arm/include/asm/arch-rockchip/sdram.h    |  14 +-
 arch/arm/mach-rockchip/rk3288-board-spl.c     |  25 +-
 arch/arm/mach-rockchip/rk3288/sdram_rk3288.c  | 125 +++++++--
 arch/arm/mach-rockchip/rk3288/syscon_rk3288.c |  38 +++
 arch/sandbox/Kconfig                          |   7 +-
 arch/sandbox/config.mk                        |   5 +
 arch/sandbox/cpu/Makefile                     |   1 +
 arch/sandbox/cpu/cpu.c                        |   6 +-
 arch/sandbox/cpu/os.c                         |  51 ++++
 arch/sandbox/cpu/spl.c                        |  60 +++++
 arch/sandbox/cpu/start.c                      |   2 +
 arch/sandbox/cpu/u-boot-spl.lds               |  24 ++
 arch/sandbox/dts/sandbox.dts                  |  13 +
 arch/sandbox/include/asm/spl.h                |  23 ++
 arch/sandbox/lib/Makefile                     |   2 +
 board/sandbox/MAINTAINERS                     |   7 +
 common/spl/spl.c                              |   6 +-
 configs/firefly-rk3288_defconfig              |   3 +
 configs/sandbox_spl_defconfig                 | 177 +++++++++++++
 doc/driver-model/of-plat.txt                  | 311 ++++++++++++++++++++++
 drivers/clk/clk-uclass.c                      |  20 ++
 drivers/clk/clk_fixed_rate.c                  |   2 +
 drivers/clk/clk_rk3288.c                      |  38 ++-
 drivers/core/device-remove.c                  |   2 +-
 drivers/core/device.c                         |  45 +++-
 drivers/core/lists.c                          |   2 +-
 drivers/core/regmap.c                         |  57 +++-
 drivers/core/root.c                           |   4 +-
 drivers/core/syscon-uclass.c                  |  13 +
 drivers/misc/Makefile                         |   5 +
 drivers/misc/spltest_sandbox.c                |  28 ++
 drivers/mmc/rockchip_dw_mmc.c                 |  60 +++--
 drivers/pinctrl/rockchip/pinctrl_rk3288.c     |   8 +-
 drivers/serial/Kconfig                        |   9 +
 drivers/serial/Makefile                       |   3 +
 drivers/serial/ns16550.c                      |   4 +-
 drivers/serial/sandbox.c                      |   2 +
 drivers/serial/serial-uclass.c                |   8 +-
 drivers/serial/serial_rockchip.c              |  43 +++
 dts/Kconfig                                   |  21 ++
 include/clk.h                                 |   4 +
 include/configs/sandbox.h                     |   4 +
 include/configs/sandbox_spl.h                 |  20 ++
 include/dm/device.h                           |   6 +-
 include/dm/platdata.h                         |   5 +
 include/dt-structs.h                          |  19 ++
 include/os.h                                  |  25 ++
 include/regmap.h                              |  16 ++
 include/syscon.h                              |  11 +
 lib/Makefile                                  |   5 +-
 lib/libfdt/libfdt.swig                        |  81 ++++++
 lib/libfdt/setup.py                           |  38 +++
 lib/libfdt/test_libfdt.py                     |  14 +
 lib/tiny-printf.c                             |   9 +
 scripts/Makefile.host                         |   9 +-
 scripts/Makefile.spl                          |  47 +++-
 tools/Makefile                                |  14 +
 tools/dtoc/.gitignore                         |   1 +
 tools/dtoc/dtoc                               |   1 +
 tools/dtoc/dtoc.py                            | 368 ++++++++++++++++++++++++++
 tools/dtoc/fdt.py                             | 174 ++++++++++++
 tools/dtoc/fdt_fallback.py                    | 207 +++++++++++++++
 tools/dtoc/fdt_util.py                        |  71 +++++
 66 files changed, 2303 insertions(+), 131 deletions(-)
 create mode 100644 arch/sandbox/cpu/spl.c
 create mode 100644 arch/sandbox/cpu/u-boot-spl.lds
 create mode 100644 arch/sandbox/include/asm/spl.h
 create mode 100644 configs/sandbox_spl_defconfig
 create mode 100644 doc/driver-model/of-plat.txt
 create mode 100644 drivers/misc/spltest_sandbox.c
 create mode 100644 drivers/serial/serial_rockchip.c
 create mode 100644 include/configs/sandbox_spl.h
 create mode 100644 include/dt-structs.h
 create mode 100644 lib/libfdt/libfdt.swig
 create mode 100644 lib/libfdt/setup.py
 create mode 100644 lib/libfdt/test_libfdt.py
 create mode 100644 tools/dtoc/.gitignore
 create mode 120000 tools/dtoc/dtoc
 create mode 100755 tools/dtoc/dtoc.py
 create mode 100644 tools/dtoc/fdt.py
 create mode 100644 tools/dtoc/fdt_fallback.py
 create mode 100644 tools/dtoc/fdt_util.py

-- 
2.8.0.rc3.226.g39d4020



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