Hi Heinrich, On Thu, 2 Jul 2020 at 20:24, Heinrich Schuchardt <xypron.g...@gmx.de> wrote: > > > > Am 2. Juli 2020 23:10:01 MESZ schrieb Simon Glass <s...@chromium.org>: > >This series provides a proposed enhancement to driver model to reduce > >overhead in SPL. > > > >These patches should not be reviewed other than to comment on the > >approach. The code is all lumped together in a few patches and so > >cannot > >be applied as is. > > > >For now, the source tree is available at: > > > > https://gitlab.denx.de/u-boot/custodians/u-boot-dm/-/tree/dtoc-working > > > >Comments welcome! > > > >Benefits (good news) > >-------------------- > > > >As an example of the impact of tiny-dm, chromebook_jerry is converted > >to > >use it. This shows approximately a 30% reduction in code and data size > >and > >a 85% reduction in malloc() space over of-platdata: > > > > text data bss dec hex filename > >25248 1836 12 27096 69d8 spl/u-boot-spl (original with DT) > > 19727 3436 12 23175 5a87 spl/u-boot-spl (OF_PLATDATA) > > 78% 187% 100% 86% as %age of original > > > > 13784 1408 12 15204 3b64 spl/u-boot-spl (SPL_TINY) > > 70% 41% 100% 66% as %age of platdata > > 55% 77% 100% 56% as %age of original > > > >SPL malloc() usage drops from 944 bytes (OF_PLATDATA) to 116 > >(SPL_TINY). > > > >Overall the 'overhead' of tiny-dm is much less than the full driver > >model. Code size is currently about 600 bytes for these functions on > >Thumb2: > > > > 00000054 T tiny_dev_probe > > 00000034 T tiny_dev_get_by_drvdata > > 00000024 T tiny_dev_find > > 0000001a T tiny_dev_get > > 0000003c T tinydev_alloc_data > > 0000002a t tinydev_lookup_data > > 00000022 T tinydev_ensure_data > > 00000014 T tinydev_get_data > > 00000004 T tinydev_get_parent > > > >Effort (bad news) > >----------------- > > > >Unfortunately it is quite a bit of work to convert drivers over to > >tiny-dm. First, the of-platdata conversion must be done. But on top of > >that, tiny-dm needs entirely separate code for dealing with devices. > >This > >means that instead of 'struct udevice' and 'struct uclass' there is > >just > >'struct tinydev'. Each driver and uclass must be modified to support > >both, pulling common code into internal static functions. > > > The code size reductions sound quite impressive. > > Somehow I have missed the start of your investigation. Could you, please, > summarize what the main differences between tiny DM and the current DM are > and explain why tiny DM cannot be used in main U-Boot.
See patch 2 (doc/driver-model/tiny-dm.rst). I probably didn't send out v1 widely enough, but it was only a starting point then. It is quite limited and it would be fiddly to use in U-Boot proper. Things like automatic power domains, uclass features like setting up a bus and full devicetree access are not available with tiny DM. Regards, Simon > > Best regards > > Heinrich > > > > >Another option > >-------------- > > > >Note: It is assumed that any board that is space-contrained should use > >of-platdata in SPL (see doc/driver-model/of-plat.rst). This is shown to > >reduce device-tree overhead by approximately 4KB. > > > >Designing tiny-dm has suggested a number of things that could be > >changed > >in the current driver model to make it more space-efficient for TPL and > >SPL. The ones with least impact on driver code are (CS=reduces code > >size, > >DS=reduces data size): > > > > CS - drop driver_bind() and create devices (struct udevice) at > > build-time > > CS - allocate all device- and uclass-private data at build-time > > CS - remove all but the basic operations for each uclass (e.g. SPI > > flash only supports reading) > > DS - use 8-bit indexes instead of 32/64-bit pointers for device > > pointers possible since these are created at build-time) > > DS - use singly-linked lists > > DS - use 16-bit offsets to private data, instead of 32/64-bit pointers > > (possible since it is all in SRAM relative to malloc() base, > > presumably word-aligned and < 256KB) > >DS - move private pointers into a separate data structure so that NULLs > > are not stored > > CS / DS - Combine req_seq and seq and calculate the new value at > > build-time > > > >More difficult are: > > > > DS - drop some of the lesser-used driver and uclass methods > > DS - drop all uclass methods except init() > > DS - drop all driver methods except probe() > > CS / DS - drop uclasses and require drivers to manually call uclass > > functions > > > >Even with all of this we would not reach tiny-dm and it would muddy up > >the > >driver-model datas structures. But we might come close to tiny-dm on > >size > >and there are some advantages: > > > >- much of the benefit would apply to all boards that use of-platdata > >(i.e. > > with very little effort on behalf of board maintainers) > >- the impact on the code base is much less (we keep a single, unified > > driver mode in SPL and U-Boot proper) > > > >Overall I think it is worth looking at this option. While it doesn't > >have > >the 'nuclear' impact of tiny-dm, neither does it mess with the U-Boot > >driver code as much and it is easier to learn. > > > >Changes in v2: > >- Various updates, and ported to chromebook_jerry (rockchip) > > > >Simon Glass (3): > > dm: Driver and uclass changes for tiny-dm > > dm: Arch-specific changes for tiny-dm > > dm: Core changes for tiny-dm > > > > arch/arm/dts/rk3288-u-boot.dtsi | 17 +- > > arch/arm/dts/rk3288-veyron.dtsi | 26 +- > > arch/arm/dts/rk3288.dtsi | 3 + > > arch/arm/include/asm/arch-rockchip/clock.h | 9 + > > .../include/asm/arch-rockchip/sdram_rk3288.h | 21 ++ > > arch/arm/include/asm/arch-rockchip/spi.h | 1 + > > arch/arm/include/asm/io.h | 18 + > > arch/arm/mach-rockchip/rk3288/clk_rk3288.c | 46 +++ > > arch/arm/mach-rockchip/rk3288/rk3288.c | 2 + > > arch/arm/mach-rockchip/rk3288/syscon_rk3288.c | 45 +-- > > arch/arm/mach-rockchip/sdram.c | 33 +- > > arch/sandbox/cpu/u-boot-spl.lds | 12 + > > arch/sandbox/dts/sandbox.dts | 3 +- > > arch/sandbox/dts/sandbox.dtsi | 2 +- > > arch/x86/cpu/apollolake/cpu_spl.c | 5 +- > > arch/x86/cpu/apollolake/uart.c | 56 ++++ > > arch/x86/dts/chromebook_coral.dts | 1 + > > arch/x86/lib/tpl.c | 4 +- > > board/Synology/ds109/ds109.c | 3 +- > > common/console.c | 2 +- > > common/log.c | 36 +- > > common/malloc_simple.c | 31 ++ > > common/spl/spl.c | 17 +- > > common/spl/spl_spi.c | 91 +++-- > > configs/chromebook_coral_defconfig | 1 + > > configs/chromebook_jerry_defconfig | 11 + > > configs/rock2_defconfig | 3 + > > doc/develop/debugging.rst | 35 ++ > > doc/driver-model/tiny-dm.rst | 315 +++++++++++++++++ > > drivers/clk/Kconfig | 54 +++ > > drivers/clk/Makefile | 4 +- > > drivers/clk/clk-uclass.c | 53 ++- > > drivers/clk/rockchip/clk_rk3288.c | 106 ++++-- > > drivers/core/Kconfig | 106 ++++++ > > drivers/core/Makefile | 3 + > > drivers/core/of_extra.c | 49 ++- > > drivers/core/regmap.c | 3 +- > > drivers/core/syscon-uclass.c | 68 +++- > > drivers/core/tiny.c | 249 ++++++++++++++ > > drivers/mtd/spi/Kconfig | 18 + > > drivers/mtd/spi/sf-uclass.c | 76 +++++ > > drivers/mtd/spi/sf_probe.c | 4 + > > drivers/mtd/spi/spi-nor-tiny.c | 166 ++++++++- > > drivers/ram/Kconfig | 18 + > > drivers/ram/ram-uclass.c | 12 + > > drivers/ram/rockchip/sdram_rk3188.c | 2 +- > > drivers/ram/rockchip/sdram_rk322x.c | 2 +- > > drivers/ram/rockchip/sdram_rk3288.c | 231 ++++++++----- > > drivers/ram/rockchip/sdram_rk3328.c | 2 +- > > drivers/ram/rockchip/sdram_rk3399.c | 2 +- > > drivers/reset/reset-rockchip.c | 4 +- > > drivers/serial/Kconfig | 38 +++ > > drivers/serial/ns16550.c | 195 +++++++++-- > > drivers/serial/sandbox.c | 59 +++- > > drivers/serial/serial-uclass.c | 77 +++++ > > drivers/serial/serial_omap.c | 2 +- > > drivers/serial/serial_rockchip.c | 59 ++++ > > drivers/spi/Kconfig | 18 + > > drivers/spi/Makefile | 2 + > > drivers/spi/rk_spi.c | 301 ++++++++++++----- > > drivers/spi/spi-uclass.c | 77 +++++ > > drivers/sysreset/Kconfig | 18 + > > drivers/sysreset/sysreset-uclass.c | 124 ++++--- > > drivers/sysreset/sysreset_rockchip.c | 61 +++- > > include/asm-generic/global_data.h | 7 +- > > include/clk-uclass.h | 11 + > > include/clk.h | 32 +- > > include/dm/device.h | 121 +++++++ > > include/dm/of_extra.h | 6 + > > include/dm/platdata.h | 20 +- > > include/dm/tiny_struct.h | 42 +++ > > include/linker_lists.h | 6 + > > include/linux/mtd/mtd.h | 23 +- > > include/linux/mtd/spi-nor.h | 22 ++ > > include/log.h | 6 + > > include/malloc.h | 3 + > > include/ns16550.h | 7 +- > > include/ram.h | 25 ++ > > include/regmap.h | 4 +- > > include/serial.h | 45 ++- > > include/spi.h | 31 ++ > > include/spi_flash.h | 7 + > > include/spl.h | 8 +- > > include/syscon.h | 2 + > > include/sysreset.h | 9 + > > scripts/Makefile.spl | 6 +- > > tools/dtoc/dtb_platdata.py | 316 +++++++++++++++--- > > tools/dtoc/dtoc_test_simple.dts | 12 +- > > tools/dtoc/fdt.py | 7 +- > > tools/dtoc/main.py | 9 +- > > tools/dtoc/test_dtoc.py | 91 ++++- > > tools/patman/tools.py | 4 +- > > 92 files changed, 3454 insertions(+), 540 deletions(-) > > create mode 100644 doc/develop/debugging.rst > > create mode 100644 doc/driver-model/tiny-dm.rst > > create mode 100644 drivers/core/tiny.c > > create mode 100644 include/dm/tiny_struct.h > > -- > Diese Nachricht wurde von meinem Android-Gerät mit K-9 Mail gesendet.
