On 11/30/20 2:53 AM, Simon Glass wrote:
At present each device has two sequence numbers, with 'req_seq' being set up at bind time and 'seq' at probe time. The idea is that devices can 'request' a sequence number and then the conflicts are resolved when the device is probed.
This makes things complicated in a few cases, since we don't really know (at bind time) what the sequence number will end up being. We want to honour the bind-time requests if at all possible, but in fact the only source of these at present is the devicetree aliases.
Apart from the obvious need for sequence numbers to supports U-Boot's numbering on devices on the command line, the current scheme was designed to:
- avoid calculating the sequence number until it is needed, to save execution time
- allow multiple devices to obtain a particular sequence number as they are probed and removed
- retain a record of the 'requested' sequence number even if it turns out that a device could not get it (to allow debugging and retrying)
After some years using the current scheme it seems on balance that these goals don't have as much merit as first thought. The first point would be persuasive except that we end up reading the devicetree aliases at bind-time anyway. So the work of resolving the sequence numbers during probing is not that great. The second point hasn't really been an issue, as there is typically no contention for sequence numbers (boards tend to allocate them statically in the devicetree). Re the third point, we can often figure out what was requested by looking at aliases, and in the cases where we can't, it doesn't seem to matter much.
Since we have the devicetree available at bind time, we may as well just use it, in the hope that the required processing will turn out to be useful later (i.e. the device actually gets used). In addition, it is simpler to use a single sequence number, since it avoids confusion and some extra code.
This series moves U-Boot to use a single, bind-time sequence number. All uclasses with the DM_UC_FLAG_SEQ_ALIAS flag enabled will assign sequence numbers to their devices, so that as soon as a device is bound, it has a sequence number. If a devicetree alias provides the number, it will be used. Otherwise, during initial binding, the first free number is used. For ad-hoc calls to device_bind() afterwards (e.g. from driver code), the sequence is set to the maximum sequence number for the uclass + 1.
Apart from the simplicity gains, overall these changes seem to reduce the number of tweaks and workarounds needed to get the desired behaviour.
However there will certainly be some problems created, so board maintainers should test this out.
What is the effect of the series on removable devices like USB storage, USB Ethernet, SATA disks, ...?
Is there a test for removable devices?
Best regards
Heinrich
Simon Glass (27): linker_lists: Fix alignment issue efi: Drop unwanted message in efi_uc_destroy() dm: Avoid accessing seq directly dm: core: Update uclass_find_next_free_req_seq() args dm: core: Add a new sequence number for devices dm: test: Add support for new sequence numbers dm: core: Switch binding to use new sequence numbers dm: Fix return value in dev_read_alias_seq() dm: test: Drop assumptions of no sequence numbers octeon: Don't attempt to set the sequence number i2c: Update for new sequence numbers net: Update to use new sequence numbers pci: Update to use new sequence numbers spi: Update for new sequence numbers usb: ehci-mx6: Drop assignment of sequence number usb: Update for new sequence numbers x86: Drop unnecessary mp_init logic x86: Simplify acpi_device_infer_name() gpio: Update for new sequence numbers pinctrl: Update for new sequence numbers dm: Switch over to use new sequence number for dev_seq() dm: Drop uclass_resolve_seq() dm: Drop the unused arg in uclass_find_device_by_seq() dm: core: Simplify uclass_find_next_free_req_seq() cmd: Drop use of old sequence numbers in commands dm: core: Drop seq and req_seq dm: Update documentation for new sequence numbers
arch/Kconfig | 11 +++ arch/arm/include/asm/mach-imx/mxc_i2c.h | 2 +- arch/arm/mach-k3/am6_init.c | 2 +- arch/arm/mach-k3/j721e_init.c | 2 +- arch/arm/mach-k3/sysfw-loader.c | 2 +- arch/sandbox/dts/test.dts | 2 +- arch/x86/cpu/apollolake/cpu.c | 2 +- arch/x86/cpu/broadwell/cpu_full.c | 2 +- arch/x86/cpu/ivybridge/model_206ax.c | 2 +- arch/x86/cpu/mp_init.c | 23 ++--- arch/x86/include/asm/mp.h | 2 +- board/xilinx/versal/board.c | 12 +-- board/xilinx/zynqmp/zynqmp.c | 12 +-- cmd/axi.c | 6 +- cmd/cpu.c | 2 +- cmd/i2c.c | 6 +- cmd/misc.c | 2 +- cmd/osd.c | 6 +- cmd/pci.c | 7 +- cmd/pmic.c | 4 +- cmd/remoteproc.c | 2 +- cmd/w1.c | 4 +- doc/api/linker_lists.rst | 62 ++++++++++++ doc/driver-model/design.rst | 58 +++++++----- drivers/core/device-remove.c | 1 - drivers/core/device.c | 52 ++++------ drivers/core/dump.c | 4 +- drivers/core/read.c | 4 +- drivers/core/root.c | 21 ++++- drivers/core/uclass.c | 115 ++++++++++------------- drivers/gpio/imx_rgpio2p.c | 2 +- drivers/gpio/iproc_gpio.c | 2 +- drivers/gpio/mvebu_gpio.c | 2 +- drivers/gpio/mxc_gpio.c | 2 +- drivers/gpio/octeon_gpio.c | 2 +- drivers/gpio/vybrid_gpio.c | 2 +- drivers/i2c/ast_i2c.c | 4 +- drivers/i2c/davinci_i2c.c | 2 +- drivers/i2c/designware_i2c_pci.c | 16 +--- drivers/i2c/exynos_hs_i2c.c | 2 +- drivers/i2c/i2c-gpio.c | 2 +- drivers/i2c/i2c-uclass.c | 8 +- drivers/i2c/i2c-versatile.c | 5 - drivers/i2c/imx_lpi2c.c | 12 +-- drivers/i2c/intel_i2c.c | 12 +-- drivers/i2c/lpc32xx_i2c.c | 6 +- drivers/i2c/muxes/i2c-mux-uclass.c | 4 +- drivers/i2c/mvtwsi.c | 4 +- drivers/i2c/mxc_i2c.c | 10 +- drivers/i2c/nx_i2c.c | 2 +- drivers/i2c/octeon_i2c.c | 3 +- drivers/i2c/s3c24x0_i2c.c | 2 +- drivers/i2c/tegra_i2c.c | 5 +- drivers/mmc/fsl_esdhc_imx.c | 4 +- drivers/mmc/octeontx_hsmmc.c | 2 - drivers/mtd/spi/sandbox.c | 4 +- drivers/net/dwc_eth_qos.c | 2 +- drivers/net/fec_mxc.c | 7 +- drivers/net/fsl-mc/mc.c | 2 +- drivers/net/fsl_mcdmafec.c | 2 +- drivers/net/ftgmac100.c | 2 +- drivers/net/higmacv300.c | 2 +- drivers/net/mcffec.c | 2 +- drivers/net/octeontx/nicvf_main.c | 9 +- drivers/net/octeontx/smi.c | 3 +- drivers/net/octeontx2/nix.c | 2 +- drivers/net/octeontx2/rvu_pf.c | 6 +- drivers/net/xilinx_axi_emac.c | 2 +- drivers/net/xilinx_emaclite.c | 2 +- drivers/net/zynq_gem.c | 2 +- drivers/pci/pci-aardvark.c | 2 +- drivers/pci/pci-uclass.c | 42 ++++----- drivers/pci/pci_auto.c | 6 +- drivers/pci/pcie_dw_mvebu.c | 6 +- drivers/pci/pcie_dw_ti.c | 6 +- drivers/pci/pcie_ecam_generic.c | 2 +- drivers/pci/pcie_fsl.c | 16 ++-- drivers/pci/pcie_intel_fpga.c | 2 +- drivers/pci/pcie_layerscape_fixup.c | 4 +- drivers/pci/pcie_layerscape_gen4.c | 10 +- drivers/pci/pcie_layerscape_gen4_fixup.c | 2 +- drivers/pci/pcie_layerscape_rc.c | 12 +-- drivers/pci/pcie_mediatek.c | 2 +- drivers/pci/pcie_rockchip.c | 6 +- drivers/pinctrl/exynos/pinctrl-exynos.c | 2 +- drivers/serial/serial_mcf.c | 2 +- drivers/serial/serial_s5p.c | 2 +- drivers/spi/altera_spi.c | 2 +- drivers/spi/cf_spi.c | 12 +-- drivers/spi/fsl_dspi.c | 8 +- drivers/spi/fsl_espi.c | 2 +- drivers/spi/octeon_spi.c | 2 +- drivers/spi/pic32_spi.c | 4 +- drivers/spi/rk_spi.c | 1 - drivers/spi/sandbox_spi.c | 2 +- drivers/spi/spi-uclass.c | 4 +- drivers/spi/tegra114_spi.c | 2 +- drivers/spi/tegra20_sflash.c | 2 +- drivers/spi/tegra20_slink.c | 2 +- drivers/spi/tegra210_qspi.c | 2 +- drivers/spi/xilinx_spi.c | 2 +- drivers/spi/zynq_qspi.c | 2 +- drivers/spi/zynq_spi.c | 2 +- drivers/usb/gadget/max3420_udc.c | 2 +- drivers/usb/host/ehci-mx5.c | 2 +- drivers/usb/host/ehci-mx6.c | 14 ++- drivers/usb/host/ehci-omap.c | 2 +- drivers/usb/host/ehci-vf.c | 8 +- drivers/usb/host/usb-sandbox.c | 2 +- drivers/usb/host/usb-uclass.c | 6 +- drivers/video/vidconsole-uclass.c | 4 +- drivers/virtio/virtio-uclass.c | 2 +- drivers/watchdog/ast_wdt.c | 2 +- drivers/watchdog/at91sam9_wdt.c | 2 +- drivers/watchdog/cdns_wdt.c | 2 +- drivers/watchdog/omap_wdt.c | 2 +- drivers/watchdog/orion_wdt.c | 2 +- drivers/watchdog/sbsa_gwdt.c | 2 +- drivers/watchdog/sp805_wdt.c | 2 +- drivers/watchdog/tangier_wdt.c | 2 +- drivers/watchdog/xilinx_tb_wdt.c | 2 +- drivers/watchdog/xilinx_wwdt.c | 2 +- include/asm-generic/global_data.h | 2 + include/configs/sandbox.h | 2 +- include/dm/device.h | 32 +++---- include/dm/uclass-internal.h | 34 +++---- include/dm/uclass.h | 15 +-- include/linker_lists.h | 3 +- include/pci.h | 2 +- include/spi.h | 2 +- lib/acpi/acpi_device.c | 27 +----- lib/efi_driver/efi_uclass.c | 1 - lib/efi_loader/efi_device_path.c | 4 +- net/eth-uclass.c | 24 +++-- test/dm/acpi.c | 6 +- test/dm/blk.c | 3 - test/dm/bus.c | 15 +-- test/dm/core.c | 19 ++++ test/dm/eth.c | 14 +-- test/dm/i2c.c | 3 - test/dm/spi.c | 3 - test/dm/test-fdt.c | 100 ++++++++++++-------- test/dm/test-main.c | 6 ++ 143 files changed, 583 insertions(+), 569 deletions(-)