I am implemting Device Tree support for Panasonic UniPhier platform, but while I was working on that, I noticed some problems in DM core implementation.
What I want to solve the most here is the inconsistency in terms of how to pass the pre-reloc attribute. The driver model provides two ways to pass the device information, platform data and device tree. In the platform data way, the pre-reloc DM scan checks if each driver has DM_FLAG_PRE_RELOC flag, that is, each **driver** has the pre-reloc attribute. In the device tree control, the existence of "u-boot,dm-pre-reloc" is checked for each device node. The driver flag "DM_FLAG_PRE_RELOC" is never checked. That is, each **device** owns the pre-reloc attribute. Drivers should generally work both with platform data and device tree, but this inconsitency has made our life difficult. This series aims to abolish "u-boot,dm-pre-reloc" property because: - Having a U-Boot specific property makes it difficult to share the device tree sources between Linux and U-Boot. - The number of devices is generally larger than that of drivers. Each driver often has multiple devices with different base addresses. It seems more reasonable to add the pre-reloc attribute to drivers than devices. 8/8 commit abolishes "u-boot,dm-pre-reloc" property and replaces it with some *driver* attribute. When I am working on that, I came up with another idea. I thought it is unefficient to scan all the drivers and then check the DM_FLAG_PRE_RELOC. Becuase the DM_FLAG_PRE_RELOC is a static data, we know if each driver is a pre-reloc one or not. So, 6/8 introduces more efficient driver scanning. 1/8 thru 5/8 are some cleanups before I do new things. Masahiro Yamada (8): dm: core: a trivial clean up dm: core: remove meaningless if conditional dm: core: remove unnecessary return condition in driver lookup dm: core: remove unnecessary return condition in uclass lookup dm: core: refactor linker lists lookup code dm: core: look up drivers more efficiently dm: core: declare pre-reloc drivers with U_BOOT_DRIVER_F dm: core: abolish u-boot,dm-pre-reloc property arch/arm/dts/exynos5.dtsi | 1 - doc/driver-model/README.txt | 5 ++-- drivers/core/device.c | 4 +-- drivers/core/lists.c | 57 ++++++++++++++++++---------------------- drivers/core/root.c | 13 ++++----- drivers/core/simple-bus.c | 2 +- drivers/serial/sandbox.c | 3 +-- drivers/serial/serial_mxc.c | 3 +-- drivers/serial/serial_omap.c | 3 +-- drivers/serial/serial_pl01x.c | 3 +-- drivers/serial/serial_s5p.c | 3 +-- drivers/serial/serial_uniphier.c | 3 +-- include/dm/device.h | 11 ++++---- include/dm/lists.h | 29 +++++++++++++++----- include/dm/root.h | 20 +++++++------- test/dm/test-driver.c | 3 +-- test/dm/test-fdt.c | 2 +- test/dm/test.dts | 2 -- 18 files changed, 80 insertions(+), 87 deletions(-) -- 1.9.1 _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
