diff options
Diffstat (limited to 'doc/driver-model')
| -rw-r--r-- | doc/driver-model/README.txt | 31 |
1 files changed, 19 insertions, 12 deletions
diff --git a/doc/driver-model/README.txt b/doc/driver-model/README.txt index 22c3fcb..907ff67 100644 --- a/doc/driver-model/README.txt +++ b/doc/driver-model/README.txt @@ -95,26 +95,24 @@ are provided in test/dm. To run them, try: You should see something like this: <...U-Boot banner...> - Running 12 driver model tests + Running 14 driver model tests Test: dm_test_autobind Test: dm_test_autoprobe Test: dm_test_children Test: dm_test_fdt + Test: dm_test_fdt_pre_reloc Test: dm_test_gpio sandbox_gpio: sb_gpio_get_value: error: offset 4 not reserved Test: dm_test_leak - Warning: Please add '#define DEBUG' to the top of common/dlmalloc.c - Warning: Please add '#define DEBUG' to the top of common/dlmalloc.c Test: dm_test_lifecycle Test: dm_test_operations Test: dm_test_ordering Test: dm_test_platdata + Test: dm_test_pre_reloc Test: dm_test_remove Test: dm_test_uclass Failures: 0 -(You can add '#define DEBUG' as suggested to check for memory leaks) - What is going on? ----------------- @@ -538,26 +536,35 @@ dealing with this might not be worth it. - Implemented a GPIO system, trying to keep it simple +Pre-Relocation Support +---------------------- + +For pre-relocation we simply call the driver model init function. Only +drivers marked with DM_FLAG_PRE_RELOC or the device tree +'u-boot,dm-pre-reloc' flag are initialised prior to relocation. This helps +to reduce the driver model overhead. + +Then post relocation we throw that away and re-init driver model again. +For drivers which require some sort of continuity between pre- and +post-relocation devices, we can provide access to the pre-relocation +device pointers, but this is not currently implemented (the root device +pointer is saved but not made available through the driver model API). + + Things to punt for later ------------------------ - SPL support - this will have to be present before many drivers can be converted, but it seems like we can add it once we are happy with the core implementation. -- Pre-relocation support - similar story -That is not to say that no thinking has gone into these - in fact there +That is not to say that no thinking has gone into this - in fact there is quite a lot there. However, getting these right is non-trivial and there is a high cost associated with going down the wrong path. For SPL, it may be possible to fit in a simplified driver model with only bind and probe methods, to reduce size. -For pre-relocation we can simply call the driver model init function. Then -post relocation we throw that away and re-init driver model again. For drivers -which require some sort of continuity between pre- and post-relocation -devices, we can provide access to the pre-relocation device pointers. - Uclasses are statically numbered at compile time. It would be possible to change this to dynamic numbering, but then we would require some sort of lookup service, perhaps searching by name. This is slightly less efficient |