diff options
author | Simon Glass <sjg@chromium.org> | 2019-12-07 07:41:37 +0300 |
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committer | Bin Meng <bmeng.cn@gmail.com> | 2019-12-15 03:52:29 +0300 |
commit | 2206ac248a550a4e796cd246ce57300fe7995d91 (patch) | |
tree | ba6cafc679517bc39897da03342deca45cb91071 /doc | |
parent | b14c53398683952723540f82027fb0cbfba4f7de (diff) | |
download | u-boot-2206ac248a550a4e796cd246ce57300fe7995d91.tar.xz |
dm: pci: Allow delaying auto-config until after relocation
At present PCI auto-configuration happens in U-Boot both before and after
relocation. This is a waste of time and may mess up static addresses used
in board_init_f(). Adjust the code to supporting doing auto-configuration
once, after relocation, under control of a device-tree property.
This is needed for Apollo Lake for debugging the silicon-init code. Once
the UART is moved to a different MMIO address the debug UART does not work
and any debug output in Apollo Lake's arch_fsp_init_r() causes a hang.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Diffstat (limited to 'doc')
-rw-r--r-- | doc/device-tree-bindings/pci/x86-pci.txt | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/doc/device-tree-bindings/pci/x86-pci.txt b/doc/device-tree-bindings/pci/x86-pci.txt new file mode 100644 index 0000000000..3aa5bd9a46 --- /dev/null +++ b/doc/device-tree-bindings/pci/x86-pci.txt @@ -0,0 +1,24 @@ +x86 PCI DT details: +=================== + +Some options are available to affect how PCI operates on x86. + +Optional properties: +- u-boot,skip-auto-config-until-reloc : Don't set up PCI configuration until + after U-Boot has relocated. Normally if PCI is used before relocation, + this happens before relocation also. Some platforms set up static + configuration in TPL/SPL to reduce code size and boot time, since these + phases only know about a small subset of PCI devices. + +Example: + +pci { + compatible = "pci-x86"; + #address-cells = <3>; + #size-cells = <2>; + u-boot,dm-pre-reloc; + ranges = <0x02000000 0x0 0xc0000000 0xc0000000 0 0x10000000 + 0x42000000 0x0 0xb0000000 0xb0000000 0 0x10000000 + 0x01000000 0x0 0x1000 0x1000 0 0xefff>; + u-boot,skip-auto-config-until-reloc; +}; |