[U-Boot] ide support for linux, doubts about "IDE" and device tree blob

Carlo Pisani carlojpisani at gmail.com
Wed Oct 9 11:47:05 UTC 2019

I am a bit confused about two things
1) is the "ide" (disk read/write/boot) module intended to be PCI-MEM
"memory-mapped" oriented concerning the harddrive? or is it PCI_IO
oriented? there are too many layers of code and this makes me confused
2) what is the philosophy about initializing the PCI_bridge? and what
is u-boot supposed to do concerning the device-tree-blog to be passed
to the kernel?

there are pieces of code in the kernel source telling me this

* Older u-boots don't set PCI up properly.
 * Update the hardware to match the device tree.
 * The prefetch mem region and non-prefetch mem region
 * must be contiguous in the host bus.
 * As required by the PCI binding, PCI #addr/#size must be 3/2.
 * The parent bus must be 1/1.
 * Only 32-bit PCI is supported.
 * All three region types
 *    prefetchable mem
 *    non-prefetchable mem
 *    I/O
 * must be present

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