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Update functions which copy to and from MMIO to load bytes as Little Endian, and also support unaligned buffers. PCI devices almost universally use Little Endian ordering for MMIO registers, mt76 is no exception. PCI hardware that is designed to work with Big Endian CPUs often (but not always) "helps" by transparently byte-swapping MMIO reads and writes on the wire. If this is enabled then it cannot be turned off for a single write. On hardware which does not support this, writel() does the swap in software. When we are transferring arbitrary bytes to MMIO space, we need them to arrive in the same order they were in memory, so when the hardware swaps them this is a problem. Rather than care about how our PCI host controller works, we instead load bytes as Little Endian - so on a Big Endian machine this will reverse them, then we use writel() which will put them back in the right order again. This way we do not make it our business whether the swapping is done in software or hardware. Furthermore, inspection of the code shows that these functions are often called with stack-allocated u8 arrays which have no alignment guarantees so we now use (get|put)_unaligned_le32(). Fixes this issue: mt76x2e 0000:02:00.0: ROM patch build: 20141115060606a mt76x2e 0000:02:00.0: Firmware Version: 0.0.00 mt76x2e 0000:02:00.0: Build: 1 mt76x2e 0000:02:00.0: Build Time: 201607111443____ mt76x2e 0000:02:00.0: Firmware failed to start mt76x2e 0000:02:00.0: probe with driver mt76x2e failed with error -145 Tested on: SmartFiber XP8421-B (Big Endian MIPS 34Kc) - MT7612 -> 5g / ap / psk2 - MT7603 -> 2g / sta / psk2 - MT7603 -> 2g / ap / psk2 TpLink Archer v1200v-v2 (Big Endian MIPS 34Kc) - MT7613 -> 5g / ap / psk2 - MT7603 -> 2g / sta / psk2 Signed-off-by: Caleb James DeLisle <cjd@cjdns.fr> Link: https://patch.msgid.link/20251029184143.3991388-1-cjd@cjdns.fr Signed-off-by: Felix Fietkau <nbd@nbd.name>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.