https://github.com/torvalds/linux
Revision b7fb7729c94fb2d23c79ff44f7a2da089c92d81c authored by Tobias Jakobi (Compleo) on 04 March 2024, 15:41:35 UTC, committed by Jakub Kicinski on 06 March 2024, 03:10:49 UTC
This bug was noticed while re-implementing parts of the kernel driver in userspace using spidev. The goal was to enable some of the errata workarounds that Microchip describes in their errata sheet [1]. Both the errata sheet and the regular datasheet of e.g. the KSZ8795 imply that you need to do this for indirect register accesses: - write a 16-bit value to a control register pair (this value consists of the indirect register table, and the offset inside the table) - either read or write an 8-bit value from the data storage register (indicated by REG_IND_BYTE in the kernel) The current implementation has the order swapped. It can be proven, by reading back some indirect register with known content (the EEE register modified in ksz8_handle_global_errata() is one of these), that this implementation does not work. Private discussion with Oleksij Rempel of Pengutronix has revealed that the workaround was apparantly never tested on actual hardware. [1] https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/Errata/KSZ87xx-Errata-DS80000687C.pdf Signed-off-by: Tobias Jakobi (Compleo) <tobias.jakobi.compleo@gmail.com> Reviewed-by: Oleksij Rempel <o.rempel@pengutronix.de> Fixes: 7b6e6235b664 ("net: dsa: microchip: ksz8795: handle eee specif erratum") Link: https://lore.kernel.org/r/20240304154135.161332-1-tobias.jakobi.compleo@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Tip revision: b7fb7729c94fb2d23c79ff44f7a2da089c92d81c authored by Tobias Jakobi (Compleo) on 04 March 2024, 15:41:35 UTC
net: dsa: microchip: fix register write order in ksz8_ind_write8()
net: dsa: microchip: fix register write order in ksz8_ind_write8()
Tip revision: b7fb772
File | Mode | Size |
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LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
io_uring | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
rust | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | -rw-r--r-- | 21.7 KB |
.cocciconfig | -rw-r--r-- | 59 bytes |
.editorconfig | -rw-r--r-- | 672 bytes |
.get_maintainer.ignore | -rw-r--r-- | 151 bytes |
.gitattributes | -rw-r--r-- | 105 bytes |
.gitignore | -rw-r--r-- | 2.0 KB |
.mailmap | -rw-r--r-- | 37.3 KB |
.rustfmt.toml | -rw-r--r-- | 369 bytes |
COPYING | -rw-r--r-- | 496 bytes |
CREDITS | -rw-r--r-- | 101.6 KB |
Kbuild | -rw-r--r-- | 2.5 KB |
Kconfig | -rw-r--r-- | 555 bytes |
MAINTAINERS | -rw-r--r-- | 724.2 KB |
Makefile | -rw-r--r-- | 66.1 KB |
README | -rw-r--r-- | 727 bytes |
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