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Bernd Edlinger 6264994be8 net: stmmac: Wait a bit for the reset to take effect
[ Upstream commit a5f5eee282 ]

otherwise the synopsys_id value may be read out wrong,
because the GMAC_VERSION register might still be in reset
state, for at least 1 us after the reset is de-asserted.

Add a wait for 10 us before continuing to be on the safe side.

> From what have you got that delay value?

Just try and error, with very old linux versions and old gcc versions
the synopsys_id was read out correctly most of the time (but not always),
with recent linux versions and recnet gcc versions it was read out
wrongly most of the time, but again not always.
I don't have access to the VHDL code in question, so I cannot
tell why it takes so long to get the correct values, I also do not
have more than a few hardware samples, so I cannot tell how long
this timeout must be in worst case.
Experimentally I can tell that the register is read several times
as zero immediately after the reset is de-asserted, also adding several
no-ops is not enough, adding a printk is enough, also udelay(1) seems to
be enough but I tried that not very often, and I have not access to many
hardware samples to be 100% sure about the necessary delay.
And since the udelay here is only executed once per device instance,
it seems acceptable to delay the boot for 10 us.

BTW: my hardware's synopsys id is 0x37.

Fixes: c5e4ddbdfa ("net: stmmac: Add support for optional reset control")
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/AS8P193MB1285A810BD78C111E7F6AA34E4752@AS8P193MB1285.EURP193.PROD.OUTLOOK.COM
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-01-31 16:19:03 -08:00
arch LoongArch/smp: Call rcutree_report_cpu_starting() earlier 2024-01-31 16:18:57 -08:00
block block: ensure we hold a queue reference when using queue limits 2024-01-25 15:35:57 -08:00
certs certs: Reference revocation list for all keyrings 2023-08-17 20:12:41 +00:00
crypto crypto: api - Disallow identical driver names 2024-01-31 16:18:49 -08:00
Documentation dt-bindings: net: snps,dwmac: Tx coe unsupported 2024-01-31 16:18:58 -08:00
drivers net: stmmac: Wait a bit for the reset to take effect 2024-01-31 16:19:03 -08:00
fs afs: Hide silly-rename files from userspace 2024-01-31 16:19:01 -08:00
include net/mlx5: Bridge, fix multicast packets sent to uplink 2024-01-31 16:19:02 -08:00
init rootfs: Fix support for rootfstype= when root= is given 2024-01-25 15:35:46 -08:00
io_uring io_uring: adjust defer tw counting 2024-01-25 15:36:00 -08:00
ipc Add x86 shadow stack support 2023-08-31 12:20:12 -07:00
kernel rcu: Defer RCU kthreads wakeup when CPU is dying 2024-01-31 16:19:03 -08:00
lib crypto: lib/mpi - Fix unexpected pointer access in mpi_ec_init 2024-01-31 16:18:49 -08:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm mm: page_alloc: unreserve highatomic page blocks before oom 2024-01-31 16:18:57 -08:00
net netfilter: nf_tables: validate NFPROTO_* family 2024-01-31 16:19:03 -08:00
rust rust: Ignore preserve-most functions 2024-01-25 15:35:41 -08:00
samples vfio/mtty: Overhaul mtty interrupt handling 2024-01-10 17:16:55 +01:00
scripts scripts/get_abi: fix source path leak 2024-01-31 16:18:55 -08:00
security lsm: new security_file_ioctl_compat() hook 2024-01-31 16:18:54 -08:00
sound soundwire: fix initializing sysfs for same devices on different buses 2024-01-31 16:18:47 -08:00
tools selftests: fill in some missing configs for net 2024-01-31 16:19:02 -08:00
usr initramfs: Encode dependency on KBUILD_BUILD_TIMESTAMP 2023-06-06 17:54:49 +09:00
virt ARM: 2023-09-07 13:52:20 -07:00
.clang-format iommu: Add for_each_group_device() 2023-05-23 08:15:51 +02:00
.cocciconfig
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: rpm-pkg: rename binkernel.spec to kernel.spec 2023-07-25 00:59:33 +09:00
.mailmap 20 hotfixes. 12 are cc:stable and the remainder address post-6.5 issues 2023-10-24 09:52:16 -10:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS USB: Remove Wireless USB and UWB documentation 2023-08-09 14:17:32 +02:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Char/Misc driver fixes for 6.6-final 2023-10-28 07:51:27 -10:00
Makefile Linux 6.6.14 2024-01-25 15:36:01 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
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    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text 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.