On some architectures, u_long isn't large enough for resource definitions.
Particularly, powerpc and arm allow 36-bit (or larger) physical addresses, but
type `long' is only 32-bit. This extends rman's resources to uintmax_t. With
this change, any resource can feasibly be placed anywhere in physical memory
(within the constraints of the driver).
Why uintmax_t and not something machine dependent, or uint64_t? Though it's
possible for uintmax_t to grow, it's highly unlikely it will become 128-bit on
32-bit architectures. 64-bit architectures should have plenty of RAM to absorb
the increase on resource sizes if and when this occurs, and the number of
resources on memory-constrained systems should be sufficiently small as to not
pose a drastic overhead. That being said, uintmax_t was chosen for source
clarity. If it's specified as uint64_t, all printf()-like calls would either
need casts to uintmax_t, or be littered with PRI*64 macros. Casts to uintmax_t
aren't horrible, but it would also bake into the API for
resource_list_print_type() either a hidden assumption that entries get cast to
uintmax_t for printing, or these calls would need the PRI*64 macros. Since
source code is meant to be read more often than written, I chose the clearest
path of simply using uintmax_t.
Tested on a PowerPC p5020-based board, which places all device resources in
0xfxxxxxxxx, and has 8GB RAM.
Regression tested on qemu-system-i386
Regression tested on qemu-system-mips (malta profile)
Tested PAE and devinfo on virtualbox (live CD)
Special thanks to bz for his testing on ARM.
Reviewed By: bz, jhb (previous)
Relnotes: Yes
Sponsored by: Alex Perez/Inertial Computing
Differential Revision: https://reviews.freebsd.org/D4544
This simplifies checking for default resource range for bus_alloc_resource(),
and improves readability.
This is part of, and related to, the migration of rman_res_t from u_long to
uintmax_t.
Discussed with: jhb
Suggested by: marcel
Use driver settable callbacks for handling of:
- core post reset
- reading actual port speed
Typically, OTG enabled EHCI cores wants setting of USBMODE register,
but this register is not defined in EHCI specification and different
cores can have it on different offset.
Also, for cores with TT extension, actual port speed must be determinable.
But again, EHCI specification not covers this so this patch provides
function for two most common variant of speed bits layout.
Reviewed by: hselasky
Differential Revision: https://reviews.freebsd.org/D5088
Summary:
Migrate to using the semi-opaque type rman_res_t to specify rman resources. For
now, this is still compatible with u_long.
This is step one in migrating rman to use uintmax_t for resources instead of
u_long.
Going forward, this could feasibly be used to specify architecture-specific
definitions of resource ranges, rather than baking a specific integer type into
the API.
This change has been broken out to facilitate MFC'ing drivers back to 10 without
breaking ABI.
Reviewed By: jhb
Sponsored by: Alex Perez/Inertial Computing
Differential Revision: https://reviews.freebsd.org/D5075
This is a holdover from how reset is handled in the ARGE_MDIO world.
You need to define the mdio bus device if you want to use the ethernet
device or the arge setup path doesn't bring the MAC out of reset.
The QCA953x SoC is an integrated 2x2 2GHz 11n + MIPS24k core, with
a 5 port FE switch, gige WAN port, and all the same stuff you'd find on
its predecessor - the AR9331.
However, buried deep in here somewhere is also a PCIe EP/RC for various
applications and some other weird bits I don't yet know about.
This is enough to get the reference board up and booting. I haven't yet
had it pass lots of packets - I need to finalise the ethernet switch
bits and the GMAC configuration (ie, how the ethernet ports and switch
are wired up) and I'll bring that in when I commit the base configuration
files to use the thing.
The wifi stuff will come much later. I have to port that support from
Linux ath9k and extend our vendor HAL to support it.
The reference board (AP143) comes with 32MB RAM and 4MB flash, so in order
to use it I need to get USB working fully so I can run root from there.
Thankyou to Qualcomm Atheros for access to the reference design board.
Details:
* Add register definitions from openwrt;
* It looks like a QCA955x but shrunk down to a QCA933x footprint, so
use the QCA955x bits and fix up the clock detection code to do the
QCA953x bits (they're very subtly different);
* Teach GPIO about it;
* Teach EHCI about it;
* Teach if_arge about it;
* Teach the CPU detection code about it.
Tested:
* AP143, QCA9533v2 SoC
Obtained from: Linux, Linux OpenWRT
* use barriers in a slightly better fashion. You can blame this
glass of whiskey on putting barriers in the wrong spot. Grr adrian.
* steal/rewrite the mdio busy check from ag7100 from openwrt and
refactor the existing code out. This is .. more correct.
This seems to fix the boot-to-boot variation that I've been seeing
and it quietens the switch port status flapping.
Tested:
* QCA9558 SoC (AP135.)
Obtained from: Linux OpenWRT
This driver and the linux ag71xx driver both treat the transmit ring
as a circular linked list of descriptors. There's no "end" pointer
that is ever NULL - instead, it expects the MAC to hit a finished
descriptor (ARGE_DESC_EMPTY) and stop.
Now, since it's a circular buffer, we may end up with the hardware
hitting the beginning of our multi-descriptor frame before we've finished
setting it up. It then DMA's it in, starts sending it, and we finish
writing out the new descriptor. The hardware may then write its
completion for the next descriptor out; then we do, and when we next
read it it'll show up as "not done" and transmit completion stops.
This unfortunately manifests itself as the transmit queue always
being active and a massive TX interrupt storm. We need to actively
ACK packets back from the transmit engine and if we don't (eg because
we think the transmit isn't finished but it is) then the unit will
just keep generating interrupts.
I hit this finally with the below testing setup. This fixed it for me.
Strictly speaking I should put in a sync in between writing out all of
the descriptors and writing out that final descriptor.
Tested:
* QCA9558 SoC (AP135 reference board) w/ arge1 + vlans acting as a
router, and iperf -d (tcp, bidirectional traffic.)
Obtained from: Linux OpenWRT (ag71xx_main.c.)
The MIPS busdma sync operations currently are a big no-op on coherent memory.
This isn't strictly correct behaviour as we need a SYNC in here to ensure that
the writes have finished and are visible in main memory before the MMIO accesses
occur. This will have to be addressed in a later commit.
But, before that happens, let's at least do a flush here to make things
more "correct".
This is required for even remotely sensible behaviour on mips74k with
write-through memory enabled.
The mips74k programmers guide notes that reads can be re-ordered, even
uncached ones, so we need an explicit SYNC between them.
Yes, this is a case of a driver author actively doing a bus barrier
operation.
This ends up being necessary when the mips74k core is run in write-back
mode rather than write-through mode. That's coming in an upcoming
commit.
Tested:
* mips74k, QCA9558 SoC (AP135 reference board), arge<->arge interface
routing traffic tests.
send frames.
This matches the other check for space.
"enough" is a misnomer, for "reasons". The biggest reason is that
the TX ring is actually a circular linked list, with no head/tail pointers.
This is just a bit more headroom between head/tail so we have time to
schedule frames before we hit where the hardware is at.
Ideally this would be tunable and a little larger.
This flushes out the write to the system before anything continues.
The mips74k guide, chapter 3.3.3 (write gathering) notes that writes
can be buffered in FIFOs - even uncached ones - so we can't guarantee
the device has felt its effects. Now, since we're all lazy driver
authors and don't pepper read/write barriers everywhere, fake it here.
tested:
* mips74k - QCA9558 SoC (AP135 reference board)
This should make it easier to track down interrupt storms from arge.
Tested:
* AP135 (QCA955x) SoC - defaults to ARGE_DEBUG enabled
* Carambola2 (AR9331 SoC) - defaults to ARGE_DEBUG disabled
I couldn't test arge0->arge1 bridging, only arge0 VLAN bridging.
The DIR-825C1 only hooks up arge0 to the switch GMAC0 and so
you need to abuse VLANs to test.
Tested:
* DIR-825C1 (AR9344)
This part seems to work bug-free with single byte TX/RX buffer alignment.
This drops the CPU requirement to bridge 100mbit iperf from 100% CPU
to ~ 50% CPU.
Tested:
* AP121 (AR9330) SoC, highly magic netbooted kernel + USB rootfs
due to 4mb flash, 16mb RAM; doing bridging between arge0 and arge1.
Notes:
* Yes, I likely can also turn this on for the AR934x SoC family now.
But since hardware design apparently follows similar branching
strategies to software design, I'll go and make sure all the AR934x's
that made it out into shipping products work before I flip it on.
This was triggering when using it as an AP bridge rather than an ethernet
bridge.
The code is unclear but it works; I'll fix it to be clearer and test
performance at a later stage.
The existing code meets the "alignment" requirement for the l3 payload
by offsetting the mbuf by uint64_t and then calling an rx fixup routine
to copy the frame backwards by 2 bytes. This DWORD aligns the
L3 payload so tcp, etc doesn't panic on unaligned access.
This is .. slow.
For arge MACs that support 1 byte TX/RX address alignment, we can do
the "other" hack: offset the RX address of the mbuf so the L3 payload
again is hopefully DWORD aligned.
This is much cheaper - since TX/RX is both 1 byte align ready (thanks
to the previous commit) there's no bounce buffering going on and there
is no rx fixup copying.
This gets bridging performance up from 180mbit/sec -> 410mbit/sec.
There's around 10% of CPU cycles spent in _bus_dmamap_sync(); I'll
investigate that later.
Tested:
* QCA955x SoC (AP135 reference board), bridging arge0/arge1
by programming the switch to have two vlangroups in dot1q mode:
# ifconfig bridge0 inet 192.168.2.20/24
# etherswitchcfg config vlan_mode dot1q
# etherswitchcfg vlangroup0 members 0,1,2,3,4
# etherswitchcfg vlangroup1 vlan 2 members 5,6
# etherswitchcfg port5 pvid 2
# etherswitchcfg port6 pvid 2
# ifconfig arge1 up
# ifconfig bridge0 addm arge1
The early ethernet MACs (I think AR71xx and AR913x) require that both
TX and RX require 4-byte alignment for all packets.
The later MACs have started relaxing the requirements.
For now, the 1-byte TX and 1-byte RX alignment requirements are only for
the QCA955x SoCs. I'll add in the relaxed requirements as I review the
datasheets and do testing.
* Add a hardware flags field and 1-byte / 4-byte TX/RX alignment.
* .. defaulting to 4-byte TX and 4-byte RX alignment.
* Only enforce the TX alignment fixup if the hardware requires a 4-byte
TX alignment. This avoids a call to m_defrag().
* Add counters for various situations for further debugging.
* Set the 1-byte and 4-byte busdma alignment requirement when
the tag is created.
This improves the straight bridging performance from 130mbit/sec
to 180mbit/sec, purely by removing the need for TX path bounce buffers.
The main performance issue is the RX alignment requirement and any RX
bounce buffering that's occuring. (In a local test, removing the RX
fixup path and just aligning buffers raises the performance to above
400mbit/sec.
In theory it's a no-op for SoCs before the QCA955x.
Tested:
* QCA9558 SoC in AP135 board, using software bridging between arge0/arge1.
When the system has more than a single PCI domain, the bus numbers
are not unique, thus they cannot be used for "pci" device numbering.
Change bus numbers to -1 (i.e. to-be-determined automatically)
wherever the code did not care about domains.
Reviewed by: jhb
Obtained from: Semihalf
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D3406
and start teaching subsystems about it.
The Atheros MIPS platforms don't guarantee any kind of FIFO consistency
with interrupts in hardware. So software needs to do a flush when it
receives an interrupt and before it calls the interrupt handler.
There are new ones for the QCA934x and QCA955x, so do a few things:
* Get rid of the individual ones (for ethernet and IP2);
* Create a mux and enum listing all the variations on DDR flushes;
* replace the uses of IP2 with the relevant one (which will typically
be "PCI" here);
* call the USB DDR flush before calling the real USB interrupt handlers;
* call the ethernet one upon receiving an interrupt that's for us,
rather than never calling it during operation.
Tested:
* QCA9558 (TP-Link archer c7 v2)
* AR9331 (Carambola 2)
TODO:
* PCI, USB, ethernet, etc need to do a double-check to see if the
interrupt was truely for them before doing the DDR. For now I
prefer "correct" over "fast".
The QCA955x looks a lot like the AR724x PCIe controller, except it
supports two root complexes. Unfortunately I only have one, so
although this code has started down the path of supporting more than
one, it's definitely not yet ready.
Tested:
* AP135 board (QCA9558 SoC), with the 11ac NIC swapped for an AR9380
PCIe NIC.
Notes:
* Yes, this driver isn't very pretty. I decided to commit what I have
versus holding onto something that isn't yet finished. It is enough
to bring up the above NIC and interrupt routing works, so it's a good
start.
* However, yes, the DDR flush routine hooks need to be fixed up.
I don't think I'm firing the right one at the moment.
This is needed with the pl011 driver. Before this change it would default
to a shift of 0, however the hardware places the registers at 4-byte
addresses meaning the value should be 2.
This patch fixes this for the pl011 when configured using the fdt. The
other drivers have a default value of 0 to keep this a no-op.
MFC after: 1 week
A lot of these dinky atheros based MIPS boards don't have a nice, well,
anything consistent defining their MAC addresses for things.
The Atheros reference design boards will happily put MAC addresses
into the wifi module calibration data like they should, and individual
ethernet MAC addresses into the calibration area in flash.
That makes my life easy - "hint.arge.X.eeprommac=<addr>" reads from
that flash address to extract a MAC, and everything works fine.
However, aside from some very well behaved vendors (eg the Carambola 2
board), everyone else does something odd.
eg:
* a MAC address in the environment (eg ubiquiti routerstation/RSPRO)
that you derive arge0/arge1 MAC addresses from.
* a MAC address in flash that you derive arge0/arge1 MAC addresses from.
* The wifi devices having their own MAC addresses in calibration data,
like normal.
* The wifi devices having a fixed, default or garbage value for a MAC
address in calibration data, and it has to be derived from the
system MAC.
So to support this complete nonsense of a situation, there needs to be
a few hacks:
* The "board" MAC address needs to be derived from somewhere and squirreled
away. For now it's either redboot or a MAC address stored in calibration
flash.
* Then, a "map" set of hints to populate kenv with some MAC addresses
that are derived/local, based on the board address. Each board has
a totally different idea of what you do to derive things, so each
map entry has an "offset" (+ve or -ve) that's added to the board
MAC address.
* Then if_arge (and later, if_ath) should check kenv for said hint and
if it's found, use that rather than the EEPROM MAC address - which may
be totally garbage and not actually work right.
In order to do this, I've undone some of the custom redboot expecting
hacks in if_arge and the stuff that magically adds one to the MAC
address supplied by the board - instead, as I continue to test this
out on more hardware, I'll update the hints file with a map explaining
(a) where the board MAC should come from, and (b) what offsets to use
for each device.
The aim is to have all of the tplink, dlink and other random hardware
we run on have valid MAC addresses at boot, so (a) people don't get
random B:S:D❌x:x ethernet MACs, and (b) the wifi MAC is valid
so it works rather than trying to use an invalid address that
actually upsets systems (think: multicast bit set in BSSID.)
Tested:
* TP-Link TL_WDR3600 - subsequent commits will add the hints map
and the if_ath support.
TODO:
* Since this is -HEAD, and I'm all for debugging, there's a lot of
printf()s in here. They'll eventually go under bootverbose.
* I'd like to turn the macaddr routines into something available
to all drivers - too many places hand-roll random MAC addresses
and parser stuff. I'd rather it just be shared code.
However, that'll require more formal review.
* More boards.
The AR934x (and maybe others in this family) have a more complicated
GPIO mux. The AR71xx just has a single function register for a handful
of "GPIO or X" options, however the AR934x allows for one of roughly
100 behaviours for each GPIO pin.
So, this adds a quick hints based mechanism to configure the output
functions, which is required for some of the more interesting board
configurations. Specifically, some use external LNAs to improve
RX, and without the MUX/output configured right, the 2GHz RX side
will be plain terrible.
It doesn't yet configure the "input" side yet; I'll add that if
it's required.
Tested:
* TP-Link TL-WDR3600, testing 2GHz STA/AP modes, checking some
basic RX sensitivity things (ie, "can I see the AP on the other
side of the apartment that intentionally has poor signal reception
from where I am right now.")
Whilst here, fix a silly bug in the maxpin routine; I was missing
a break.
A lot of these embedded boards don't have a unique MAC address per
device stored somewhere unique - sometimes they'll have one MAC
for both arge NICs; someties they'll have one MAC for both arge NICs
/and/ the ath NICs. In these instances, we need to derive device
specific MAC addresses from the base MAC address.
These functions will be used by some follow-up code that'll slot
into if_arge and if_ath.
Otherwise, the initial media speed would change if a PHY is hooked up,
sending PHY speed notifications. For the AP135 at least, the RGMII
PHY has a static speed/duplex configured and if the PHY plumbing
attaches the PHY to the if_arge interface, the first link speed change
from 1000/full will set the MAC to something that isn't useful.
This shouldn't affect any other platforms - everything I looked at is
using hard-coded speed/duplex as static, as they're facing a switch
with no PHY attached.
There's two EHCI controllers in the QCA955x SoCs - they have different
interrupts available via various demux registers, but they both tie to
IP3.
So for now, allow them to be sharable so they can hang off of IP3.
There's a lot more to come - the QCA955x has a bunch more GPIO MUX
configuration, reminiscent of what the ARM chips let you do - but
it'll have to come later.
The QCA955x has more mux interrupts going on - and the AR934x actually does,
but I cheated and assigned wlan and pcie to the same interrupt line.
They are, there's just a status register mux that I should've been using.
Luckily this isn't too bad a change in itself - almost all of the
Atheros MIPS configurations use a _BASE file to inherit from.
Except PB92, which I should really fix up at some point.
The AR934x will use the legacy apb for now until I write its replacement.
The QCA955x SoC I'm doing bring-up on will have a separate qca955x_apb.c
implementation that includes hooking into IP2/IP3 and doing further
interrupt demuxing as appropriate.
APB mux.
It's larger than the AR71xx because it needs to replace the nexus
for some devices (notably wifi) and the wifi driver (if_ath_ahb.c)
reads the SPI data directly at early boot whilst it's memory mapped
in.
I'm eventually going to rip it out and replace it with a firmware
interface similar to what exists for the if_ath_pci.c path -
something early on (likely something new that I'll write) will
suck in the calibration data into a firmware API blob and that'll
be accessed from if_ath_ahb.c.
But, one thing at a time.
Tested:
* QCA955x SoC, AP135 development board
This adds the initial frequency poking and configures up enough
for it to boot and spit out data over the console.
There's still a whole bunch of work to do in the reset path
and devices to support this thing, but hey, it's alive!
ath> go 0x80050100
## Starting application at 0x80050100 ...
CPU platform: Atheros AR9558 rev 0
CPU Frequency=720 MHz
CPU DDR Frequency=600 MHz
CPU AHB Frequency=200 MHz
platform frequency: 720 MHz
CPU reference clock: 0 MHz
CPU MDIO clock: 40 MHz
Done at: hackathon
Obtained from: Linux OpenWRT, Qualcomm Atheros
There's likely a bunch of register offsets that I have to add the
register window base to before I use them.
Done at: Hackathon
Obtained from: Linux OpenWRT
The AR934x and later (which will turn up eventually) have a new GPIO
output configuration option - a real MUX rather than a "GPIO or this
function."
For now I'm squirreling it away in the CPU code just so it's done -
I may move this to the GPIO layer later.
Specifically, this is required for setting up some boards that have
external receive side LNA (low noise amplifier) that gets switched on/off
by the on-chip wireless MAC. If we don't add this support for those
boards then we'll end up with really poor performance.
(I don't yet have one of those APs, but it'll likely show up in a week.)
Obtained from: Linux OpenWRT
unit 0.
It seems that this 'simplification' was copied to all GPIO drivers in tree.
This fix a bug where a GPIO controller could fail to attach its children
(gpioc and gpiobus) if another GPIO driver attach first.
in userland rename in-kernel getenv()/setenv() to kern_setenv()/kern_getenv().
This fixes a namespace collision with libc symbols.
Submitted by: kmacy
Tested by: make universe
There's a bug in the AR7240 PCIe hardware where a correct BAR will end
up having the device disappear.
It turns out that for the device address it should be all 0's.
However, this meant that the PCI probe code would try writing 0xffffffff
in to see how big the window was, read back 0x0, and think the window
was 32 bits. It then ended up calculating a resource size of 0 bytes,
failed to find anything via an rman call, and this would fail to attach.
I have quite absolutely no idea how in the various planes of existence
this particular bit of code and how it worked with the PCI bus code
ever worked. But, well, it did.
Tested:
* Atheros AP93 - AR7240 + AR9280 reference board
It was doing incorrect things with masks. This was fixed in the
AR71xx codebase but it wasn't yet fixed in the AR724x code.
This ended up having config space reads return larger/incorrect values
in some situations.
Tested:
* AR7240
TODO:
* test ar7241, AR7242, and AR934x.
be able to claim I know how the UART code works."
* Just return 115200 as the current baud rate. I should cache it in the
device struct and return that but I'm lazy right now.
* don't error out on other ioctl settings for now, just silently ignore them.
* remove some code that was copied from the 8250 driver that isn't needed
any longer.
Tested:
* AR9331, Carambola-2 board.
handle packets up to 1536 bytes)
This fixes the need to frag that could happen when using vlans on top of
if_arge (which is a common case for the use the switch ports as individual
NICs).
Previously to this commit any vlan setup with if_arge as parent would have
the MTU of the parent interface reduced by the size of dot1q header
(4 bytes).
Tested on TP-Link 1043ND (where the WAN port is just a switch port setup to
tag packets in a different VLAN than the LAN ports).
Reported and tested by: Harm Weites (harm at weites.com)
In particular, don't check the value of the bus_dma map against NULL
to determine if either bus_dmamem_alloc() or bus_dmamap_load() succeeded.
Instead, assume that bus_dmamap_load() succeeeded (and thus that
bus_dmamap_unload() should be called) if the bus address for a resource
is non-zero, and assume that bus_dmamem_alloc() succeeded (and thus
that bus_dmamem_free() should be called) if the virtual address for a
resource is not NULL.
In many cases these bugs could result in leaks when a driver was detached.
Reviewed by: yongari
MFC after: 2 weeks
the GPIO pin is connected to a push button (or other devices).
Instead keep the boot loader settings.
Calling ar71xx_gpio_pin_configure() with DEFAULT_CAPS was probably a
mistake and was causing all the pins to be set as outputs.
at that time, but AFAIK it is only used on routerboards.
Enabling GPIO_FUNC_SPI_CS[1|2]_EN will claim the use of gpio pins 0 and 1
respectivelly for use as SPI CS pins.
When really needed, this can still be enabled on kernel hints using the
function_set and function_clear knobs.
chips have more.
So for now, let's allow more. We should teach the apb code to just
reject interrupts that lie outside what the chip can do at runtime.
later. If the interrupts are ACKed even if they're not masked, we get
the interrupts again later. Grr.
* The AR724x and later chips want the interrupt bits cleared by writing the
relevant bit to it, NOT by writing all but the current interrupt to it.
Tested:
* AR9344, DB120 reference board
TODO:
* Test ar724x and later chips to ensure no regressions have occured.
'eeprommac'.
The existing driver would just make arge units past 0 take the primary
MAC and increment it by the unit number, without correct address wrapping.
That has to be fixed at a later date.
Tested:
* Atheros DB120 reference obard
console, it calls the grab functions. These functions should turn off
the RX interrupts, and any others that interfere. This makes mountroot
prompt work again. If there's more generalized need other than
prompting, many of these routines should be expanded to do those new
things.
Reviewed by: bde (with reservations)
shifts into the sign bit. Instead use (1U << 31) which gets the
expected result.
This fix is not ideal as it assumes a 32 bit int, but does fix the issue
for most cases.
A similar change was made in OpenBSD.
Discussed with: -arch, rdivacky
Reviewed by: cperciva
return BUS_PROBE_NOWILDCARD from their probe routines to avoid claiming
wildcard devices on their parent bus. Do a sweep through the MIPS tree.
MFC after: 2 weeks
The MDIO bus frequency is configured as a divisor off of the MDIO bus
reference clock. For the AR9344 and later, the MDIO bus frequency can
be faster than normal (ie, up to 100MHz) and thus a static divisor may
not be very applicable.
So, for those boards that may require an actual frequency to be selected
regardless of what crazy stuff the vendor throws in uboot, one can now
set the MDIO bus frequency. It uses the MDIO frequency and the target
frequency to choose a divisor that doesn't exceed the target frequency.
By default it will choose:
* DIV_28 on everything; except
* DIV_58 on the AR9344 to be conservative.
Whilst I'm here, add some comments about the defaults being not quite
right. For the other internal switch devices (like the AR933x, AR724x)
the divisor can be higher - it's internal and the reference MDIO clock
is much lower than 100MHz.
The divisor tables and loop code is inspired from Linux/OpenWRT. It's very
simple; I didn't feel that reimplementing it would yield a substantially
different solution.
Tested:
* AR9331 (mips24k)
* AR9344 (mips74k)
Obtained from: Linux/OpenWRT
up and running.
* The MAC FIFO configurations needed updating;
* Reset the MDIO block at the same time the MAC block is reset;
* The default divisor needs changing as the DB120 runs at a higher
base MDIO bus clock compared to other chips.
The long-term fix is to allow the system to have a target MDIO bus
clock rate and then calculate the most suitable divider to meet
that. This will likely need implementing before stable external
PHY or switch support can be committed.
Tested:
* AR9344 (mips74k)
* AR9331 (mips24k)
