Applied to u-boot-marvell/master

Thanks,
Stefan


On 26.04.22 00:01, Tony Dinh wrote:
Hi Stefan,
On Mon, Apr 25, 2022 at 4:18 AM Stefan Roese <s...@denx.de> wrote:

Hi Tony,

On 4/25/22 11:33, Tony Dinh wrote:
Hi Stefan,

On Sun, Apr 24, 2022 at 11:00 PM Stefan Roese <s...@denx.de> wrote:

Hi Tony,

On 4/23/22 04:15, Tony Dinh wrote:
Hi Stefan,

Please see my various comments below. And my thoughts at the end.

On Thu, Apr 21, 2022 at 11:15 PM Stefan Roese <s...@denx.de> wrote:

Hi Tony,

On 4/21/22 23:21, Tony Dinh wrote:

<snip>

What really puzzles me is, why the page address is set to a non-zero
value at all at this early boot stage? Could you perhaps add some
debugging code, to check, if and where the page address gets set?
I find it hard to belief, that this starts with non-zero after
powering up the device / PHY.

Or did I miss something?

Other Kirkwood boards behave correctly (such as the Sheevaplug,
Dreamplug, and Dell Kace M300). The Page Select register (22) contains
0 in these boards, and all have PHY id 1410e90.  The NSA310s also has
PHY id 1410e90.

Yes. I'm pretty sure that the page select register is set to 0 upon
PHY startup. Even though there might be some strapping possibilities
to configure some PHY registers, the page select is most likely always
0 after power-up. So if nobody writes to this reg, then is should be 0.

Agree. All other Kirkwood boards execute the same code so I think we
would see if somebody writes to this register.

But I could not find in the uclass MVGBE where the Page Select
register is set before phy_connect is called. So my guess is that
memory location just happens to be zero in other boards but not in
this NSA310S board. Perhaps the memory location needs to be set to
zero, to make sure all registers point to page 0 in the beginning.

Please see above.

Possibly, it is here that the Page Select register should be zero out
after the priv data is copied:  dev_get_priv(). mvgbe_of_to_plat() is
called very early on (during the uclass MVGBE creation).

static int mvgbe_of_to_plat(struct udevice *dev)
{
struct eth_pdata *pdata = dev_get_plat(dev);
struct mvgbe_device *dmvgbe = dev_get_priv(dev);

Possibly. Again my suggestion is to add some debug code to check at
different boot times, which value is currently set in the page select
register. By just reading is out and printing it's value. You might need
to add some "special code" at the early code paths, as the MDIO driver
is not started there.

Another idea is, if it's possible to issue a HW-reset to the PHY on the
NSA310 board. Do you know if some GPIO is connected to the PHY's reset
pin which could be toggled by the SoC?

I don't think there is a GPIO that does. I looked at the GPL source
code for this board from way back, and created the DTS for this based
on info in that GPL source. I don't recall that it was available.

Note: We could of course just add the reset to 0 as you have done in the
MAC driver or some board specific code. But I really would like to
understand why the page select reg is non-zero in this case.

My conclusion is the register was polluted by something in the board
hardware. This is the comments (paraphrase)  we got from this board
GPL source:
           /* The ZyXEL NSA310S uses the 88E1310S Alaska (interface
identical to 88E1318) */
           /* and has an MCU attached to the LED[2] via tristate interrupt */

I've rebuilt and rerun the tests for both the Sheevaplug and NSA310S.
Please see the debug log from mvgbe_probe. This is as early as we can
see the uclass initializing.

==== NSA310S boot log
U-Boot 2022.04-00569-gca51a8dc04-dirty (Apr 22 2022 - 16:49:50 -0700)
ZyXEL NSA310S/320S 1/2-Bay Power Media Server

SoC:   Kirkwood 88F6281_A1
DRAM:  256 MiB
Core:  7 devices, 5 uclasses, devicetree: separate
NAND:  128 MiB
Loading Environment from NAND... OK
In:    serial
Out:   serial
Err:   serial

Net:   mvgbe_of_to_plat called
mvgbe_of_to_plat phy-mode 7
mvgbe_of_to_plat phy addr 1
mvgbe_probe called
smi_reg_read: phy_addr 1 reg_ofs 22 devad  -1
__mvgbe_mdio_read:(adr 1, off 22) value= 0011
eth0: ethernet-controller@72000
Hit any key to stop autoboot:  0

===== Sheevaplug boot log

U-Boot 2022.04-00569-gca51a8dc04-dirty (Apr 22 2022 - 18:16:25 -0700)
Marvell-Sheevaplug

SoC:   Kirkwood 88F6281_A1
DRAM:  512 MiB
Core:  9 devices, 7 uclasses, devicetree: separate
NAND:  512 MiB
MMC:   mvsdio@90000: 0
Loading Environment from NAND... OK
In:    serial
Out:   serial
Err:   serial

Net:   mvgbe_of_to_plat called
mvgbe_of_to_plat phy-mode 1
mvgbe_of_to_plat phy addr 0
mvgbe_probe called
smi_reg_read: phy_addr 0 reg_ofs 22 devad  -1
__mvgbe_mdio_read:(adr 0, off 22) value= 0000
eth0: ethernet-controller@72000
Hit any key to stop autoboot:  0

Still very strange. Perhaps really some HW pin strapping responsible
for this difference?

It could be. The Zyxel Kirkwood NAS series NSA310s, 320, and 325 all
behave like this. The Sheevaplug and Dreamplug don't have this
behavior, while using the same network chip (I've confirmed that the
detected PHY id is the same, it is 1410e90).


========

My thoughts:

I think we probably need to refactor some constants in the uclass
drivers/net/mvgbe.c and/or create a helper in  the Marvell PHY driver
drivers/net/phy/marvell.c.

The mvgbe uclass is a generic Ethernet class for all Kirkwood and
Orion-5x boards (CONFIG_ARCH_KIRKWOOD and CONFIG_ARCH_ORION5X).
However, as of right now, it lacks knowledge about specific things
such as the PHY Page Select register for a specific network chip.

Yes. And the MAC driver should not know anything about any PHY
specific registers IMHO, such as PHY page or whatever. This needs
to be done in the PHY driver instead.

Those constants are defined only in drivers/net/phy/marvell.c. For
example,

#define MII_MARVELL_PHY_PAGE            22
#define MIIM_88E1121_PHY_PAGE           22
#define MIIM_88E1145_PHY_PAGE   29
#define MIIM_88E1310_PHY_PAGE           22

When the mvgbe uclass calls mvgbe_of_to_plat() during initialization,
it extracts several parameters from the DTS, such as PHY address, but
has no way to "reset" PHY page in a general way so it will work for
all network chips used in Kirkwood and Orion-5x boards.

I think my hack to reset the PHY page to 0 would not work for the
88E1145 chip as seen above. But none of the Kirkwood boards uses this
chip, AFAIK.

What do you think? Would the patch be OK as is, or perhaps we need to
add a helper to drivers/net/phy/marvell.c to get the PHY Page Select
register? or perhaps you have other thoughts about the solution!

One more question: I know that currently phy_connect() does not work on
this board, since the PHY page register is non-zero. Is the PHY not
detected in this case (PHY ID matching etc)?

Right, the phy_find_by_mask() in phy.c failed to create the PHY, since
it cannot match with anything.

Too bad. Newer PHYs seem to mirror the PHY ID registers on all pages,
so at least identifying does work there, regardless of the configured
PHY page address. The 88e1310 seems to be inferior here unfortunately.

Note that it is the cold start that
failed. During a warm start, the PHY is always found as an existing
PHY (if the network is working already in the kernel, and a warm
reboot is executed).

Here is the log for the failure to create PHY:

phy.c phy_connect:
phy.c phy_find_by_mask 2
phy.c get_phy_device_by_mask: mask: 0x2
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  -1
__mvgbe_mdio_read:(adr 1, off 2) value= 0000
smi_reg_read: phy_addr 1 reg_ofs 3 devad  -1
__mvgbe_mdio_read:(adr 1, off 3) value= 0000
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  1
__mvgbe_mdio_read:(adr 1, off 2) value= 0000
smi_reg_read: phy_addr 1 reg_ofs 3 devad  1
__mvgbe_mdio_read:(adr 1, off 3) value= 0000
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  2
__mvgbe_mdio_read:(adr 1, off 2) value= 0000
smi_reg_read: phy_addr 1 reg_ofs 3 devad  2
__mvgbe_mdio_read:(adr 1, off 3) value= 0000
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  3
__mvgbe_mdio_read:(adr 1, off 2) value= 0000
smi_reg_read: phy_addr 1 reg_ofs 3 devad  3
__mvgbe_mdio_read:(adr 1, off 3) value= 0000
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  4
__mvgbe_mdio_read:(adr 1, off 2) value= 0000
smi_reg_read: phy_addr 1 reg_ofs 3 devad  4
__mvgbe_mdio_read:(adr 1, off 3) value= 0000
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  30
__mvgbe_mdio_read:(adr 1, off 2) value= 0000
smi_reg_read: phy_addr 1 reg_ofs 3 devad  30
__mvgbe_mdio_read:(adr 1, off 3) value= 0000
phy.c get_phy_device_by_mask: not found and could not create PHY for
ethernet-controller@72000
Could not get PHY for ethernet-controller@72000: addr 1
phy_connect failed
ping failed; host 192.168.0.224 is not alive

While in the successful case the log is like this:

phy.c phy_connect:
phy.c phy_find_by_mask 2
phy.c get_phy_device_by_mask: mask: 0x2
create_phy_by_mask phy mask 0x2
smi_reg_read: phy_addr 1 reg_ofs 2 devad  -1
__mvgbe_mdio_read:(adr 1, off 2) value= 0141
smi_reg_read: phy_addr 1 reg_ofs 3 devad  -1
__mvgbe_mdio_read:(adr 1, off 3) value= 0e90
phy.c phy_device_create phy_id 21040784
phy.c get_phy_driver PHY driver found - PHY id 1410e90


Did you try calling miiphy_reset() directly before calling phy_connect?
Like this:

          /* Set phy address of the port */
          miiphy_write(dev->name, MV_PHY_ADR_REQUEST, MV_PHY_ADR_REQUEST,
                       phyid);

+       /* Soft-reset the PHY, especially needed on the NSA310s */
+       miiphy_reset(dev->name, phyid);
+
          phydev = phy_connect(bus, phyid, dev, phy_interface);
          if (!phydev) {
                  printf("phy_connect failed\n");
                  return NULL;
          }

Does this work? Might be I missed something.

No, it did not work. I've mentioned previously that I tried this
miiphy_reset at this location, and the board just hung. I needed to
recycle the power to reboot. I also tried the soft reset (phy_reset)
and it also hung.

Thanks for clarifying.

If this still does not work then yes, we might need some generic PHY
page reset function. BTW, I introduced a marvell_write_page() function
with this patch, which is still pending:

https://www.mail-archive.com/u-boot@lists.denx.de/msg436238.html

Oh. I already tried this patch and have not mentioned that to you yet.
This reg-init occurs too late in the execution path (in Marvel PHY
driver config function). It would have been possibly a great solution
to set up the register 22 earlier for this problem.

While I think you're absolutely right above about the MAC driver being
separated from the PHY driver, I think there is probably a need for
some additional PHY initialization when necessary. Currently, very
early on, we have several phy_register calls to register all the
Marvell drivers in phy_marvell_init(), but that's the only thing it
does.

I think we might be lacking a small but necessary glue between the
generic PHY driver (phy.c), mvgbe uclass, and the Marvell PHY driver.

That might very well be the case. Perhaps one of the net custodians
whats to chime in. Joe, Ramon?

I still need to re-work this a bit.

And also I just noticed that the Kernel has a .write_page PHY function
and exports this via the common function phy_select_page().

Cool! sounds like something promising.

Yes, a very handy addition. Still, somebody needs to work on this and
also make sure, that this "page access" support does not bloat the image
size on all platforms, not in need of this "feature".

I also thought of another approach we can take is to have a weak
function in the mvgbe.c like,
__weak void __mvgbe_board_eth_init(const char *name, int phyaddr) {}
The mvgbe uclass can call it at the end of __mvgbe_init(). And this
NSA310S board file can define the concrete function to set the PHY
page.

This is definitely easier than the generic approach envisioned above.
But there weak functions do not scale well. Frankly, I tend a just go
with your current approach with setting the PHY page address in this
MAC driver and be done with it. One reason being, that this driver is
pretty outdated and we will very unlikely see many other new Kirwood
and/or Orion SoC based boards come up in the U-Boot source tree that
need support non-Marvell PHYs. I'm not totally happy with this version
but perhaps it's just "good enough" for these platforms at this stage.

Comment welcome.

I think so too. It is good enough for old boards like the Kirkwood
SoCs. Not likely we will see these boards with non-Marvell PHYs. We
can go with this version to set the PHY page in this MAC driver.

When you have the marvell_write_page function already in the tree and
exported in the header file, I could try that, too. It's all academic,
but I think it will make it a bit better, because the info about the
page register (MII_MARVELL_PHY_PAGE) is encapsulated in marvell.c.

Thanks,
Tony


But this weak-function approach is too much a cop-out. If we can solve
this nicely within the current design it would be much better.

Agreed.

Thanks,
Stefan

Viele Grüße,
Stefan Roese

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