[PATCH 8/8] arm64: dts: hikey: Fix WiFi support

On 6 June 2017 at 12:08, Ulf Hansson [off-list ref] wrote:

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John, thanks for the report!

After a some investigation, I realized that the mmc pwrseq_simple
driver returns -EPROBE_DEFER as it's not able to get the "ext" clock.
Hence the SDIO card will not be detected.

To fix the problem, you need to enable CONFIG_COMMON_CLK_HI655X in the
kernel config. This is actually also the case when using the arm64
defconfig for a plain 4.12 rc3 and later. We should probably make this
driver enabled per default when building the arm64 defconfig.

Can you run a re-test at your side with the CONFIG_COMMON_CLK_HI655X
set? Just to make sure it works also with those boot binaries you are
using...

So unfortunately, now I'm seeing a side-effect from enabling
CONFIG_COMMON_CLK_HI655X.

Using the serial-dev driver for the TI bluetooth, it seems I'm seeing
failures when CONFIG_COMMON_CLK_HI655X is enabled, but configuring it
out, bluetooth works (and wifi then fails).

Looking through the dmesg logs, the bluetooth driver seems to
initialize up properly and load the firmware, but with CLK_HI655X
enabled, we see:

Bluetooth: hci0 command 0xff05 tx timeout
Bluetooth: hci0: send command failed\x0a
Bluetooth: hci0 command 0xff36 tx timeout
Bluetooth: hci0 command 0x1003 tx timeout
Bluetooth: hci0 command 0x1001 tx timeout
Bluetooth: hci0 command 0x1009 tx timeout
...

As Rob said below, this is because the blue-tooth driver doesn't
properly deal with the power on/off sequence.

I guess it works for you because your versions of the boot binaries
turns all needed resources on. That isn't the case for me, blue-tooth
is neither working before or after this change, but wifi is.

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This effectively seems to make bluetooth an wifi functionality
exclusive.  So I don't think this is a sufficient solution (over
reverting the original patch that changes the dts - which allows both
to function).

Since the issues you are reporting about is depending on the
boot-binaries and not a really bugs in the kernel, may I suggest that
we invest our efforts in fixing the blue-tooth driver instead, as it's
there the real problem is!?

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If the clock to the TI chip is described in DT for WiFi, then the BT
side needs it as well (as does the driver) for proper refcounting. The
same would apply to regulators as well. I looked at the regulators for
HiKey and the 2 supplies (Vbat and i/o) appear to both be always on.

Rob

Correct.

I am working on patch, I keep you on cc.

Rob, John,

I have now looked into this a bit more. So I have some local patches,
which in principle adds the external clock to the bluetooth node for
the hikey dts, and adapts the uart bluetooth driver
(drivers/bluetooth/hci_ll.c) to also take the ext clock into
consideration while powering on/off the chip. I am working on a
vanilla kernel, thus not John's tree.

However, I can't get the uart1 amba device to be added because of this
error during boot:
"OF: amba_device_add() failed (-19) for /soc/uart at f7111000"

The reason why it fails is because amba_device_try_add() fails to read
the amba periphid of the uart1 device. I haven't yet been able to
figure out why.

Is this problem something you have seen before? I tried out v4.11,
v4.12-rc3 and John's tree (dev/hikey-mainline-WIP which is based upon
4.12.rc3), they all suffer from the same problem, not being able to
add the uart1 device.

The consequence then becomes that the bluetooth node (which is a child
node for the uart1 node), added in the below commit by Rob, never gets
parsed and thus the device don't become added. In other words, I
haven't been able to test my changes since I can't even get the
bluetooth device to be added.

John, are you using the pcm bluetooth interface or the uart?

commit 019aa56b7df8a796b2c01a56269a370ad3442ec7
Author: Rob Herring [off-list ref]
Date:   Thu Apr 13 10:03:53 2017 -0500

    arm64: dts: hikey: add WL1835 Bluetooth device node

    This adds the serial slave device for the WL1835 Bluetooth interface.

    Signed-off-by: Rob Herring [off-list ref]
    Cc: Wei Xu [off-list ref]
    Cc: Mark Rutland [off-list ref]
    Signed-off-by: Marcel Holtmann [off-list ref]

Kind regards
Uffe