Date:   Sat, 30 Jan 2021 17:37:13 +0100
From:   Tomasz Maciej Nowak <tmn505@...il.com>
To:     Pali Rohár <pali@...nel.org>
Cc:     Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Gregory CLEMENT <gregory.clement@...tlin.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Peter Chen <peter.chen@....com>
Subject: Re: [PATCH] usb: host: xhci: mvebu: make USB 3.0 PHY optional for
 Armada 3720

W dniu 30.01.2021 o 17:35, Pali Rohár pisze:
> On Saturday 30 January 2021 17:31:41 Tomasz Maciej Nowak wrote:
>> W dniu 23.12.2020 o 17:24, Pali Rohár pisze:
>>> Older ATF does not provide SMC call for USB 3.0 phy power on functionality
>>> and therefore initialization of xhci-hcd is failing when older version of
>>> ATF is used. In this case phy_power_on() function returns -EOPNOTSUPP.
>>>
>>> [    3.108467] mvebu-a3700-comphy d0018300.phy: unsupported SMC call, try updating your firmware
>>> [    3.117250] phy phy-d0018300.phy.0: phy poweron failed --> -95
>>> [    3.123465] xhci-hcd: probe of d0058000.usb failed with error -95
>>>
>>> This patch calls phy_power_on() in xhci_mvebu_a3700_init_quirk() function
>>> and in case it returns -EOPNOTSUPP then XHCI_SKIP_PHY_INIT quirk is set to
>>> instruct xhci-plat to skip PHY initialization.
>>>
>>> This patch fixes above failure by ignoring 'not supported' error in
>>> aardvark driver. In this case it is expected that phy is already power on.
>>>
>>> It fixes initialization of xhci-hcd on Espressobin boards where is older
>>> Marvell's Arm Trusted Firmware without SMC call for USB 3.0 phy power.
>>>
>>> This is regression introduced in commit bd3d25b07342 ("arm64: dts: marvell:
>>> armada-37xx: link USB hosts with their PHYs") where USB 3.0 phy was defined
>>> and therefore xhci-hcd on Espressobin with older ATF started failing.
>>>
>>> Fixes: bd3d25b07342 ("arm64: dts: marvell: armada-37xx: link USB hosts with their PHYs")
>>> Signed-off-by: Pali Rohár <pali@...nel.org>
>>> Cc: <stable@...r.kernel.org> # 5.1+: ea17a0f153af: phy: marvell: comphy: Convert internal SMCC firmware return codes to errno
>>> Cc: <stable@...r.kernel.org> # 5.1+: f768e718911e: usb: host: xhci-plat: add priv quirk for skip PHY initialization
>>>
>>> ---
>>>
>>> When applying this patch, please include additional line
>>>
>>> Cc: <stable@...r.kernel.org> # 5.1+: <COMMIT_ID>: usb: host: xhci-plat: fix support for XHCI_SKIP_PHY_INIT quirk
>>>
>>> with correct COMMIT_ID of mentioned patch which is available in the thread:
>>
>> Hi,
>> and sorry for late reply, but that might be good reminder for maintainers.
>> Anyway I tested this patch in conjunction with v2 from this topic:
>>> https://lore.kernel.org/lkml/20201221150903.26630-1-pali@kernel.org/T/#u
>> The USB ports work flawlessly with older ATF, so:
>>
>> Tested-by: Tomasz Maciej Nowak <tmn505@...il.com>
> 
> Thank you for testing. But as was mentioned in discussion in above
> patch, I have to rework both patches. I have new changes prepared but
> have not had a chance to test new changes yet. If you want I can send
> you a new version of those untested patches.

Yes, will gladly test them.

> 
>> At OpenWrt we are using patch which removes Comphy assignments from nodes
>> in dts, but that is sub optimal, since that "discriminates" users with
>> updated ATF. I would prefer this patch instead of what we are doing now
>> in OpenWrt.
>>
>> Thanks.
>>
>>>
>>> As mentioned patch is required for change in this patch to work. Above
>>> mentioned patch is prerequisite for this patch and therefore needs to be
>>> reviewed and applied prior this patch.
>>>
>>> Note that same issue as in this USB 3.0 PHY patch was already resolved and
>>> applied also for SATA PHY and PCIe PHY on A3720 SOC in following commits:
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=45aefe3d2251e4e229d7662052739f96ad1d08d9
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b0c6ae0f8948a2be6bf4e8b4bbab9ca1343289b6
>>>
>>> And these commits were also backported to stable kernel versions (where
>>> were affected commits which broke drivers initialization).
>>> ---
>>>  drivers/usb/host/xhci-mvebu.c | 35 +++++++++++++++++++++++++++++++++++
>>>  1 file changed, 35 insertions(+)
>>>
>>> diff --git a/drivers/usb/host/xhci-mvebu.c b/drivers/usb/host/xhci-mvebu.c
>>> index 60651a50770f..ec4f6d6e44cf 100644
>>> --- a/drivers/usb/host/xhci-mvebu.c
>>> +++ b/drivers/usb/host/xhci-mvebu.c
>>> @@ -8,6 +8,7 @@
>>>  #include <linux/mbus.h>
>>>  #include <linux/of.h>
>>>  #include <linux/platform_device.h>
>>> +#include <linux/phy/phy.h>
>>>  
>>>  #include <linux/usb.h>
>>>  #include <linux/usb/hcd.h>
>>> @@ -77,9 +78,43 @@ int xhci_mvebu_mbus_init_quirk(struct usb_hcd *hcd)
>>>  int xhci_mvebu_a3700_init_quirk(struct usb_hcd *hcd)
>>>  {
>>>  	struct xhci_hcd	*xhci = hcd_to_xhci(hcd);
>>> +	struct device *dev = hcd->self.controller;
>>> +	struct phy *phy;
>>> +	int ret;
>>>  
>>>  	/* Without reset on resume, the HC won't work at all */
>>>  	xhci->quirks |= XHCI_RESET_ON_RESUME;
>>>  
>>> +	/* Old bindings miss the PHY handle */
>>> +	phy = of_phy_get(dev->of_node, "usb3-phy");
>>> +	if (IS_ERR(phy) && PTR_ERR(phy) == -EPROBE_DEFER)
>>> +		return -EPROBE_DEFER;
>>> +	else if (IS_ERR(phy))
>>> +		goto phy_out;
>>> +
>>> +	ret = phy_init(phy);
>>> +	if (ret)
>>> +		goto phy_put;
>>> +
>>> +	ret = phy_set_mode(phy, PHY_MODE_USB_HOST_SS);
>>> +	if (ret)
>>> +		goto phy_exit;
>>> +
>>> +	ret = phy_power_on(phy);
>>> +	if (ret == -EOPNOTSUPP) {
>>> +		/* Skip initializatin of XHCI PHY when it is unsupported by firmware */
>>> +		dev_warn(dev, "PHY unsupported by firmware\n");
>>> +		xhci->quirks |= XHCI_SKIP_PHY_INIT;
>>> +	}
>>> +	if (ret)
>>> +		goto phy_exit;
>>> +
>>> +	phy_power_off(phy);
>>> +phy_exit:
>>> +	phy_exit(phy);
>>> +phy_put:
>>> +	of_phy_put(phy);
>>> +phy_out:
>>> +
>>>  	return 0;
>>>  }
>>>
>>
>> -- 
>> TMN


-- 
TMN

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