linux-kernel - Re: [PATCH] usb: host: xhci: mvebu: make USB 3.0 PHY optional for Armada 3720

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Date:   Sat, 30 Jan 2021 17:31:41 +0100
From:   Tomasz Maciej Nowak <tmn505@...il.com>
To:     Pali Rohár <pali@...nel.org>,
        Mathias Nyman <mathias.nyman@...el.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Gregory CLEMENT <gregory.clement@...tlin.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     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 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>

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