From: Felipe Balbi <balbi@kernel.org>
To: Li Jun <jun.li@nxp.com>
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
john.stultz@linaro.org, chenyu56@huawei.com
Subject: Re: [PATCH] usb: dwc3: use readl_poll_timeout_atomic for register polling
Date: Fri, 08 May 2020 15:36:56 +0300 [thread overview]
Message-ID: <87blmymwlz.fsf@kernel.org> (raw)
In-Reply-To: <1588928985-1585-1-git-send-email-jun.li@nxp.com>
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Hi,
Li Jun <jun.li@nxp.com> writes:
> Introduce dwc3_read_poll_timeout_atomic for register polling to
> simplify code, this way we use time(us) instead of register read
> iteration counter to wait register value change, this is also to
> resolve one ep command timeout issue found on imx8M, Chen Yu also
> encoutered this problem on his Hisilicon Kirin Soc[1], on imx8M,
> some ep command need more time to complete when SS PHY is at P3
> because suspend_clk(32K) is used, trace shows it takes about 400us
> to complete, see below trace(44.286278 - 44.285897 = 0.000381):
>
> configfs_acm.sh-822 [000] d..1 44.285896: dwc3_writel: addr
> 000000006d59aae1 value 00000401
> configfs_acm.sh-822 [000] d..1 44.285897: dwc3_readl: addr
> 000000006d59aae1 value 00000401
> ... ...
> configfs_acm.sh-822 [000] d..1 44.286278: dwc3_readl: addr
> 000000006d59aae1 value 00000001
> configfs_acm.sh-822 [000] d..1 44.286279: dwc3_gadget_ep_cmd:
> ep0out: cmd 'Set Endpoint Configuration' [401] params 00001000
> 00000500 00000000 --> status: Successful
>
> So set timeout to be 500us for dwc3_send_gadget_ep_cmd().
>
> [1] https://lkml.org/lkml/2019/9/25/754
>
> Signed-off-by: Li Jun <jun.li@nxp.com>
Let's fix the original bug first. This patch is likely to need changes
after that ;-)
--
balbi
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prev parent reply other threads:[~2020-05-08 12:37 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-08 9:09 [PATCH] usb: dwc3: use readl_poll_timeout_atomic for register polling Li Jun
2020-05-08 12:36 ` Felipe Balbi [this message]
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