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Date: Thu, 15 Feb 2024 14:35:13 +0100
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Subject: Re: [PATCH] PCI: dwc: Use the correct sleep function in wait_for_link
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To: Konrad Dybcio <konrad.dybcio@linaro.org>
CC: Jingoo Han <jingoohan1@gmail.com>, Gustavo Pimentel
	<gustavo.pimentel@synopsys.com>, Manivannan Sadhasivam
	<manivannan.sadhasivam@linaro.org>, Lorenzo Pieralisi
	<lpieralisi@kernel.org>, =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?=
	<kw@linux.com>, Rob Herring <robh@kernel.org>, Bjorn Helgaas
	<bhelgaas@google.com>, Marijn Suijten <marijn.suijten@somainline.org>,
	<linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>, Johan Hovold
	<johan+linaro@kernel.org>
References: <20240215-topic-pci_sleep-v1-1-7ac79ac9739a@linaro.org>
From: Alexander Lobakin <aleksander.lobakin@intel.com>
In-Reply-To: <20240215-topic-pci_sleep-v1-1-7ac79ac9739a@linaro.org>
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From: Konrad Dybcio <konrad.dybcio@linaro.org>
Date: Thu, 15 Feb 2024 11:39:31 +0100

> According to [1], msleep should be used for large sleeps, such as the
> 100-ish ms one in this function. Comply with the guide and use it.
> 
> [1] https://www.kernel.org/doc/Documentation/timers/timers-howto.txt
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
> ---
> Tested on Qualcomm SC8280XP CRD
> ---
>  drivers/pci/controller/dwc/pcie-designware.c | 2 +-
>  drivers/pci/controller/dwc/pcie-designware.h | 3 +--
>  2 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
> index 250cf7f40b85..abce6afceb91 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.c
> +++ b/drivers/pci/controller/dwc/pcie-designware.c
> @@ -655,7 +655,7 @@ int dw_pcie_wait_for_link(struct dw_pcie *pci)
>  		if (dw_pcie_link_up(pci))
>  			break;
>  
> -		usleep_range(LINK_WAIT_USLEEP_MIN, LINK_WAIT_USLEEP_MAX);
> +		msleep(LINK_WAIT_MSLEEP_MAX);

Just use fsleep(LINK_WAIT_USLEEP_MAX) and let the kernel decide which
function to pick.

>  	}
>  
>  	if (retries >= LINK_WAIT_MAX_RETRIES) {
> diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
> index 26dae4837462..3f145d6a8a31 100644
> --- a/drivers/pci/controller/dwc/pcie-designware.h
> +++ b/drivers/pci/controller/dwc/pcie-designware.h
> @@ -63,8 +63,7 @@
>  
>  /* Parameters for the waiting for link up routine */
>  #define LINK_WAIT_MAX_RETRIES		10
> -#define LINK_WAIT_USLEEP_MIN		90000
> -#define LINK_WAIT_USLEEP_MAX		100000
> +#define LINK_WAIT_MSLEEP_MAX		100
>  
>  /* Parameters for the waiting for iATU enabled routine */
>  #define LINK_WAIT_MAX_IATU_RETRIES	5
> 
> ---
> base-commit: 26d7d52b6253574d5b6fec16a93e1110d1489cef
> change-id: 20240215-topic-pci_sleep-368108a1fb6f
> 
> Best regards,

Thanks,
Olek