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Message-ID: <3492e396-e693-83eb-2d85-bb29fc014caf@quicinc.com>
Date:   Wed, 3 May 2023 09:19:13 +0530
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Subject: Re: [PATCH v7 4/9] usb: dwc3: core: Skip setting event buffers for
 host only controllers
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To:     Thinh Nguyen <Thinh.Nguyen@synopsys.com>
CC:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Felipe Balbi <balbi@kernel.org>,
        "Wesley Cheng" <quic_wcheng@quicinc.com>,
        "linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "quic_pkondeti@quicinc.com" <quic_pkondeti@quicinc.com>,
        "quic_ppratap@quicinc.com" <quic_ppratap@quicinc.com>,
        "quic_jackp@quicinc.com" <quic_jackp@quicinc.com>,
        "quic_harshq@quicinc.com" <quic_harshq@quicinc.com>,
        "ahalaney@redhat.com" <ahalaney@redhat.com>,
        "quic_shazhuss@quicinc.com" <quic_shazhuss@quicinc.com>
References: <20230501143445.3851-1-quic_kriskura@quicinc.com>
 <20230501143445.3851-5-quic_kriskura@quicinc.com>
 <20230502214419.rzybyuozzvslinwe@synopsys.com>
From:   Krishna Kurapati PSSNV <quic_kriskura@quicinc.com>
In-Reply-To: <20230502214419.rzybyuozzvslinwe@synopsys.com>
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On 5/3/2023 3:14 AM, Thinh Nguyen wrote:
> On Mon, May 01, 2023, Krishna Kurapati wrote:
>> On some SoC's like SA8295P where the tertiary controller is host-only
>> capable, GEVTADDRHI/LO, GEVTSIZ, GEVTCOUNT registers are not accessible.
>> Trying to setup them up during core_init leads to a crash.
>>
>> For DRD/Peripheral supported controllers, event buffer setup is done
>> again in gadget_pullup. Skip setup or cleanup of event buffers if
>> controller is host-only capable.
>>
>> Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
>> ---
>>   drivers/usb/dwc3/core.c | 22 ++++++++++++++++------
>>   1 file changed, 16 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
>> index b8ac7bcee391..8625fc5c7ab4 100644
>> --- a/drivers/usb/dwc3/core.c
>> +++ b/drivers/usb/dwc3/core.c
>> @@ -835,7 +835,12 @@ static void dwc3_clk_disable(struct dwc3 *dwc)
>>   
>>   static void dwc3_core_exit(struct dwc3 *dwc)
>>   {
>> -	dwc3_event_buffers_cleanup(dwc);
>> +	unsigned int	hw_mode;
>> +
>> +	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
>> +	if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST)
>> +		dwc3_event_buffers_cleanup(dwc);
> 
> I think it's cleaner to do these checks in dwc3_event_buffers_cleanup
> and dwc3_event_buffers_setup.
> 
> Thanks,
> Thinh
> 

Hi Thinh,

  Good point. Will move these checks to respective functions in next 
version. Thanks for pointing it out.

Regards,
Krishna,
>> +
>>   	dwc3_phy_power_off(dwc);
>>   	dwc3_phy_exit(dwc);
>>   	dwc3_clk_disable(dwc);
>> @@ -1141,10 +1146,12 @@ static int dwc3_core_init(struct dwc3 *dwc)
>>   	if (ret)
>>   		goto err_exit_phy;
>>   
>> -	ret = dwc3_event_buffers_setup(dwc);
>> -	if (ret) {
>> -		dev_err(dwc->dev, "failed to setup event buffers\n");
>> -		goto err_power_off_phy;
>> +	if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST) {
>> +		ret = dwc3_event_buffers_setup(dwc);
>> +		if (ret) {
>> +			dev_err(dwc->dev, "failed to setup event buffers\n");
>> +			goto err_power_off_phy;
>> +		}
>>   	}
>>   
>>   	/*
>> @@ -1958,7 +1965,10 @@ static int dwc3_probe(struct platform_device *pdev)
>>   
>>   err_exit_debugfs:
>>   	dwc3_debugfs_exit(dwc);
>> -	dwc3_event_buffers_cleanup(dwc);
>> +
>> +	if (hw_mode != DWC3_GHWPARAMS0_MODE_HOST)
>> +		dwc3_event_buffers_cleanup(dwc);
>> +
>>   	dwc3_phy_power_off(dwc);
>>   	dwc3_phy_exit(dwc);
>>   	dwc3_ulpi_exit(dwc);
>> -- 
>> 2.40.0