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Date: Tue, 30 Jan 2024 18:48:35 +0530
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Subject: Re: [PATCH v1 5/6] PCI: qcom-ep: Provide number of read/write channel
 for HDMA
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
CC: <vkoul@kernel.org>, <jingoohan1@gmail.com>, <conor+dt@kernel.org>,
        <konrad.dybcio@linaro.org>, <robh+dt@kernel.org>,
        <quic_shazhuss@quicinc.com>, <quic_nitegupt@quicinc.com>,
        <quic_ramkri@quicinc.com>, <quic_nayiluri@quicinc.com>,
        <dmitry.baryshkov@linaro.org>, <quic_krichai@quicinc.com>,
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        Gustavo Pimentel
	<gustavo.pimentel@synopsys.com>,
        Serge Semin <fancer.lancer@gmail.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=c5=84ski?= <kw@linux.com>,
        Rob Herring
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        "Kishon Vijay Abraham
 I" <kishon@kernel.org>,
        <dmaengine@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-pci@vger.kernel.org>, <linux-arm-msm@vger.kernel.org>,
        <mhi@lists.linux.dev>
References: <1705669223-5655-1-git-send-email-quic_msarkar@quicinc.com>
 <1705669223-5655-6-git-send-email-quic_msarkar@quicinc.com>
 <20240130085301.GB83288@thinkpad>
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From: Mrinmay Sarkar <quic_msarkar@quicinc.com>
In-Reply-To: <20240130085301.GB83288@thinkpad>
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On 1/30/2024 2:23 PM, Manivannan Sadhasivam wrote:
> On Fri, Jan 19, 2024 at 06:30:21PM +0530, Mrinmay Sarkar wrote:
>> There is no standard way to auto detect the number of available
>> read/write channels in a platform. So adding this change to provide
>> read/write channels count and also provide "EDMA_MF_HDMA_NATIVE"
>> flag to support HDMA for 8775 platform.
>>
>> 8775 has IP version 1.34.0 so intruduce a new cfg(cfg_1_34_0) for
>> this platform. Add struct qcom_pcie_ep_cfg as match data. Assign
>> hdma_supported flag into struct qcom_pcie_ep_cfg and set it true
>> in cfg_1_34_0.
>>
>> Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
>> ---
>>   drivers/pci/controller/dwc/pcie-qcom-ep.c | 19 ++++++++++++++++++-
>>   1 file changed, 18 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
>> index 45008e0..8d56435 100644
>> --- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
>> +++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
>> @@ -149,6 +149,10 @@ enum qcom_pcie_ep_link_status {
>>   	QCOM_PCIE_EP_LINK_DOWN,
>>   };
>>   
> Add kdoc comment please as like the below struct.
>
>> +struct qcom_pcie_ep_cfg {
>> +	bool hdma_supported;
>> +};
>> +
>>   /**
>>    * struct qcom_pcie_ep - Qualcomm PCIe Endpoint Controller
>>    * @pci: Designware PCIe controller struct
>> @@ -167,6 +171,7 @@ enum qcom_pcie_ep_link_status {
>>    * @num_clks: PCIe clocks count
>>    * @perst_en: Flag for PERST enable
>>    * @perst_sep_en: Flag for PERST separation enable
>> + * @cfg: PCIe EP config struct
>>    * @link_status: PCIe Link status
>>    * @global_irq: Qualcomm PCIe specific Global IRQ
>>    * @perst_irq: PERST# IRQ
>> @@ -194,6 +199,7 @@ struct qcom_pcie_ep {
>>   	u32 perst_en;
>>   	u32 perst_sep_en;
>>   
>> +	const struct qcom_pcie_ep_cfg *cfg;
>>   	enum qcom_pcie_ep_link_status link_status;
>>   	int global_irq;
>>   	int perst_irq;
>> @@ -511,6 +517,10 @@ static void qcom_pcie_perst_assert(struct dw_pcie *pci)
>>   	pcie_ep->link_status = QCOM_PCIE_EP_LINK_DISABLED;
>>   }
>>   
>> +static const struct qcom_pcie_ep_cfg cfg_1_34_0 = {
>> +	.hdma_supported = true,
>> +};
>> +
>>   /* Common DWC controller ops */
>>   static const struct dw_pcie_ops pci_ops = {
>>   	.link_up = qcom_pcie_dw_link_up,
>> @@ -816,6 +826,13 @@ static int qcom_pcie_ep_probe(struct platform_device *pdev)
>>   	pcie_ep->pci.ops = &pci_ops;
>>   	pcie_ep->pci.ep.ops = &pci_ep_ops;
>>   	pcie_ep->pci.edma.nr_irqs = 1;
>> +
>> +	pcie_ep->cfg = of_device_get_match_data(dev);
> Why do you want to cache "cfg" since it is only used in probe()?

Yes Mani, no need to cache "cfg" we can use directly here .

>> +	if (pcie_ep->cfg && pcie_ep->cfg->hdma_supported) {
>> +		pcie_ep->pci.edma.ll_wr_cnt = 1;
>> +		pcie_ep->pci.edma.ll_rd_cnt = 1;
> Is the platform really has a single r/w channel?
the platform has 8 r/w channels. but as per the use case we need to use 
single r/w channel.
> - Mani
Thanks,
Mrinmay