linux-kernel - Re: [PATCH 2/7] fpga: dfl: pci: add irq info for feature devices enumeration

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Date:   Tue, 10 Mar 2020 10:46:26 +0800
From:   Wu Hao <hao.wu@...el.com>
To:     Xu Yilun <yilun.xu@...el.com>
Cc:     mdf@...nel.org, linux-fpga@...r.kernel.org,
        linux-kernel@...r.kernel.org, Luwei Kang <luwei.kang@...el.com>
Subject: Re: [PATCH 2/7] fpga: dfl: pci: add irq info for feature devices
 enumeration

Hi Yilun

Some comments inline. : )

On Mon, Mar 09, 2020 at 06:29:45PM +0800, Xu Yilun wrote:
> Some DFL FPGA PCIe cards (e.g. Intel FPGA Programmable Acceleration
> Card) support MSI-X based interrupts. This patch allows PCIe driver
> to prepare and pass interrupt resources to DFL via enumeration API.
> These interrupt resources could then be assigned to actual features
> which use them.
> 
> Signed-off-by: Luwei Kang <luwei.kang@...el.com>
> Signed-off-by: Wu Hao <hao.wu@...el.com>
> Signed-off-by: Xu Yilun <yilun.xu@...el.com>
> ---
>  drivers/fpga/dfl-pci.c | 66 ++++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 61 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index 5387550..a3370e5 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -80,8 +80,23 @@ static void cci_remove_feature_devs(struct pci_dev *pcidev)
>  	dfl_fpga_feature_devs_remove(drvdata->cdev);
>  }
>  
> +static int *cci_pci_create_irq_table(struct pci_dev *pcidev, unsigned int nvec)
> +{
> +	int *table, i;
> +
> +	table = kcalloc(nvec, sizeof(int), GFP_KERNEL);

Maybe devm_ version is better?

> +	if (!table)
> +		return NULL;
> +
> +	for (i = 0; i < nvec; i++)

i should be unsigned int as well?

> +		table[i] = pci_irq_vector(pcidev, i);
> +
> +	return table;
> +}
> +
>  /* enumerate feature devices under pci device */
> -static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
> +static int cci_enumerate_feature_devs(struct pci_dev *pcidev,
> +				      unsigned int nvec)
>  {
>  	struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
>  	struct dfl_fpga_enum_info *info;
> @@ -89,6 +104,7 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
>  	resource_size_t start, len;
>  	int port_num, bar, i, ret = 0;
>  	void __iomem *base;
> +	int *irq_table;
>  	u32 offset;
>  	u64 v;
>  
> @@ -97,6 +113,18 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
>  	if (!info)
>  		return -ENOMEM;
>  
> +	/* add irq info for enumeration if really needed */
> +	if (nvec) {
> +		irq_table = cci_pci_create_irq_table(pcidev, nvec);
> +		if (irq_table) {
> +			dfl_fpga_enum_info_add_irq(info, nvec, irq_table);
> +			kfree(irq_table);
> +		} else {
> +			ret = -ENOMEM;
> +			goto enum_info_free_exit;
> +		}
> +	}
> +
>  	/* start to find Device Feature List from Bar 0 */
>  	base = cci_pci_ioremap_bar(pcidev, 0);
>  	if (!base) {
> @@ -173,6 +201,28 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
>  	return ret;
>  }
>  
> +static int cci_pci_alloc_irq(struct pci_dev *pcidev)
> +{
> +	int nvec = pci_msix_vec_count(pcidev);
> +	int ret;
> +
> +	if (nvec <= 0) {
> +		dev_dbg(&pcidev->dev, "fpga interrupt not supported\n");
> +		return 0;
> +	}
> +
> +	ret = pci_alloc_irq_vectors(pcidev, nvec, nvec, PCI_IRQ_MSIX);
> +	if (ret < 0)
> +		return ret;
> +
> +	return nvec;
> +}
> +
> +static void cci_pci_free_irq(struct pci_dev *pcidev)
> +{
> +	pci_free_irq_vectors(pcidev);
> +}
> +
>  static
>  int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
>  {
> @@ -210,14 +260,19 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
>  		goto disable_error_report_exit;
>  	}
>  
> -	ret = cci_enumerate_feature_devs(pcidev);
> -	if (ret) {
> -		dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);
> +	ret = cci_pci_alloc_irq(pcidev);
> +	if (ret < 0) {
> +		dev_err(&pcidev->dev, "Fail to alloc irq %d.\n", ret);

we prepare mmio resources in side cci_enumerate_feature_devs.

maybe we could put irq resources code in side cce_enumerate_feature_devs too?


Thanks
Hao

>  		goto disable_error_report_exit;
>  	}
>  
> -	return ret;
> +	ret = cci_enumerate_feature_devs(pcidev, (unsigned int)ret);
> +	if (!ret)
> +		return ret;
> +
> +	dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);
>  
> +	cci_pci_free_irq(pcidev);
>  disable_error_report_exit:
>  	pci_disable_pcie_error_reporting(pcidev);
>  	return ret;
> @@ -263,6 +318,7 @@ static void cci_pci_remove(struct pci_dev *pcidev)
>  		cci_pci_sriov_configure(pcidev, 0);
>  
>  	cci_remove_feature_devs(pcidev);
> +	cci_pci_free_irq(pcidev);
>  	pci_disable_pcie_error_reporting(pcidev);
>  }
>  
> -- 
> 2.7.4