Re: [PATCH v5 2/7] fpga: dfl: pci: add irq info for feature devices enumeration

Moritz Fischer
2020-05-12T04:13:06Z

On Mon, Apr 20, 2020 at 04:11:38PM +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@intel.com>
> Signed-off-by: Wu Hao <hao.wu@intel.com>
> Signed-off-by: Xu Yilun <yilun.xu@intel.com>
> Acked-by: Wu Hao <hao.wu@intel.com>
> ----
> v2: put irq resources init code inside cce_enumerate_feature_dev()
> Some minor changes for Hao's comments.
> v3: Some minor fix for Hao's comments for v2.
> v4: Some minor fix for Hao's comments for v3.
> v5: No change.
> ---
> drivers/fpga/dfl-pci.c | 80 ++++++++++++++++++++++++++++++++++++++++++++------
> 1 file changed, 71 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c
> index a78c409..2ff1274 100644
> --- a/drivers/fpga/dfl-pci.c
> +++ b/drivers/fpga/dfl-pci.c
> @@ -39,6 +39,27 @@ static void __iomem *cci_pci_ioremap_bar(struct pci_dev *pcidev, int bar)
> return pcim_iomap_table(pcidev)[bar];
> }
>
> +static int cci_pci_alloc_irq(struct pci_dev *pcidev)
> +{
> + int ret, nvec = pci_msix_vec_count(pcidev);
> +
> + 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);
> +}
> +
> /* PCI Device ID */
> #define PCIE_DEVICE_ID_PF_INT_5_X 0xBCBD
> #define PCIE_DEVICE_ID_PF_INT_6_X 0xBCC0
> @@ -78,17 +99,38 @@ static void cci_remove_feature_devs(struct pci_dev *pcidev)
>
> /* remove all children feature devices */
> dfl_fpga_feature_devs_remove(drvdata->cdev);
> + cci_pci_free_irq(pcidev);
> +}
> +
> +static int *cci_pci_create_irq_table(struct pci_dev *pcidev, unsigned int nvec)
> +{
> + unsigned int i;
> + int *table;
> +
> + table = kcalloc(nvec, sizeof(int), GFP_KERNEL);
> + if (table) {
> + for (i = 0; i < nvec; i++)
> + table[i] = pci_irq_vector(pcidev, i);
> + }

Have you considered:
if (!table)
return table;

for (i = 0; i < nvec; i++)
table[i] = pci_irq_vector(pcidev, i);

return table;
> +
> + return table;
> +}
> +
> +static void cci_pci_free_irq_table(int *table)
> +{
> + kfree(table);
> }

Have you considered just using kfree()?
>
> /* enumerate feature devices under pci device */
> static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
> {
> struct cci_drvdata *drvdata = pci_get_drvdata(pcidev);
> + int port_num, bar, i, nvec, ret = 0;
> struct dfl_fpga_enum_info *info;
> struct dfl_fpga_cdev *cdev;
> resource_size_t start, len;
> - int port_num, bar, i, ret = 0;
> void __iomem *base;
> + int *irq_table;
> u32 offset;
> u64 v;
>
> @@ -97,11 +139,30 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
> if (!info)
> return -ENOMEM;
>
> + /* add irq info for enumeration if the device support irq */
> + nvec = cci_pci_alloc_irq(pcidev);
> + if (nvec < 0) {
> + dev_err(&pcidev->dev, "Fail to alloc irq %d.\n", nvec);
> + ret = nvec;
> + goto enum_info_free_exit;
> + } else if (nvec) {
> + irq_table = cci_pci_create_irq_table(pcidev, nvec);
> + if (!irq_table) {
> + ret = -ENOMEM;
> + goto irq_free_exit;
> + }
> +
> + ret = dfl_fpga_enum_info_add_irq(info, nvec, irq_table);
> + cci_pci_free_irq_table(irq_table);
> + if (ret)
> + goto irq_free_exit;
> + }
> +
> /* start to find Device Feature List from Bar 0 */
> base = cci_pci_ioremap_bar(pcidev, 0);
> if (!base) {
> ret = -ENOMEM;
> - goto enum_info_free_exit;
> + goto irq_free_exit;
> }
>
> /*
> @@ -154,7 +215,7 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
> dfl_fpga_enum_info_add_dfl(info, start, len, base);
> } else {
> ret = -ENODEV;
> - goto enum_info_free_exit;
> + goto irq_free_exit;
> }
>
> /* start enumeration with prepared enumeration information */
> @@ -162,11 +223,14 @@ static int cci_enumerate_feature_devs(struct pci_dev *pcidev)
> if (IS_ERR(cdev)) {
> dev_err(&pcidev->dev, "Enumeration failure\n");
> ret = PTR_ERR(cdev);
> - goto enum_info_free_exit;
> + goto irq_free_exit;
> }
>
> drvdata->cdev = cdev;
>
> +irq_free_exit:
> + if (ret)
> + cci_pci_free_irq(pcidev);
> enum_info_free_exit:
> dfl_fpga_enum_info_free(info);
>
> @@ -211,12 +275,10 @@ int cci_pci_probe(struct pci_dev *pcidev, const struct pci_device_id *pcidevid)
> }
>
> ret = cci_enumerate_feature_devs(pcidev);
> - if (ret) {
> - dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);
> - goto disable_error_report_exit;
> - }
> + if (!ret)
> + return ret;
>
> - return ret;
> + dev_err(&pcidev->dev, "enumeration failure %d.\n", ret);
>
> disable_error_report_exit:
> pci_disable_pcie_error_reporting(pcidev);
> --
> 2.7.4
>

Thanks,
Moritz