On Mon, Apr 20, 2020 at 04:11:39PM +0800, Xu Yilun wrote:
> FPGA user applications may be interested in interrupts generated by
> DFL features. For example, users can implement their own FPGA
> logics with interrupts enabled in AFU (Accelerated Function Unit,
> dynamic region of DFL based FPGA). So user applications need to be
> notified to handle these interrupts.
>
> In order to allow userspace applications to monitor interrupts,
> driver requires userspace to provide eventfds as interrupt
> notification channels. Applications then poll/select on the eventfds
> to get notified.
>
> This patch introduces a generic helper functions to do eventfds binding
> with given interrupts.
>
> Sub feature drivers are expected to use XXX_GET_IRQ_NUM to query irq
> info, and XXX_SET_IRQ to set eventfds for interrupts. This patch also
> introduces helper functions for these 2 ioctls.
>
> Signed-off-by: Luwei Kang <luwei.k...@intel.com>
> Signed-off-by: Wu Hao <hao...@intel.com>
> Signed-off-by: Xu Yilun <yilun...@intel.com>
> Acked-by: Wu Hao <hao...@intel.com>
> ----
> v2: use unsigned int instead of int for irq array indexes in
> dfl_fpga_set_irq_triggers()
> Improves comments for NULL fds param in dfl_fpga_set_irq_triggers()
> v3: Improve comments of dfl_fpga_set_irq_triggers()
> refines code for dfl_fpga_set_irq_triggers, delete local variable j
> v4: Introduce 2 helper functions to help handle the XXX_GET_IRQ_NUM &
> XXX_SET_IRQ ioctls for sub feature drivers.
> v5: Some minor fix for Hao's comments
> ---
> drivers/fpga/dfl.c | 156
> ++++++++++++++++++++++++++++++++++++++++++
> drivers/fpga/dfl.h | 17 +++++
> include/uapi/linux/fpga-dfl.h | 13 ++++
> 3 files changed, 186 insertions(+)
>
> diff --git a/drivers/fpga/dfl.c b/drivers/fpga/dfl.c
> index b49fbed..208d8f0 100644
> --- a/drivers/fpga/dfl.c
> +++ b/drivers/fpga/dfl.c
> @@ -10,7 +10,9 @@
> * Wu Hao <hao...@intel.com>
> * Xiao Guangrong <guangrong.x...@linux.intel.com>
> */
> +#include <linux/fpga-dfl.h>
> #include <linux/module.h>
> +#include <linux/uaccess.h>
>
> #include "dfl.h"
>
> @@ -534,6 +536,7 @@ static int build_info_commit_dev(struct
> build_feature_devs_info *binfo)
> unsigned int i;
>
> /* save resource information for each feature */
> + feature->dev = fdev;
> feature->id = finfo->fid;
> feature->resource_index = index;
> feature->ioaddr = finfo->ioaddr;
> @@ -1395,6 +1398,159 @@ int dfl_fpga_cdev_config_ports_vf(struct
> dfl_fpga_cdev *cdev, int num_vfs)
> }
> EXPORT_SYMBOL_GPL(dfl_fpga_cdev_config_ports_vf);
>
> +static irqreturn_t dfl_irq_handler(int irq, void *arg)
> +{
> + struct eventfd_ctx *trigger = arg;
> +
> + eventfd_signal(trigger, 1);
> + return IRQ_HANDLED;
> +}
> +
> +static int do_set_irq_trigger(struct dfl_feature *feature, unsigned int idx,
> + int fd)
> +{
> + struct platform_device *pdev = feature->dev;
> + struct eventfd_ctx *trigger;
> + int irq, ret;
> +
> + if (idx >= feature->nr_irqs)
> + return -EINVAL;
> +
> + irq = feature->irq_ctx[idx].irq;
> +
> + if (feature->irq_ctx[idx].trigger) {
> + free_irq(irq, feature->irq_ctx[idx].trigger);
> + kfree(feature->irq_ctx[idx].name);
> + eventfd_ctx_put(feature->irq_ctx[idx].trigger);
> + feature->irq_ctx[idx].trigger = NULL;
> + }
> +
> + if (fd < 0)
> + return 0;
> +
> + feature->irq_ctx[idx].name =
> + kasprintf(GFP_KERNEL, "fpga-irq[%u](%s-%llx)", idx,
> + dev_name(&pdev->dev),
> + (unsigned long long)feature->id);
> + if (!feature->irq_ctx[idx].name)
> + return -ENOMEM;
> +
> + trigger = eventfd_ctx_fdget(fd);
> + if (IS_ERR(trigger)) {
> + ret = PTR_ERR(trigger);
> + goto free_name;
> + }
> +
> + ret = request_irq(irq, dfl_irq_handler, 0,
> + feature->irq_ctx[idx].name, trigger);
> + if (!ret) {
> + feature->irq_ctx[idx].trigger = trigger;
> + return ret;
> + }
> +
> + eventfd_ctx_put(trigger);
> +free_name:
> + kfree(feature->irq_ctx[idx].name);
> +
> + return ret;
> +}
> +
> +/**
> + * dfl_fpga_set_irq_triggers - set eventfd triggers for dfl feature
> interrupts
> + *
> + * @feature: dfl sub feature.
> + * @start: start of irq index in this dfl sub feature.
> + * @count: number of irqs.
> + * @fds: eventfds to bind with irqs. unbind related irq if fds[n] is
> negative.
> + * unbind "count" specified number of irqs if fds ptr is NULL.
> + *
> + * Bind given eventfds with irqs in this dfl sub feature. Unbind related irq
> if
> + * fds[n] is negative. Unbind "count" specified number of irqs if fds ptr is
> + * NULL.
> + *
> + * Return: 0 on success, negative error code otherwise.
> + */
> +int dfl_fpga_set_irq_triggers(struct dfl_feature *feature, unsigned int
> start,
> + unsigned int count, int32_t *fds)
> +{
> + unsigned int i;
> + int ret = 0;
> +
> + if (start + count < start || start + count > feature->nr_irqs)
> + return -EINVAL;
> +
> + for (i = 0; i < count; i++) {
> + int fd = fds ? fds[i] : -1;
> +
> + ret = do_set_irq_trigger(feature, start + i, fd);
> + if (ret) {
> + while (i--)
> + do_set_irq_trigger(feature, start + i, -1);
> + break;
> + }
> + }
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(dfl_fpga_set_irq_triggers);
> +
> +/**
> + * dfl_feature_ioctl_get_num_irqs - dfl feature _GET_IRQ_NUM ioctl interface.
> + * @pdev: the feature device which has the sub feature
> + * @feature: the dfl sub feature
> + * @arg: ioctl argument
> + *
> + * Return: 0 on success, negative error code otherwise.
> + */
> +long dfl_feature_ioctl_get_num_irqs(struct platform_device *pdev,
> + struct dfl_feature *feature,
> + unsigned long arg)
> +{
> + return put_user(feature->nr_irqs, (__u32 __user *)arg);
> +}
> +EXPORT_SYMBOL_GPL(dfl_feature_ioctl_get_num_irqs);
> +
> +/**
> + * dfl_feature_ioctl_set_irq - dfl feature _SET_IRQ ioctl interface.
> + * @pdev: the feature device which has the sub feature
> + * @feature: the dfl sub feature
> + * @arg: ioctl argument
> + *
> + * Return: 0 on success, negative error code otherwise.
> + */
> +long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
> + struct dfl_feature *feature,
> + unsigned long arg)
> +{
> + struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
> + struct dfl_fpga_irq_set hdr;
> + s32 *fds;
> + long ret;
> +
> + if (!feature->nr_irqs)
> + return -ENOENT;
> +
> + if (copy_from_user(&hdr, (void __user *)arg, sizeof(hdr)))
> + return -EFAULT;
> +
> + if (!hdr.count || (hdr.start + hdr.count > feature->nr_irqs) ||
> + (hdr.start + hdr.count < hdr.start))
> + return -EINVAL;
> +
> + fds = memdup_user((void __user *)(arg + sizeof(hdr)),
> + hdr.count * sizeof(s32));
> + if (IS_ERR(fds))
> + return PTR_ERR(fds);
> +
> + mutex_lock(&pdata->lock);
> + ret = dfl_fpga_set_irq_triggers(feature, hdr.start, hdr.count, fds);
> + mutex_unlock(&pdata->lock);
> +
> + kfree(fds);
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(dfl_feature_ioctl_set_irq);
> +
> static void __exit dfl_fpga_exit(void)
> {
> dfl_chardev_uinit();
> diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
> index 4bc165f..f7a8c59 100644
> --- a/drivers/fpga/dfl.h
> +++ b/drivers/fpga/dfl.h
> @@ -17,7 +17,9 @@
> #include <linux/bitfield.h>
> #include <linux/cdev.h>
> #include <linux/delay.h>
> +#include <linux/eventfd.h>
> #include <linux/fs.h>
> +#include <linux/interrupt.h>
> #include <linux/iopoll.h>
> #include <linux/io-64-nonatomic-lo-hi.h>
> #include <linux/platform_device.h>
> @@ -213,14 +215,19 @@ struct dfl_feature_driver {
> * struct dfl_feature_irq_ctx - dfl private feature interrupt context
> *
> * @irq: Linux IRQ number of this interrupt.
> + * @trigger: eventfd context to signal when interrupt happens.
> + * @name: irq name needed when requesting irq.
> */
> struct dfl_feature_irq_ctx {
> int irq;
> + struct eventfd_ctx *trigger;
> + char *name;
> };
>
> /**
> * struct dfl_feature - sub feature of the feature devices
> *
> + * @dev: ptr to pdev of the feature device which has the sub feature.
> * @id: sub feature id.
> * @resource_index: each sub feature has one mmio resource for its registers.
> * this index is used to find its mmio resource from the
> @@ -231,6 +238,7 @@ struct dfl_feature_irq_ctx {
> * @ops: ops of this sub feature.
> */
> struct dfl_feature {
> + struct platform_device *dev;
> u64 id;
> int resource_index;
> void __iomem *ioaddr;
> @@ -506,4 +514,13 @@ int dfl_fpga_cdev_release_port(struct dfl_fpga_cdev
> *cdev, int port_id);
> int dfl_fpga_cdev_assign_port(struct dfl_fpga_cdev *cdev, int port_id);
> void dfl_fpga_cdev_config_ports_pf(struct dfl_fpga_cdev *cdev);
> int dfl_fpga_cdev_config_ports_vf(struct dfl_fpga_cdev *cdev, int num_vf);
> +int dfl_fpga_set_irq_triggers(struct dfl_feature *feature, unsigned int
> start,
> + unsigned int count, int32_t *fds);
> +long dfl_feature_ioctl_get_num_irqs(struct platform_device *pdev,
> + struct dfl_feature *feature,
> + unsigned long arg);
> +long dfl_feature_ioctl_set_irq(struct platform_device *pdev,
> + struct dfl_feature *feature,
> + unsigned long arg);
> +
> #endif /* __FPGA_DFL_H */
> diff --git a/include/uapi/linux/fpga-dfl.h b/include/uapi/linux/fpga-dfl.h
> index ec70a0746..7331350 100644
> --- a/include/uapi/linux/fpga-dfl.h
> +++ b/include/uapi/linux/fpga-dfl.h
> @@ -151,6 +151,19 @@ struct dfl_fpga_port_dma_unmap {
>
> #define DFL_FPGA_PORT_DMA_UNMAP _IO(DFL_FPGA_MAGIC,
> DFL_PORT_BASE + 4)
>
> +/**
> + * struct dfl_fpga_irq_set - the argument for DFL_FPGA_XXX_SET_IRQ ioctl.
> + *
> + * @start: Index of the first irq.
> + * @count: The number of eventfd handler.
> + * @evtfds: Eventfd handlers.
> + */
> +struct dfl_fpga_irq_set {
> + __u32 start;
> + __u32 count;
> + __s32 evtfds[];
> +};
> +
> /* IOCTLs for FME file descriptor */
>
> /**
> --
> 2.7.4
Reviewed-by: Marcelo Tosatti <mtosa...@redhat.com>
