Re: [PATCH v3 6/7] fpga: dfl: afu: add user interrupt support

[Xu Yilun <yilun.xu@intel.com>]

On Tue, Mar 31, 2020 at 01:15:50PM +0800, Wu Hao wrote:
> On Tue, Mar 24, 2020 at 04:32:42PM +0800, Xu Yilun wrote:
> > AFU (Accelerated Function Unit) is dynamic region of the DFL based FPGA,
> > and always defined by users. Some DFL based FPGA cards allow users to
> > implement their own interrupts in AFU. In order to support this,
> > hardware implements a new UINT (User Interrupt) private feature with
> 
> User Interrupt seems a little confusing, maybe we can just call it
> AFU Interrupt whenever possible. How do you think?

OK. It's more clear. I'll change it.

> 
> Thanks
> Hao
> 
> > related capability register which describes the number of supported
> > user interrupts as well as the local index of the interrupts for
> > software enumeration, and from software side, driver follows the common
> > DFL interrupt notification and handling mechanism, and it implements
> > two ioctls below for user to query number of irqs supported and set/unset
> > interrupt triggers.
> > 
> >  Ioctls:
> >  * DFL_FPGA_PORT_UINT_GET_IRQ_NUM
> >    get the number of irqs, which is used to determine how many interrupts
> >    UINT feature supports.
> > 
> >  * DFL_FPGA_PORT_UINT_SET_IRQ
> >    set/unset eventfds as AFU user interrupt triggers.
> > 
> > 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>
> > ----
> > v2: use DFL_FPGA_PORT_UINT_GET_IRQ_NUM instead of
> >     DFL_FPGA_PORT_UINT_GET_INFO
> >     Delete flags field for DFL_FPGA_PORT_UINT_SET_IRQ
> > v3: put_user() instead of copy_to_user()
> >     improves comments
> > ---
> >  drivers/fpga/dfl-afu-main.c   | 70 +++++++++++++++++++++++++++++++++++++++++++
> >  include/uapi/linux/fpga-dfl.h | 23 ++++++++++++++
> >  2 files changed, 93 insertions(+)
> > 
> > diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
> > index 357cd5d..d2db5b6 100644
> > --- a/drivers/fpga/dfl-afu-main.c
> > +++ b/drivers/fpga/dfl-afu-main.c
> > @@ -529,6 +529,72 @@ static const struct dfl_feature_ops port_stp_ops = {
> >  	.init = port_stp_init,
> >  };
> >  
> > +static long
> > +port_uint_get_num_irqs(struct platform_device *pdev,
> > +		       struct dfl_feature *feature, unsigned long arg)
> > +{
> > +	return put_user(feature->nr_irqs, (__u32 __user *)arg);
> > +}
> > +
> > +static long port_uint_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;
> > +}
> > +
> > +static long
> > +port_uint_ioctl(struct platform_device *pdev, struct dfl_feature *feature,
> > +		unsigned int cmd, unsigned long arg)
> > +{
> > +	long ret = -ENODEV;
> > +
> > +	switch (cmd) {
> > +	case DFL_FPGA_PORT_UINT_GET_IRQ_NUM:
> > +		ret = port_uint_get_num_irqs(pdev, feature, arg);
> > +		break;
> > +	case DFL_FPGA_PORT_UINT_SET_IRQ:
> > +		ret = port_uint_set_irq(pdev, feature, arg);
> > +		break;
> > +	default:
> > +		dev_dbg(&pdev->dev, "%x cmd not handled", cmd);
> > +	}
> > +	return ret;
> > +}
> > +
> > +static const struct dfl_feature_id port_uint_id_table[] = {
> > +	{.id = PORT_FEATURE_ID_UINT,},
> > +	{0,}
> > +};
> > +
> > +static const struct dfl_feature_ops port_uint_ops = {
> > +	.ioctl = port_uint_ioctl,
> > +};
> > +
> >  static struct dfl_feature_driver port_feature_drvs[] = {
> >  	{
> >  		.id_table = port_hdr_id_table,
> > @@ -547,6 +613,10 @@ static struct dfl_feature_driver port_feature_drvs[] = {
> >  		.ops = &port_stp_ops,
> >  	},
> >  	{
> > +		.id_table = port_uint_id_table,
> > +		.ops = &port_uint_ops,
> > +	},
> > +	{
> >  		.ops = NULL,
> >  	}
> >  };
> > diff --git a/include/uapi/linux/fpga-dfl.h b/include/uapi/linux/fpga-dfl.h
> > index 206bad9..5f885a8 100644
> > --- a/include/uapi/linux/fpga-dfl.h
> > +++ b/include/uapi/linux/fpga-dfl.h
> > @@ -180,6 +180,29 @@ struct dfl_fpga_irq_set {
> >  					     DFL_PORT_BASE + 6,	\
> >  					     struct dfl_fpga_irq_set)
> >  
> > +/**
> > + * DFL_FPGA_PORT_UINT_GET_IRQ_NUM - _IOR(DFL_FPGA_MAGIC, DFL_PORT_BASE + 7,
> > + *								__u32 num_irqs)
> > + *
> > + * Get the number of irqs supported by the fpga AFU user interrupt private
> > + * feature.
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +#define DFL_FPGA_PORT_UINT_GET_IRQ_NUM	_IOR(DFL_FPGA_MAGIC,	\
> > +					     DFL_PORT_BASE + 7, __u32)
> > +
> > +/**
> > + * DFL_FPGA_PORT_UINT_SET_IRQ - _IOW(DFL_FPGA_MAGIC, DFL_PORT_BASE + 8,
> > + *						struct dfl_fpga_irq_set)
> > + *
> > + * Set fpga afu user interrupt trigger if evtfds[n] is valid.
> > + * Unset related interrupt trigger if evtfds[n] is a negative value.
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +#define DFL_FPGA_PORT_UINT_SET_IRQ	_IOW(DFL_FPGA_MAGIC,	\
> > +					     DFL_PORT_BASE + 8,	\
> > +					     struct dfl_fpga_irq_set)
> > +
> >  /* IOCTLs for FME file descriptor */
> >  
> >  /**
> > -- 
> > 2.7.4