Re: [PATCH v2 4/7] fpga: dfl: afu: add interrupt support for error reporting

[Xu Yilun]

On Wed, Mar 18, 2020 at 04:54:26PM +0800, Wu Hao wrote:
> On Mon, Mar 16, 2020 at 12:16:59PM +0800, Xu Yilun wrote:
> > Error reporting interrupt is very useful to notify users that some
> > errors are detected by the hardware. Once users are notified, they
> > could query hardware logged error states, no need to continuously
> > poll on these states.
> > 
> > This patch follows the common DFL interrupt notification and handling
> > mechanism, implements two ioctl commands below for user to query
> > number of irqs supported, and set/unset interrupt triggers.
> > 
> >  Ioctls:
> >  * DFL_FPGA_PORT_ERR_GET_IRQ_NUM
> >    get the number of irqs, which is used to determine whether/how many
> >    interrupts error reporting feature supports.
> > 
> >  * DFL_FPGA_PORT_ERR_SET_IRQ
> >    set/unset given eventfds as error interrupt triggers.
> > 
> > Signed-off-by: Luwei Kang <luwei.kang@xxxxxxxxx>
> > Signed-off-by: Wu Hao <hao.wu@xxxxxxxxx>
> > Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxx>
> > ----
> > v2: use DFL_FPGA_PORT_ERR_GET_IRQ_NUM instead of
> >     DFL_FPGA_PORT_ERR_GET_INFO
> >     Delete flag field for DFL_FPGA_PORT_ERR_SET_IRQ param
> > ---
> >  drivers/fpga/dfl-afu-error.c  | 64 +++++++++++++++++++++++++++++++++++++++++++
> >  drivers/fpga/dfl-afu-main.c   |  4 +++
> >  include/uapi/linux/fpga-dfl.h | 29 ++++++++++++++++++++
> >  3 files changed, 97 insertions(+)
> > 
> > diff --git a/drivers/fpga/dfl-afu-error.c b/drivers/fpga/dfl-afu-error.c
> > index c1467ae..4d478b2f 100644
> > --- a/drivers/fpga/dfl-afu-error.c
> > +++ b/drivers/fpga/dfl-afu-error.c
> > @@ -15,6 +15,7 @@
> >   */
> >  
> >  #include <linux/uaccess.h>
> > +#include <linux/fpga-dfl.h>
> >  
> >  #include "dfl-afu.h"
> >  
> > @@ -219,6 +220,68 @@ static void port_err_uinit(struct platform_device *pdev,
> >  	afu_port_err_mask(&pdev->dev, true);
> >  }
> >  
> > +static long
> > +port_err_get_num_irqs(struct platform_device *pdev,
> > +		      struct dfl_feature *feature, unsigned long arg)
> > +{
> > +	if (copy_to_user((void __user *)arg, &feature->nr_irqs,
> > +			 sizeof(feature->nr_irqs)))
> > +		return -EFAULT;
> 
> maybe use put_user is simpler here.

I'll change it.

> 
> > +
> > +	return 0;
> > +}
> > +
> > +static long port_err_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_err_ioctl(struct platform_device *pdev, struct dfl_feature *feature,
> > +	       unsigned int cmd, unsigned long arg)
> > +{
> > +	long ret = -ENODEV;
> > +
> > +	switch (cmd) {
> > +	case DFL_FPGA_PORT_ERR_GET_IRQ_NUM:
> > +		ret = port_err_get_num_irqs(pdev, feature, arg);
> > +		break;
> > +	case DFL_FPGA_PORT_ERR_SET_IRQ:
> > +		ret = port_err_set_irq(pdev, feature, arg);
> > +		break;
> > +	default:
> > +		dev_dbg(&pdev->dev, "%x cmd not handled", cmd);
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> >  const struct dfl_feature_id port_err_id_table[] = {
> >  	{.id = PORT_FEATURE_ID_ERROR,},
> >  	{0,}
> > @@ -227,4 +290,5 @@ const struct dfl_feature_id port_err_id_table[] = {
> >  const struct dfl_feature_ops port_err_ops = {
> >  	.init = port_err_init,
> >  	.uinit = port_err_uinit,
> > +	.ioctl = port_err_ioctl,
> >  };
> > diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
> > index 435bde4..fc8b9cf 100644
> > --- a/drivers/fpga/dfl-afu-main.c
> > +++ b/drivers/fpga/dfl-afu-main.c
> > @@ -577,6 +577,7 @@ static int afu_release(struct inode *inode, struct file *filp)
> >  {
> >  	struct platform_device *pdev = filp->private_data;
> >  	struct dfl_feature_platform_data *pdata;
> > +	struct dfl_feature *feature;
> >  
> >  	dev_dbg(&pdev->dev, "Device File Release\n");
> >  
> > @@ -586,6 +587,9 @@ static int afu_release(struct inode *inode, struct file *filp)
> >  	dfl_feature_dev_use_end(pdata);
> >  
> >  	if (!dfl_feature_dev_use_count(pdata)) {
> > +		dfl_fpga_dev_for_each_feature(pdata, feature)
> > +			dfl_fpga_set_irq_triggers(feature, 0,
> > +						  feature->nr_irqs, NULL);
> >  		__port_reset(pdev);
> >  		afu_dma_region_destroy(pdata);
> >  	}
> > diff --git a/include/uapi/linux/fpga-dfl.h b/include/uapi/linux/fpga-dfl.h
> > index ec70a0746..ced859d 100644
> > --- a/include/uapi/linux/fpga-dfl.h
> > +++ b/include/uapi/linux/fpga-dfl.h
> > @@ -151,6 +151,35 @@ struct dfl_fpga_port_dma_unmap {
> >  
> >  #define DFL_FPGA_PORT_DMA_UNMAP		_IO(DFL_FPGA_MAGIC, DFL_PORT_BASE + 4)
> >  
> > +/**
> > + * DFL_FPGA_PORT_ERR_GET_IRQ_NUM - _IOR(DFL_FPGA_MAGIC, DFL_PORT_BASE + 5,
> > + *								__u32 num_irqs)
> > + *
> > + * Get the number of irqs supported by the fpga port error reporting private
> > + * feature.
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +#define DFL_FPGA_PORT_ERR_GET_IRQ_NUM	_IOR(DFL_FPGA_MAGIC,	\
> > +					     DFL_PORT_BASE + 5, __u32)
> > +
> > +/**
> > + * DFL_FPGA_PORT_ERR_SET_IRQ - _IOW(DFL_FPGA_MAGIC, DFL_PORT_BASE + 6,
> > + *						struct dfl_fpga_irq_set)
> > + *
> > + * Set fpga port error reporting interrupt trigger if evtfds[n] is valid.
> > + * Unset related interrupt trigger if evtfds[n] is a NULL or negative value.
> 
> Looks like the code only unset trigger if fd < 0, right?

Yes, will fix it.

> 
> > + * Return: 0 on success, -errno on failure.
> > + */
> > +struct dfl_fpga_irq_set {
> > +	__u32 start;		/* First irq number */
> 
> Sounds a little confusing, what about index of the first irq?

I'll take this change.

Thanks.

> 
> 
> Thanks
> Hao
> 
> > +	__u32 count;		/* The number of eventfd handler */
> > +	__s32 evtfds[];		/* Eventfd handler */
> > +};
> > +
> > +#define DFL_FPGA_PORT_ERR_SET_IRQ	_IOW(DFL_FPGA_MAGIC,	\
> > +					     DFL_PORT_BASE + 6,	\
> > +					     struct dfl_fpga_irq_set)
> > +
> >  /* IOCTLs for FME file descriptor */
> >  
> >  /**
> > -- 
> > 2.7.4