fpga: dfl: introduce interrupt trigger setting API

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.kang@intel.com>
Signed-off-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Xu Yilun <yilun.xu@intel.com>
Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Acked-by: Wu Hao <hao.wu@intel.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/uapi/linux/fpga-dfl.h b/include/uapi/linux/fpga-dfl.h
index ec70a0746e59..7331350f3067 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 */
 
 /**