fpga: Add scatterlist based programming

Requiring contiguous kernel memory is not a good idea, this is a limited
resource and allocation can fail under normal work loads.

This introduces a .write_sg op that supporting drivers can provide
to DMA directly from dis-contiguous memory and a new entry point
fpga_mgr_buf_load_sg that users can call to directly provide page
lists.

The full matrix of compatibility is provided, either the linear or sg
interface can be used by the user with a driver supporting either
interface.

A notable change for drivers is that the .write op can now be called
multiple times.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Acked-by: Alan Tull <atull@opensource.altera.com>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
index 16551d5eac36..57beb5d09bfc 100644
--- a/include/linux/fpga/fpga-mgr.h
+++ b/include/linux/fpga/fpga-mgr.h
@@ -22,6 +22,7 @@
 #define _LINUX_FPGA_MGR_H
 
 struct fpga_manager;
+struct sg_table;
 
 /**
  * enum fpga_mgr_states - fpga framework states
@@ -88,6 +89,7 @@ struct fpga_image_info {
  * @state: returns an enum value of the FPGA's state
  * @write_init: prepare the FPGA to receive confuration data
  * @write: write count bytes of configuration data to the FPGA
+ * @write_sg: write the scatter list of configuration data to the FPGA
  * @write_complete: set FPGA to operating state after writing is done
  * @fpga_remove: optional: Set FPGA into a specific state during driver remove
  *
@@ -102,6 +104,7 @@ struct fpga_manager_ops {
                           struct fpga_image_info *info,
                           const char *buf, size_t count);
         int (*write)(struct fpga_manager *mgr, const char *buf, size_t count);
+        int (*write_sg)(struct fpga_manager *mgr, struct sg_table *sgt);
         int (*write_complete)(struct fpga_manager *mgr,
                               struct fpga_image_info *info);
         void (*fpga_remove)(struct fpga_manager *mgr);
@@ -129,6 +132,8 @@ struct fpga_manager {
 
 int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
                       const char *buf, size_t count);
+int fpga_mgr_buf_load_sg(struct fpga_manager *mgr, struct fpga_image_info *info,
+                         struct sg_table *sgt);
 
 int fpga_mgr_firmware_load(struct fpga_manager *mgr,
                            struct fpga_image_info *info,