2 files changed, 5 insertions, 2 deletions

diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
index 79ce2eea44db..f0a69d3e60a5 100644
--- a/drivers/fpga/fpga-mgr.c
+++ b/drivers/fpga/fpga-mgr.c
@@ -53,10 +53,12 @@ int fpga_mgr_buf_load(struct fpga_manager *mgr, struct fpga_image_info *info,
         /*
          * Call the low level driver's write_init function.  This will do the
          * device-specific things to get the FPGA into the state where it is
-         * ready to receive an FPGA image.
+         * ready to receive an FPGA image. The low level driver only gets to
+         * see the first initial_header_size bytes in the buffer.
          */
         mgr->state = FPGA_MGR_STATE_WRITE_INIT;
-        ret = mgr->mops->write_init(mgr, info, buf, count);
+        ret = mgr->mops->write_init(mgr, info, buf,
+                                    min(mgr->mops->initial_header_size, count));
         if (ret) {
                 dev_err(dev, "Error preparing FPGA for writing\n");
                 mgr->state = FPGA_MGR_STATE_WRITE_INIT_ERR;
diff --git a/drivers/fpga/socfpga-a10.c b/drivers/fpga/socfpga-a10.c
index ccd9fb23bd52..f8770af0f6b5 100644
--- a/drivers/fpga/socfpga-a10.c
+++ b/drivers/fpga/socfpga-a10.c
@@ -470,6 +470,7 @@ static enum fpga_mgr_states socfpga_a10_fpga_state(struct fpga_manager *mgr)
 }
 
 static const struct fpga_manager_ops socfpga_a10_fpga_mgr_ops = {
+        .initial_header_size = (RBF_DECOMPRESS_OFFSET + 1) * 4,
         .state = socfpga_a10_fpga_state,
         .write_init = socfpga_a10_fpga_write_init,
         .write = socfpga_a10_fpga_write,