From 8ebab40fd8f1683140890a77fadf571db98686b8 Mon Sep 17 00:00:00 2001
From: Tom Rix <trix@redhat.com>
Date: Fri, 25 Jun 2021 12:51:44 -0700
Subject: [PATCH] fpga: fpga-mgr: wrap the write() op
Git-commit: 8ebab40fd8f1683140890a77fadf571db98686b8
Patch-mainline: v5.15-rc1
References: jsc#PED-1263

An FPGA manager should not be required to provide a
write function. Move the op check to the wrapper.
Default to -EOPNOTSUP so its users will fail
gracefully.

[mdf@kernel.org: Reworded message]
Signed-off-by: Tom Rix <trix@redhat.com>
Signed-off-by: Moritz Fischer <mdf@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/fpga/fpga-mgr.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

--- a/drivers/fpga/fpga-mgr.c
+++ b/drivers/fpga/fpga-mgr.c
@@ -25,6 +25,13 @@ struct fpga_mgr_devres {
 	struct fpga_manager *mgr;
 };
 
+static inline int fpga_mgr_write(struct fpga_manager *mgr, const char *buf, size_t count)
+{
+	if (mgr->mops->write)
+		return  mgr->mops->write(mgr, buf, count);
+	return -EOPNOTSUPP;
+}
+
 /*
  * After all the FPGA image has been written, do the device specific steps to
  * finish and set the FPGA into operating mode.
@@ -204,7 +211,7 @@ static int fpga_mgr_buf_load_sg(struct f
 
 		sg_miter_start(&miter, sgt->sgl, sgt->nents, SG_MITER_FROM_SG);
 		while (sg_miter_next(&miter)) {
-			ret = mgr->mops->write(mgr, miter.addr, miter.length);
+			ret = fpga_mgr_write(mgr, miter.addr, miter.length);
 			if (ret)
 				break;
 		}
@@ -234,7 +241,7 @@ static int fpga_mgr_buf_load_mapped(stru
 	 * Write the FPGA image to the FPGA.
 	 */
 	mgr->state = FPGA_MGR_STATE_WRITE;
-	ret = mgr->mops->write(mgr, buf, count);
+	ret = fpga_mgr_write(mgr, buf, count);
 	if (ret) {
 		dev_err(&mgr->dev, "Error while writing image data to FPGA\n");
 		mgr->state = FPGA_MGR_STATE_WRITE_ERR;
@@ -578,9 +585,7 @@ struct fpga_manager *fpga_mgr_create(str
 	struct fpga_manager *mgr;
 	int id, ret;
 
-	if (!mops || !mops->state ||
-	    (!mops->write && !mops->write_sg) ||
-	    (mops->write && mops->write_sg)) {
+	if (!mops || !mops->state) {
 		dev_err(parent, "Attempt to register without fpga_manager_ops\n");
 		return NULL;
 	}