[PATCH] fpga: xilinx-pr-decoupler: add shutdown() handler

[Aravind Thokala <aravind.thokala@amd.com>]

Add a .shutdown() handler to decouple the Reconfigurable Partition
from the static logic on reboot, shutdown, and kexec.

The handler writes CTRL_CMD_DECOUPLE to the control register. On the
PR Decoupler, this turns decoupling on, which stops signal changes
passing through the bridge. On the DFX AXI Shutdown Manager, it
requests that the IP stop passing AXI transactions through.

Signed-off-by: Aravind Thokala <aravind.thokala@amd.com>
---
 drivers/fpga/xilinx-pr-decoupler.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/fpga/xilinx-pr-decoupler.c b/drivers/fpga/xilinx-pr-decoupler.c
index 1405ddbe88f1..75b59edbf440 100644
--- a/drivers/fpga/xilinx-pr-decoupler.c
+++ b/drivers/fpga/xilinx-pr-decoupler.c
@@ -137,6 +137,13 @@ static int xlnx_pr_decoupler_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static void xlnx_pr_decoupler_shutdown(struct platform_device *pdev)
+{
+	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
+
+	xlnx_pr_decoupler_enable_set(bridge, false);
+}
+
 static void xlnx_pr_decoupler_remove(struct platform_device *pdev)
 {
 	struct fpga_bridge *bridge = platform_get_drvdata(pdev);
@@ -147,6 +154,7 @@ static void xlnx_pr_decoupler_remove(struct platform_device *pdev)
 static struct platform_driver xlnx_pr_decoupler_driver = {
 	.probe = xlnx_pr_decoupler_probe,
 	.remove = xlnx_pr_decoupler_remove,
+	.shutdown = xlnx_pr_decoupler_shutdown,
 	.driver = {
 		.name = "xlnx_pr_decoupler",
 		.of_match_table = xlnx_pr_decoupler_of_match,

---
base-commit: b3dfbde62cf1981c4638939c159dfd087b7a72e9
change-id: 20261110-pr_decoupler_shutdown_handler-bf2596f6d1de

Best regards,
--  
Aravind Thokala <aravind.thokala@amd.com>