linux-kernel - [PATCH v3] remoteproc: xlnx: allow single core use in split mode

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Message-ID: <20250618181933.1253033-1-tanmay.shah@amd.com>
Date: Wed, 18 Jun 2025 11:19:33 -0700
From: Tanmay Shah <tanmay.shah@....com>
To: <andersson@...nel.org>, <mathieu.poirier@...aro.org>
CC: <linux-remoteproc@...r.kernel.org>, <linux-kernel@...r.kernel.org>, Tanmay
 Shah <tanmay.shah@....com>
Subject: [PATCH v3] remoteproc: xlnx: allow single core use in split mode

When operating in split mode, it is a valid usecase to have
only one core enabled in the cluster. Remove exact core count
expecatation from the driver.

Signed-off-by: Tanmay Shah <tanmay.shah@....com>
---

Changes in v3:
  - Fix commit message
  - Add details about split mode configuration in comment

Change in v2:
  - limit core_count to max 2

 drivers/remoteproc/xlnx_r5_remoteproc.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/remoteproc/xlnx_r5_remoteproc.c b/drivers/remoteproc/xlnx_r5_remoteproc.c
index 1af89782e116..5aa3fd1b0530 100644
--- a/drivers/remoteproc/xlnx_r5_remoteproc.c
+++ b/drivers/remoteproc/xlnx_r5_remoteproc.c
@@ -1329,19 +1329,23 @@ static int zynqmp_r5_cluster_init(struct zynqmp_r5_cluster *cluster)
 
 	/*
 	 * Number of cores is decided by number of child nodes of
-	 * r5f subsystem node in dts. If Split mode is used in dts
-	 * 2 child nodes are expected.
+	 * r5f subsystem node in dts.
+	 * In split mode maximum two child nodes are expected.
+	 * However, only single core can be enabled too.
+	 * Driver can handle following configuration in split mode:
+	 * 1) core0 enabled, core1 disabled
+	 * 2) core0 disabled, core1 enabled
+	 * 3) core0 and core1 both are enabled.
+	 * For now, no more than two cores are expected per cluster
+	 * in split mode.
 	 * In lockstep mode if two child nodes are available,
 	 * only use first child node and consider it as core0
 	 * and ignore core1 dt node.
 	 */
 	core_count = of_get_available_child_count(dev_node);
-	if (core_count == 0) {
+	if (core_count == 0 || core_count > 2) {
 		dev_err(dev, "Invalid number of r5 cores %d", core_count);
 		return -EINVAL;
-	} else if (cluster_mode == SPLIT_MODE && core_count != 2) {
-		dev_err(dev, "Invalid number of r5 cores for split mode\n");
-		return -EINVAL;
 	} else if (cluster_mode == LOCKSTEP_MODE && core_count == 2) {
 		dev_warn(dev, "Only r5 core0 will be used\n");
 		core_count = 1;

base-commit: d293da1e4dbebb40560e4c6a417b29ce3393659a
-- 
2.34.1