[PATCH v7 1/3] remoteproc: k3-r5: Simplify cluster mode setting usage

[Devarsh Thakkar <devarsht@ti.com>]

Check the validity of mode against SoC supported modes right
at the probe to minimize the usage of same check further in the code.

Set default value of cluster-mode only if cluster-mode device tree property
is empty.

In case devicetree provided cluster-mode property is invalid For e.g. using
CLUSTER_MODE_SINGLECPU on any SoC other than am64x then return error.

If firmware has set the PROC_BOOT_STATUS_FLAG_R5_SINGLECORE_ONLY flag then
what it means is that only CLUSTER_MODE_SINGLECPU is possible to use [1]
and hence there is no need to check for soc_data->single_cpu_mode first and
then checking cluster mode.

PROC_BOOT_CFG_FLAG_R5_SINGLE_CORE flag can be set directly for
CLUSTER_MODE_SINGLECPU without checking for soc_data->single_cpu_mode since
that check has already been done during probe.

Link:
[1] https://software-dl.ti.com/tisci/esd/latest/2_tisci_msgs/security/PROC_BOOT.html?highlight=singlecore_only#arm-r5

Signed-off-by: Devarsh Thakkar <devarsht@ti.com>
---
V1->V6: No changelog (Patch introduced in V6)
V6->V7:
- Override to appropriate cluster mode per firmware status flag directly
  without checking for soc_data
- Set appropriate mode as default if not provided in DT
- Check mode validity against SoC data during probe
- Rebase on top of 6.3 linux-next
---
 drivers/remoteproc/ti_k3_r5_remoteproc.c | 57 +++++++++++++-----------
 1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
index 0481926c6975..c2ec0f432921 100644
--- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
+++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
@@ -852,38 +852,33 @@ static int k3_r5_rproc_configure(struct k3_r5_rproc *kproc)
 	dev_dbg(dev, "boot_vector = 0x%llx, cfg = 0x%x ctrl = 0x%x stat = 0x%x\n",
 		boot_vec, cfg, ctrl, stat);
 
-	/* check if only Single-CPU mode is supported on applicable SoCs */
-	if (cluster->soc_data->single_cpu_mode) {
-		single_cpu =
-			!!(stat & PROC_BOOT_STATUS_FLAG_R5_SINGLECORE_ONLY);
-		if (single_cpu && cluster->mode == CLUSTER_MODE_SPLIT) {
-			dev_err(cluster->dev, "split-mode not permitted, force configuring for single-cpu mode\n");
-			cluster->mode = CLUSTER_MODE_SINGLECPU;
-		}
-		goto config;
+	single_cpu = !!(stat & PROC_BOOT_STATUS_FLAG_R5_SINGLECORE_ONLY);
+	lockstep_en = !!(stat & PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED);
+
+	/* Override to single CPU mode if set in status flag */
+	if (single_cpu && cluster->mode == CLUSTER_MODE_SPLIT) {
+		dev_err(cluster->dev, "split-mode not permitted, force configuring for single-cpu mode\n");
+		cluster->mode = CLUSTER_MODE_SINGLECPU;
 	}
 
-	/* check conventional LockStep vs Split mode configuration */
-	lockstep_en = !!(stat & PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED);
+	/* Override to split mode if lockstep enable bit is not set in status flag */
 	if (!lockstep_en && cluster->mode == CLUSTER_MODE_LOCKSTEP) {
 		dev_err(cluster->dev, "lockstep mode not permitted, force configuring for split-mode\n");
 		cluster->mode = CLUSTER_MODE_SPLIT;
 	}
 
-config:
 	/* always enable ARM mode and set boot vector to 0 */
 	boot_vec = 0x0;
 	if (core == core0) {
 		clr_cfg = PROC_BOOT_CFG_FLAG_R5_TEINIT;
-		if (cluster->soc_data->single_cpu_mode) {
-			/*
-			 * Single-CPU configuration bit can only be configured
-			 * on Core0 and system firmware will NACK any requests
-			 * with the bit configured, so program it only on
-			 * permitted cores
-			 */
-			if (cluster->mode == CLUSTER_MODE_SINGLECPU)
-				set_cfg = PROC_BOOT_CFG_FLAG_R5_SINGLE_CORE;
+		/*
+		 * Single-CPU configuration bit can only be configured
+		 * on Core0 and system firmware will NACK any requests
+		 * with the bit configured, so program it only on
+		 * permitted cores
+		 */
+		if (cluster->mode == CLUSTER_MODE_SINGLECPU) {
+			set_cfg = PROC_BOOT_CFG_FLAG_R5_SINGLE_CORE;
 		} else {
 			/*
 			 * LockStep configuration bit is Read-only on Split-mode
@@ -1700,12 +1695,6 @@ static int k3_r5_probe(struct platform_device *pdev)
 		return -ENOMEM;
 
 	cluster->dev = dev;
-	/*
-	 * default to most common efuse configurations - Split-mode on AM64x
-	 * and LockStep-mode on all others
-	 */
-	cluster->mode = data->single_cpu_mode ?
-				CLUSTER_MODE_SPLIT : CLUSTER_MODE_LOCKSTEP;
 	cluster->soc_data = data;
 	INIT_LIST_HEAD(&cluster->cores);
 
@@ -1716,6 +1705,20 @@ static int k3_r5_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	if (ret == -EINVAL) {
+		/*
+		 * default to most common efuse configurations - Split-mode on AM64x
+		 * and LockStep-mode on all others
+		 */
+		cluster->mode = data->single_cpu_mode ?
+					CLUSTER_MODE_SPLIT : CLUSTER_MODE_LOCKSTEP;
+	}
+
+	if (cluster->mode == CLUSTER_MODE_SINGLECPU && !data->single_cpu_mode) {
+		dev_err(dev, "Cluster mode = %d is not supported on this SoC\n", cluster->mode);
+		return -EINVAL;
+	}
+
 	num_cores = of_get_available_child_count(np);
 	if (num_cores != 2) {
 		dev_err(dev, "MCU cluster requires both R5F cores to be enabled, num_cores = %d\n",
-- 
2.34.1