[PATCH] remoteproc: k3-r5: Fix rproc init failure on Split-mode _only_ devices

[Suman Anna]

The R5F subsystem/cluster on K3 SoCs can support both LockStep and
Split-modes (superset) or just Split-mode depending on an eFUSE
capability register. The LockStep configuration bit is Read-only
though on Split-mode _only_ devices and as such the System Firmware
does not allow the LockStep mode bit to be configured on such devices.
The current logic in k3_r5f_rproc_configure() fails on Split-mode
devices because of this unconditional programming of the LockStep
mode bit, and results in the probe failure shown during the
"rproc init" step at U-Boot prompt.

Fix this by limiting the LockStep mode bit clear configuration only on
devices supporting both LockStep/Split-modes.

Fixes: 4c850356a83f ("remoteproc: Introduce K3 remoteproc driver for R5F subsystem")
Signed-off-by: Suman Anna <s-anna at ti.com>
Signed-off-by: Andreas Dannenberg <dannenberg at ti.com>
Signed-off-by: Lokesh Vutla <lokeshvutla at ti.com>
---
Hi Lokesh,

Verified the behavior on top of the ti/next branch on a custom
board with the Split-mode only SoC.

regards
Suman

 drivers/remoteproc/ti_k3_r5f_rproc.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/remoteproc/ti_k3_r5f_rproc.c b/drivers/remoteproc/ti_k3_r5f_rproc.c
index 2e2665f3750d..c01b29d90f1b 100644
--- a/drivers/remoteproc/ti_k3_r5f_rproc.c
+++ b/drivers/remoteproc/ti_k3_r5f_rproc.c
@@ -543,6 +543,7 @@ static int k3_r5f_rproc_configure(struct k3_r5f_core *core)
 {
 	struct k3_r5f_cluster *cluster = core->cluster;
 	u32 set_cfg = 0, clr_cfg = 0, cfg, ctrl, sts;
+	bool lockstep_permitted;
 	u64 boot_vec = 0;
 	int ret;
 
@@ -560,8 +561,9 @@ static int k3_r5f_rproc_configure(struct k3_r5f_core *core)
 		goto out;
 
 	/* Sanity check for Lockstep mode */
-	if (cluster->mode && is_primary_core(core) &&
-	    !(sts & PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED)) {
+	lockstep_permitted = !!(sts &
+				PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED);
+	if (cluster->mode && is_primary_core(core) && !lockstep_permitted) {
 		dev_err(core->dev, "LockStep mode not permitted on this device\n");
 		ret = -EINVAL;
 		goto out;
@@ -573,7 +575,7 @@ static int k3_r5f_rproc_configure(struct k3_r5f_core *core)
 		clr_cfg |= PROC_BOOT_CFG_FLAG_R5_TEINIT;
 		if (cluster->mode == CLUSTER_MODE_LOCKSTEP)
 			set_cfg |= PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
-		else
+		else if (lockstep_permitted)
 			clr_cfg |= PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
 	}
 
-- 
2.23.0