[PATCH net v2 2/2] net: ti: icssg-prueth: Fix clearing of IEP_CMP_CFG registers during iep_init

[Meghana Malladi <m-malladi@ti.com>]

When ICSSG interfaces are brought down and brought up again, the
pru cores are shut down and booted again, flushing out all the memories
and start again in a clean state. Hence it is expected that the
IEP_CMP_CFG register needs to be flushed during iep_init() to ensure
that the existing residual configuration doesn't cause any unusual
behavior. If the register is not cleared, existing IEP_CMP_CFG set for
CMP1 will result in SYNC0_OUT signal based on the SYNC_OUT register values.

After bringing the interface up, calling PPS enable doesn't work as
the driver believes PPS is already enabled, (iep->pps_enabled is not
cleared during interface bring down) and driver will just return true
even though there is no signal. Fix this by disabling pps and perout.

Fixes: c1e0230eeaab ("net: ti: icss-iep: Add IEP driver")
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
---

Hi all,

This patch is based on net-next tagged next-2024110.
v1:https://lore.kernel.org/all/20241106074040.3361730-3-m-malladi@ti.com/

Changes since v1 (v2-v1):
- Move clear CMP_CFG inside clear CMP_STAT loop as suggested by
Roger Quadros <rogerq@kernel.org>
- Disable pps/perout instead of setting to false as suggested by
Roger Quadros <rogerq@kernel.org>

 drivers/net/ethernet/ti/icssg/icss_iep.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/ethernet/ti/icssg/icss_iep.c b/drivers/net/ethernet/ti/icssg/icss_iep.c
index 5d6d1cf78e93..a96861debbe3 100644
--- a/drivers/net/ethernet/ti/icssg/icss_iep.c
+++ b/drivers/net/ethernet/ti/icssg/icss_iep.c
@@ -215,6 +215,10 @@ static void icss_iep_enable_shadow_mode(struct icss_iep *iep)
 	for (cmp = IEP_MIN_CMP; cmp < IEP_MAX_CMP; cmp++) {
 		regmap_update_bits(iep->map, ICSS_IEP_CMP_STAT_REG,
 				   IEP_CMP_STATUS(cmp), IEP_CMP_STATUS(cmp));
+
+		regmap_update_bits(iep->map, ICSS_IEP_CMP_CFG_REG,
+				   IEP_CMP_CFG_CMP_EN(cmp), 0);
+
 	}
 
 	/* enable reset counter on CMP0 event */
@@ -780,6 +784,11 @@ int icss_iep_exit(struct icss_iep *iep)
 	}
 	icss_iep_disable(iep);
 
+	if (iep->pps_enabled)
+		icss_iep_pps_enable(iep, false);
+	else if (iep->perout_enabled)
+		icss_iep_perout_enable(iep, NULL, false);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(icss_iep_exit);
-- 
2.25.1