[PATCH net 0/2] net: dsa: hellcreek: 802.1Qbv Fixes

Hi,

while using TAPRIO offloading on the Hirschmann hellcreek switch, I've noticed
two issues in the current implementation:

1. The gate control list is incorrectly programmed
2. The admin base time is not set properly

Fix it.

Thanks,
Kurt

Kurt Kanzenbach (2):
  net: dsa: hellcreek: Fix incorrect setting of GCL
  net: dsa: hellcreek: Adjust schedule look ahead window

 drivers/net/dsa/hirschmann/hellcreek.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

-- 
2.30.2

Traffic schedules can only be started up to eight seconds within the
future. Therefore, the driver periodically checks every two seconds whether the
admin base time provided by the user is inside that window. If so the schedule
is started. Otherwise the check is deferred.

However, according to the programming manual the look ahead window size should
be four - not eight - seconds. By using the proposed value of four seconds
starting a schedule at a specified admin base time actually works as expected.

Fixes: 24dfc6eb39b2 ("net: dsa: hellcreek: Add TAPRIO offloading support")
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
---
 drivers/net/dsa/hirschmann/hellcreek.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/dsa/hirschmann/hellcreek.c b/drivers/net/dsa/hirschmann/hellcreek.c
index b57aea92684b..7062db6a083c 100644
--- a/drivers/net/dsa/hirschmann/hellcreek.c
+++ b/drivers/net/dsa/hirschmann/hellcreek.c

@@ -1550,7 +1550,7 @@ static bool hellcreek_schedule_startable(struct hellcreek *hellcreek, int port)
 	/* Calculate difference to admin base time */
 	base_time_ns = ktime_to_ns(hellcreek_port->current_schedule->base_time);
 
-	return base_time_ns - current_ns < (s64)8 * NSEC_PER_SEC;
+	return base_time_ns - current_ns < (s64)4 * NSEC_PER_SEC;
 }
 
 static void hellcreek_start_schedule(struct hellcreek *hellcreek, int port)

-- 
2.30.2

Currently the gate control list which is programmed into the hardware is
incorrect resulting in wrong traffic schedules. The problem is the loop
variables are incremented before they are referenced. Therefore, move the
increment to the end of the loop.

Fixes: 24dfc6eb39b2 ("net: dsa: hellcreek: Add TAPRIO offloading support")
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
---
 drivers/net/dsa/hirschmann/hellcreek.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dsa/hirschmann/hellcreek.c b/drivers/net/dsa/hirschmann/hellcreek.c
index 5c54ae1be62c..b57aea92684b 100644
--- a/drivers/net/dsa/hirschmann/hellcreek.c
+++ b/drivers/net/dsa/hirschmann/hellcreek.c

@@ -1472,9 +1472,6 @@ static void hellcreek_setup_gcl(struct hellcreek *hellcreek, int port,
 		u16 data;
 		u8 gates;
 
-		cur++;
-		next++;
-
 		if (i == schedule->num_entries)
 			gates = initial->gate_mask ^
 				cur->gate_mask;

@@ -1503,6 +1500,9 @@ static void hellcreek_setup_gcl(struct hellcreek *hellcreek, int port,
 			(initial->gate_mask <<
 			 TR_GCLCMD_INIT_GATE_STATES_SHIFT);
 		hellcreek_write(hellcreek, data, TR_GCLCMD);
+
+		cur++;
+		next++;
 	}
 }
 

-- 
2.30.2

On 8/25/2021 3:58 PM, Kurt Kanzenbach wrote:

Currently the gate control list which is programmed into the hardware is
incorrect resulting in wrong traffic schedules. The problem is the loop
variables are incremented before they are referenced. Therefore, move the
increment to the end of the loop.

Fixes: 24dfc6eb39b2 ("net: dsa: hellcreek: Add TAPRIO offloading support")
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

On 8/25/2021 3:58 PM, Kurt Kanzenbach wrote:

Traffic schedules can only be started up to eight seconds within the
future. Therefore, the driver periodically checks every two seconds whether the
admin base time provided by the user is inside that window. If so the schedule
is started. Otherwise the check is deferred.

Uber nit: this probably ought to be just one sentence starting from 
"Therefore" and ending at deferred.

However, according to the programming manual the look ahead window size should
be four - not eight - seconds. By using the proposed value of four seconds
starting a schedule at a specified admin base time actually works as expected.

Fixes: 24dfc6eb39b2 ("net: dsa: hellcreek: Add TAPRIO offloading support")
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
-- 
Florian

Hello:

This series was applied to netdev/net.git (refs/heads/master):

On Wed, 25 Aug 2021 15:58:11 +0200 you wrote:

Hi,

while using TAPRIO offloading on the Hirschmann hellcreek switch, I've noticed
two issues in the current implementation:

1. The gate control list is incorrectly programmed
2. The admin base time is not set properly

[...]

Here is the summary with links:
  - [net,1/2] net: dsa: hellcreek: Fix incorrect setting of GCL
    https://git.kernel.org/netdev/net/c/a7db5ed8632c
  - [net,2/2] net: dsa: hellcreek: Adjust schedule look ahead window
    https://git.kernel.org/netdev/net/c/b7658ed35a5f

You are awesome, thank you!
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