[PATCH net-next 0/2] net: macb: fix ENST configuration for all queues

[PATCH net-next 0/2] net: macb: fix ENST configuration for all queues

[Vineeth Karumanchi]

This series fixes the ENST (Enhanced Scheduled Traffic) queue
configuration in the macb driver and removes leftover dead defines.

When a TAPRIO schedule configured only a subset of queues, the driver
left the ENST timing registers of the unconfigured queues at their
reset values, resulting in an invalid setup. Patch 2 configures all
queues unconditionally, zero-initializing the unconfigured ones, and
derives the queue index directly from the gate mask instead of storing
a redundant queue_id.

Patch 1 removes the fixed per-queue ENST time register defines that are
no longer referenced, since the driver computes these addresses from the
ENST base offset and the queue index.

Vineeth Karumanchi (2):
  net: macb: remove unused ENST Q0/Q1 time register defines
  net: macb: configure ENST registers for all queues

 drivers/net/ethernet/cadence/macb.h      |  8 --------
 drivers/net/ethernet/cadence/macb_main.c | 20 +++++++++-----------
 2 files changed, 9 insertions(+), 19 deletions(-)

-- 
2.44.4

[PATCH net-next 1/2] net: macb: remove unused ENST Q0/Q1 time register defines

[Vineeth Karumanchi]

The ENST start/on/off time register definitions for Q0 and Q1 are not
referenced anywhere in the driver. The driver calculates these register
addresses from the ENST base offset and the queue index instead of using
fixed defines, removing the unused macros.

Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
---
 drivers/net/ethernet/cadence/macb.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 2de56017ee0d..a11052565436 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -184,12 +184,6 @@
 #define GEM_DCFG8		0x029C /* Design Config 8 */
 #define GEM_DCFG10		0x02A4 /* Design Config 10 */
 #define GEM_DCFG12		0x02AC /* Design Config 12 */
-#define GEM_ENST_START_TIME_Q0	0x0800 /* ENST Q0 start time */
-#define GEM_ENST_START_TIME_Q1	0x0804 /* ENST Q1 start time */
-#define GEM_ENST_ON_TIME_Q0	0x0820 /* ENST Q0 on time */
-#define GEM_ENST_ON_TIME_Q1	0x0824 /* ENST Q1 on time */
-#define GEM_ENST_OFF_TIME_Q0	0x0840 /* ENST Q0 off time */
-#define GEM_ENST_OFF_TIME_Q1	0x0844 /* ENST Q1 off time */
 #define GEM_ENST_CONTROL	0x0880 /* ENST control register */
 #define GEM_USX_CONTROL		0x0A80 /* High speed PCS control register */
 #define GEM_USX_STATUS		0x0A88 /* High speed PCS status register */
-- 
2.44.4

Re: [PATCH net-next 1/2] net: macb: remove unused ENST Q0/Q1 time register defines

[Théo Lebrun]

Hello Vineeth,

On Fri Jul 24, 2026 at 6:32 AM CEST, Vineeth Karumanchi wrote:
> The ENST start/on/off time register definitions for Q0 and Q1 are not
> referenced anywhere in the driver. The driver calculates these register
> addresses from the ENST base offset and the queue index instead of using
> fixed defines, removing the unused macros.
>
> Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
> ---
>  drivers/net/ethernet/cadence/macb.h | 6 ------
>  1 file changed, 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 2de56017ee0d..a11052565436 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -184,12 +184,6 @@
>  #define GEM_DCFG8		0x029C /* Design Config 8 */
>  #define GEM_DCFG10		0x02A4 /* Design Config 10 */
>  #define GEM_DCFG12		0x02AC /* Design Config 12 */
> -#define GEM_ENST_START_TIME_Q0	0x0800 /* ENST Q0 start time */
> -#define GEM_ENST_START_TIME_Q1	0x0804 /* ENST Q1 start time */
> -#define GEM_ENST_ON_TIME_Q0	0x0820 /* ENST Q0 on time */
> -#define GEM_ENST_ON_TIME_Q1	0x0824 /* ENST Q1 on time */
> -#define GEM_ENST_OFF_TIME_Q0	0x0840 /* ENST Q0 off time */
> -#define GEM_ENST_OFF_TIME_Q1	0x0844 /* ENST Q1 off time */
>  #define GEM_ENST_CONTROL	0x0880 /* ENST control register */
>  #define GEM_USX_CONTROL		0x0A80 /* High speed PCS control register */
>  #define GEM_USX_STATUS		0x0A88 /* High speed PCS status register */

Reviewed-by: Théo Lebrun <theo.lebrun@bootlin.com>

Thanks,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH net-next 1/2] net: macb: remove unused ENST Q0/Q1 time register defines

[Nicolai Buchwitz]

Hi Vineeth

On 24.7.2026 06:32, Vineeth Karumanchi wrote:
> The ENST start/on/off time register definitions for Q0 and Q1 are not
> referenced anywhere in the driver. The driver calculates these register
> addresses from the ENST base offset and the queue index instead of 
> using
> fixed defines, removing the unused macros.
> 
> Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
> ---
>  drivers/net/ethernet/cadence/macb.h | 6 ------
>  1 file changed, 6 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb.h 
> b/drivers/net/ethernet/cadence/macb.h
> index 2de56017ee0d..a11052565436 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -184,12 +184,6 @@
>  #define GEM_DCFG8		0x029C /* Design Config 8 */
>  #define GEM_DCFG10		0x02A4 /* Design Config 10 */
>  #define GEM_DCFG12		0x02AC /* Design Config 12 */
> -#define GEM_ENST_START_TIME_Q0	0x0800 /* ENST Q0 start time */
> -#define GEM_ENST_START_TIME_Q1	0x0804 /* ENST Q1 start time */
> -#define GEM_ENST_ON_TIME_Q0	0x0820 /* ENST Q0 on time */
> -#define GEM_ENST_ON_TIME_Q1	0x0824 /* ENST Q1 on time */
> -#define GEM_ENST_OFF_TIME_Q0	0x0840 /* ENST Q0 off time */
> -#define GEM_ENST_OFF_TIME_Q1	0x0844 /* ENST Q1 off time */
>  #define GEM_ENST_CONTROL	0x0880 /* ENST control register */
>  #define GEM_USX_CONTROL		0x0A80 /* High speed PCS control register */
>  #define GEM_USX_STATUS		0x0A88 /* High speed PCS status register */

Reviewed-by: Nicolai Buchwitz <nb@tipi-net.de>

Thanks
Nicolai

[PATCH net-next 2/2] net: macb: configure ENST registers for all queues

[Vineeth Karumanchi]

The initial "tc" command was not overwriting the reset value of ENST
registers if only a subset of queues were configured, leading to an
invalid setup. To fix this, configure all queues unconditionally.
Unconfigured queues are zero-initialized via kcalloc(), ensuring a
complete and consistent configuration.

The queue_id field in struct macb_queue_enst_config becomes redundant
once the array is indexed by queue id, so drop it.

Key changes:
- Drop queue_id from struct macb_queue_enst_config
- Allocate enst_queue[] based on bp->num_queues instead of
  conf->num_entries
- Index enst_queue[] directly with the queue number
- Program ENST registers for all queues

Fixes: 89934dbf169e ("net: macb: Add TAPRIO traffic scheduling support")
Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
---
 drivers/net/ethernet/cadence/macb.h      |  2 --
 drivers/net/ethernet/cadence/macb_main.c | 20 +++++++++-----------
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index a11052565436..4cc9aa9b2f9e 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -1490,7 +1490,6 @@ struct macb_platform_data {
  * @start_time_mask:  Bitmask representing the start time for the queue
  * @on_time_bytes:    "on" time nsec expressed in bytes
  * @off_time_bytes:   "off" time nsec expressed in bytes
- * @queue_id:         Identifier for the queue
  *
  * This structure holds the configuration parameters for an ENST queue,
  * used to control time-based transmission scheduling in the MACB driver.
@@ -1499,7 +1498,6 @@ struct macb_queue_enst_config {
 	u32 start_time_mask;
 	u32 on_time_bytes;
 	u32 off_time_bytes;
-	u8 queue_id;
 };
 
 #endif /* _MACB_H */
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index d394f1f43b68..d58430fe9c41 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4329,7 +4329,7 @@ static int macb_taprio_setup_replace(struct net_device *ndev,
 	struct macb_queue *queue;
 	u32 queue_mask;
 	u8 queue_id;
-	size_t i;
+	size_t i, q;
 	int err;
 
 	if (conf->num_entries > bp->num_queues) {
@@ -4357,7 +4357,7 @@ static int macb_taprio_setup_replace(struct net_device *ndev,
 		return -EINVAL;
 	}
 
-	enst_queue = kcalloc(conf->num_entries, sizeof(*enst_queue), GFP_KERNEL);
+	enst_queue = kcalloc(bp->num_queues, sizeof(*enst_queue), GFP_KERNEL);
 	if (unlikely(!enst_queue))
 		return -ENOMEM;
 
@@ -4416,13 +4416,12 @@ static int macb_taprio_setup_replace(struct net_device *ndev,
 			goto cleanup;
 		}
 
-		enst_queue[i].queue_id = queue_id;
-		enst_queue[i].start_time_mask =
+		enst_queue[queue_id].start_time_mask =
 			(start_time_sec << GEM_START_TIME_SEC_OFFSET) |
 			start_time_nsec;
-		enst_queue[i].on_time_bytes =
+		enst_queue[queue_id].on_time_bytes =
 			enst_ns_to_hw_units(entry->interval, speed);
-		enst_queue[i].off_time_bytes =
+		enst_queue[queue_id].off_time_bytes =
 			enst_ns_to_hw_units(conf->cycle_time - entry->interval, speed);
 
 		configured_queues |= entry->gate_mask;
@@ -4448,15 +4447,14 @@ static int macb_taprio_setup_replace(struct net_device *ndev,
 		gem_writel(bp, ENST_CONTROL,
 			   queue_mask << GEM_ENST_DISABLE_QUEUE_OFFSET);
 
-		for (i = 0; i < conf->num_entries; i++) {
-			queue = &bp->queues[enst_queue[i].queue_id];
+		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
 			/* Configure queue timing registers */
 			queue_writel(queue, ENST_START_TIME,
-				     enst_queue[i].start_time_mask);
+				     enst_queue[q].start_time_mask);
 			queue_writel(queue, ENST_ON_TIME,
-				     enst_queue[i].on_time_bytes);
+				     enst_queue[q].on_time_bytes);
 			queue_writel(queue, ENST_OFF_TIME,
-				     enst_queue[i].off_time_bytes);
+				     enst_queue[q].off_time_bytes);
 		}
 
 		/* Enable ENST for all configured queues in one write */
-- 
2.44.4

Re: [PATCH net-next 2/2] net: macb: configure ENST registers for all queues

[Théo Lebrun]

Hello Vineeth,

On Fri Jul 24, 2026 at 6:32 AM CEST, Vineeth Karumanchi wrote:
> The initial "tc" command was not overwriting the reset value of ENST
> registers if only a subset of queues were configured, leading to an
> invalid setup. To fix this, configure all queues unconditionally.
> Unconfigured queues are zero-initialized via kcalloc(), ensuring a
> complete and consistent configuration.

But if a subset of queues are configured, the remaining queues don't
have their ENST support enabled thanks to ENST_CONTROL and their ENST
per-queue register values aren't read? Or HW is broken and reads ENST
registers anyway? Or something else I misunderstood?

What reset value of ENST regs you observed that caused you trouble?
That info could make it into the commit message.

> The queue_id field in struct macb_queue_enst_config becomes redundant
> once the array is indexed by queue id, so drop it.
>
> Key changes:
> - Drop queue_id from struct macb_queue_enst_config
> - Allocate enst_queue[] based on bp->num_queues instead of
>   conf->num_entries
> - Index enst_queue[] directly with the queue number
> - Program ENST registers for all queues
>
> Fixes: 89934dbf169e ("net: macb: Add TAPRIO traffic scheduling support")
> Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>

Thanks,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Re: [PATCH net-next 2/2] net: macb: configure ENST registers for all queues

[Nicolai Buchwitz]

Hi Vineeth

On 24.7.2026 06:32, Vineeth Karumanchi wrote:
> The initial "tc" command was not overwriting the reset value of ENST
> registers if only a subset of queues were configured, leading to an
> invalid setup. To fix this, configure all queues unconditionally.
> Unconfigured queues are zero-initialized via kcalloc(), ensuring a
> complete and consistent configuration.
> 
> The queue_id field in struct macb_queue_enst_config becomes redundant
> once the array is indexed by queue id, so drop it.
> 
> Key changes:
> - Drop queue_id from struct macb_queue_enst_config
> - Allocate enst_queue[] based on bp->num_queues instead of
>   conf->num_entries
> - Index enst_queue[] directly with the queue number
> - Program ENST registers for all queues
> 
> Fixes: 89934dbf169e ("net: macb: Add TAPRIO traffic scheduling 
> support")

In addition to what Théo already mentioned:

The series targets net-next, but if this is a real bug fix it should
probably be routed via net. The offending commit is in stable since 
v6.18.

> Signed-off-by: Vineeth Karumanchi <vineeth.karumanchi@amd.com>
> ---
>  drivers/net/ethernet/cadence/macb.h      |  2 --
>  drivers/net/ethernet/cadence/macb_main.c | 20 +++++++++-----------
>  2 files changed, 9 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb.h 
> b/drivers/net/ethernet/cadence/macb.h
> index a11052565436..4cc9aa9b2f9e 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -1490,7 +1490,6 @@ struct macb_platform_data {
>   * @start_time_mask:  Bitmask representing the start time for the 
> queue
>   * @on_time_bytes:    "on" time nsec expressed in bytes
>   * @off_time_bytes:   "off" time nsec expressed in bytes
> - * @queue_id:         Identifier for the queue
>   *
>   * This structure holds the configuration parameters for an ENST 
> queue,
>   * used to control time-based transmission scheduling in the MACB 
> driver.
> @@ -1499,7 +1498,6 @@ struct macb_queue_enst_config {
>  	u32 start_time_mask;
>  	u32 on_time_bytes;
>  	u32 off_time_bytes;
> -	u8 queue_id;
>  };
> 
>  #endif /* _MACB_H */
> diff --git a/drivers/net/ethernet/cadence/macb_main.c 
> b/drivers/net/ethernet/cadence/macb_main.c
> index d394f1f43b68..d58430fe9c41 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -4329,7 +4329,7 @@ static int macb_taprio_setup_replace(struct 
> net_device *ndev,
>  	struct macb_queue *queue;
>  	u32 queue_mask;
>  	u8 queue_id;
> -	size_t i;
> +	size_t i, q;
>  	int err;
> 
>  	if (conf->num_entries > bp->num_queues) {
> @@ -4357,7 +4357,7 @@ static int macb_taprio_setup_replace(struct 
> net_device *ndev,
>  		return -EINVAL;
>  	}
> 
> -	enst_queue = kcalloc(conf->num_entries, sizeof(*enst_queue), 
> GFP_KERNEL);
> +	enst_queue = kcalloc(bp->num_queues, sizeof(*enst_queue), 
> GFP_KERNEL);
>  	if (unlikely(!enst_queue))
>  		return -ENOMEM;
> 
> @@ -4416,13 +4416,12 @@ static int macb_taprio_setup_replace(struct 
> net_device *ndev,
>  			goto cleanup;
>  		}
> 
> -		enst_queue[i].queue_id = queue_id;
> -		enst_queue[i].start_time_mask =
> +		enst_queue[queue_id].start_time_mask =
>  			(start_time_sec << GEM_START_TIME_SEC_OFFSET) |
>  			start_time_nsec;
> -		enst_queue[i].on_time_bytes =
> +		enst_queue[queue_id].on_time_bytes =
>  			enst_ns_to_hw_units(entry->interval, speed);
> -		enst_queue[i].off_time_bytes =
> +		enst_queue[queue_id].off_time_bytes =
>  			enst_ns_to_hw_units(conf->cycle_time - entry->interval, speed);
> 
>  		configured_queues |= entry->gate_mask;
> @@ -4448,15 +4447,14 @@ static int macb_taprio_setup_replace(struct 
> net_device *ndev,
>  		gem_writel(bp, ENST_CONTROL,
>  			   queue_mask << GEM_ENST_DISABLE_QUEUE_OFFSET);
> 
> -		for (i = 0; i < conf->num_entries; i++) {
> -			queue = &bp->queues[enst_queue[i].queue_id];
> +		for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
>  			/* Configure queue timing registers */
>  			queue_writel(queue, ENST_START_TIME,
> -				     enst_queue[i].start_time_mask);
> +				     enst_queue[q].start_time_mask);
>  			queue_writel(queue, ENST_ON_TIME,
> -				     enst_queue[i].on_time_bytes);
> +				     enst_queue[q].on_time_bytes);
>  			queue_writel(queue, ENST_OFF_TIME,
> -				     enst_queue[i].off_time_bytes);
> +				     enst_queue[q].off_time_bytes);
>  		}
> 
>  		/* Enable ENST for all configured queues in one write */

Regards,
Nicolai