[PATCH v4 0/1] Adjust macb max_tx_len for mpfs

[PATCH v4 0/1] Adjust macb max_tx_len for mpfs

[daire.mcnamara]

From: Daire McNamara <daire.mcnamara@microchip.com>

Several customers have reported unexpected ethernet issues whereby
the GEM stops transmitting and receiving. Performing an action such
as ifconfig <ethX> down; ifconfig <ethX> up clears this particular
condition.

The origin of the issue is a stream of AMBA_ERRORS (bit 6) from the
tx queues.

This patch sets the max_tx_length to SRAM size (16 KiB
in the case of mpfs) divided by num_queues (4 in the case of mpfs)
and then subtracts 56 bytes from that figure - resulting in max_tx_len
of 4040.  The max jumbo length is also set to 4040.  These figures
are derived from Cadence erratum 1686.

Change from v3
- Simplified the if/else ladder

Change from v2
- Remove pointless check for existence of macb_config.

Change from v1
- Switched from using macb_is_gem() to hw_is_gem() as macb_is_gem()
  relies on capabilities being read and these have not been ascertained
  at this point of the probe routine.

Daire McNamara (1):
  net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs

 drivers/net/ethernet/cadence/macb.h      |  1 +
 drivers/net/ethernet/cadence/macb_main.c | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)


base-commit: 09a9639e56c01c7a00d6c0ca63f4c7c41abe075d
-- 
2.25.1

[PATCH v4 1/1] net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs

[daire.mcnamara]

From: Daire McNamara <daire.mcnamara@microchip.com>

On mpfs, with SRAM configured for 4 queues, setting max_tx_len
to GEM_TX_MAX_LEN=0x3f0 results multiple AMBA errors.
Setting max_tx_len to (4KiB - 56) removes those errors.

The details are described in erratum 1686 by Cadence

The max jumbo frame size is also reduced for mpfs to (4KiB - 56).

Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>
---
 drivers/net/ethernet/cadence/macb.h      |  1 +
 drivers/net/ethernet/cadence/macb_main.c | 12 +++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 14dfec4db8f9..989e7c5db9b9 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/drivers/net/ethernet/cadence/macb.h
@@ -1175,6 +1175,7 @@ struct macb_config {
 			    struct clk **hclk, struct clk **tx_clk,
 			    struct clk **rx_clk, struct clk **tsu_clk);
 	int	(*init)(struct platform_device *pdev);
+	unsigned int		max_tx_length;
 	int	jumbo_max_len;
 	const struct macb_usrio_config *usrio;
 };
diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
index 66e30561569e..3a46b75ae54f 100644
--- a/drivers/net/ethernet/cadence/macb_main.c
+++ b/drivers/net/ethernet/cadence/macb_main.c
@@ -4095,14 +4095,12 @@ static int macb_init(struct platform_device *pdev)
 
 	/* setup appropriated routines according to adapter type */
 	if (macb_is_gem(bp)) {
-		bp->max_tx_length = GEM_MAX_TX_LEN;
 		bp->macbgem_ops.mog_alloc_rx_buffers = gem_alloc_rx_buffers;
 		bp->macbgem_ops.mog_free_rx_buffers = gem_free_rx_buffers;
 		bp->macbgem_ops.mog_init_rings = gem_init_rings;
 		bp->macbgem_ops.mog_rx = gem_rx;
 		dev->ethtool_ops = &gem_ethtool_ops;
 	} else {
-		bp->max_tx_length = MACB_MAX_TX_LEN;
 		bp->macbgem_ops.mog_alloc_rx_buffers = macb_alloc_rx_buffers;
 		bp->macbgem_ops.mog_free_rx_buffers = macb_free_rx_buffers;
 		bp->macbgem_ops.mog_init_rings = macb_init_rings;
@@ -4839,7 +4837,8 @@ static const struct macb_config mpfs_config = {
 	.clk_init = macb_clk_init,
 	.init = init_reset_optional,
 	.usrio = &macb_default_usrio,
-	.jumbo_max_len = 10240,
+	.max_tx_length = 4040, /* Cadence Erratum 1686 */
+	.jumbo_max_len = 4040,
 };
 
 static const struct macb_config sama7g5_gem_config = {
@@ -4989,6 +4988,13 @@ static int macb_probe(struct platform_device *pdev)
 	if (macb_config)
 		bp->jumbo_max_len = macb_config->jumbo_max_len;
 
+	if (!hw_is_gem(bp->regs, bp->native_io))
+		bp->max_tx_length = MACB_MAX_TX_LEN;
+	else if (macb_config->max_tx_length)
+		bp->max_tx_length = macb_config->max_tx_length;
+	else
+		bp->max_tx_length = GEM_MAX_TX_LEN;
+
 	bp->wol = 0;
 	if (of_property_read_bool(np, "magic-packet"))
 		bp->wol |= MACB_WOL_HAS_MAGIC_PACKET;
-- 
2.25.1

Re: [PATCH v4 1/1] net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 598 bytes --]

On Fri, May 12, 2023 at 01:20:32PM +0100, daire.mcnamara@microchip.com wrote:
> From: Daire McNamara <daire.mcnamara@microchip.com>
> 
> On mpfs, with SRAM configured for 4 queues, setting max_tx_len
> to GEM_TX_MAX_LEN=0x3f0 results multiple AMBA errors.
> Setting max_tx_len to (4KiB - 56) removes those errors.
> 
> The details are described in erratum 1686 by Cadence
> 
> The max jumbo frame size is also reduced for mpfs to (4KiB - 56).
> 
> Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>

Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Thanks,
Conor.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

Re: [PATCH v4 1/1] net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs

[Simon Horman]

On Fri, May 12, 2023 at 01:20:32PM +0100, daire.mcnamara@microchip.com wrote:
> From: Daire McNamara <daire.mcnamara@microchip.com>
> 
> On mpfs, with SRAM configured for 4 queues, setting max_tx_len
> to GEM_TX_MAX_LEN=0x3f0 results multiple AMBA errors.
> Setting max_tx_len to (4KiB - 56) removes those errors.
> 
> The details are described in erratum 1686 by Cadence
> 
> The max jumbo frame size is also reduced for mpfs to (4KiB - 56).
> 
> Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>

Reviewed-by: Simon Horman <simon.horman@corigine.com>

Re: [PATCH v4 1/1] net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs

[Claudiu.Beznea]

On 12.05.2023 15:20, daire.mcnamara@microchip.com wrote:
> From: Daire McNamara <daire.mcnamara@microchip.com>
> 
> On mpfs, with SRAM configured for 4 queues, setting max_tx_len
> to GEM_TX_MAX_LEN=0x3f0 results multiple AMBA errors.
> Setting max_tx_len to (4KiB - 56) removes those errors.
> 
> The details are described in erratum 1686 by Cadence
> 
> The max jumbo frame size is also reduced for mpfs to (4KiB - 56).
> 
> Signed-off-by: Daire McNamara <daire.mcnamara@microchip.com>

Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>


> ---
>  drivers/net/ethernet/cadence/macb.h      |  1 +
>  drivers/net/ethernet/cadence/macb_main.c | 12 +++++++++---
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 14dfec4db8f9..989e7c5db9b9 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -1175,6 +1175,7 @@ struct macb_config {
>  			    struct clk **hclk, struct clk **tx_clk,
>  			    struct clk **rx_clk, struct clk **tsu_clk);
>  	int	(*init)(struct platform_device *pdev);
> +	unsigned int		max_tx_length;
>  	int	jumbo_max_len;
>  	const struct macb_usrio_config *usrio;
>  };
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 66e30561569e..3a46b75ae54f 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -4095,14 +4095,12 @@ static int macb_init(struct platform_device *pdev)
>  
>  	/* setup appropriated routines according to adapter type */
>  	if (macb_is_gem(bp)) {
> -		bp->max_tx_length = GEM_MAX_TX_LEN;
>  		bp->macbgem_ops.mog_alloc_rx_buffers = gem_alloc_rx_buffers;
>  		bp->macbgem_ops.mog_free_rx_buffers = gem_free_rx_buffers;
>  		bp->macbgem_ops.mog_init_rings = gem_init_rings;
>  		bp->macbgem_ops.mog_rx = gem_rx;
>  		dev->ethtool_ops = &gem_ethtool_ops;
>  	} else {
> -		bp->max_tx_length = MACB_MAX_TX_LEN;
>  		bp->macbgem_ops.mog_alloc_rx_buffers = macb_alloc_rx_buffers;
>  		bp->macbgem_ops.mog_free_rx_buffers = macb_free_rx_buffers;
>  		bp->macbgem_ops.mog_init_rings = macb_init_rings;
> @@ -4839,7 +4837,8 @@ static const struct macb_config mpfs_config = {
>  	.clk_init = macb_clk_init,
>  	.init = init_reset_optional,
>  	.usrio = &macb_default_usrio,
> -	.jumbo_max_len = 10240,
> +	.max_tx_length = 4040, /* Cadence Erratum 1686 */
> +	.jumbo_max_len = 4040,
>  };
>  
>  static const struct macb_config sama7g5_gem_config = {
> @@ -4989,6 +4988,13 @@ static int macb_probe(struct platform_device *pdev)
>  	if (macb_config)
>  		bp->jumbo_max_len = macb_config->jumbo_max_len;
>  
> +	if (!hw_is_gem(bp->regs, bp->native_io))
> +		bp->max_tx_length = MACB_MAX_TX_LEN;
> +	else if (macb_config->max_tx_length)
> +		bp->max_tx_length = macb_config->max_tx_length;
> +	else
> +		bp->max_tx_length = GEM_MAX_TX_LEN;
> +
>  	bp->wol = 0;
>  	if (of_property_read_bool(np, "magic-packet"))
>  		bp->wol |= MACB_WOL_HAS_MAGIC_PACKET;

Re: [PATCH v4 0/1] Adjust macb max_tx_len for mpfs

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by David S. Miller <davem@davemloft.net>:

On Fri, 12 May 2023 13:20:31 +0100 you wrote:
> From: Daire McNamara <daire.mcnamara@microchip.com>
> 
> Several customers have reported unexpected ethernet issues whereby
> the GEM stops transmitting and receiving. Performing an action such
> as ifconfig <ethX> down; ifconfig <ethX> up clears this particular
> condition.
> 
> [...]

Here is the summary with links:
  - [v4,1/1] net: macb: Shorten max_tx_len to 4KiB - 56 on mpfs
    https://git.kernel.org/netdev/net-next/c/314cf958de2a

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html