RE: [EXTERNAL] [PATCH v7 net-next 6/8] net: ethernet: ti: am65-cpsw-qos: Add Frame Preemption MAC Merge support

["Varis, Pekka" <p-varis@ti.com>]

> -----Original Message-----
> From: Roger Quadros <rogerq@kernel.org>
> 
> Add driver support for viewing / changing the MAC Merge sublayer
> parameters and seeing the verification state machine's current state via
> ethtool.
> 
> As hardware does not support interrupt notification for verification events
> we resort to polling on link up. On link up we try a couple of times for
> verification success and if unsuccessful then give up.
> 
> The Frame Preemption feature is described in the Technical Reference
> Manual [1] in section:
> 	12.3.1.4.6.7 Intersperced Express Traffic (IET – P802.3br/D2.0)
> 
> Due to Silicon Errata i2208 [2] we set limit min IET fragment size to 124.

Should be 128 not 124

> 
> [1] AM62x TRM - https://www.ti.com/lit/ug/spruiv7a/spruiv7a.pdf
> [2] AM62x Silicon Errata - https://www.ti.com/lit/er/sprz487c/sprz487c.pdf
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-ethtool.c | 157 ++++++++++++++++++
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c    |   2 +
>  drivers/net/ethernet/ti/am65-cpsw-nuss.h    |   5 +
>  drivers/net/ethernet/ti/am65-cpsw-qos.c     | 175 ++++++++++++++++++++
>  drivers/net/ethernet/ti/am65-cpsw-qos.h     | 102 ++++++++++++
>  5 files changed, 441 insertions(+)
> 
> Changelog:
> 
> v7:
> - use else if
> - drop FIXME comment
> - fix lldp kselftest failure by limiting max_verify_time to spec limit of 128ms.
> - now passes all ethtool_mm.sh kselftests (patch 8 required)
> 
> v6:
> - get mutex around am65_cpsw_iet_commit_preemptible_tcs() in
>   am65_cpsw_iet_change_preemptible_tcs()
> - use "preemption" instead of "pre-emption"
> - call am65_cpsw_setup_mqprio() from within am65_cpsw_setup_taprio()
> - Now works with kselftest except the last test which fails
> 
> v5:
> - No change
> 
> v4:
> - Rebase and include in the same series as mqprio support.
> 
> v3:
> - Rebase on top of v6.6-rc1 and mqprio support [1]
> - Support ethtool_ops :: get_mm_stats()
> - drop unused variables cmn_ctrl and verify_cnt
> - make am65_cpsw_iet_link_state_update() and
>   am65_cpsw_iet_change_preemptible_tcs() static
> 
> [1] https://lore.kernel.org/all/20230918075358.5878-1-rogerq@kernel.org/
> 
> v2:
> - Use proper control bits for PMAC enable
> (AM65_CPSW_PN_CTL_IET_PORT_EN)
>   and TX enable (AM65_CPSW_PN_IET_MAC_PENABLE)
> - Common IET Enable (AM65_CPSW_CTL_IET_EN) is set if any port has
>   AM65_CPSW_PN_CTL_IET_PORT_EN set.
> - Fix workaround for erratum i2208. i.e. Limit rx_min_frag_size to 124

Should be 128 not 124

> - Fix am65_cpsw_iet_get_verify_timeout_ms() to default to timeout for
>   1G link if link is inactive.
> - resize the RX FIFO based on pmac_enabled, not tx_enabled.
> 
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> index b9e1d568604b..5571385b4baf 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-ethtool.c
> @@ -11,6 +11,7 @@
>  #include <linux/pm_runtime.h>
> 
>  #include "am65-cpsw-nuss.h"
> +#include "am65-cpsw-qos.h"
>  #include "cpsw_ale.h"
>  #include "am65-cpts.h"
> 
> @@ -740,6 +741,159 @@ static int am65_cpsw_set_ethtool_priv_flags(struct
> net_device *ndev, u32 flags)
>  	return 0;
>  }
> 
> +static void am65_cpsw_port_iet_rx_enable(struct am65_cpsw_port *port,
> +bool enable) {
> +	u32 val;
> +
> +	val = readl(port->port_base + AM65_CPSW_PN_REG_CTL);
> +	if (enable)
> +		val |= AM65_CPSW_PN_CTL_IET_PORT_EN;
> +	else
> +		val &= ~AM65_CPSW_PN_CTL_IET_PORT_EN;
> +
> +	writel(val, port->port_base + AM65_CPSW_PN_REG_CTL);
> +	am65_cpsw_iet_common_enable(port->common);
> +}
> +
> +static void am65_cpsw_port_iet_tx_enable(struct am65_cpsw_port *port,
> +bool enable) {
> +	u32 val;
> +
> +	val = readl(port->port_base + AM65_CPSW_PN_REG_IET_CTRL);
> +	if (enable)
> +		val |= AM65_CPSW_PN_IET_MAC_PENABLE;
> +	else
> +		val &= ~AM65_CPSW_PN_IET_MAC_PENABLE;
> +
> +	writel(val, port->port_base + AM65_CPSW_PN_REG_IET_CTRL); }
> +
> +static int am65_cpsw_get_mm(struct net_device *ndev, struct
> +ethtool_mm_state *state) {
> +	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
> +	struct am65_cpsw_ndev_priv *priv = netdev_priv(ndev);
> +	u32 port_ctrl, iet_ctrl, iet_status;
> +	u32 add_frag_size;
> +
> +	mutex_lock(&priv->mm_lock);
> +
> +	iet_ctrl = readl(port->port_base + AM65_CPSW_PN_REG_IET_CTRL);
> +	port_ctrl = readl(port->port_base + AM65_CPSW_PN_REG_CTL);
> +
> +	state->tx_enabled = !!(iet_ctrl &
> AM65_CPSW_PN_IET_MAC_PENABLE);
> +	state->pmac_enabled = !!(port_ctrl &
> AM65_CPSW_PN_CTL_IET_PORT_EN);
> +
> +	iet_status = readl(port->port_base +
> AM65_CPSW_PN_REG_IET_STATUS);
> +
> +	if (iet_ctrl & AM65_CPSW_PN_IET_MAC_DISABLEVERIFY)
> +		state->verify_status =
> ETHTOOL_MM_VERIFY_STATUS_DISABLED;
> +	else if (iet_status & AM65_CPSW_PN_MAC_VERIFIED)
> +		state->verify_status =
> ETHTOOL_MM_VERIFY_STATUS_SUCCEEDED;
> +	else if (iet_status & AM65_CPSW_PN_MAC_VERIFY_FAIL)
> +		state->verify_status =
> ETHTOOL_MM_VERIFY_STATUS_FAILED;
> +	else
> +		state->verify_status =
> ETHTOOL_MM_VERIFY_STATUS_UNKNOWN;
> +
> +	add_frag_size =
> AM65_CPSW_PN_IET_MAC_GET_ADDFRAGSIZE(iet_ctrl);
> +	state->tx_min_frag_size =
> +ethtool_mm_frag_size_add_to_min(add_frag_size);
> +
> +	/* Errata i2208: RX min fragment size cannot be less than 124 */
> +	state->rx_min_frag_size = 124;

/* Errata i2208: RX min fragment size cannot be less than 128 */
state->rx_min_frag_size = 128;

  Pekka