[PATCH net-next v2 0/2] net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

[PATCH net-next v2 0/2] net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

[Roger Quadros]

Configure DSCP to Priority mapping registers so that IP precedence
field (top 3 bits of DSCP) map it to one of the 8 priority queues
for RX traffic.
    
Also update Priority to Thread maping to be compliant with
IEEE802.1Q-2014. Priority Code Point (PCP) 2 is higher priority than
PCP 0 (Best Effort). PCP 1 (Background) is lower priority than
PCP 0 (Best Effort).

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
Changes in v2:
- Updated references to more recent standard IEEE802.1Q-2014.
- Dropped reference to web link which might change in the future.
- Typo fix in commit log.
- Link to v1: https://lore.kernel.org/r/20241105-am65-cpsw-multi-rx-dscp-v1-0-38db85333c88@kernel.org

---
Roger Quadros (2):
      net: ethernet: ti: am65-cpsw: update pri_thread_map as per IEEE802.1Q-2014
      net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 50 ++++++++++++++++++++++++++++++++
 drivers/net/ethernet/ti/cpsw_ale.c       | 36 ++++++++++++++---------
 2 files changed, 72 insertions(+), 14 deletions(-)
---
base-commit: 42f7652d3eb527d03665b09edac47f85fb600924
change-id: 20241101-am65-cpsw-multi-rx-dscp-000b2c4af6d0

Best regards,
-- 
Roger Quadros <rogerq@kernel.org>

[PATCH net-next v2 1/2] net: ethernet: ti: am65-cpsw: update pri_thread_map as per IEEE802.1Q-2014

[Roger Quadros]

IEEE802.1Q-2014 supersedes IEEE802.1D-2004. Now Priority Code Point (PCP)
2 is no longer at a lower priority than PCP 0. PCP 1 (Background) is still
at a lower priority than PCP 0 (Best Effort).

Reference:
IEEE802.1Q-2014, Standard for Local and metropolitan area networks
  Table I-2 - Traffic type acronyms
  Table I-3 - Defining traffic types

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/cpsw_ale.c | 36 ++++++++++++++++++++++--------------
 1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/ti/cpsw_ale.c b/drivers/net/ethernet/ti/cpsw_ale.c
index 8d02d2b21429..9f79056b3f48 100644
--- a/drivers/net/ethernet/ti/cpsw_ale.c
+++ b/drivers/net/ethernet/ti/cpsw_ale.c
@@ -1692,26 +1692,34 @@ static void cpsw_ale_policer_reset(struct cpsw_ale *ale)
 void cpsw_ale_classifier_setup_default(struct cpsw_ale *ale, int num_rx_ch)
 {
 	int pri, idx;
-	/* IEEE802.1D-2004, Standard for Local and metropolitan area networks
-	 *    Table G-2 - Traffic type acronyms
-	 *    Table G-3 - Defining traffic types
-	 * User priority values 1 and 2 effectively communicate a lower
-	 * priority than 0. In the below table 0 is assigned to higher priority
-	 * thread than 1 and 2 wherever possible.
-	 * The below table maps which thread the user priority needs to be
+
+	/* Reference:
+	 * IEEE802.1Q-2014, Standard for Local and metropolitan area networks
+	 *    Table I-2 - Traffic type acronyms
+	 *    Table I-3 - Defining traffic types
+	 * Section I.4 Traffic types and priority values, states:
+	 * "0 is thus used both for default priority and for Best Effort, and
+	 *  Background is associated with a priority value of 1. This means
+	 * that the value 1 effectively communicates a lower priority than 0."
+	 *
+	 * In the table below, Priority Code Point (PCP) 0 is assigned
+	 * to a higher priority thread than PCP 1 wherever possible.
+	 * The table maps which thread the PCP traffic needs to be
 	 * sent to for a given number of threads (RX channels). Upper threads
 	 * have higher priority.
 	 * e.g. if number of threads is 8 then user priority 0 will map to
-	 * pri_thread_map[8-1][0] i.e. thread 2
+	 * pri_thread_map[8-1][0] i.e. thread 1
 	 */
-	int pri_thread_map[8][8] = {	{ 0, 0, 0, 0, 0, 0, 0, 0, },
+
+	int pri_thread_map[8][8] = {   /* BK,BE,EE,CA,VI,VO,IC,NC */
+					{ 0, 0, 0, 0, 0, 0, 0, 0, },
 					{ 0, 0, 0, 0, 1, 1, 1, 1, },
 					{ 0, 0, 0, 0, 1, 1, 2, 2, },
-					{ 1, 0, 0, 1, 2, 2, 3, 3, },
-					{ 1, 0, 0, 1, 2, 3, 4, 4, },
-					{ 1, 0, 0, 2, 3, 4, 5, 5, },
-					{ 1, 0, 0, 2, 3, 4, 5, 6, },
-					{ 2, 0, 1, 3, 4, 5, 6, 7, } };
+					{ 0, 0, 1, 1, 2, 2, 3, 3, },
+					{ 0, 0, 1, 1, 2, 2, 3, 4, },
+					{ 1, 0, 2, 2, 3, 3, 4, 5, },
+					{ 1, 0, 2, 3, 4, 4, 5, 6, },
+					{ 1, 0, 2, 3, 4, 5, 6, 7 } };
 
 	cpsw_ale_policer_reset(ale);
 

-- 
2.34.1

[PATCH net-next v2 2/2] net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

[Roger Quadros]

AM65 CPSW hardware can map the 6-bit DSCP/TOS field to
appropriate priority queue via DSCP to Priority mapping registers
(CPSW_PN_RX_PRI_MAP_REG).

We use the upper 3 bits of the DSCP field that indicate IP Precedence
to map traffic to 8 priority queues.

Signed-off-by: Roger Quadros <rogerq@kernel.org>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 50 ++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index 0520e9f4bea7..65fbf6727e02 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -71,6 +71,8 @@
 #define AM65_CPSW_PORT_REG_RX_PRI_MAP		0x020
 #define AM65_CPSW_PORT_REG_RX_MAXLEN		0x024
 
+#define AM65_CPSW_PORTN_REG_CTL			0x004
+#define AM65_CPSW_PORTN_REG_DSCP_MAP		0x120
 #define AM65_CPSW_PORTN_REG_SA_L		0x308
 #define AM65_CPSW_PORTN_REG_SA_H		0x30c
 #define AM65_CPSW_PORTN_REG_TS_CTL              0x310
@@ -94,6 +96,10 @@
 /* AM65_CPSW_PORT_REG_PRI_CTL */
 #define AM65_CPSW_PORT_REG_PRI_CTL_RX_PTYPE_RROBIN	BIT(8)
 
+/* AM65_CPSW_PN_REG_CTL */
+#define AM65_CPSW_PN_REG_CTL_DSCP_IPV4_EN	BIT(1)
+#define AM65_CPSW_PN_REG_CTL_DSCP_IPV6_EN	BIT(2)
+
 /* AM65_CPSW_PN_TS_CTL register fields */
 #define AM65_CPSW_PN_TS_CTL_TX_ANX_F_EN		BIT(4)
 #define AM65_CPSW_PN_TS_CTL_TX_VLAN_LT1_EN	BIT(5)
@@ -176,6 +182,49 @@ static void am65_cpsw_port_set_sl_mac(struct am65_cpsw_port *slave,
 	writel(mac_lo, slave->port_base + AM65_CPSW_PORTN_REG_SA_L);
 }
 
+#define AM65_CPSW_DSCP_MAX	GENMASK(5, 0)
+#define AM65_CPSW_PRI_MAX	GENMASK(2, 0)
+static int am65_cpsw_port_set_dscp_map(struct am65_cpsw_port *slave, u8 dscp, u8 pri)
+{
+	int reg_ofs;
+	int bit_ofs;
+	u32 val;
+
+	if (dscp > AM65_CPSW_DSCP_MAX)
+		return -EINVAL;
+
+	if (pri > AM65_CPSW_PRI_MAX)
+		return -EINVAL;
+
+	reg_ofs = (dscp / 8) * 4;	/* reg offset to this dscp */
+	bit_ofs = 4 * (dscp % 8);	/* bit offset to this dscp */
+	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
+	val &= ~(AM65_CPSW_PRI_MAX << bit_ofs);	/* clear */
+	val |= pri << bit_ofs;			/* set */
+	writel(val, slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
+	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
+
+	return 0;
+}
+
+static void am65_cpsw_port_enable_dscp_map(struct am65_cpsw_port *slave)
+{
+	int dscp, pri;
+	u32 val;
+
+	/* Map IP Precedence field to Priority */
+	for (dscp = 0; dscp <= AM65_CPSW_DSCP_MAX; dscp++) {
+		pri = dscp >> 3; /* Extract IP Precedence */
+		am65_cpsw_port_set_dscp_map(slave, dscp, pri);
+	}
+
+	/* enable port IPV4 and IPV6 DSCP for this port */
+	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_CTL);
+	val |= AM65_CPSW_PN_REG_CTL_DSCP_IPV4_EN |
+		AM65_CPSW_PN_REG_CTL_DSCP_IPV6_EN;
+	writel(val, slave->port_base + AM65_CPSW_PORTN_REG_CTL);
+}
+
 static void am65_cpsw_sl_ctl_reset(struct am65_cpsw_port *port)
 {
 	cpsw_sl_reset(port->slave.mac_sl, 100);
@@ -921,6 +970,7 @@ static int am65_cpsw_nuss_ndo_slave_open(struct net_device *ndev)
 	common->usage_count++;
 
 	am65_cpsw_port_set_sl_mac(port, ndev->dev_addr);
+	am65_cpsw_port_enable_dscp_map(port);
 
 	if (common->is_emac_mode)
 		am65_cpsw_init_port_emac_ale(port);

-- 
2.34.1

Re: [PATCH net-next v2 1/2] net: ethernet: ti: am65-cpsw: update pri_thread_map as per IEEE802.1Q-2014

[Siddharth Vadapalli]

On Thu, Nov 07, 2024 at 02:29:29PM +0200, Roger Quadros wrote:
> IEEE802.1Q-2014 supersedes IEEE802.1D-2004. Now Priority Code Point (PCP)
> 2 is no longer at a lower priority than PCP 0. PCP 1 (Background) is still
> at a lower priority than PCP 0 (Best Effort).
> 
> Reference:
> IEEE802.1Q-2014, Standard for Local and metropolitan area networks
>   Table I-2 - Traffic type acronyms
>   Table I-3 - Defining traffic types
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>

Reviewed-by: Siddharth Vadapalli <s-vadapalli@ti.com>

Regards,
Siddharth.

Re: [PATCH net-next v2 2/2] net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

[Siddharth Vadapalli]

On Thu, Nov 07, 2024 at 02:29:30PM +0200, Roger Quadros wrote:

Hello Roger,

I accidentally reviewed and replied to the patch from the v1 series, but
the comments still hold for this patch. For the sake of convenience, I
am providing the same feedback as the v1 patch below.

> AM65 CPSW hardware can map the 6-bit DSCP/TOS field to
> appropriate priority queue via DSCP to Priority mapping registers
> (CPSW_PN_RX_PRI_MAP_REG).
> 
> We use the upper 3 bits of the DSCP field that indicate IP Precedence
> to map traffic to 8 priority queues.
> 
> Signed-off-by: Roger Quadros <rogerq@kernel.org>
> ---
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c | 50 ++++++++++++++++++++++++++++++++
>  1 file changed, 50 insertions(+)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index 0520e9f4bea7..65fbf6727e02 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -71,6 +71,8 @@
>  #define AM65_CPSW_PORT_REG_RX_PRI_MAP		0x020
>  #define AM65_CPSW_PORT_REG_RX_MAXLEN		0x024
>  
> +#define AM65_CPSW_PORTN_REG_CTL			0x004

nitpick: indentation needs to be fixed here to align with the macros
below.

> +#define AM65_CPSW_PORTN_REG_DSCP_MAP		0x120
>  #define AM65_CPSW_PORTN_REG_SA_L		0x308
>  #define AM65_CPSW_PORTN_REG_SA_H		0x30c
>  #define AM65_CPSW_PORTN_REG_TS_CTL              0x310
> @@ -94,6 +96,10 @@
>  /* AM65_CPSW_PORT_REG_PRI_CTL */
>  #define AM65_CPSW_PORT_REG_PRI_CTL_RX_PTYPE_RROBIN	BIT(8)
>  
> +/* AM65_CPSW_PN_REG_CTL */
> +#define AM65_CPSW_PN_REG_CTL_DSCP_IPV4_EN	BIT(1)
> +#define AM65_CPSW_PN_REG_CTL_DSCP_IPV6_EN	BIT(2)
> +
>  /* AM65_CPSW_PN_TS_CTL register fields */
>  #define AM65_CPSW_PN_TS_CTL_TX_ANX_F_EN		BIT(4)
>  #define AM65_CPSW_PN_TS_CTL_TX_VLAN_LT1_EN	BIT(5)
> @@ -176,6 +182,49 @@ static void am65_cpsw_port_set_sl_mac(struct am65_cpsw_port *slave,
>  	writel(mac_lo, slave->port_base + AM65_CPSW_PORTN_REG_SA_L);
>  }
>  
> +#define AM65_CPSW_DSCP_MAX	GENMASK(5, 0)
> +#define AM65_CPSW_PRI_MAX	GENMASK(2, 0)
> +static int am65_cpsw_port_set_dscp_map(struct am65_cpsw_port *slave, u8 dscp, u8 pri)
> +{
> +	int reg_ofs;
> +	int bit_ofs;
> +	u32 val;
> +
> +	if (dscp > AM65_CPSW_DSCP_MAX)
> +		return -EINVAL;

am65_cpsw_port_set_dscp_map() seems to be invoked by
am65_cpsw_port_enable_dscp_map() below, where the above check is guaranteed
to be satisfied. Is the check added for future-proofing this function?

> +
> +	if (pri > AM65_CPSW_PRI_MAX)
> +		return -EINVAL;
> +
> +	reg_ofs = (dscp / 8) * 4;	/* reg offset to this dscp */
> +	bit_ofs = 4 * (dscp % 8);	/* bit offset to this dscp */

Maybe a macro can be used for the "4" since it is not clear what it
corresponds to. Or maybe two macros can be used for "reg_ofs" and
"bit_ofs".

> +	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
> +	val &= ~(AM65_CPSW_PRI_MAX << bit_ofs);	/* clear */
> +	val |= pri << bit_ofs;			/* set */
> +	writel(val, slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);
> +	val = readl(slave->port_base + AM65_CPSW_PORTN_REG_DSCP_MAP + reg_ofs);

The above readback seems to be just to flush the writel(). A comment of
the form:
/* flush */
might help, considering that other drivers do the same. Also, assigning
the returned value to "val" might not be required unless it is intended to
be checked.

[...]

Regards,
Siddharth.

Re: [PATCH net-next v2 2/2] net: ethernet: ti: am65-cpsw: enable DSCP to priority map for RX

[Roger Quadros]

On 08/11/2024 14:37, Siddharth Vadapalli wrote:
> On Thu, Nov 07, 2024 at 02:29:30PM +0200, Roger Quadros wrote:
> 
> Hello Roger,
> 
> I accidentally reviewed and replied to the patch from the v1 series, but
> the comments still hold for this patch. For the sake of convenience, I
> am providing the same feedback as the v1 patch below.

No problem, let's continue the discussion in v1 as I have already replied there.

-- 
cheers,
-roger