[PATCH net-next v4 4/9] net: dsa: microchip: add multi queue support for KSZ88X3 variants

From: Oleksij Rempel
Date: Mon Apr 08 2024 - 03:52:54 EST


KSZ88X3 switches support up to 4 queues. Rework ksz8795_set_prio_queue()
to support KSZ8795 and KSZ88X3 families of switches.

Per default, configure KSZ88X3 to use one queue, since it need special
handling due to priority related errata. Errata handling is implemented
in a separate patch.

Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
---
drivers/net/dsa/microchip/ksz8795.c | 87 ++++++++++++++++---------
drivers/net/dsa/microchip/ksz8795_reg.h | 9 ++-
2 files changed, 61 insertions(+), 35 deletions(-)

diff --git a/drivers/net/dsa/microchip/ksz8795.c b/drivers/net/dsa/microchip/ksz8795.c
index ecef6f6f830b3..afe61c75944d4 100644
--- a/drivers/net/dsa/microchip/ksz8795.c
+++ b/drivers/net/dsa/microchip/ksz8795.c
@@ -127,37 +127,56 @@ int ksz8_change_mtu(struct ksz_device *dev, int port, int mtu)
return -EOPNOTSUPP;
}

-static void ksz8795_set_prio_queue(struct ksz_device *dev, int port, int queue)
+static int ksz8_port_queue_split(struct ksz_device *dev, int port, int queues)
{
- u8 hi, lo;
+ u8 mask_4q, mask_2q;
+ u8 reg_4q, reg_2q;
+ u8 data_4q = 0;
+ u8 data_2q = 0;
+ int ret;

- /* Number of queues can only be 1, 2, or 4. */
- switch (queue) {
- case 4:
- case 3:
- queue = PORT_QUEUE_SPLIT_4;
- break;
- case 2:
- queue = PORT_QUEUE_SPLIT_2;
- break;
- default:
- queue = PORT_QUEUE_SPLIT_1;
+ if (ksz_is_ksz88x3(dev)) {
+ mask_4q = KSZ8873_PORT_4QUEUE_SPLIT_EN;
+ mask_2q = KSZ8873_PORT_2QUEUE_SPLIT_EN;
+ reg_4q = REG_PORT_CTRL_0;
+ reg_2q = REG_PORT_CTRL_2;
+
+ /* KSZ8795 family switches have Weighted Fair Queueing (WFQ)
+ * enabled by default. Enable it for KSZ8873 family switches
+ * too. Default value for KSZ8873 family is strict priority,
+ * which should be enabled by using TC_SETUP_QDISC_ETS, not
+ * by default.
+ */
+ ret = ksz_rmw8(dev, REG_SW_CTRL_3, WEIGHTED_FAIR_QUEUE_ENABLE,
+ WEIGHTED_FAIR_QUEUE_ENABLE);
+ if (ret)
+ return ret;
+ } else {
+ mask_4q = KSZ8795_PORT_4QUEUE_SPLIT_EN;
+ mask_2q = KSZ8795_PORT_2QUEUE_SPLIT_EN;
+ reg_4q = REG_PORT_CTRL_13;
+ reg_2q = REG_PORT_CTRL_0;
+
+ /* TODO: this is legacy from initial KSZ8795 driver, should be
+ * moved to appropriate place in the future.
+ */
+ ret = ksz_rmw8(dev, REG_SW_CTRL_19,
+ SW_OUT_RATE_LIMIT_QUEUE_BASED,
+ SW_OUT_RATE_LIMIT_QUEUE_BASED);
+ if (ret)
+ return ret;
}
- ksz_pread8(dev, port, REG_PORT_CTRL_0, &lo);
- ksz_pread8(dev, port, P_DROP_TAG_CTRL, &hi);
- lo &= ~PORT_QUEUE_SPLIT_L;
- if (queue & PORT_QUEUE_SPLIT_2)
- lo |= PORT_QUEUE_SPLIT_L;
- hi &= ~PORT_QUEUE_SPLIT_H;
- if (queue & PORT_QUEUE_SPLIT_4)
- hi |= PORT_QUEUE_SPLIT_H;
- ksz_pwrite8(dev, port, REG_PORT_CTRL_0, lo);
- ksz_pwrite8(dev, port, P_DROP_TAG_CTRL, hi);
-
- /* Default is port based for egress rate limit. */
- if (queue != PORT_QUEUE_SPLIT_1)
- ksz_cfg(dev, REG_SW_CTRL_19, SW_OUT_RATE_LIMIT_QUEUE_BASED,
- true);
+
+ if (queues == 4)
+ data_4q = mask_4q;
+ if (queues == 2)
+ data_2q = mask_2q;
+
+ ret = ksz_prmw8(dev, port, reg_4q, mask_4q, data_4q);
+ if (ret)
+ return ret;
+
+ return ksz_prmw8(dev, port, reg_2q, mask_2q, data_2q);
}

void ksz8_r_mib_cnt(struct ksz_device *dev, int port, u16 addr, u64 *cnt)
@@ -1513,6 +1532,7 @@ void ksz8_port_setup(struct ksz_device *dev, int port, bool cpu_port)
{
struct dsa_switch *ds = dev->ds;
const u32 *masks;
+ int queues;
u8 member;

masks = dev->info->masks;
@@ -1520,8 +1540,15 @@ void ksz8_port_setup(struct ksz_device *dev, int port, bool cpu_port)
/* enable broadcast storm limit */
ksz_port_cfg(dev, port, P_BCAST_STORM_CTRL, PORT_BROADCAST_STORM, true);

- if (!ksz_is_ksz88x3(dev))
- ksz8795_set_prio_queue(dev, port, 4);
+ /* For KSZ88x3 enable only one queue by default, otherwise we won't
+ * be able to get rid of PCP prios on Port 2.
+ */
+ if (ksz_is_ksz88x3(dev))
+ queues = 1;
+ else
+ queues = dev->info->num_tx_queues;
+
+ ksz8_port_queue_split(dev, port, queues);

/* disable DiffServ priority */
ksz_port_cfg(dev, port, P_PRIO_CTRL, PORT_DIFFSERV_ENABLE, false);
diff --git a/drivers/net/dsa/microchip/ksz8795_reg.h b/drivers/net/dsa/microchip/ksz8795_reg.h
index 0d13a6e29b0e6..69566a5d9cda1 100644
--- a/drivers/net/dsa/microchip/ksz8795_reg.h
+++ b/drivers/net/dsa/microchip/ksz8795_reg.h
@@ -124,7 +124,8 @@
#define PORT_BASED_PRIO_3 3
#define PORT_INSERT_TAG BIT(2)
#define PORT_REMOVE_TAG BIT(1)
-#define PORT_QUEUE_SPLIT_L BIT(0)
+#define KSZ8795_PORT_2QUEUE_SPLIT_EN BIT(0)
+#define KSZ8873_PORT_4QUEUE_SPLIT_EN BIT(0)

#define REG_PORT_1_CTRL_1 0x11
#define REG_PORT_2_CTRL_1 0x21
@@ -143,6 +144,7 @@
#define REG_PORT_4_CTRL_2 0x42
#define REG_PORT_5_CTRL_2 0x52

+#define KSZ8873_PORT_2QUEUE_SPLIT_EN BIT(7)
#define PORT_INGRESS_FILTER BIT(6)
#define PORT_DISCARD_NON_VID BIT(5)
#define PORT_FORCE_FLOW_CTRL BIT(4)
@@ -463,10 +465,7 @@
#define REG_PORT_4_CTRL_13 0xE1
#define REG_PORT_5_CTRL_13 0xF1

-#define PORT_QUEUE_SPLIT_H BIT(1)
-#define PORT_QUEUE_SPLIT_1 0
-#define PORT_QUEUE_SPLIT_2 1
-#define PORT_QUEUE_SPLIT_4 2
+#define KSZ8795_PORT_4QUEUE_SPLIT_EN BIT(1)
#define PORT_DROP_TAG BIT(0)

#define REG_PORT_1_CTRL_14 0xB2
--
2.39.2