net: dsa: microchip: monitor potential faults in half-duplex mode

The errata DS80000754 recommends monitoring potential faults in
half-duplex mode for the KSZ9477 family.

half-duplex is not very common so I just added a critical message
when the fault conditions are detected. The switch can be expected
to be unable to communicate anymore in these states and a software
reset of the switch would be required which I did not implement.

Fixes: b987e98e50ab ("dsa: add DSA switch driver for Microchip KSZ9477")
Signed-off-by: Enguerrand de Ribaucourt <enguerrand.de-ribaucourt@savoirfairelinux.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/dsa/microchip/ksz9477.c b/drivers/net/dsa/microchip/ksz9477.c
index cbaca4140cda3b72c606af852f3140219917e645..425e20daf1e92dbf3fcd626efddff17e57ac881a 100644 (file)
--- a/drivers/net/dsa/microchip/ksz9477.c
+++ b/drivers/net/dsa/microchip/ksz9477.c
@@ -427,6 +427,57 @@ void ksz9477_freeze_mib(struct ksz_device *dev, int port, bool freeze)
        mutex_unlock(&p->mib.cnt_mutex);
 }
 
+int ksz9477_errata_monitor(struct ksz_device *dev, int port,
+                          u64 tx_late_col)
+{
+       u32 pmavbc;
+       u8 status;
+       u16 pqm;
+       int ret;
+
+       ret = ksz_pread8(dev, port, REG_PORT_STATUS_0, &status);
+       if (ret)
+               return ret;
+       if (!(FIELD_GET(PORT_INTF_SPEED_MASK, status) == PORT_INTF_SPEED_NONE) &&
+           !(status & PORT_INTF_FULL_DUPLEX)) {
+               /* Errata DS80000754 recommends monitoring potential faults in
+                * half-duplex mode. The switch might not be able to communicate anymore
+                * in these states.
+                * If you see this message, please read the errata-sheet for more information:
+                * https://ww1.microchip.com/downloads/aemDocuments/documents/UNG/ProductDocuments/Errata/KSZ9477S-Errata-DS80000754.pdf
+                * To workaround this issue, half-duplex mode should be avoided.
+                * A software reset could be implemented to recover from this state.
+                */
+               dev_warn_once(dev->dev,
+                             "Half-duplex detected on port %d, transmission halt may occur\n",
+                             port);
+               if (tx_late_col != 0) {
+                       /* Transmission halt with late collisions */
+                       dev_crit_once(dev->dev,
+                                     "TX late collisions detected, transmission may be halted on port %d\n",
+                                     port);
+               }
+               ret = ksz_read8(dev, REG_SW_LUE_CTRL_0, &status);
+               if (ret)
+                       return ret;
+               if (status & SW_VLAN_ENABLE) {
+                       ret = ksz_pread16(dev, port, REG_PORT_QM_TX_CNT_0__4, &pqm);
+                       if (ret)
+                               return ret;
+                       ret = ksz_read32(dev, REG_PMAVBC, &pmavbc);
+                       if (ret)
+                               return ret;
+                       if ((FIELD_GET(PMAVBC_MASK, pmavbc) <= PMAVBC_MIN) ||
+                           (FIELD_GET(PORT_QM_TX_CNT_M, pqm) >= PORT_QM_TX_CNT_MAX)) {
+                               /* Transmission halt with Half-Duplex and VLAN */
+                               dev_crit_once(dev->dev,
+                                             "resources out of limits, transmission may be halted\n");
+                       }
+               }
+       }
+       return ret;
+}
+
 void ksz9477_port_init_cnt(struct ksz_device *dev, int port)
 {
        struct ksz_port_mib *mib = &dev->ports[port].mib;

diff --git a/drivers/net/dsa/microchip/ksz9477.h b/drivers/net/dsa/microchip/ksz9477.h
index ce1e656b800b157cde165c034b2a731af6a69111..239a281da10b3fc5d75ea4a0e021e64ad853146a 100644 (file)
--- a/drivers/net/dsa/microchip/ksz9477.h
+++ b/drivers/net/dsa/microchip/ksz9477.h
@@ -36,6 +36,8 @@ int ksz9477_port_mirror_add(struct ksz_device *dev, int port,
                            bool ingress, struct netlink_ext_ack *extack);
 void ksz9477_port_mirror_del(struct ksz_device *dev, int port,
                             struct dsa_mall_mirror_tc_entry *mirror);
+int ksz9477_errata_monitor(struct ksz_device *dev, int port,
+                          u64 tx_late_col);
 void ksz9477_get_caps(struct ksz_device *dev, int port,
                      struct phylink_config *config);
 int ksz9477_fdb_dump(struct ksz_device *dev, int port,

diff --git a/drivers/net/dsa/microchip/ksz9477_reg.h b/drivers/net/dsa/microchip/ksz9477_reg.h
index fb124be8edd30dd28b8bd47c70312fda45b1db6a..d5354c600ea1e9dd3efd1744396bf0aa8aced625 100644 (file)
--- a/drivers/net/dsa/microchip/ksz9477_reg.h
+++ b/drivers/net/dsa/microchip/ksz9477_reg.h
@@ -843,8 +843,8 @@
 
 #define REG_PORT_STATUS_0              0x0030
 
-#define PORT_INTF_SPEED_M              0x3
-#define PORT_INTF_SPEED_S              3
+#define PORT_INTF_SPEED_MASK           GENMASK(4, 3)
+#define PORT_INTF_SPEED_NONE           GENMASK(1, 0)
 #define PORT_INTF_FULL_DUPLEX          BIT(2)
 #define PORT_TX_FLOW_CTRL              BIT(1)
 #define PORT_RX_FLOW_CTRL              BIT(0)
@@ -1168,6 +1168,11 @@
 #define PORT_RMII_CLK_SEL              BIT(7)
 #define PORT_MII_SEL_EDGE              BIT(5)
 
+#define REG_PMAVBC                     0x03AC
+
+#define PMAVBC_MASK                    GENMASK(26, 16)
+#define PMAVBC_MIN                     0x580
+
 /* 4 - MAC */
 #define REG_PORT_MAC_CTRL_0            0x0400
 
@@ -1495,6 +1500,7 @@
 
 #define PORT_QM_TX_CNT_USED_S          0
 #define PORT_QM_TX_CNT_M               (BIT(11) - 1)
+#define PORT_QM_TX_CNT_MAX             0x200
 
 #define REG_PORT_QM_TX_CNT_1__4                0x0A14
 

diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c
index 2818e24e2a51dd39073ee1bc8d51ea7dfa2dc1e0..0433109b42e570b113c233dd0d31f096e578bde5 100644 (file)
--- a/drivers/net/dsa/microchip/ksz_common.c
+++ b/drivers/net/dsa/microchip/ksz_common.c
@@ -1382,6 +1382,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
                .tc_cbs_supported = true,
                .ops = &ksz9477_dev_ops,
                .phylink_mac_ops = &ksz9477_phylink_mac_ops,
+               .phy_errata_9477 = true,
                .mib_names = ksz9477_mib_names,
                .mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
                .reg_mib_cnt = MIB_COUNTER_NUM,
@@ -1416,6 +1417,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
                .num_ipms = 8,
                .ops = &ksz9477_dev_ops,
                .phylink_mac_ops = &ksz9477_phylink_mac_ops,
+               .phy_errata_9477 = true,
                .mib_names = ksz9477_mib_names,
                .mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
                .reg_mib_cnt = MIB_COUNTER_NUM,
@@ -1450,6 +1452,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
                .num_ipms = 8,
                .ops = &ksz9477_dev_ops,
                .phylink_mac_ops = &ksz9477_phylink_mac_ops,
+               .phy_errata_9477 = true,
                .mib_names = ksz9477_mib_names,
                .mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
                .reg_mib_cnt = MIB_COUNTER_NUM,
@@ -1540,6 +1543,7 @@ const struct ksz_chip_data ksz_switch_chips[] = {
                .tc_cbs_supported = true,
                .ops = &ksz9477_dev_ops,
                .phylink_mac_ops = &ksz9477_phylink_mac_ops,
+               .phy_errata_9477 = true,
                .mib_names = ksz9477_mib_names,
                .mib_cnt = ARRAY_SIZE(ksz9477_mib_names),
                .reg_mib_cnt = MIB_COUNTER_NUM,
@@ -1820,6 +1824,7 @@ void ksz_r_mib_stats64(struct ksz_device *dev, int port)
        struct rtnl_link_stats64 *stats;
        struct ksz_stats_raw *raw;
        struct ksz_port_mib *mib;
+       int ret;
 
        mib = &dev->ports[port].mib;
        stats = &mib->stats64;
@@ -1861,6 +1866,12 @@ void ksz_r_mib_stats64(struct ksz_device *dev, int port)
        pstats->rx_pause_frames = raw->rx_pause;
 
        spin_unlock(&mib->stats64_lock);
+
+       if (dev->info->phy_errata_9477) {
+               ret = ksz9477_errata_monitor(dev, port, raw->tx_late_col);
+               if (ret)
+                       dev_err(dev->dev, "Failed to monitor transmission halt\n");
+       }
 }
 
 void ksz88xx_r_mib_stats64(struct ksz_device *dev, int port)

diff --git a/drivers/net/dsa/microchip/ksz_common.h b/drivers/net/dsa/microchip/ksz_common.h
index c784fd23a993724dd6bafd20d9f041d3f46e2aa0..ee7db46e469d59425d71c2bac9a977b75c293999 100644 (file)
--- a/drivers/net/dsa/microchip/ksz_common.h
+++ b/drivers/net/dsa/microchip/ksz_common.h
@@ -66,6 +66,7 @@ struct ksz_chip_data {
        bool tc_cbs_supported;
        const struct ksz_dev_ops *ops;
        const struct phylink_mac_ops *phylink_mac_ops;
+       bool phy_errata_9477;
        bool ksz87xx_eee_link_erratum;
        const struct ksz_mib_names *mib_names;
        int mib_cnt;