--- /dev/null
+From 5652d1741574eb89cc02576e50ee3e348bd6dd77 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
+Date: Wed, 4 Oct 2023 11:19:03 +0200
+Subject: [PATCH 1/2] net: dsa: qca8k: fix regmap bulk read/write methods on
+ big endian systems
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Commit c766e077d927 ("net: dsa: qca8k: convert to regmap read/write
+API") introduced bulk read/write methods to qca8k's regmap.
+
+The regmap bulk read/write methods get the register address in a buffer
+passed as a void pointer parameter (the same buffer contains also the
+read/written values). The register address occupies only as many bytes
+as it requires at the beginning of this buffer. For example if the
+.reg_bits member in regmap_config is 16 (as is the case for this
+driver), the register address occupies only the first 2 bytes in this
+buffer, so it can be cast to u16.
+
+But the original commit implementing these bulk read/write methods cast
+the buffer to u32:
+ u32 reg = *(u32 *)reg_buf & U16_MAX;
+taking the first 4 bytes. This works on little endian systems where the
+first 2 bytes of the buffer correspond to the low 16-bits, but it
+obviously cannot work on big endian systems.
+
+Fix this by casting the beginning of the buffer to u16 as
+ u32 reg = *(u16 *)reg_buf;
+
+Fixes: c766e077d927 ("net: dsa: qca8k: convert to regmap read/write API")
+Signed-off-by: Marek BehĂșn <kabel@kernel.org>
+Tested-by: Christian Marangi <ansuelsmth@gmail.com>
+Reviewed-by: Christian Marangi <ansuelsmth@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/dsa/qca/qca8k-8xxx.c | 4 ++--
+ 1 file changed, 2 insertions(+), 2 deletions(-)
+
+--- a/drivers/net/dsa/qca/qca8k-8xxx.c
++++ b/drivers/net/dsa/qca/qca8k-8xxx.c
+@@ -504,8 +504,8 @@ qca8k_bulk_read(void *ctx, const void *r
+ void *val_buf, size_t val_len)
+ {
+ int i, count = val_len / sizeof(u32), ret;
+- u32 reg = *(u32 *)reg_buf & U16_MAX;
+ struct qca8k_priv *priv = ctx;
++ u32 reg = *(u16 *)reg_buf;
+
+ if (priv->mgmt_master &&
+ !qca8k_read_eth(priv, reg, val_buf, val_len))
+@@ -526,8 +526,8 @@ qca8k_bulk_gather_write(void *ctx, const
+ const void *val_buf, size_t val_len)
+ {
+ int i, count = val_len / sizeof(u32), ret;
+- u32 reg = *(u32 *)reg_buf & U16_MAX;
+ struct qca8k_priv *priv = ctx;
++ u32 reg = *(u16 *)reg_buf;
+ u32 *val = (u32 *)val_buf;
+
+ if (priv->mgmt_master &&
--- /dev/null
+From 526c8ee04bdbd4d8d19a583b1f3b06700229a815 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Marek=20Beh=C3=BAn?= <kabel@kernel.org>
+Date: Wed, 4 Oct 2023 11:19:04 +0200
+Subject: [PATCH 2/2] net: dsa: qca8k: fix potential MDIO bus conflict when
+ accessing internal PHYs via management frames
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Besides the QCA8337 switch the Turris 1.x device has on it's MDIO bus
+also Micron ethernet PHY (dedicated to the WAN port).
+
+We've been experiencing a strange behavior of the WAN ethernet
+interface, wherein the WAN PHY started timing out the MDIO accesses, for
+example when the interface was brought down and then back up.
+
+Bisecting led to commit 2cd548566384 ("net: dsa: qca8k: add support for
+phy read/write with mgmt Ethernet"), which added support to access the
+QCA8337 switch's internal PHYs via management ethernet frames.
+
+Connecting the MDIO bus pins onto an oscilloscope, I was able to see
+that the MDIO bus was active whenever a request to read/write an
+internal PHY register was done via an management ethernet frame.
+
+My theory is that when the switch core always communicates with the
+internal PHYs via the MDIO bus, even when externally we request the
+access via ethernet. This MDIO bus is the same one via which the switch
+and internal PHYs are accessible to the board, and the board may have
+other devices connected on this bus. An ASCII illustration may give more
+insight:
+
+ +---------+
+ +----| |
+ | | WAN PHY |
+ | +--| |
+ | | +---------+
+ | |
+ | | +----------------------------------+
+ | | | QCA8337 |
+MDC | | | +-------+ |
+------o-+--|--------o------------o--| | |
+MDIO | | | | | PHY 1 |-|--to RJ45
+--------o--|---o----+---------o--+--| | |
+ | | | | | +-------+ |
+ | +-------------+ | o--| | |
+ | | MDIO MDC | | | | PHY 2 |-|--to RJ45
+eth1 | | | o--+--| | |
+-----------|-|port0 | | | +-------+ |
+ | | | | o--| | |
+ | | switch core | | | | PHY 3 |-|--to RJ45
+ | +-------------+ o--+--| | |
+ | | | +-------+ |
+ | | o--| ... | |
+ +----------------------------------+
+
+When we send a request to read an internal PHY register via an ethernet
+management frame via eth1, the switch core receives the ethernet frame
+on port 0 and then communicates with the internal PHY via MDIO. At this
+time, other potential devices, such as the WAN PHY on Turris 1.x, cannot
+use the MDIO bus, since it may cause a bus conflict.
+
+Fix this issue by locking the MDIO bus even when we are accessing the
+PHY registers via ethernet management frames.
+
+Fixes: 2cd548566384 ("net: dsa: qca8k: add support for phy read/write with mgmt Ethernet")
+Signed-off-by: Marek BehĂșn <kabel@kernel.org>
+Reviewed-by: Christian Marangi <ansuelsmth@gmail.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ drivers/net/dsa/qca/qca8k-8xxx.c | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+--- a/drivers/net/dsa/qca/qca8k-8xxx.c
++++ b/drivers/net/dsa/qca/qca8k-8xxx.c
+@@ -665,6 +665,15 @@ qca8k_phy_eth_command(struct qca8k_priv
+ goto err_read_skb;
+ }
+
++ /* It seems that accessing the switch's internal PHYs via management
++ * packets still uses the MDIO bus within the switch internally, and
++ * these accesses can conflict with external MDIO accesses to other
++ * devices on the MDIO bus.
++ * We therefore need to lock the MDIO bus onto which the switch is
++ * connected.
++ */
++ mutex_lock(&priv->bus->mdio_lock);
++
+ /* Actually start the request:
+ * 1. Send mdio master packet
+ * 2. Busy Wait for mdio master command
+@@ -677,6 +686,7 @@ qca8k_phy_eth_command(struct qca8k_priv
+ mgmt_master = priv->mgmt_master;
+ if (!mgmt_master) {
+ mutex_unlock(&mgmt_eth_data->mutex);
++ mutex_unlock(&priv->bus->mdio_lock);
+ ret = -EINVAL;
+ goto err_mgmt_master;
+ }
+@@ -764,6 +774,7 @@ exit:
+ QCA8K_ETHERNET_TIMEOUT);
+
+ mutex_unlock(&mgmt_eth_data->mutex);
++ mutex_unlock(&priv->bus->mdio_lock);
+
+ return ret;
+
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
-@@ -778,21 +778,6 @@ err_clear_skb:
+@@ -789,21 +789,6 @@ err_clear_skb:
return ret;
}
static void
qca8k_split_addr(u32 regaddr, u16 *r1, u16 *r2, u16 *page)
-@@ -1829,6 +1830,10 @@ qca8k_setup(struct dsa_switch *ds)
+@@ -1840,6 +1841,10 @@ qca8k_setup(struct dsa_switch *ds)
if (ret)
return ret;
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
-@@ -1993,6 +1993,8 @@ static const struct dsa_switch_ops qca8k
+@@ -2004,6 +2004,8 @@ static const struct dsa_switch_ops qca8k
.port_fdb_add = qca8k_port_fdb_add,
.port_fdb_del = qca8k_port_fdb_del,
.port_fdb_dump = qca8k_port_fdb_dump,
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
-@@ -1882,15 +1882,12 @@ qca8k_setup(struct dsa_switch *ds)
+@@ -1893,15 +1893,12 @@ qca8k_setup(struct dsa_switch *ds)
}
}
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
-@@ -1719,6 +1719,117 @@ qca8k_get_tag_protocol(struct dsa_switch
+@@ -1730,6 +1730,117 @@ qca8k_get_tag_protocol(struct dsa_switch
return DSA_TAG_PROTO_QCA;
}
static void
qca8k_master_change(struct dsa_switch *ds, const struct net_device *master,
bool operational)
-@@ -2005,8 +2116,9 @@ static const struct dsa_switch_ops qca8k
+@@ -2016,8 +2127,9 @@ static const struct dsa_switch_ops qca8k
.phylink_mac_link_down = qca8k_phylink_mac_link_down,
.phylink_mac_link_up = qca8k_phylink_mac_link_up,
.get_phy_flags = qca8k_get_phy_flags,
--- a/drivers/net/dsa/qca/qca8k-8xxx.c
+++ b/drivers/net/dsa/qca/qca8k-8xxx.c
-@@ -1991,6 +1991,12 @@ qca8k_setup(struct dsa_switch *ds)
+@@ -2002,6 +2002,12 @@ qca8k_setup(struct dsa_switch *ds)
dev_err(priv->dev, "failed enabling QCA header mode on port %d", dp->index);
return ret;
}
}
/* Forward all unknown frames to CPU port for Linux processing */
-@@ -2020,11 +2026,6 @@ qca8k_setup(struct dsa_switch *ds)
+@@ -2031,11 +2037,6 @@ qca8k_setup(struct dsa_switch *ds)
if (ret)
return ret;
/* For port based vlans to work we need to set the
* default egress vid
*/
-@@ -2076,6 +2077,9 @@ qca8k_setup(struct dsa_switch *ds)
+@@ -2087,6 +2088,9 @@ qca8k_setup(struct dsa_switch *ds)
/* Set max number of LAGs supported */
ds->num_lag_ids = QCA8K_NUM_LAGS;