[PATCH net-next v4 0/2] net: phy: fix PHY interface mask initialization and XPCS usage

[PATCH net-next v4 0/2] net: phy: fix PHY interface mask initialization and XPCS usage

[Coia Prant]

This series fixes issues related to the handling of the PHY interface mask
(supported_interfaces) at the core level and in the XPCS driver.

Patch 1 fixes a local macro in the txgbe driver.
DECLARE_PHY_INTERFACE_MASK_ZERO() incorrectly uses PHY_INTERFACE_MODE_MAX
as the array length instead of BITS_TO_LONGS(), which wastes stack space.
Move it to include/linux/phy.h and base it on
DECLARE_PHY_INTERFACE_MASK() so the bitmap is correctly sized while
still being zero-initialized.

Patch 2 makes the XPCS supported_interfaces mask authoritative. The
generic compat table advertises modes that a specific integration may
not support. The Rockchip glue now builds a platform mask (1000BASE-X,
SGMII, QSGMII) and intersects it with the inherited core mask using
phy_interface_and(). In addition, xpcs_find_compat() now checks
supported_interfaces before looking up the compat table, ensuring the
core respects the narrowed mask.

Note: checkpatch.pl reports "Macros with complex values should be
enclosed in parentheses" for the new macro in Patch 1. This is a known
false positive for declarative macros that expand to variable
declarations; wrapping it would break compilation.

Changes since v3:
- Rebased onto net-next as suggested by Paolo.
- Patch 1: drop the Fixes tag, as this is a cleanup/optimization rather
  than a bug fix.
- Patch 2: move DECLARE_PHY_INTERFACE_MASK_ZERO() to the top of the
  function to comply with the reverse Christmas tree order.
- Patch 2: clarify in the commit message that QSGMII is currently a
  no-op because the core does not support it, demonstrating the
  intersection behavior.
---
Coia Prant (2):
  net: phy: move DECLARE_PHY_INTERFACE_MASK_ZERO to core
  net: pcs: xpcs: make supported_interfaces authoritative

 drivers/net/ethernet/wangxun/txgbe/txgbe_type.h |  3 ---
 drivers/net/pcs/pcs-xpcs-rk.c                   | 10 ++++++++++
 drivers/net/pcs/pcs-xpcs.c                      |  3 +++
 include/linux/phy.h                             |  3 +++
 4 files changed, 16 insertions(+), 3 deletions(-)

-- 
2.47.3

[PATCH net-next v4 1/2] net: phy: move DECLARE_PHY_INTERFACE_MASK_ZERO to core

[Coia Prant]

The txgbe driver currently defines DECLARE_PHY_INTERFACE_MASK_ZERO()
locally, but incorrectly uses PHY_INTERFACE_MODE_MAX as the array
length instead of BITS_TO_LONGS(). This allocates significantly more
space on the stack than necessary.

Move the macro to include/linux/phy.h and build it on top of
DECLARE_PHY_INTERFACE_MASK() to correctly size the bitmap, while still
initializing the stack variable to zero.

Signed-off-by: Coia Prant <coiaprant@gmail.com>
Cc: Jiawen Wu <jiawenwu@trustnetic.com>
---
 drivers/net/ethernet/wangxun/txgbe/txgbe_type.h | 3 ---
 include/linux/phy.h                             | 3 +++
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h b/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
index 757d1ce8d3ad..8071464c7b90 100644
--- a/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
+++ b/drivers/net/ethernet/wangxun/txgbe/txgbe_type.h
@@ -315,9 +315,6 @@ void txgbe_up(struct wx *wx);
 int txgbe_setup_tc(struct net_device *dev, u8 tc);
 void txgbe_do_reset(struct net_device *netdev, bool reinit);
 
-#define DECLARE_PHY_INTERFACE_MASK_ZERO(name) \
-	unsigned long name[PHY_INTERFACE_MODE_MAX] = { 0, }
-
 #define TXGBE_LINK_SPEED_UNKNOWN        0
 #define TXGBE_LINK_SPEED_10GB_FULL      4
 #define TXGBE_LINK_SPEED_25GB_FULL      0x10
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 21afc2082b17..43aba23109fa 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -159,6 +159,9 @@ typedef enum {
 #define DECLARE_PHY_INTERFACE_MASK(name) \
 	DECLARE_BITMAP(name, PHY_INTERFACE_MODE_MAX)
 
+#define DECLARE_PHY_INTERFACE_MASK_ZERO(name) \
+	DECLARE_PHY_INTERFACE_MASK(name) = { 0, }
+
 static inline void phy_interface_zero(unsigned long *intf)
 {
 	bitmap_zero(intf, PHY_INTERFACE_MODE_MAX);
-- 
2.47.3

[PATCH net-next v4 2/2] net: pcs: xpcs: make supported_interfaces authoritative

[Coia Prant]

pcs.supported_interfaces is the mask of interfaces a given xpcs
instance actually supports. The compat table describes what the
Synopsys IP can do in general, but a specific integration may support
a different subset. For example, the RK3568 XPCS supports 1000BASE-X,
SGMII and QSGMII in hardware, but does not implement the C73,
10GBASE-R or 2500BASE-X modes that the Synopsys compat table
advertises.

However, xpcs_find_compat() only walks desc->compat[] and does not look
at pcs.supported_interfaces. If a caller ever passes an interface
outside the mask, the core would still find and configure a compat
entry for it, contradicting the mask the glue already set. This was a
known gap: the mask was written but never consulted by the core.

Fix both sides:

- In xpcs_find_compat(), return NULL when the interface is not in
  pcs.supported_interfaces, so the mask is authoritative for what the
  core will configure.
- In the Rockchip glue, build a platform mask with the three modes
  supported by RK3568 (1000BASE-X, SGMII, QSGMII) and intersect it
  with the core's supported_interfaces using phy_interface_and().
  This narrows the mask inherited from the generic compat table so it
  reflects the actual SoC capabilities.

Note that QSGMII is currently filtered out (a no-op) because the core's
compat table does not support it yet, which demonstrates the intended
filtering behavior of this intersection. If the core adds QSGMII
support in the future, the glue will automatically pick it up.

This is a logical inconsistency rather than a user-visible bug in a
released kernel: the affected Rockchip platform is not present in any
released version, and the MAC side forces the phy mode, so phylink does
not normally pass an interface outside the mask. The patch makes the
mask the single source of truth for both the core and the glue.

Signed-off-by: Coia Prant <coiaprant@gmail.com>
---
 drivers/net/pcs/pcs-xpcs-rk.c | 10 ++++++++++
 drivers/net/pcs/pcs-xpcs.c    |  3 +++
 2 files changed, 13 insertions(+)

diff --git a/drivers/net/pcs/pcs-xpcs-rk.c b/drivers/net/pcs/pcs-xpcs-rk.c
index ad187fba4e9d..e29f473776b2 100644
--- a/drivers/net/pcs/pcs-xpcs-rk.c
+++ b/drivers/net/pcs/pcs-xpcs-rk.c
@@ -480,6 +480,7 @@ MODULE_DEVICE_TABLE(of, xpcs_rk_of_ids);
 
 struct dw_xpcs *xpcs_rk_create(struct device *dev, struct device_node *pcs, int port)
 {
+	DECLARE_PHY_INTERFACE_MASK_ZERO(supported_interfaces);
 	struct platform_device *pdev;
 	struct dw_xpcs_rk *pxpcs;
 	struct dw_xpcs *xpcs;
@@ -536,6 +537,15 @@ struct dw_xpcs *xpcs_rk_create(struct device *dev, struct device_node *pcs, int
 		return xpcs;
 	}
 
+	/*
+	 * The RK3568 XPCS supports 1000BASE-X, SGMII and QSGMII.
+	 */
+	__set_bit(PHY_INTERFACE_MODE_1000BASEX, supported_interfaces);
+	__set_bit(PHY_INTERFACE_MODE_SGMII, supported_interfaces);
+	__set_bit(PHY_INTERFACE_MODE_QSGMII, supported_interfaces);
+	phy_interface_and(xpcs->pcs.supported_interfaces, xpcs->pcs.supported_interfaces,
+			  supported_interfaces);
+
 	xpcs_config_eee_mult_fact(xpcs, pxpcs->eee_mult_fact);
 	put_device(&pdev->dev);
 	return xpcs;
diff --git a/drivers/net/pcs/pcs-xpcs.c b/drivers/net/pcs/pcs-xpcs.c
index 6466e0ff2a98..46878a66064e 100644
--- a/drivers/net/pcs/pcs-xpcs.c
+++ b/drivers/net/pcs/pcs-xpcs.c
@@ -169,6 +169,9 @@ xpcs_find_compat(struct dw_xpcs *xpcs, phy_interface_t interface)
 {
 	const struct dw_xpcs_compat *compat;
 
+	if (!test_bit(interface, xpcs->pcs.supported_interfaces))
+		return NULL;
+
 	for (compat = xpcs->desc->compat; compat->supported; compat++)
 		if (compat->interface == interface)
 			return compat;
-- 
2.47.3