[PATCH] lan743x: Added fixed link support

Roelof Berg
2020-05-20T17:10:51Z

Microchip lan7431 is frequently connected to a phy. However, it
can also be directly connected to a MII remote peer without
any phy in between. For supporting such a phyless hardware setup
in Linux we added the capability to the driver to understand
the fixed-link and the phy-connection-type entries in the device
tree.

New behavior:
. If no device tree node is configured the behavior of the driver remains
unchanged. This will ensure backwards compatibility to off-the-shelve
PC hardware.

. If a device tree node is configured but no fixed-link node is present
the phy-connection-type (as specified in the device tree) will be
applied and of_phy_connect() will be used instead of
phy_connect_direct().

. If a device tree node is configured and a fixed-link node is present
the phy-connection-type will be applied, of_phy_connect() will be
used and the MAC will be configured to use the fix speed and duplex
mode configured in the fixed-link node. Also ASD and ADD will be
switched off.

Example:

&pcie {
status = "okay";

host@0 {
reg = <0 0 0 0 0>;

#address-cells = <3>;
#size-cells = <2>;

ethernet@0 {
compatible = "weyland-yutani,noscom1", "microchip,lan743x";
status = "okay";
reg = <0 0 0 0 0>;
phy-connection-type = "rgmii";

fixed-link {
speed = <100>;
full-duplex;
};
};
};
};

Signed-off-by: Roelof Berg <rberg@berg-solutions.de>
---
drivers/net/ethernet/microchip/lan743x_main.c | 101 ++++++++++++++++--
drivers/net/ethernet/microchip/lan743x_main.h | 4 +
2 files changed, 97 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c
index a43140f7b5eb..50ca223e8b8f 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.c
+++ b/drivers/net/ethernet/microchip/lan743x_main.c
@@ -9,9 +9,12 @@
#include <linux/microchipphy.h>
#include <linux/net_tstamp.h>
#include <linux/phy.h>
+#include <linux/phy_fixed.h>
#include <linux/rtnetlink.h>
#include <linux/iopoll.h>
#include <linux/crc16.h>
+#include <linux/of_mdio.h>
+#include <linux/of_net.h>
#include "lan743x_main.h"
#include "lan743x_ethtool.h"

@@ -946,6 +949,10 @@ static void lan743x_phy_link_status_change(struct net_device *netdev)
{
struct lan743x_adapter *adapter = netdev_priv(netdev);
struct phy_device *phydev = netdev->phydev;
+ struct device_node *phynode;
+ phy_interface_t phyifc;
+ int ret = -EIO;
+ u32 data;

phy_print_status(phydev);
if (phydev->state == PHY_RUNNING) {
@@ -953,6 +960,53 @@ static void lan743x_phy_link_status_change(struct net_device *netdev)
int remote_advertisement = 0;
int local_advertisement = 0;

+ /* check if a device-tree configuration is present */
+ phynode = of_node_get(adapter->pdev->dev.of_node);
+ if (phynode) {
+ data = lan743x_csr_read(adapter, MAC_CR);
+
+ /* set interface mode */
+ ret = of_get_phy_mode(phynode, &phyifc);
+ if (ret)
+ phyifc = PHY_INTERFACE_MODE_GMII;
+
+ if (phy_interface_mode_is_rgmii(phyifc))
+ /* RGMII */
+ data &= ~MAC_CR_MII_EN_;
+ else
+ /* GMII */
+ data |= MAC_CR_MII_EN_;
+
+ /* apply fixed-link configuration */
+ if (of_phy_is_fixed_link(phynode)) {
+ /* disable auto duplex, and speed detection */
+ data &= ~(MAC_CR_ADD_ | MAC_CR_ASD_);
+ /* set fixed duplex mode */
+ if (phydev->duplex)
+ data |= MAC_CR_DPX_;
+ else
+ data &= ~MAC_CR_DPX_;
+ /* set fixed bus speed */
+ switch (phydev->speed) {
+ case 10:
+ data &= ~MAC_CR_CFG_H_;
+ data &= ~MAC_CR_CFG_L_;
+ break;
+ case 100:
+ data &= ~MAC_CR_CFG_H_;
+ data |= MAC_CR_CFG_L_;
+ break;
+ case 1000:
+ data |= MAC_CR_CFG_H_;
+ data |= MAC_CR_CFG_L_;
+ break;
+ }
+ }
+
+ lan743x_csr_write(adapter, MAC_CR, data);
+ of_node_put(phynode);
+ }
+
memset(&ksettings, 0, sizeof(ksettings));
phy_ethtool_get_link_ksettings(netdev, &ksettings);
local_advertisement =
@@ -974,26 +1028,57 @@ static void lan743x_phy_close(struct lan743x_adapter *adapter)

phy_stop(netdev->phydev);
phy_disconnect(netdev->phydev);
+ if (of_phy_is_fixed_link(adapter->pdev->dev.of_node))
+ of_phy_deregister_fixed_link(adapter->pdev->dev.of_node);
netdev->phydev = NULL;
}

static int lan743x_phy_open(struct lan743x_adapter *adapter)
{
struct lan743x_phy *phy = &adapter->phy;
+ struct device_node *phynode;
struct phy_device *phydev;
struct net_device *netdev;
+ phy_interface_t phyifc;
int ret = -EIO;

netdev = adapter->netdev;
- phydev = phy_find_first(adapter->mdiobus);
- if (!phydev)
- goto return_error;

- ret = phy_connect_direct(netdev, phydev,
- lan743x_phy_link_status_change,
- PHY_INTERFACE_MODE_GMII);
- if (ret)
- goto return_error;
+ /* is a device tree configuration present */
+ phynode = of_node_get(adapter->pdev->dev.of_node);
+ if (phynode) {
+ /* apply device tree configuration */
+ if (of_phy_is_fixed_link(phynode)) {
+ ret = of_phy_register_fixed_link(phynode);
+ if (ret) {
+ netdev_err(netdev, "cannot register fixed PHY\n");
+ of_node_put(phynode);
+ goto return_error;
+ }
+ }
+
+ ret = of_get_phy_mode(phynode, &phyifc);
+ if (ret)
+ phyifc = PHY_INTERFACE_MODE_GMII;
+
+ phydev = of_phy_connect(netdev, phynode,
+ lan743x_phy_link_status_change,
+ 0, phyifc);
+ of_node_put(phynode);
+ if (!phydev)
+ goto return_error;
+ } else {
+ /* no device tree configuration */
+ phydev = phy_find_first(adapter->mdiobus);
+ if (!phydev)
+ goto return_error;
+
+ ret = phy_connect_direct(netdev, phydev,
+ lan743x_phy_link_status_change,
+ PHY_INTERFACE_MODE_GMII);
+ if (ret)
+ goto return_error;
+ }

/* MAC doesn't support 1000T Half */
phy_remove_link_mode(phydev, ETHTOOL_LINK_MODE_1000baseT_Half_BIT);
diff --git a/drivers/net/ethernet/microchip/lan743x_main.h b/drivers/net/ethernet/microchip/lan743x_main.h
index 3b02eeae5f45..e49f6b6cd440 100644
--- a/drivers/net/ethernet/microchip/lan743x_main.h
+++ b/drivers/net/ethernet/microchip/lan743x_main.h
@@ -104,10 +104,14 @@
((value << 0) & FCT_FLOW_CTL_ON_THRESHOLD_)

#define MAC_CR (0x100)
+#define MAC_CR_MII_EN_ BIT(19)
#define MAC_CR_EEE_EN_ BIT(17)
#define MAC_CR_ADD_ BIT(12)
#define MAC_CR_ASD_ BIT(11)
#define MAC_CR_CNTR_RST_ BIT(5)
+#define MAC_CR_DPX_ BIT(3)
+#define MAC_CR_CFG_H_ BIT(2)
+#define MAC_CR_CFG_L_ BIT(1)
#define MAC_CR_RST_ BIT(0)

#define MAC_RX (0x104)
--
2.25.1