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net: phy: realtek: configure SerDes mode for rtl822xb PHYs
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The rtl8221b and rtl8226b series support switching SerDes mode between
2500base-x and sgmii based on the negotiated copper speed.

Configure this switching mode according to SerDes modes supported by
host.

There is an additional datasheet for RTL8226B/RTL8221B called
"SERDES MODE SETTING FLOW APPLICATION NOTE" where a sequence is
described to setup interface and rate adapter mode.

However, there is no documentation about the meaning of registers
and bits, it's literally just magic numbers and pseudo-code.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
[ refactored, dropped HiSGMII mode and changed commit message ]
Signed-off-by: Marek Behún <kabel@kernel.org>
[ changed rtl822x_update_interface() to use vendor register ]
[ always fill in possible interfaces ]
[ only apply to rtl8221b and rtl8226b phy's ]
[ set phydev->rate_matching in .config_init() ]
Signed-off-by: Eric Woudstra <ericwouds@gmail.com>

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: should come before them, without any blank lines. As the
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexander Couzens authored and David S. Miller committed Apr 12, 2024
1 parent af74be9 commit deb8af5
Showing 1 changed file with 110 additions and 4 deletions.
114 changes: 110 additions & 4 deletions drivers/net/phy/realtek.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,16 @@
RTL8201F_ISR_LINK)
#define RTL8201F_IER 0x13

#define RTL822X_VND1_SERDES_OPTION 0x697a
#define RTL822X_VND1_SERDES_OPTION_MODE_MASK GENMASK(5, 0)
#define RTL822X_VND1_SERDES_OPTION_MODE_2500BASEX_SGMII 0
#define RTL822X_VND1_SERDES_OPTION_MODE_2500BASEX 2

#define RTL822X_VND1_SERDES_CTRL3 0x7580
#define RTL822X_VND1_SERDES_CTRL3_MODE_MASK GENMASK(5, 0)
#define RTL822X_VND1_SERDES_CTRL3_MODE_SGMII 0x02
#define RTL822X_VND1_SERDES_CTRL3_MODE_2500BASEX 0x16

#define RTL8366RB_POWER_SAVE 0x15
#define RTL8366RB_POWER_SAVE_ON BIT(12)

Expand Down Expand Up @@ -659,6 +669,63 @@ static int rtl822x_write_mmd(struct phy_device *phydev, int devnum, u16 regnum,
return ret;
}

static int rtl822xb_config_init(struct phy_device *phydev)
{
bool has_2500, has_sgmii;
u16 mode;
int ret;

has_2500 = test_bit(PHY_INTERFACE_MODE_2500BASEX,
phydev->host_interfaces) ||
phydev->interface == PHY_INTERFACE_MODE_2500BASEX;

has_sgmii = test_bit(PHY_INTERFACE_MODE_SGMII,
phydev->host_interfaces) ||
phydev->interface == PHY_INTERFACE_MODE_SGMII;

/* fill in possible interfaces */
__assign_bit(PHY_INTERFACE_MODE_2500BASEX, phydev->possible_interfaces,
has_2500);
__assign_bit(PHY_INTERFACE_MODE_SGMII, phydev->possible_interfaces,
has_sgmii);

if (!has_2500 && !has_sgmii)
return 0;

/* determine SerDes option mode */
if (has_2500 && !has_sgmii) {
mode = RTL822X_VND1_SERDES_OPTION_MODE_2500BASEX;
phydev->rate_matching = RATE_MATCH_PAUSE;
} else {
mode = RTL822X_VND1_SERDES_OPTION_MODE_2500BASEX_SGMII;
phydev->rate_matching = RATE_MATCH_NONE;
}

/* the following sequence with magic numbers sets up the SerDes
* option mode
*/
ret = phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x75f3, 0);
if (ret < 0)
return ret;

ret = phy_modify_mmd_changed(phydev, MDIO_MMD_VEND1,
RTL822X_VND1_SERDES_OPTION,
RTL822X_VND1_SERDES_OPTION_MODE_MASK,
mode);
if (ret < 0)
return ret;

ret = phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x6a04, 0x0503);
if (ret < 0)
return ret;

ret = phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x6f10, 0xd455);
if (ret < 0)
return ret;

return phy_write_mmd(phydev, MDIO_MMD_VEND1, 0x6f11, 0x8020);
}

static int rtl822x_get_features(struct phy_device *phydev)
{
int val;
Expand Down Expand Up @@ -695,6 +762,28 @@ static int rtl822x_config_aneg(struct phy_device *phydev)
return __genphy_config_aneg(phydev, ret);
}

static void rtl822xb_update_interface(struct phy_device *phydev)
{
int val;

if (!phydev->link)
return;

/* Change interface according to serdes mode */
val = phy_read_mmd(phydev, MDIO_MMD_VEND1, RTL822X_VND1_SERDES_CTRL3);
if (val < 0)
return;

switch (val & RTL822X_VND1_SERDES_CTRL3_MODE_MASK) {
case RTL822X_VND1_SERDES_CTRL3_MODE_2500BASEX:
phydev->interface = PHY_INTERFACE_MODE_2500BASEX;
break;
case RTL822X_VND1_SERDES_CTRL3_MODE_SGMII:
phydev->interface = PHY_INTERFACE_MODE_SGMII;
break;
}
}

static int rtl822x_read_status(struct phy_device *phydev)
{
int ret;
Expand All @@ -716,6 +805,19 @@ static int rtl822x_read_status(struct phy_device *phydev)
return rtlgen_get_speed(phydev);
}

static int rtl822xb_read_status(struct phy_device *phydev)
{
int ret;

ret = rtl822x_read_status(phydev);
if (ret < 0)
return ret;

rtl822xb_update_interface(phydev);

return 0;
}

static bool rtlgen_supports_2_5gbps(struct phy_device *phydev)
{
int val;
Expand Down Expand Up @@ -988,7 +1090,8 @@ static struct phy_driver realtek_drvs[] = {
.name = "RTL8226B_RTL8221B 2.5Gbps PHY",
.get_features = rtl822x_get_features,
.config_aneg = rtl822x_config_aneg,
.read_status = rtl822x_read_status,
.config_init = rtl822xb_config_init,
.read_status = rtl822xb_read_status,
.suspend = genphy_suspend,
.resume = rtlgen_resume,
.read_page = rtl821x_read_page,
Expand All @@ -1010,7 +1113,8 @@ static struct phy_driver realtek_drvs[] = {
.name = "RTL8226B-CG_RTL8221B-CG 2.5Gbps PHY",
.get_features = rtl822x_get_features,
.config_aneg = rtl822x_config_aneg,
.read_status = rtl822x_read_status,
.config_init = rtl822xb_config_init,
.read_status = rtl822xb_read_status,
.suspend = genphy_suspend,
.resume = rtlgen_resume,
.read_page = rtl821x_read_page,
Expand All @@ -1020,7 +1124,8 @@ static struct phy_driver realtek_drvs[] = {
.name = "RTL8221B-VB-CG 2.5Gbps PHY",
.get_features = rtl822x_get_features,
.config_aneg = rtl822x_config_aneg,
.read_status = rtl822x_read_status,
.config_init = rtl822xb_config_init,
.read_status = rtl822xb_read_status,
.suspend = genphy_suspend,
.resume = rtlgen_resume,
.read_page = rtl821x_read_page,
Expand All @@ -1030,7 +1135,8 @@ static struct phy_driver realtek_drvs[] = {
.name = "RTL8221B-VM-CG 2.5Gbps PHY",
.get_features = rtl822x_get_features,
.config_aneg = rtl822x_config_aneg,
.read_status = rtl822x_read_status,
.config_init = rtl822xb_config_init,
.read_status = rtl822xb_read_status,
.suspend = genphy_suspend,
.resume = rtlgen_resume,
.read_page = rtl821x_read_page,
Expand Down

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