Re: [PATCH net-next v7 4/7] stmmac: intel: configure SerDes according to the interface mode

Intel platform will configure the SerDes through PMC API based on the
provided interface mode.

This patch adds several new functions below:-
- intel_tsn_lane_is_available(): This new function reads FIA lane
  ownership registers and common lane registers through IPC commands
  to know which lane the mGbE port is assigned to.
- intel_mac_finish(): To configure the SerDes based on the assigned
  lane and latest interface mode, it sends IPC command to the PMC through
  PMC driver/API. The PMC acts as a proxy for R/W on behalf of the driver.
- intel_set_reg_access(): Set the register access to the available TSN
  interface.

Signed-off-by: Choong Yong Liang <redacted>
---
 drivers/net/ethernet/stmicro/stmmac/Kconfig   |   2 +
 .../net/ethernet/stmicro/stmmac/dwmac-intel.c | 146 +++++++++++++++++-
 .../net/ethernet/stmicro/stmmac/dwmac-intel.h |  29 ++++
 include/linux/stmmac.h                        |   4 +
 4 files changed, 179 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
index 4cc85a36a1ab..25154b915b02 100644
--- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
+++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -307,6 +307,8 @@ config DWMAC_INTEL
 	default X86
 	depends on X86 && STMMAC_ETH && PCI
 	depends on COMMON_CLK
+	depends on ACPI
+	select INTEL_PMC_IPC
 	help
 	  This selects the Intel platform specific bus support for the
 	  stmmac driver. This driver is used for Intel Quark/EHL/TGL.

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
index 48acba5eb178..837fd3fbaedb 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c

@@ -5,15 +5,30 @@
 #include <linux/clk-provider.h>
 #include <linux/pci.h>
 #include <linux/dmi.h>
+#include <linux/platform_data/x86/intel_pmc_ipc.h>
 #include "dwmac-intel.h"
 #include "dwmac4.h"
 #include "stmmac.h"
 #include "stmmac_ptp.h"
 
+struct pmc_serdes_regs {
+	u8 index;
+	u32 val;
+};
+
+struct pmc_serdes_reg_info {
+	const struct pmc_serdes_regs *regs;
+	u8 num_regs;
+};
+
 struct intel_priv_data {
 	int mdio_adhoc_addr;	/* mdio address for serdes & etc */
 	unsigned long crossts_adj;
 	bool is_pse;
+	const int *tsn_lane_regs;
+	int max_tsn_lane_regs;
+	struct pmc_serdes_reg_info pid_1g;
+	struct pmc_serdes_reg_info pid_2p5g;
 };
 
 /* This struct is used to associate PCI Function of MAC controller on a board,

@@ -35,6 +50,42 @@ struct stmmac_pci_info {
 	int (*setup)(struct pci_dev *pdev, struct plat_stmmacenet_data *plat);
 };
 
+static const struct pmc_serdes_regs pid_modphy3_1g_regs[] = {
+	{ PID_MODPHY3_B_MODPHY_PCR_LCPLL_DWORD0,	B_MODPHY_PCR_LCPLL_DWORD0_1G },
+	{ PID_MODPHY3_N_MODPHY_PCR_LCPLL_DWORD2,	N_MODPHY_PCR_LCPLL_DWORD2_1G },
+	{ PID_MODPHY3_N_MODPHY_PCR_LCPLL_DWORD7,	N_MODPHY_PCR_LCPLL_DWORD7_1G },
+	{ PID_MODPHY3_N_MODPHY_PCR_LPPLL_DWORD10,	N_MODPHY_PCR_LPPLL_DWORD10_1G },
+	{ PID_MODPHY3_N_MODPHY_PCR_CMN_ANA_DWORD30,	N_MODPHY_PCR_CMN_ANA_DWORD30_1G },
+	{}
+};
+
+static const struct pmc_serdes_regs pid_modphy3_2p5g_regs[] = {
+	{ PID_MODPHY3_B_MODPHY_PCR_LCPLL_DWORD0,	B_MODPHY_PCR_LCPLL_DWORD0_2P5G },
+	{ PID_MODPHY3_N_MODPHY_PCR_LCPLL_DWORD2,	N_MODPHY_PCR_LCPLL_DWORD2_2P5G },
+	{ PID_MODPHY3_N_MODPHY_PCR_LCPLL_DWORD7,	N_MODPHY_PCR_LCPLL_DWORD7_2P5G },
+	{ PID_MODPHY3_N_MODPHY_PCR_LPPLL_DWORD10,	N_MODPHY_PCR_LPPLL_DWORD10_2P5G },
+	{ PID_MODPHY3_N_MODPHY_PCR_CMN_ANA_DWORD30,	N_MODPHY_PCR_CMN_ANA_DWORD30_2P5G },
+	{}
+};
+
+static const struct pmc_serdes_regs pid_modphy1_1g_regs[] = {
+	{ PID_MODPHY1_B_MODPHY_PCR_LCPLL_DWORD0,	B_MODPHY_PCR_LCPLL_DWORD0_1G },
+	{ PID_MODPHY1_N_MODPHY_PCR_LCPLL_DWORD2,	N_MODPHY_PCR_LCPLL_DWORD2_1G },
+	{ PID_MODPHY1_N_MODPHY_PCR_LCPLL_DWORD7,	N_MODPHY_PCR_LCPLL_DWORD7_1G },
+	{ PID_MODPHY1_N_MODPHY_PCR_LPPLL_DWORD10,	N_MODPHY_PCR_LPPLL_DWORD10_1G },
+	{ PID_MODPHY1_N_MODPHY_PCR_CMN_ANA_DWORD30,	N_MODPHY_PCR_CMN_ANA_DWORD30_1G },
+	{}
+};
+
+static const struct pmc_serdes_regs pid_modphy1_2p5g_regs[] = {
+	{ PID_MODPHY1_B_MODPHY_PCR_LCPLL_DWORD0,	B_MODPHY_PCR_LCPLL_DWORD0_2P5G },
+	{ PID_MODPHY1_N_MODPHY_PCR_LCPLL_DWORD2,	N_MODPHY_PCR_LCPLL_DWORD2_2P5G },
+	{ PID_MODPHY1_N_MODPHY_PCR_LCPLL_DWORD7,	N_MODPHY_PCR_LCPLL_DWORD7_2P5G },
+	{ PID_MODPHY1_N_MODPHY_PCR_LPPLL_DWORD10,	N_MODPHY_PCR_LPPLL_DWORD10_2P5G },
+	{ PID_MODPHY1_N_MODPHY_PCR_CMN_ANA_DWORD30,	N_MODPHY_PCR_CMN_ANA_DWORD30_2P5G },
+	{}
+};
+
 static int stmmac_pci_find_phy_addr(struct pci_dev *pdev,
 				    const struct dmi_system_id *dmi_list)
 {

@@ -93,7 +144,7 @@ static int intel_serdes_powerup(struct net_device *ndev, void *priv_data)
 	data &= ~SERDES_RATE_MASK;
 	data &= ~SERDES_PCLK_MASK;
 
-	if (priv->plat->max_speed == 2500)
+	if (priv->plat->phy_interface == PHY_INTERFACE_MODE_2500BASEX)
 		data |= SERDES_RATE_PCIE_GEN2 << SERDES_RATE_PCIE_SHIFT |
 			SERDES_PCLK_37p5MHZ << SERDES_PCLK_SHIFT;
 	else

@@ -415,6 +466,95 @@ static void intel_mgbe_pse_crossts_adj(struct intel_priv_data *intel_priv,
 	}
 }
 
+static int intel_tsn_lane_is_available(struct net_device *ndev,
+				       struct intel_priv_data *intel_priv)
+{
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	struct pmc_ipc_cmd tmp = {};
+	u32 rbuf[4] = {};
+	int ret = 0, i, j;
+	const int max_fia_regs = 5;
+
+	tmp.cmd = IPC_SOC_REGISTER_ACCESS;
+	tmp.sub_cmd = IPC_SOC_SUB_CMD_READ;
+
+	for (i = 0; i < max_fia_regs; i++) {

+		tmp.wbuf[0] = R_PCH_FIA_15_PCR_LOS1_REG_BASE + i;
+
+		ret = intel_pmc_ipc(&tmp, rbuf);
+		if (ret < 0) {
+			netdev_info(priv->dev, "Failed to read from PMC.\n");
+			return ret;
+		}
+
+		for (j = 0; j <= intel_priv->max_tsn_lane_regs; j++)
+			if ((rbuf[0] >>
+				(4 * (intel_priv->tsn_lane_regs[j] % 8)) &
+					B_PCH_FIA_PCR_L0O) == 0xB)
+				return ret;
+	}
+
+	return ret;
+}
+
+static int intel_set_reg_access(const struct pmc_serdes_regs *regs, int max_regs)
+{
+	int ret = 0, i;
+
+	for (i = 0; i < max_regs; i++) {
+		struct pmc_ipc_cmd tmp = {};
+		u32 buf[4] = {};
+
+		tmp.cmd = IPC_SOC_REGISTER_ACCESS;
+		tmp.sub_cmd = IPC_SOC_SUB_CMD_WRITE;
+		tmp.wbuf[0] = (u32)regs[i].index;
+		tmp.wbuf[1] = regs[i].val;
+
+		ret = intel_pmc_ipc(&tmp, buf);
+		if (ret < 0)
+			return ret;
+	}
+
+	return ret;
+}
+
+static int intel_mac_finish(struct net_device *ndev,
+			    void *intel_data,
+			    unsigned int mode,
+			    phy_interface_t interface)
+{
+	struct intel_priv_data *intel_priv = intel_data;
+	struct stmmac_priv *priv = netdev_priv(ndev);
+	const struct pmc_serdes_regs *regs;
+	int max_regs = 0;
+	int ret = 0;
+
+	ret = intel_tsn_lane_is_available(ndev, intel_priv);
+	if (ret < 0) {
+		netdev_info(priv->dev, "No TSN lane available to set the registers.\n");
+		return ret;
+	}
+
+	if (interface == PHY_INTERFACE_MODE_2500BASEX) {
+		regs = intel_priv->pid_2p5g.regs;
+		max_regs = intel_priv->pid_2p5g.num_regs;
+	} else {
+		regs = intel_priv->pid_1g.regs;
+		max_regs = intel_priv->pid_1g.num_regs;
+	}
+
+	ret = intel_set_reg_access(regs, max_regs);
+	if (ret < 0)
+		return ret;

+
+	priv->plat->phy_interface = interface;
+
+	intel_serdes_powerdown(ndev, intel_priv);
+	intel_serdes_powerup(ndev, intel_priv);
+
+	return ret;
+}