soc/intel/ehl: Provide function to change PHY-to-MAC IRQ polarity

EHL MAC side expects a rising edge signal for an IRQ. Based on the
mainboard wiring it could be necessary to change the interrupt polarity.
This patch provides the functionality to invert a falling edge signal
that comes from an external PHY. The inverting can be activated via
devicetree parameter.

Change-Id: Ia314014c7cacbeb72629c773c8c0bb5f002a3f54
Signed-off-by: Mario Scheithauer <mario.scheithauer@siemens.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/63888
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>

src/soc/intel/elkhartlake/chip.h

@@ -56,6 +56,12 @@ enum tsn_phy_type {
 	SGMII_plus	= 3,
 };
 
+/* TSN GBE PHY-to-MAC IRQ polarity:  0: falling edge, 1: rising edge */
+enum tsn_phy_irq_polarity {
+	FALLING_EDGE,
+	RISING_EDGE,
+};
+
 /*
  * PSE native pins and ownership assignment:-
  * 0: Disable/pins are not owned by PSE/host
@@ -395,6 +401,8 @@ struct soc_intel_elkhartlake_config {
 	bool PseTsnGbeMultiVcEnable[MAX_PSE_TSN_PORTS];
 	/* PSE TSN Phy Interface Type */
 	enum tsn_phy_type PseTsnGbePhyType[MAX_PSE_TSN_PORTS];
+	enum tsn_phy_irq_polarity pch_tsn_phy_irq_edge;
+	enum tsn_phy_irq_polarity pse_tsn_phy_irq_edge[MAX_PSE_TSN_PORTS];
 
 	/* PSE related */
 	/*

src/soc/intel/elkhartlake/include/soc/tsn_gbe.h

@@ -8,8 +8,33 @@
 #define TSN_MAC_ADD0_HIGH		0x300		/* MAC Address0 High register */
 #define TSN_MAC_ADD0_LOW		0x304		/* MAC Address0 Low register */
 
+#define TSN_GMII_TIMEOUT_MS		20
+
+#define TSN_MAC_MDIO_ADR		0x200		/* MAC MDIO Address register */
+#define TSN_MAC_MDIO_ADR_MASK		0x03FF7F0E
+#define  TSN_MAC_PHYAD(pa)		(pa << 21)	/* Physical Layer Address */
+#define  TSN_MAC_REGAD(rda)		(rda << 16)	/* Register/Device Address */
+#define  TSN_MAC_CLK_TRAIL_4		(4 << 12)	/* 4 Trailing Clocks */
+#define  TSN_MAC_CSR_CLK_DIV_62		(1 << 8)	/* 0001: CSR=100-150 MHz; CSR/62 */
+#define  TSN_MAC_OP_CMD_WRITE		(1 << 2)	/* GMII Operation Command Write */
+#define  TSN_MAC_OP_CMD_READ		(3 << 2)	/* GMII Operation Command Read */
+#define  TSN_MAC_GMII_BUSY		(1 << 0)	/* GMII Busy bit */
+
+/* MDIO - Adhoc PHY Sublayer Register */
+#define TSN_MAC_MDIO_ADHOC_ADR		0x15
+/* Global Configuration Register */
+#define TSN_MAC_MDIO_GCR		0x0
+/* PHY to MAC Interrupt Polarity bit */
+#define  TSN_MAC_PHY2MAC_INTR_POL	(1 << 6)
+
+#define TSN_MAC_MDIO_DATA		0x204		/* MAC MDIO Data register */
+
 /* We need one function we can call to get a MAC address to use. */
 /* This function can be coded somewhere else but must exist. */
 enum cb_err mainboard_get_mac_address(struct device *dev, uint8_t mac[MAC_ADDR_LEN]);
 
+enum cb_err phy_gmii_ready(void *base);
+uint16_t tsn_mdio_read(void *base, uint8_t phy_adr, uint8_t reg_adr);
+void tsn_mdio_write(void *base, uint8_t phy_adr, uint8_t reg_adr, uint16_t data);
+
 #endif /* _SOC_ELKHARTLAKE_TSN_GBE_H_ */

src/soc/intel/elkhartlake/tsn_gbe.c

@@ -3,7 +3,9 @@
 #include <console/console.h>
 #include <device/pci.h>
 #include <device/pci_ids.h>
+#include <soc/soc_chip.h>
 #include <soc/tsn_gbe.h>
+#include <timer.h>
 
 static void program_mac_address(struct device *dev, void *base)
 {
@@ -26,14 +28,99 @@ static void program_mac_address(struct device *dev, void *base)
 			(mac[3] << 24) | (mac[2] << 16) | (mac[1] << 8) | mac[0]);
 }
 
+enum cb_err phy_gmii_ready(void *base)
+{
+	struct stopwatch sw;
+
+	stopwatch_init_msecs_expire(&sw, TSN_GMII_TIMEOUT_MS);
+	do {
+		if (!(read32((base + TSN_MAC_MDIO_ADR)) & TSN_MAC_GMII_BUSY))
+			return CB_SUCCESS;
+
+	} while (!stopwatch_expired(&sw));
+
+	printk(BIOS_ERR, "%s Timeout after %ld msec\n", __func__,
+			stopwatch_duration_msecs(&sw));
+	return CB_ERR;
+}
+
+uint16_t tsn_mdio_read(void *base, uint8_t phy_adr, uint8_t reg_adr)
+{
+	uint16_t data = 0;
+	enum cb_err status;
+
+	clrsetbits32(base + TSN_MAC_MDIO_ADR, TSN_MAC_MDIO_ADR_MASK,
+			TSN_MAC_PHYAD(phy_adr) | TSN_MAC_REGAD(reg_adr)
+			| TSN_MAC_CLK_TRAIL_4 | TSN_MAC_CSR_CLK_DIV_62
+			| TSN_MAC_OP_CMD_READ | TSN_MAC_GMII_BUSY);
+
+	/* Wait for MDIO frame transfer to complete before reading MDIO DATA register */
+	status = phy_gmii_ready(base);
+	if (status == CB_ERR) {
+		printk(BIOS_ERR, "%s TSN GMII busy. PHY Adr: 0x%x, Reg 0x%x\n",
+				__func__, phy_adr, reg_adr);
+	} else {
+		data = read16(base + TSN_MAC_MDIO_DATA);
+		printk(BIOS_DEBUG, "%s PHY Adr: 0x%x, Reg: 0x%x , Data: 0x%x\n",
+				__func__, phy_adr, reg_adr, data);
+	}
+	return data;
+}
+
+void tsn_mdio_write(void *base, uint8_t phy_adr, uint8_t reg_adr, uint16_t data)
+{
+	enum cb_err status;
+
+	setbits16(base + TSN_MAC_MDIO_DATA, data);
+	clrsetbits32(base + TSN_MAC_MDIO_ADR, TSN_MAC_MDIO_ADR_MASK,
+			TSN_MAC_PHYAD(phy_adr) | TSN_MAC_REGAD(reg_adr)
+			| TSN_MAC_CLK_TRAIL_4 | TSN_MAC_CSR_CLK_DIV_62
+			| TSN_MAC_OP_CMD_WRITE | TSN_MAC_GMII_BUSY);
+
+	/* Wait for MDIO frame transfer to complete before do next */
+	status = phy_gmii_ready(base);
+	if (status == CB_ERR)
+		printk(BIOS_ERR, "%s TSN GMII busy. PHY Adr: 0x%x, Reg 0x%x\n",
+				__func__, phy_adr, reg_adr);
+	else
+		printk(BIOS_DEBUG, "%s PHY Adr: 0x%x, Reg: 0x%x , Data: 0x%x\n",
+				__func__, phy_adr, reg_adr, data);
+}
+
+static void tsn_set_phy2mac_irq_polarity(void *base, enum tsn_phy_irq_polarity pol)
+{
+	uint16_t gcr_reg;
+
+	if (pol == RISING_EDGE) {
+		/* Read TSN adhoc PHY sublayer register - global configuration register */
+		gcr_reg = tsn_mdio_read(base, TSN_MAC_MDIO_ADHOC_ADR, TSN_MAC_MDIO_GCR);
+		gcr_reg |= TSN_MAC_PHY2MAC_INTR_POL;
+		tsn_mdio_write(base, TSN_MAC_MDIO_ADHOC_ADR, TSN_MAC_MDIO_GCR, gcr_reg);
+	}
+}
+
 static void gbe_tsn_init(struct device *dev)
 {
 	/* Get the base address of the I/O registers in memory space */
 	struct resource *gbe_tsn_res = find_resource(dev, PCI_BASE_ADDRESS_0);
 	void *io_mem_base = (void *)(uintptr_t)gbe_tsn_res->base;
+	config_t *config = config_of(dev);
 
 	/* Program MAC address */
 	program_mac_address(dev, io_mem_base);
+
+	/* Set PHY-to-MAC IRQ polarity according to devicetree */
+	switch (dev->path.pci.devfn) {
+	case PCH_DEVFN_GBE:
+		tsn_set_phy2mac_irq_polarity(io_mem_base, config->pch_tsn_phy_irq_edge);
+		break;
+	case PCH_DEVFN_PSEGBE0:
+		tsn_set_phy2mac_irq_polarity(io_mem_base, config->pse_tsn_phy_irq_edge[0]);
+		break;
+	case PCH_DEVFN_PSEGBE1:
+		tsn_set_phy2mac_irq_polarity(io_mem_base, config->pse_tsn_phy_irq_edge[1]);
+		break;
+	}
 }
 
 static struct device_operations gbe_tsn_ops  = {