net: stmmac: Add hardware supported cross-timestamp

Cross timestamping is supported on Integrated Ethernet Controller in
Intel SoC such as EHL and TGL with Always Running Timer.

The hardware cross-timestamp result is made available to
applications through the PTP_SYS_OFFSET_PRECISE ioctl which calls
stmmac_getcrosststamp().

Device time is stored in the MAC Auxiliary register. The 64-bit System
time (ART timestamp) is stored in registers that are only addressable
by using MDIO space.

Signed-off-by: Tan Tee Min <tee.min.tan@intel.com>
Co-developed-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/common.h

@@ -388,6 +388,8 @@ struct dma_features {
 	unsigned int estsel;
 	unsigned int fpesel;
 	unsigned int tbssel;
+	/* Numbers of Auxiliary Snapshot Inputs */
+	unsigned int aux_snapshot_n;
 };
 
 /* RX Buffer size must be multiple of 4/8/16 bytes */

drivers/net/ethernet/stmicro/stmmac/dwmac-intel.c

@@ -8,6 +8,7 @@
 #include "dwmac-intel.h"
 #include "dwmac4.h"
 #include "stmmac.h"
+#include "stmmac_ptp.h"
 
 #define INTEL_MGBE_ADHOC_ADDR	0x15
 #define INTEL_MGBE_XPCS_ADDR	0x16
@@ -240,6 +241,108 @@ static void intel_mgbe_ptp_clk_freq_config(void *npriv)
 	writel(gpio_value, priv->ioaddr + GMAC_GPIO_STATUS);
 }
 
+static void get_arttime(struct mii_bus *mii, int intel_adhoc_addr,
+			u64 *art_time)
+{
+	u64 ns;
+
+	ns = mdiobus_read(mii, intel_adhoc_addr, PMC_ART_VALUE3);
+	ns <<= GMAC4_ART_TIME_SHIFT;
+	ns |= mdiobus_read(mii, intel_adhoc_addr, PMC_ART_VALUE2);
+	ns <<= GMAC4_ART_TIME_SHIFT;
+	ns |= mdiobus_read(mii, intel_adhoc_addr, PMC_ART_VALUE1);
+	ns <<= GMAC4_ART_TIME_SHIFT;
+	ns |= mdiobus_read(mii, intel_adhoc_addr, PMC_ART_VALUE0);
+
+	*art_time = ns;
+}
+
+static int intel_crosststamp(ktime_t *device,
+			     struct system_counterval_t *system,
+			     void *ctx)
+{
+	struct intel_priv_data *intel_priv;
+
+	struct stmmac_priv *priv = (struct stmmac_priv *)ctx;
+	void __iomem *ptpaddr = priv->ptpaddr;
+	void __iomem *ioaddr = priv->hw->pcsr;
+	unsigned long flags;
+	u64 art_time = 0;
+	u64 ptp_time = 0;
+	u32 num_snapshot;
+	u32 gpio_value;
+	u32 acr_value;
+	int ret;
+	u32 v;
+	int i;
+
+	if (!boot_cpu_has(X86_FEATURE_ART))
+		return -EOPNOTSUPP;
+
+	intel_priv = priv->plat->bsp_priv;
+
+	/* Enable Internal snapshot trigger */
+	acr_value = readl(ptpaddr + PTP_ACR);
+	acr_value &= ~PTP_ACR_MASK;
+	switch (priv->plat->int_snapshot_num) {
+	case AUX_SNAPSHOT0:
+		acr_value |= PTP_ACR_ATSEN0;
+		break;
+	case AUX_SNAPSHOT1:
+		acr_value |= PTP_ACR_ATSEN1;
+		break;
+	case AUX_SNAPSHOT2:
+		acr_value |= PTP_ACR_ATSEN2;
+		break;
+	case AUX_SNAPSHOT3:
+		acr_value |= PTP_ACR_ATSEN3;
+		break;
+	default:
+		return -EINVAL;
+	}
+	writel(acr_value, ptpaddr + PTP_ACR);
+
+	/* Clear FIFO */
+	acr_value = readl(ptpaddr + PTP_ACR);
+	acr_value |= PTP_ACR_ATSFC;
+	writel(acr_value, ptpaddr + PTP_ACR);
+
+	/* Trigger Internal snapshot signal
+	 * Create a rising edge by just toggle the GPO1 to low
+	 * and back to high.
+	 */
+	gpio_value = readl(ioaddr + GMAC_GPIO_STATUS);
+	gpio_value &= ~GMAC_GPO1;
+	writel(gpio_value, ioaddr + GMAC_GPIO_STATUS);
+	gpio_value |= GMAC_GPO1;
+	writel(gpio_value, ioaddr + GMAC_GPIO_STATUS);
+
+	/* Poll for time sync operation done */
+	ret = readl_poll_timeout(priv->ioaddr + GMAC_INT_STATUS, v,
+				 (v & GMAC_INT_TSIE), 100, 10000);
+
+	if (ret == -ETIMEDOUT) {
+		pr_err("%s: Wait for time sync operation timeout\n", __func__);
+		return ret;
+	}
+
+	num_snapshot = (readl(ioaddr + GMAC_TIMESTAMP_STATUS) &
+			GMAC_TIMESTAMP_ATSNS_MASK) >>
+			GMAC_TIMESTAMP_ATSNS_SHIFT;
+
+	/* Repeat until the timestamps are from the FIFO last segment */
+	for (i = 0; i < num_snapshot; i++) {
+		spin_lock_irqsave(&priv->ptp_lock, flags);
+		stmmac_get_ptptime(priv, ptpaddr, &ptp_time);
+		*device = ns_to_ktime(ptp_time);
+		spin_unlock_irqrestore(&priv->ptp_lock, flags);
+		get_arttime(priv->mii, intel_priv->mdio_adhoc_addr, &art_time);
+		*system = convert_art_to_tsc(art_time);
+	}
+
+	return 0;
+}
+
 static void common_default_data(struct plat_stmmacenet_data *plat)
 {
 	plat->clk_csr = 2;	/* clk_csr_i = 20-35MHz & MDC = clk_csr_i/16 */
@@ -384,6 +487,11 @@ static int intel_mgbe_common_data(struct pci_dev *pdev,
 	plat->mdio_bus_data->phy_mask = 1 << INTEL_MGBE_ADHOC_ADDR;
 	plat->mdio_bus_data->phy_mask |= 1 << INTEL_MGBE_XPCS_ADDR;
 
+	plat->int_snapshot_num = AUX_SNAPSHOT1;
+
+	plat->has_crossts = true;
+	plat->crosststamp = intel_crosststamp;
+
 	return 0;
 }
 

drivers/net/ethernet/stmicro/stmmac/dwmac4.h

@@ -50,6 +50,7 @@
 #define GMAC_L4_ADDR(reg)		(0x904 + (reg) * 0x30)
 #define GMAC_L3_ADDR0(reg)		(0x910 + (reg) * 0x30)
 #define GMAC_L3_ADDR1(reg)		(0x914 + (reg) * 0x30)
+#define GMAC_TIMESTAMP_STATUS		0x00000b20
 
 /* RX Queues Routing */
 #define GMAC_RXQCTRL_AVCPQ_MASK		GENMASK(2, 0)
@@ -144,6 +145,7 @@
 #define GMAC_INT_PCS_PHYIS		BIT(3)
 #define GMAC_INT_PMT_EN			BIT(4)
 #define GMAC_INT_LPI_EN			BIT(5)
+#define GMAC_INT_TSIE			BIT(12)
 
 #define	GMAC_PCS_IRQ_DEFAULT	(GMAC_INT_RGSMIIS | GMAC_INT_PCS_LINK |	\
 				 GMAC_INT_PCS_ANE)
@@ -260,6 +262,7 @@ enum power_event {
 #define GMAC_HW_RXFIFOSIZE		GENMASK(4, 0)
 
 /* MAC HW features2 bitmap */
+#define GMAC_HW_FEAT_AUXSNAPNUM		GENMASK(30, 28)
 #define GMAC_HW_FEAT_PPSOUTNUM		GENMASK(26, 24)
 #define GMAC_HW_FEAT_TXCHCNT		GENMASK(21, 18)
 #define GMAC_HW_FEAT_RXCHCNT		GENMASK(15, 12)
@@ -305,6 +308,11 @@ enum power_event {
 #define GMAC_L4DP0_SHIFT		16
 #define GMAC_L4SP0			GENMASK(15, 0)
 
+/* MAC Timestamp Status */
+#define GMAC_TIMESTAMP_AUXTSTRIG	BIT(2)
+#define GMAC_TIMESTAMP_ATSNS_MASK	GENMASK(29, 25)
+#define GMAC_TIMESTAMP_ATSNS_SHIFT	25
+
 /*  MTL registers */
 #define MTL_OPERATION_MODE		0x00000c00
 #define MTL_FRPE			BIT(15)

drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.c

@@ -412,6 +412,8 @@ static void dwmac4_get_hw_feature(void __iomem *ioaddr,
 
 	/* IEEE 1588-2002 */
 	dma_cap->time_stamp = 0;
+	/* Number of Auxiliary Snapshot Inputs */
+	dma_cap->aux_snapshot_n = (hw_cap & GMAC_HW_FEAT_AUXSNAPNUM) >> 28;
 
 	/* MAC HW feature3 */
 	hw_cap = readl(ioaddr + GMAC_HW_FEATURE3);

drivers/net/ethernet/stmicro/stmmac/hwif.h

@@ -508,6 +508,7 @@ struct stmmac_hwtimestamp {
 	int (*adjust_systime) (void __iomem *ioaddr, u32 sec, u32 nsec,
 			       int add_sub, int gmac4);
 	void (*get_systime) (void __iomem *ioaddr, u64 *systime);
+	void (*get_ptptime)(void __iomem *ioaddr, u64 *ptp_time);
 };
 
 #define stmmac_config_hw_tstamping(__priv, __args...) \
@@ -522,6 +523,8 @@ struct stmmac_hwtimestamp {
 	stmmac_do_callback(__priv, ptp, adjust_systime, __args)
 #define stmmac_get_systime(__priv, __args...) \
 	stmmac_do_void_callback(__priv, ptp, get_systime, __args)
+#define stmmac_get_ptptime(__priv, __args...) \
+	stmmac_do_void_callback(__priv, ptp, get_ptptime, __args)
 
 /* Helpers to manage the descriptors for chain and ring modes */
 struct stmmac_mode_ops {

drivers/net/ethernet/stmicro/stmmac/stmmac_hwtstamp.c

@@ -153,6 +153,16 @@ static void get_systime(void __iomem *ioaddr, u64 *systime)
 		*systime = ns;
 }
 
+static void get_ptptime(void __iomem *ptpaddr, u64 *ptp_time)
+{
+	u64 ns;
+
+	ns = readl(ptpaddr + PTP_ATNR);
+	ns += readl(ptpaddr + PTP_ATSR) * NSEC_PER_SEC;
+
+	*ptp_time = ns;
+}
+
 const struct stmmac_hwtimestamp stmmac_ptp = {
 	.config_hw_tstamping = config_hw_tstamping,
 	.init_systime = init_systime,
@@ -160,4 +170,5 @@ const struct stmmac_hwtimestamp stmmac_ptp = {
 	.config_addend = config_addend,
 	.adjust_systime = adjust_systime,
 	.get_systime = get_systime,
+	.get_ptptime = get_ptptime,
 };

drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.c

@@ -9,6 +9,7 @@
 *******************************************************************************/
 #include "stmmac.h"
 #include "stmmac_ptp.h"
+#include "dwmac4.h"
 
 /**
  * stmmac_adjust_freq
@@ -165,6 +166,36 @@ static int stmmac_enable(struct ptp_clock_info *ptp,
 	return ret;
 }
 
+/**
+ * stmmac_get_syncdevicetime
+ * @device: current device time
+ * @system: system counter value read synchronously with device time
+ * @ctx: context provided by timekeeping code
+ * Description: Read device and system clock simultaneously and return the
+ * corrected clock values in ns.
+ **/
+static int stmmac_get_syncdevicetime(ktime_t *device,
+				     struct system_counterval_t *system,
+				     void *ctx)
+{
+	struct stmmac_priv *priv = (struct stmmac_priv *)ctx;
+
+	if (priv->plat->crosststamp)
+		return priv->plat->crosststamp(device, system, ctx);
+	else
+		return -EOPNOTSUPP;
+}
+
+static int stmmac_getcrosststamp(struct ptp_clock_info *ptp,
+				 struct system_device_crosststamp *xtstamp)
+{
+	struct stmmac_priv *priv =
+		container_of(ptp, struct stmmac_priv, ptp_clock_ops);
+
+	return get_device_system_crosststamp(stmmac_get_syncdevicetime,
+					     priv, NULL, xtstamp);
+}
+
 /* structure describing a PTP hardware clock */
 static struct ptp_clock_info stmmac_ptp_clock_ops = {
 	.owner = THIS_MODULE,
@@ -180,6 +211,7 @@ static struct ptp_clock_info stmmac_ptp_clock_ops = {
 	.gettime64 = stmmac_get_time,
 	.settime64 = stmmac_set_time,
 	.enable = stmmac_enable,
+	.getcrosststamp = stmmac_getcrosststamp,
 };
 
 /**

drivers/net/ethernet/stmicro/stmmac/stmmac_ptp.h

@@ -23,6 +23,9 @@
 #define	PTP_STSUR	0x10	/* System Time – Seconds Update Reg */
 #define	PTP_STNSUR	0x14	/* System Time – Nanoseconds Update Reg */
 #define	PTP_TAR		0x18	/* Timestamp Addend Reg */
+#define	PTP_ACR		0x40	/* Auxiliary Control Reg */
+#define	PTP_ATNR	0x48	/* Auxiliary Timestamp - Nanoseconds Reg */
+#define	PTP_ATSR	0x4c	/* Auxiliary Timestamp - Seconds Reg */
 
 #define	PTP_STNSUR_ADDSUB_SHIFT	31
 #define	PTP_DIGITAL_ROLLOVER_MODE	0x3B9ACA00	/* 10e9-1 ns */
@@ -64,4 +67,24 @@
 #define	PTP_SSIR_SSINC_MASK		0xff
 #define	GMAC4_PTP_SSIR_SSINC_SHIFT	16
 
+/* Auxiliary Control defines */
+#define	PTP_ACR_ATSFC		BIT(0)	/* Auxiliary Snapshot FIFO Clear */
+#define	PTP_ACR_ATSEN0		BIT(4)	/* Auxiliary Snapshot 0 Enable */
+#define	PTP_ACR_ATSEN1		BIT(5)	/* Auxiliary Snapshot 1 Enable */
+#define	PTP_ACR_ATSEN2		BIT(6)	/* Auxiliary Snapshot 2 Enable */
+#define	PTP_ACR_ATSEN3		BIT(7)	/* Auxiliary Snapshot 3 Enable */
+#define	PTP_ACR_MASK		GENMASK(7, 4)	/* Aux Snapshot Mask */
+#define	PMC_ART_VALUE0		0x01	/* PMC_ART[15:0] timer value */
+#define	PMC_ART_VALUE1		0x02	/* PMC_ART[31:16] timer value */
+#define	PMC_ART_VALUE2		0x03	/* PMC_ART[47:32] timer value */
+#define	PMC_ART_VALUE3		0x04	/* PMC_ART[63:48] timer value */
+#define	GMAC4_ART_TIME_SHIFT	16	/* ART TIME 16-bits shift */
+
+enum aux_snapshot {
+	AUX_SNAPSHOT0 = 0x10,
+	AUX_SNAPSHOT1 = 0x20,
+	AUX_SNAPSHOT2 = 0x40,
+	AUX_SNAPSHOT3 = 0x80,
+};
+
 #endif	/* __STMMAC_PTP_H__ */

include/linux/stmmac.h

@@ -186,6 +186,8 @@ struct plat_stmmacenet_data {
 	void (*exit)(struct platform_device *pdev, void *priv);
 	struct mac_device_info *(*setup)(void *priv);
 	int (*clks_config)(void *priv, bool enabled);
+	int (*crosststamp)(ktime_t *device, struct system_counterval_t *system,
+			   void *ctx);
 	void *bsp_priv;
 	struct clk *stmmac_clk;
 	struct clk *pclk;
@@ -206,5 +208,7 @@ struct plat_stmmacenet_data {
 	u8 vlan_fail_q;
 	unsigned int eee_usecs_rate;
 	struct pci_dev *pdev;
+	bool has_crossts;
+	int int_snapshot_num;
 };
 #endif