net: macb: Add hardware PTP support

This patch is based on original Harini's patch and Andrei's patch,
implemented in a separate file to ease the review/maintanance
and integration with other platforms.

This driver supports GEM-GXL:
- Register ptp clock framework
- Initialize PTP related registers
- HW time stamp on the PTP Ethernet packets are received using the
  SO_TIMESTAMPING API. Time stamps are obtained from the dma buffer
  descriptors
- add macb_ptp to compilation chain

Signed-off-by: Rafal Ozieblo <rafalo@cadence.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/cadence/Makefile

@@ -3,5 +3,9 @@
 #
 macb-y	:= macb_main.o
 
+ifeq ($(CONFIG_MACB_USE_HWSTAMP),y)
+macb-y	+= macb_ptp.o
+endif
+
 obj-$(CONFIG_MACB) += macb.o
 obj-$(CONFIG_MACB_PCI) += macb_pci.o

drivers/net/ethernet/cadence/macb.h

@@ -11,6 +11,8 @@
 #define _MACB_H
 
 #include <linux/phy.h>
+#include <linux/ptp_clock_kernel.h>
+#include <linux/net_tstamp.h>
 
 #if defined(CONFIG_ARCH_DMA_ADDR_T_64BIT) || defined(CONFIG_MACB_USE_HWSTAMP)
 #define MACB_EXT_DESC
@@ -90,6 +92,10 @@
 #define GEM_SA3T		0x009C /* Specific3 Top */
 #define GEM_SA4B		0x00A0 /* Specific4 Bottom */
 #define GEM_SA4T		0x00A4 /* Specific4 Top */
+#define GEM_EFTSH		0x00e8 /* PTP Event Frame Transmitted Seconds Register 47:32 */
+#define GEM_EFRSH		0x00ec /* PTP Event Frame Received Seconds Register 47:32 */
+#define GEM_PEFTSH		0x00f0 /* PTP Peer Event Frame Transmitted Seconds Register 47:32 */
+#define GEM_PEFRSH		0x00f4 /* PTP Peer Event Frame Received Seconds Register 47:32 */
 #define GEM_OTX			0x0100 /* Octets transmitted */
 #define GEM_OCTTXL		0x0100 /* Octets transmitted [31:0] */
 #define GEM_OCTTXH		0x0104 /* Octets transmitted [47:32] */
@@ -159,6 +165,9 @@
 #define GEM_DCFG6		0x0294 /* Design Config 6 */
 #define GEM_DCFG7		0x0298 /* Design Config 7 */
 
+#define GEM_TXBDCTRL	0x04cc /* TX Buffer Descriptor control register */
+#define GEM_RXBDCTRL	0x04d0 /* RX Buffer Descriptor control register */
+
 #define GEM_ISR(hw_q)		(0x0400 + ((hw_q) << 2))
 #define GEM_TBQP(hw_q)		(0x0440 + ((hw_q) << 2))
 #define GEM_TBQPH(hw_q)		(0x04C8)
@@ -195,6 +204,8 @@
 #define MACB_TZQ_OFFSET		12 /* Transmit zero quantum pause frame */
 #define MACB_TZQ_SIZE		1
 #define MACB_SRTSM_OFFSET	15
+#define MACB_OSSMODE_OFFSET 24 /* Enable One Step Synchro Mode */
+#define MACB_OSSMODE_SIZE	1
 
 /* Bitfields in NCFGR */
 #define MACB_SPD_OFFSET		0 /* Speed */
@@ -452,6 +463,52 @@
 #define GEM_NSINCR_OFFSET			0
 #define GEM_NSINCR_SIZE				8
 
+/* Bitfields in TSH */
+#define GEM_TSH_OFFSET				0 /* TSU timer value (s). MSB [47:32] of seconds timer count */
+#define GEM_TSH_SIZE				16
+
+/* Bitfields in TSL */
+#define GEM_TSL_OFFSET				0 /* TSU timer value (s). LSB [31:0] of seconds timer count */
+#define GEM_TSL_SIZE				32
+
+/* Bitfields in TN */
+#define GEM_TN_OFFSET				0 /* TSU timer value (ns) */
+#define GEM_TN_SIZE					30
+
+/* Bitfields in TXBDCTRL */
+#define GEM_TXTSMODE_OFFSET			4 /* TX Descriptor Timestamp Insertion mode */
+#define GEM_TXTSMODE_SIZE			2
+
+/* Bitfields in RXBDCTRL */
+#define GEM_RXTSMODE_OFFSET			4 /* RX Descriptor Timestamp Insertion mode */
+#define GEM_RXTSMODE_SIZE			2
+
+/* Transmit DMA buffer descriptor Word 1 */
+#define GEM_DMA_TXVALID_OFFSET		23 /* timestamp has been captured in the Buffer Descriptor */
+#define GEM_DMA_TXVALID_SIZE		1
+
+/* Receive DMA buffer descriptor Word 0 */
+#define GEM_DMA_RXVALID_OFFSET		2 /* indicates a valid timestamp in the Buffer Descriptor */
+#define GEM_DMA_RXVALID_SIZE		1
+
+/* DMA buffer descriptor Word 2 (32 bit addressing) or Word 4 (64 bit addressing) */
+#define GEM_DMA_SECL_OFFSET			30 /* Timestamp seconds[1:0]  */
+#define GEM_DMA_SECL_SIZE			2
+#define GEM_DMA_NSEC_OFFSET			0 /* Timestamp nanosecs [29:0] */
+#define GEM_DMA_NSEC_SIZE			30
+
+/* DMA buffer descriptor Word 3 (32 bit addressing) or Word 5 (64 bit addressing) */
+
+/* New hardware supports 12 bit precision of timestamp in DMA buffer descriptor.
+ * Old hardware supports only 6 bit precision but it is enough for PTP.
+ * Less accuracy is used always instead of checking hardware version.
+ */
+#define GEM_DMA_SECH_OFFSET			0 /* Timestamp seconds[5:2] */
+#define GEM_DMA_SECH_SIZE			4
+#define GEM_DMA_SEC_WIDTH			(GEM_DMA_SECH_SIZE + GEM_DMA_SECL_SIZE)
+#define GEM_DMA_SEC_TOP				(1 << GEM_DMA_SEC_WIDTH)
+#define GEM_DMA_SEC_MASK			(GEM_DMA_SEC_TOP - 1)
+
 /* Bitfields in ADJ */
 #define GEM_ADDSUB_OFFSET			31
 #define GEM_ADDSUB_SIZE				1
@@ -527,6 +584,8 @@
 #define queue_readl(queue, reg)		(queue)->bp->macb_reg_readl((queue)->bp, (queue)->reg)
 #define queue_writel(queue, reg, value)	(queue)->bp->macb_reg_writel((queue)->bp, (queue)->reg, (value))
 
+#define PTP_TS_BUFFER_SIZE		128 /* must be power of 2 */
+
 /* Conditional GEM/MACB macros.  These perform the operation to the correct
  * register dependent on whether the device is a GEM or a MACB.  For registers
  * and bitfields that are common across both devices, use macb_{read,write}l
@@ -574,6 +633,11 @@ struct macb_dma_desc_ptp {
 	u32	ts_1;
 	u32	ts_2;
 };
+
+struct gem_tx_ts {
+	struct sk_buff *skb;
+	struct macb_dma_desc_ptp desc_ptp;
+};
 #endif
 
 /* DMA descriptor bitfields */
@@ -889,6 +953,11 @@ struct macb_config {
 	int	jumbo_max_len;
 };
 
+struct tsu_incr {
+	u32 sub_ns;
+	u32 ns;
+};
+
 struct macb_queue {
 	struct macb		*bp;
 	int			irq;
@@ -905,6 +974,12 @@ struct macb_queue {
 	struct macb_tx_skb	*tx_skb;
 	dma_addr_t		tx_ring_dma;
 	struct work_struct	tx_error_task;
+
+#ifdef CONFIG_MACB_USE_HWSTAMP
+	struct work_struct	tx_ts_task;
+	unsigned int		tx_ts_head, tx_ts_tail;
+	struct gem_tx_ts	tx_timestamps[PTP_TS_BUFFER_SIZE];
+#endif
 };
 
 struct macb {
@@ -976,8 +1051,59 @@ struct macb {
 #ifdef MACB_EXT_DESC
 	uint8_t hw_dma_cap;
 #endif
+	spinlock_t tsu_clk_lock; /* gem tsu clock locking */
+	unsigned int tsu_rate;
+	struct ptp_clock *ptp_clock;
+	struct ptp_clock_info ptp_clock_info;
+	struct tsu_incr tsu_incr;
+	struct hwtstamp_config tstamp_config;
 };
 
+#ifdef CONFIG_MACB_USE_HWSTAMP
+#define GEM_TSEC_SIZE  (GEM_TSH_SIZE + GEM_TSL_SIZE)
+#define TSU_SEC_MAX_VAL (((u64)1 << GEM_TSEC_SIZE) - 1)
+#define TSU_NSEC_MAX_VAL ((1 << GEM_TN_SIZE) - 1)
+
+enum macb_bd_control {
+	TSTAMP_DISABLED,
+	TSTAMP_FRAME_PTP_EVENT_ONLY,
+	TSTAMP_ALL_PTP_FRAMES,
+	TSTAMP_ALL_FRAMES,
+};
+
+void gem_ptp_init(struct net_device *ndev);
+void gem_ptp_remove(struct net_device *ndev);
+int gem_ptp_txstamp(struct macb_queue *queue, struct sk_buff *skb, struct macb_dma_desc *des);
+void gem_ptp_rxstamp(struct macb *bp, struct sk_buff *skb, struct macb_dma_desc *desc);
+static inline int gem_ptp_do_txstamp(struct macb_queue *queue, struct sk_buff *skb, struct macb_dma_desc *desc)
+{
+	if (queue->bp->tstamp_config.tx_type == TSTAMP_DISABLED)
+		return -ENOTSUPP;
+
+	return gem_ptp_txstamp(queue, skb, desc);
+}
+
+static inline void gem_ptp_do_rxstamp(struct macb *bp, struct sk_buff *skb, struct macb_dma_desc *desc)
+{
+	if (bp->tstamp_config.rx_filter == TSTAMP_DISABLED)
+		return;
+
+	gem_ptp_rxstamp(bp, skb, desc);
+}
+int gem_get_hwtst(struct net_device *dev, struct ifreq *rq);
+int gem_set_hwtst(struct net_device *dev, struct ifreq *ifr, int cmd);
+#else
+static inline void gem_ptp_init(struct net_device *ndev) { }
+static inline void gem_ptp_remove(struct net_device *ndev) { }
+
+static inline int gem_ptp_do_txstamp(struct macb_queue *queue, struct sk_buff *skb, struct macb_dma_desc *desc)
+{
+	return -1;
+}
+
+static inline void gem_ptp_do_rxstamp(struct macb *bp, struct sk_buff *skb, struct macb_dma_desc *desc) { }
+#endif
+
 static inline bool macb_is_gem(struct macb *bp)
 {
 	return !!(bp->caps & MACB_CAPS_MACB_IS_GEM);

drivers/net/ethernet/cadence/macb_main.c

@@ -847,6 +847,12 @@ static void macb_tx_interrupt(struct macb_queue *queue)
 
 			/* First, update TX stats if needed */
 			if (skb) {
+				if (gem_ptp_do_txstamp(queue, skb, desc) == 0) {
+					/* skb now belongs to timestamp buffer
+					 * and will be removed later
+					 */
+					tx_skb->skb = NULL;
+				}
 				netdev_vdbg(bp->dev, "skb %u (data %p) TX complete\n",
 					    macb_tx_ring_wrap(bp, tail),
 					    skb->data);
@@ -1013,6 +1019,8 @@ static int gem_rx(struct macb *bp, int budget)
 		bp->dev->stats.rx_packets++;
 		bp->dev->stats.rx_bytes += skb->len;
 
+		gem_ptp_do_rxstamp(bp, skb, desc);
+
 #if defined(DEBUG) && defined(VERBOSE_DEBUG)
 		netdev_vdbg(bp->dev, "received skb of length %u, csum: %08x\n",
 			    skb->len, skb->csum);
@@ -1334,7 +1342,6 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
 			if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
 				queue_writel(queue, ISR, MACB_BIT(HRESP));
 		}
-
 		status = queue_readl(queue, ISR);
 	}
 
@@ -1664,7 +1671,6 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
 	/* Make newly initialized descriptor visible to hardware */
 	wmb();
-
 	skb_tx_timestamp(skb);
 
 	macb_writel(bp, NCR, macb_readl(bp, NCR) | MACB_BIT(TSTART));
@@ -2522,6 +2528,70 @@ static int macb_set_ringparam(struct net_device *netdev,
 	return 0;
 }
 
+#ifdef CONFIG_MACB_USE_HWSTAMP
+static unsigned int gem_get_tsu_rate(struct macb *bp)
+{
+	struct clk *tsu_clk;
+	unsigned int tsu_rate;
+
+	tsu_clk = devm_clk_get(&bp->pdev->dev, "tsu_clk");
+	if (!IS_ERR(tsu_clk))
+		tsu_rate = clk_get_rate(tsu_clk);
+	/* try pclk instead */
+	else if (!IS_ERR(bp->pclk)) {
+		tsu_clk = bp->pclk;
+		tsu_rate = clk_get_rate(tsu_clk);
+	} else
+		return -ENOTSUPP;
+	return tsu_rate;
+}
+
+static s32 gem_get_ptp_max_adj(void)
+{
+	return 64000000;
+}
+
+static int gem_get_ts_info(struct net_device *dev,
+			   struct ethtool_ts_info *info)
+{
+	struct macb *bp = netdev_priv(dev);
+
+	if ((bp->hw_dma_cap & HW_DMA_CAP_PTP) == 0) {
+		ethtool_op_get_ts_info(dev, info);
+		return 0;
+	}
+
+	info->so_timestamping =
+		SOF_TIMESTAMPING_TX_SOFTWARE |
+		SOF_TIMESTAMPING_RX_SOFTWARE |
+		SOF_TIMESTAMPING_SOFTWARE |
+		SOF_TIMESTAMPING_TX_HARDWARE |
+		SOF_TIMESTAMPING_RX_HARDWARE |
+		SOF_TIMESTAMPING_RAW_HARDWARE;
+	info->tx_types =
+		(1 << HWTSTAMP_TX_ONESTEP_SYNC) |
+		(1 << HWTSTAMP_TX_OFF) |
+		(1 << HWTSTAMP_TX_ON);
+	info->rx_filters =
+		(1 << HWTSTAMP_FILTER_NONE) |
+		(1 << HWTSTAMP_FILTER_ALL);
+
+	info->phc_index = bp->ptp_clock ? ptp_clock_index(bp->ptp_clock) : -1;
+
+	return 0;
+}
+
+static struct macb_ptp_info gem_ptp_info = {
+	.ptp_init	 = gem_ptp_init,
+	.ptp_remove	 = gem_ptp_remove,
+	.get_ptp_max_adj = gem_get_ptp_max_adj,
+	.get_tsu_rate	 = gem_get_tsu_rate,
+	.get_ts_info	 = gem_get_ts_info,
+	.get_hwtst	 = gem_get_hwtst,
+	.set_hwtst	 = gem_set_hwtst,
+};
+#endif
+
 static int macb_get_ts_info(struct net_device *netdev,
 			    struct ethtool_ts_info *info)
 {
@@ -2655,12 +2725,16 @@ static void macb_configure_caps(struct macb *bp,
 		dcfg = gem_readl(bp, DCFG2);
 		if ((dcfg & (GEM_BIT(RX_PKT_BUFF) | GEM_BIT(TX_PKT_BUFF))) == 0)
 			bp->caps |= MACB_CAPS_FIFO_MODE;
-		if (IS_ENABLED(CONFIG_MACB_USE_HWSTAMP) && gem_has_ptp(bp)) {
+#ifdef CONFIG_MACB_USE_HWSTAMP
+		if (gem_has_ptp(bp)) {
 			if (!GEM_BFEXT(TSU, gem_readl(bp, DCFG5)))
 				pr_err("GEM doesn't support hardware ptp.\n");
-			else
+			else {
 				bp->hw_dma_cap |= HW_DMA_CAP_PTP;
+				bp->ptp_info = &gem_ptp_info;
+			}
 		}
+#endif
 	}
 
 	dev_dbg(&bp->pdev->dev, "Cadence caps 0x%08x\n", bp->caps);
@@ -3266,7 +3340,9 @@ static const struct macb_config np4_config = {
 };
 
 static const struct macb_config zynqmp_config = {
-	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_JUMBO,
+	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE |
+			MACB_CAPS_JUMBO |
+			MACB_CAPS_GEM_HAS_PTP,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,
@@ -3300,7 +3376,9 @@ MODULE_DEVICE_TABLE(of, macb_dt_ids);
 #endif /* CONFIG_OF */
 
 static const struct macb_config default_gem_config = {
-	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE | MACB_CAPS_JUMBO,
+	.caps = MACB_CAPS_GIGABIT_MODE_AVAILABLE |
+			MACB_CAPS_JUMBO |
+			MACB_CAPS_GEM_HAS_PTP,
 	.dma_burst_length = 16,
 	.clk_init = macb_clk_init,
 	.init = macb_init,