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>

1 files changed, 126 insertions, 0 deletions

diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
index 3aefa380f345..c93f3a2dc6c1 100644
--- a/drivers/net/ethernet/cadence/macb.h
+++ b/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);