diff mbox series

[net-next,v3,6/6] tsnep: Add free running cycle counter support

Message ID 20220501111836.10910-7-gerhard@engleder-embedded.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series ptp: Support hardware clocks with additional free running cycle counter | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 3 maintainers not CCed: edumazet@google.com liuhangbin@gmail.com pabeni@redhat.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: line length of 81 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Gerhard Engleder May 1, 2022, 11:18 a.m. UTC
The TSN endpoint Ethernet MAC supports a free running counter
additionally to its clock. This free running counter can be read and
hardware timestamps are supported. As the name implies, this counter
cannot be set and its frequency cannot be adjusted.

Add free running cycle counter support based on this free running
counter to physical clock. This also requires hardware time stamps
based on that free running counter.

Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
---
 drivers/net/ethernet/engleder/tsnep_hw.h   |  9 ++++--
 drivers/net/ethernet/engleder/tsnep_main.c | 33 ++++++++++++++++++----
 drivers/net/ethernet/engleder/tsnep_ptp.c  | 28 ++++++++++++++++++
 3 files changed, 63 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/engleder/tsnep_hw.h b/drivers/net/ethernet/engleder/tsnep_hw.h
index 71cc8577d640..916ceac3ada2 100644
--- a/drivers/net/ethernet/engleder/tsnep_hw.h
+++ b/drivers/net/ethernet/engleder/tsnep_hw.h
@@ -43,6 +43,10 @@ 
 #define ECM_RESET_CHANNEL 0x00000100
 #define ECM_RESET_TXRX 0x00010000
 
+/* counter */
+#define ECM_COUNTER_LOW 0x0028
+#define ECM_COUNTER_HIGH 0x002C
+
 /* control and status */
 #define ECM_STATUS 0x0080
 #define ECM_LINK_MODE_OFF 0x01000000
@@ -190,7 +194,8 @@  struct tsnep_tx_desc {
 /* tsnep TX descriptor writeback */
 struct tsnep_tx_desc_wb {
 	__le32 properties;
-	__le32 reserved1[3];
+	__le32 reserved1;
+	__le64 counter;
 	__le64 timestamp;
 	__le32 dma_delay;
 	__le32 reserved2;
@@ -221,7 +226,7 @@  struct tsnep_rx_desc_wb {
 
 /* tsnep RX inline meta */
 struct tsnep_rx_inline {
-	__le64 reserved;
+	__le64 counter;
 	__le64 timestamp;
 };
 
diff --git a/drivers/net/ethernet/engleder/tsnep_main.c b/drivers/net/ethernet/engleder/tsnep_main.c
index 49c93aa38862..cb069a0af7b9 100644
--- a/drivers/net/ethernet/engleder/tsnep_main.c
+++ b/drivers/net/ethernet/engleder/tsnep_main.c
@@ -470,8 +470,15 @@  static bool tsnep_tx_poll(struct tsnep_tx *tx, int napi_budget)
 		    (__le32_to_cpu(entry->desc_wb->properties) &
 		     TSNEP_DESC_EXTENDED_WRITEBACK_FLAG)) {
 			struct skb_shared_hwtstamps hwtstamps;
-			u64 timestamp =
-				__le64_to_cpu(entry->desc_wb->timestamp);
+			u64 timestamp;
+
+			if (skb_shinfo(entry->skb)->tx_flags &
+			    SKBTX_HW_TSTAMP_USE_CYCLES)
+				timestamp =
+					__le64_to_cpu(entry->desc_wb->counter);
+			else
+				timestamp =
+					__le64_to_cpu(entry->desc_wb->timestamp);
 
 			memset(&hwtstamps, 0, sizeof(hwtstamps));
 			hwtstamps.hwtstamp = ns_to_ktime(timestamp);
@@ -704,11 +711,11 @@  static int tsnep_rx_poll(struct tsnep_rx *rx, struct napi_struct *napi,
 					skb_hwtstamps(skb);
 				struct tsnep_rx_inline *rx_inline =
 					(struct tsnep_rx_inline *)skb->data;
-				u64 timestamp =
-					__le64_to_cpu(rx_inline->timestamp);
 
+				skb_shinfo(skb)->tx_flags |=
+					SKBTX_HW_TSTAMP_NETDEV;
 				memset(hwtstamps, 0, sizeof(*hwtstamps));
-				hwtstamps->hwtstamp = ns_to_ktime(timestamp);
+				hwtstamps->netdev_data = rx_inline;
 			}
 			skb_pull(skb, TSNEP_RX_INLINE_METADATA_SIZE);
 			skb->protocol = eth_type_trans(skb,
@@ -1010,6 +1017,21 @@  static int tsnep_netdev_set_mac_address(struct net_device *netdev, void *addr)
 	return 0;
 }
 
+static ktime_t tsnep_netdev_get_tstamp(struct net_device *netdev,
+				       const struct skb_shared_hwtstamps *hwtstamps,
+				       bool cycles)
+{
+	struct tsnep_rx_inline *rx_inline = hwtstamps->netdev_data;
+	u64 timestamp;
+
+	if (cycles)
+		timestamp = __le64_to_cpu(rx_inline->counter);
+	else
+		timestamp = __le64_to_cpu(rx_inline->timestamp);
+
+	return ns_to_ktime(timestamp);
+}
+
 static const struct net_device_ops tsnep_netdev_ops = {
 	.ndo_open = tsnep_netdev_open,
 	.ndo_stop = tsnep_netdev_close,
@@ -1019,6 +1041,7 @@  static const struct net_device_ops tsnep_netdev_ops = {
 
 	.ndo_get_stats64 = tsnep_netdev_get_stats64,
 	.ndo_set_mac_address = tsnep_netdev_set_mac_address,
+	.ndo_get_tstamp = tsnep_netdev_get_tstamp,
 	.ndo_setup_tc = tsnep_tc_setup,
 };
 
diff --git a/drivers/net/ethernet/engleder/tsnep_ptp.c b/drivers/net/ethernet/engleder/tsnep_ptp.c
index eaad453d487e..54fbf0126815 100644
--- a/drivers/net/ethernet/engleder/tsnep_ptp.c
+++ b/drivers/net/ethernet/engleder/tsnep_ptp.c
@@ -175,6 +175,33 @@  static int tsnep_ptp_settime64(struct ptp_clock_info *ptp,
 	return 0;
 }
 
+static int tsnep_ptp_getcyclesx64(struct ptp_clock_info *ptp,
+				  struct timespec64 *ts,
+				  struct ptp_system_timestamp *sts)
+{
+	struct tsnep_adapter *adapter = container_of(ptp, struct tsnep_adapter,
+						     ptp_clock_info);
+	u32 high_before;
+	u32 low;
+	u32 high;
+	u64 counter;
+
+	/* read high dword twice to detect overrun */
+	high = ioread32(adapter->addr + ECM_COUNTER_HIGH);
+	do {
+		ptp_read_system_prets(sts);
+		low = ioread32(adapter->addr + ECM_COUNTER_LOW);
+		ptp_read_system_postts(sts);
+		high_before = high;
+		high = ioread32(adapter->addr + ECM_COUNTER_HIGH);
+	} while (high != high_before);
+	counter = (((u64)high) << 32) | ((u64)low);
+
+	*ts = ns_to_timespec64(counter);
+
+	return 0;
+}
+
 int tsnep_ptp_init(struct tsnep_adapter *adapter)
 {
 	int retval = 0;
@@ -192,6 +219,7 @@  int tsnep_ptp_init(struct tsnep_adapter *adapter)
 	adapter->ptp_clock_info.adjtime = tsnep_ptp_adjtime;
 	adapter->ptp_clock_info.gettimex64 = tsnep_ptp_gettimex64;
 	adapter->ptp_clock_info.settime64 = tsnep_ptp_settime64;
+	adapter->ptp_clock_info.getcyclesx64 = tsnep_ptp_getcyclesx64;
 
 	spin_lock_init(&adapter->ptp_lock);