1 files changed, 443 insertions, 0 deletions
diff --git a/drivers/net/ethernet/engleder/tsnep_tc.c b/drivers/net/ethernet/engleder/tsnep_tc.c
new file mode 100644
index 000000000000..c4c6e1357317
--- /dev/null
+++ b/drivers/net/ethernet/engleder/tsnep_tc.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2021 Gerhard Engleder <gerhard@engleder-embedded.com> */
+
+#include "tsnep.h"
+
+#include <net/pkt_sched.h>
+
+/* save one operation at the end for additional operation at list change */
+#define TSNEP_MAX_GCL_NUM (TSNEP_GCL_COUNT - 1)
+
+static int tsnep_validate_gcl(struct tc_taprio_qopt_offload *qopt)
+{
+	int i;
+	u64 cycle_time;
+
+	if (!qopt->cycle_time)
+		return -ERANGE;
+	if (qopt->num_entries > TSNEP_MAX_GCL_NUM)
+		return -EINVAL;
+	cycle_time = 0;
+	for (i = 0; i < qopt->num_entries; i++) {
+		if (qopt->entries[i].command != TC_TAPRIO_CMD_SET_GATES)
+			return -EINVAL;
+		if (qopt->entries[i].gate_mask & ~TSNEP_GCL_MASK)
+			return -EINVAL;
+		if (qopt->entries[i].interval < TSNEP_GCL_MIN_INTERVAL)
+			return -EINVAL;
+		cycle_time += qopt->entries[i].interval;
+	}
+	if (qopt->cycle_time != cycle_time)
+		return -EINVAL;
+	if (qopt->cycle_time_extension >= qopt->cycle_time)
+		return -EINVAL;
+
+	return 0;
+}
+
+static void tsnep_write_gcl_operation(struct tsnep_gcl *gcl, int index,
+				      u32 properties, u32 interval, bool flush)
+{
+	void __iomem *addr = gcl->addr +
+			     sizeof(struct tsnep_gcl_operation) * index;
+
+	gcl->operation[index].properties = properties;
+	gcl->operation[index].interval = interval;
+
+	iowrite32(properties, addr);
+	iowrite32(interval, addr + sizeof(u32));
+
+	if (flush) {
+		/* flush write with read access */
+		ioread32(addr);
+	}
+}
+
+static u64 tsnep_change_duration(struct tsnep_gcl *gcl, int index)
+{
+	u64 duration;
+	int count;
+
+	/* change needs to be triggered one or two operations before start of
+	 * new gate control list
+	 * - change is triggered at start of operation (minimum one operation)
+	 * - operation with adjusted interval is inserted on demand to exactly
+	 *   meet the start of the new gate control list (optional)
+	 *
+	 * additionally properties are read directly after start of previous
+	 * operation
+	 *
+	 * therefore, three operations needs to be considered for the limit
+	 */
+	duration = 0;
+	count = 3;
+	while (count) {
+		duration += gcl->operation[index].interval;
+
+		index--;
+		if (index < 0)
+			index = gcl->count - 1;
+
+		count--;
+	}
+
+	return duration;
+}
+
+static void tsnep_write_gcl(struct tsnep_gcl *gcl,
+			    struct tc_taprio_qopt_offload *qopt)
+{
+	int i;
+	u32 properties;
+	u64 extend;
+	u64 cut;
+
+	gcl->base_time = ktime_to_ns(qopt->base_time);
+	gcl->cycle_time = qopt->cycle_time;
+	gcl->cycle_time_extension = qopt->cycle_time_extension;
+
+	for (i = 0; i < qopt->num_entries; i++) {
+		properties = qopt->entries[i].gate_mask;
+		if (i == (qopt->num_entries - 1))
+			properties |= TSNEP_GCL_LAST;
+
+		tsnep_write_gcl_operation(gcl, i, properties,
+					  qopt->entries[i].interval, true);
+	}
+	gcl->count = qopt->num_entries;
+
+	/* calculate change limit; i.e., the time needed between enable and
+	 * start of new gate control list
+	 */
+
+	/* case 1: extend cycle time for change
+	 * - change duration of last operation
+	 * - cycle time extension
+	 */
+	extend = tsnep_change_duration(gcl, gcl->count - 1);
+	extend += gcl->cycle_time_extension;
+
+	/* case 2: cut cycle time for change
+	 * - maximum change duration
+	 */
+	cut = 0;
+	for (i = 0; i < gcl->count; i++)
+		cut = max(cut, tsnep_change_duration(gcl, i));
+
+	/* use maximum, because the actual case (extend or cut) can be
+	 * determined only after limit is known (chicken-and-egg problem)
+	 */
+	gcl->change_limit = max(extend, cut);
+}
+
+static u64 tsnep_gcl_start_after(struct tsnep_gcl *gcl, u64 limit)
+{
+	u64 start = gcl->base_time;
+	u64 n;
+
+	if (start <= limit) {
+		n = div64_u64(limit - start, gcl->cycle_time);
+		start += (n + 1) * gcl->cycle_time;
+	}
+
+	return start;
+}
+
+static u64 tsnep_gcl_start_before(struct tsnep_gcl *gcl, u64 limit)
+{
+	u64 start = gcl->base_time;
+	u64 n;
+
+	n = div64_u64(limit - start, gcl->cycle_time);
+	start += n * gcl->cycle_time;
+	if (start == limit)
+		start -= gcl->cycle_time;
+
+	return start;
+}
+
+static u64 tsnep_set_gcl_change(struct tsnep_gcl *gcl, int index, u64 change,
+				bool insert)
+{
+	/* previous operation triggers change and properties are evaluated at
+	 * start of operation
+	 */
+	if (index == 0)
+		index = gcl->count - 1;
+	else
+		index = index - 1;
+	change -= gcl->operation[index].interval;
+
+	/* optionally change to new list with additional operation in between */
+	if (insert) {
+		void __iomem *addr = gcl->addr +
+				     sizeof(struct tsnep_gcl_operation) * index;
+
+		gcl->operation[index].properties |= TSNEP_GCL_INSERT;
+		iowrite32(gcl->operation[index].properties, addr);
+	}
+
+	return change;
+}
+
+static void tsnep_clean_gcl(struct tsnep_gcl *gcl)
+{
+	int i;
+	u32 mask = TSNEP_GCL_LAST | TSNEP_GCL_MASK;
+	void __iomem *addr;
+
+	/* search for insert operation and reset properties */
+	for (i = 0; i < gcl->count; i++) {
+		if (gcl->operation[i].properties & ~mask) {
+			addr = gcl->addr +
+			       sizeof(struct tsnep_gcl_operation) * i;
+
+			gcl->operation[i].properties &= mask;
+			iowrite32(gcl->operation[i].properties, addr);
+
+			break;
+		}
+	}
+}
+
+static u64 tsnep_insert_gcl_operation(struct tsnep_gcl *gcl, int ref,
+				      u64 change, u32 interval)
+{
+	u32 properties;
+
+	properties = gcl->operation[ref].properties & TSNEP_GCL_MASK;
+	/* change to new list directly after inserted operation */
+	properties |= TSNEP_GCL_CHANGE;
+
+	/* last operation of list is reserved to insert operation */
+	tsnep_write_gcl_operation(gcl, TSNEP_GCL_COUNT - 1, properties,
+				  interval, false);
+
+	return tsnep_set_gcl_change(gcl, ref, change, true);
+}
+
+static u64 tsnep_extend_gcl(struct tsnep_gcl *gcl, u64 start, u32 extension)
+{
+	int ref = gcl->count - 1;
+	u32 interval = gcl->operation[ref].interval + extension;
+
+	start -= gcl->operation[ref].interval;
+
+	return tsnep_insert_gcl_operation(gcl, ref, start, interval);
+}
+
+static u64 tsnep_cut_gcl(struct tsnep_gcl *gcl, u64 start, u64 cycle_time)
+{
+	u64 sum = 0;
+	int i;
+
+	/* find operation which shall be cutted */
+	for (i = 0; i < gcl->count; i++) {
+		u64 sum_tmp = sum + gcl->operation[i].interval;
+		u64 interval;
+
+		/* sum up operations as long as cycle time is not exceeded */
+		if (sum_tmp > cycle_time)
+			break;
+
+		/* remaining interval must be big enough for hardware */
+		interval = cycle_time - sum_tmp;
+		if (interval > 0 && interval < TSNEP_GCL_MIN_INTERVAL)
+			break;
+
+		sum = sum_tmp;
+	}
+	if (sum == cycle_time) {
+		/* no need to cut operation itself or whole cycle
+		 * => change exactly at operation
+		 */
+		return tsnep_set_gcl_change(gcl, i, start + sum, false);
+	}
+	return tsnep_insert_gcl_operation(gcl, i, start + sum,
+					  cycle_time - sum);
+}
+
+static int tsnep_enable_gcl(struct tsnep_adapter *adapter,
+			    struct tsnep_gcl *gcl, struct tsnep_gcl *curr)
+{
+	u64 system_time;
+	u64 timeout;
+	u64 limit;
+
+	/* estimate timeout limit after timeout enable, actually timeout limit
+	 * in hardware will be earlier than estimate so we are on the safe side
+	 */
+	tsnep_get_system_time(adapter, &system_time);
+	timeout = system_time + TSNEP_GC_TIMEOUT;
+
+	if (curr)
+		limit = timeout + curr->change_limit;
+	else
+		limit = timeout;
+
+	gcl->start_time = tsnep_gcl_start_after(gcl, limit);
+
+	/* gate control time register is only 32bit => time shall be in the near
+	 * future (no driver support for far future implemented)
+	 */
+	if ((gcl->start_time - system_time) >= U32_MAX)
+		return -EAGAIN;
+
+	if (curr) {
+		/* change gate control list */
+		u64 last;
+		u64 change;
+
+		last = tsnep_gcl_start_before(curr, gcl->start_time);
+		if ((last + curr->cycle_time) == gcl->start_time)
+			change = tsnep_cut_gcl(curr, last,
+					       gcl->start_time - last);
+		else if (((gcl->start_time - last) <=
+			  curr->cycle_time_extension) ||
+			 ((gcl->start_time - last) <= TSNEP_GCL_MIN_INTERVAL))
+			change = tsnep_extend_gcl(curr, last,
+						  gcl->start_time - last);
+		else
+			change = tsnep_cut_gcl(curr, last,
+					       gcl->start_time - last);
+
+		WARN_ON(change <= timeout);
+		gcl->change = true;
+		iowrite32(change & 0xFFFFFFFF, adapter->addr + TSNEP_GC_CHANGE);
+	} else {
+		/* start gate control list */
+		WARN_ON(gcl->start_time <= timeout);
+		gcl->change = false;
+		iowrite32(gcl->start_time & 0xFFFFFFFF,
+			  adapter->addr + TSNEP_GC_TIME);
+	}
+
+	return 0;
+}
+
+static int tsnep_taprio(struct tsnep_adapter *adapter,
+			struct tc_taprio_qopt_offload *qopt)
+{
+	struct tsnep_gcl *gcl;
+	struct tsnep_gcl *curr;
+	int retval;
+
+	if (!adapter->gate_control)
+		return -EOPNOTSUPP;
+
+	if (!qopt->enable) {
+		/* disable gate control if active */
+		mutex_lock(&adapter->gate_control_lock);
+
+		if (adapter->gate_control_active) {
+			iowrite8(TSNEP_GC_DISABLE, adapter->addr + TSNEP_GC);
+			adapter->gate_control_active = false;
+		}
+
+		mutex_unlock(&adapter->gate_control_lock);
+
+		return 0;
+	}
+
+	retval = tsnep_validate_gcl(qopt);
+	if (retval)
+		return retval;
+
+	mutex_lock(&adapter->gate_control_lock);
+
+	gcl = &adapter->gcl[adapter->next_gcl];
+	tsnep_write_gcl(gcl, qopt);
+
+	/* select current gate control list if active */
+	if (adapter->gate_control_active) {
+		if (adapter->next_gcl == 0)
+			curr = &adapter->gcl[1];
+		else
+			curr = &adapter->gcl[0];
+	} else {
+		curr = NULL;
+	}
+
+	for (;;) {
+		/* start timeout which discards late enable, this helps ensuring
+		 * that start/change time are in the future at enable
+		 */
+		iowrite8(TSNEP_GC_ENABLE_TIMEOUT, adapter->addr + TSNEP_GC);
+
+		retval = tsnep_enable_gcl(adapter, gcl, curr);
+		if (retval) {
+			mutex_unlock(&adapter->gate_control_lock);
+
+			return retval;
+		}
+
+		/* enable gate control list */
+		if (adapter->next_gcl == 0)
+			iowrite8(TSNEP_GC_ENABLE_A, adapter->addr + TSNEP_GC);
+		else
+			iowrite8(TSNEP_GC_ENABLE_B, adapter->addr + TSNEP_GC);
+
+		/* done if timeout did not happen */
+		if (!(ioread32(adapter->addr + TSNEP_GC) &
+		      TSNEP_GC_TIMEOUT_SIGNAL))
+			break;
+
+		/* timeout is acknowledged with any enable */
+		iowrite8(TSNEP_GC_ENABLE_A, adapter->addr + TSNEP_GC);
+
+		if (curr)
+			tsnep_clean_gcl(curr);
+
+		/* retry because of timeout */
+	}
+
+	adapter->gate_control_active = true;
+
+	if (adapter->next_gcl == 0)
+		adapter->next_gcl = 1;
+	else
+		adapter->next_gcl = 0;
+
+	mutex_unlock(&adapter->gate_control_lock);
+
+	return 0;
+}
+
+int tsnep_tc_setup(struct net_device *netdev, enum tc_setup_type type,
+		   void *type_data)
+{
+	struct tsnep_adapter *adapter = netdev_priv(netdev);
+
+	switch (type) {
+	case TC_SETUP_QDISC_TAPRIO:
+		return tsnep_taprio(adapter, type_data);
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+int tsnep_tc_init(struct tsnep_adapter *adapter)
+{
+	if (!adapter->gate_control)
+		return 0;
+
+	/* open all gates */
+	iowrite8(TSNEP_GC_DISABLE, adapter->addr + TSNEP_GC);
+	iowrite32(TSNEP_GC_OPEN | TSNEP_GC_NEXT_OPEN, adapter->addr + TSNEP_GC);
+
+	adapter->gcl[0].addr = adapter->addr + TSNEP_GCL_A;
+	adapter->gcl[1].addr = adapter->addr + TSNEP_GCL_B;
+
+	return 0;
+}
+
+void tsnep_tc_cleanup(struct tsnep_adapter *adapter)
+{
+	if (!adapter->gate_control)
+		return;
+
+	if (adapter->gate_control_active) {
+		iowrite8(TSNEP_GC_DISABLE, adapter->addr + TSNEP_GC);
+		adapter->gate_control_active = false;
+	}
+}