// SPDX-License-Identifier: GPL-2.0
/* Copyright (C) 2021 Gerhard Engleder <[email protected]> */
#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->cmd == TAPRIO_CMD_DESTROY) {
/* 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;
} else if (qopt->cmd != TAPRIO_CMD_REPLACE) {
return -EOPNOTSUPP;
}
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;
}
static int tsnep_tc_query_caps(struct tsnep_adapter *adapter,
struct tc_query_caps_base *base)
{
switch (base->type) {
case TC_SETUP_QDISC_TAPRIO: {
struct tc_taprio_caps *caps = base->caps;
if (!adapter->gate_control)
return -EOPNOTSUPP;
caps->gate_mask_per_txq = true;
return 0;
}
default:
return -EOPNOTSUPP;
}
}
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_QUERY_CAPS:
return tsnep_tc_query_caps(adapter, type_data);
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;
}
}
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