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sfc: Make queue flushes more reliable
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Increase the potential retry count for RX flushes from 5 to 100.

Stop polling the RX_DESC_PTR_TBL to infer that a flush might have
happened. Instead absolutely rely on the flush events, unless bug 7803
applies (Falcon rev A only).

To keep things quick, request flushes for every TX and RX queue up
front, and match up the events to requests.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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Ben Hutchings authored and Jeff Garzik committed Sep 24, 2008
1 parent 92ade88 commit 6bc5d3a
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Showing 4 changed files with 141 additions and 126 deletions.
15 changes: 7 additions & 8 deletions drivers/net/sfc/efx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -445,24 +445,24 @@ static void efx_fini_channels(struct efx_nic *efx)
struct efx_channel *channel;
struct efx_tx_queue *tx_queue;
struct efx_rx_queue *rx_queue;
int rc;

EFX_ASSERT_RESET_SERIALISED(efx);
BUG_ON(efx->port_enabled);

rc = falcon_flush_queues(efx);
if (rc)
EFX_ERR(efx, "failed to flush queues\n");
else
EFX_LOG(efx, "successfully flushed all queues\n");

efx_for_each_channel(channel, efx) {
EFX_LOG(channel->efx, "shut down chan %d\n", channel->channel);

efx_for_each_channel_rx_queue(rx_queue, channel)
efx_fini_rx_queue(rx_queue);
efx_for_each_channel_tx_queue(tx_queue, channel)
efx_fini_tx_queue(tx_queue);
}

/* Do the event queues last so that we can handle flush events
* for all DMA queues. */
efx_for_each_channel(channel, efx) {
EFX_LOG(channel->efx, "shut down evq %d\n", channel->channel);

efx_fini_eventq(channel);
}
}
Expand Down Expand Up @@ -1092,7 +1092,6 @@ static void efx_stop_all(struct efx_nic *efx)

/* Isolate the MAC from the TX and RX engines, so that queue
* flushes will complete in a timely fashion. */
falcon_deconfigure_mac_wrapper(efx);
falcon_drain_tx_fifo(efx);

/* Stop the kernel transmit interface late, so the watchdog
Expand Down
247 changes: 129 additions & 118 deletions drivers/net/sfc/falcon.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -108,10 +108,10 @@ MODULE_PARM_DESC(rx_xon_thresh_bytes, "RX fifo XON threshold");
/* Max number of internal errors. After this resets will not be performed */
#define FALCON_MAX_INT_ERRORS 4

/* Maximum period that we wait for flush events. If the flush event
* doesn't arrive in this period of time then we check if the queue
* was disabled anyway. */
#define FALCON_FLUSH_TIMEOUT 10 /* 10ms */
/* We poll for events every FLUSH_INTERVAL ms, and check FLUSH_POLL_COUNT times
*/
#define FALCON_FLUSH_INTERVAL 10
#define FALCON_FLUSH_POLL_COUNT 100

/**************************************************************************
*
Expand Down Expand Up @@ -452,6 +452,8 @@ void falcon_init_tx(struct efx_tx_queue *tx_queue)
efx_oword_t tx_desc_ptr;
struct efx_nic *efx = tx_queue->efx;

tx_queue->flushed = false;

/* Pin TX descriptor ring */
falcon_init_special_buffer(efx, &tx_queue->txd);

Expand Down Expand Up @@ -492,70 +494,25 @@ void falcon_init_tx(struct efx_tx_queue *tx_queue)
}
}

static int falcon_flush_tx_queue(struct efx_tx_queue *tx_queue)
static void falcon_flush_tx_queue(struct efx_tx_queue *tx_queue)
{
struct efx_nic *efx = tx_queue->efx;
struct efx_channel *channel = &efx->channel[0];
efx_oword_t tx_flush_descq;
unsigned int read_ptr, i;

/* Post a flush command */
EFX_POPULATE_OWORD_2(tx_flush_descq,
TX_FLUSH_DESCQ_CMD, 1,
TX_FLUSH_DESCQ, tx_queue->queue);
falcon_write(efx, &tx_flush_descq, TX_FLUSH_DESCQ_REG_KER);
msleep(FALCON_FLUSH_TIMEOUT);

if (EFX_WORKAROUND_7803(efx))
return 0;

/* Look for a flush completed event */
read_ptr = channel->eventq_read_ptr;
for (i = 0; i < FALCON_EVQ_SIZE; ++i) {
efx_qword_t *event = falcon_event(channel, read_ptr);
int ev_code, ev_sub_code, ev_queue;
if (!falcon_event_present(event))
break;

ev_code = EFX_QWORD_FIELD(*event, EV_CODE);
ev_sub_code = EFX_QWORD_FIELD(*event, DRIVER_EV_SUB_CODE);
ev_queue = EFX_QWORD_FIELD(*event, DRIVER_EV_TX_DESCQ_ID);
if ((ev_sub_code == TX_DESCQ_FLS_DONE_EV_DECODE) &&
(ev_queue == tx_queue->queue)) {
EFX_LOG(efx, "tx queue %d flush command succesful\n",
tx_queue->queue);
return 0;
}

read_ptr = (read_ptr + 1) & FALCON_EVQ_MASK;
}

if (EFX_WORKAROUND_11557(efx)) {
efx_oword_t reg;
bool enabled;

falcon_read_table(efx, &reg, efx->type->txd_ptr_tbl_base,
tx_queue->queue);
enabled = EFX_OWORD_FIELD(reg, TX_DESCQ_EN);
if (!enabled) {
EFX_LOG(efx, "tx queue %d disabled without a "
"flush event seen\n", tx_queue->queue);
return 0;
}
}

EFX_ERR(efx, "tx queue %d flush command timed out\n", tx_queue->queue);
return -ETIMEDOUT;
}

void falcon_fini_tx(struct efx_tx_queue *tx_queue)
{
struct efx_nic *efx = tx_queue->efx;
efx_oword_t tx_desc_ptr;

/* Stop the hardware using the queue */
if (falcon_flush_tx_queue(tx_queue))
EFX_ERR(efx, "failed to flush tx queue %d\n", tx_queue->queue);
/* The queue should have been flushed */
WARN_ON(!tx_queue->flushed);

/* Remove TX descriptor ring from card */
EFX_ZERO_OWORD(tx_desc_ptr);
Expand Down Expand Up @@ -643,6 +600,8 @@ void falcon_init_rx(struct efx_rx_queue *rx_queue)
rx_queue->queue, rx_queue->rxd.index,
rx_queue->rxd.index + rx_queue->rxd.entries - 1);

rx_queue->flushed = false;

/* Pin RX descriptor ring */
falcon_init_special_buffer(efx, &rx_queue->rxd);

Expand All @@ -663,88 +622,25 @@ void falcon_init_rx(struct efx_rx_queue *rx_queue)
rx_queue->queue);
}

static int falcon_flush_rx_queue(struct efx_rx_queue *rx_queue)
static void falcon_flush_rx_queue(struct efx_rx_queue *rx_queue)
{
struct efx_nic *efx = rx_queue->efx;
struct efx_channel *channel = &efx->channel[0];
unsigned int read_ptr, i;
efx_oword_t rx_flush_descq;

/* Post a flush command */
EFX_POPULATE_OWORD_2(rx_flush_descq,
RX_FLUSH_DESCQ_CMD, 1,
RX_FLUSH_DESCQ, rx_queue->queue);
falcon_write(efx, &rx_flush_descq, RX_FLUSH_DESCQ_REG_KER);
msleep(FALCON_FLUSH_TIMEOUT);

if (EFX_WORKAROUND_7803(efx))
return 0;

/* Look for a flush completed event */
read_ptr = channel->eventq_read_ptr;
for (i = 0; i < FALCON_EVQ_SIZE; ++i) {
efx_qword_t *event = falcon_event(channel, read_ptr);
int ev_code, ev_sub_code, ev_queue;
bool ev_failed;
if (!falcon_event_present(event))
break;

ev_code = EFX_QWORD_FIELD(*event, EV_CODE);
ev_sub_code = EFX_QWORD_FIELD(*event, DRIVER_EV_SUB_CODE);
ev_queue = EFX_QWORD_FIELD(*event, DRIVER_EV_RX_DESCQ_ID);
ev_failed = EFX_QWORD_FIELD(*event, DRIVER_EV_RX_FLUSH_FAIL);

if ((ev_sub_code == RX_DESCQ_FLS_DONE_EV_DECODE) &&
(ev_queue == rx_queue->queue)) {
if (ev_failed) {
EFX_INFO(efx, "rx queue %d flush command "
"failed\n", rx_queue->queue);
return -EAGAIN;
} else {
EFX_LOG(efx, "rx queue %d flush command "
"succesful\n", rx_queue->queue);
return 0;
}
}

read_ptr = (read_ptr + 1) & FALCON_EVQ_MASK;
}

if (EFX_WORKAROUND_11557(efx)) {
efx_oword_t reg;
bool enabled;

falcon_read_table(efx, &reg, efx->type->rxd_ptr_tbl_base,
rx_queue->queue);
enabled = EFX_OWORD_FIELD(reg, RX_DESCQ_EN);
if (!enabled) {
EFX_LOG(efx, "rx queue %d disabled without a "
"flush event seen\n", rx_queue->queue);
return 0;
}
}

EFX_ERR(efx, "rx queue %d flush command timed out\n", rx_queue->queue);
return -ETIMEDOUT;
}

void falcon_fini_rx(struct efx_rx_queue *rx_queue)
{
efx_oword_t rx_desc_ptr;
struct efx_nic *efx = rx_queue->efx;
int i, rc;

/* Try and flush the rx queue. This may need to be repeated */
for (i = 0; i < 5; i++) {
rc = falcon_flush_rx_queue(rx_queue);
if (rc == -EAGAIN)
continue;
break;
}
if (rc) {
EFX_ERR(efx, "failed to flush rx queue %d\n", rx_queue->queue);
efx_schedule_reset(efx, RESET_TYPE_INVISIBLE);
}
/* The queue should already have been flushed */
WARN_ON(!rx_queue->flushed);

/* Remove RX descriptor ring from card */
EFX_ZERO_OWORD(rx_desc_ptr);
Expand Down Expand Up @@ -1255,6 +1151,121 @@ void falcon_generate_test_event(struct efx_channel *channel, unsigned int magic)
falcon_generate_event(channel, &test_event);
}

/**************************************************************************
*
* Flush handling
*
**************************************************************************/


static void falcon_poll_flush_events(struct efx_nic *efx)
{
struct efx_channel *channel = &efx->channel[0];
struct efx_tx_queue *tx_queue;
struct efx_rx_queue *rx_queue;
unsigned int read_ptr, i;

read_ptr = channel->eventq_read_ptr;
for (i = 0; i < FALCON_EVQ_SIZE; ++i) {
efx_qword_t *event = falcon_event(channel, read_ptr);
int ev_code, ev_sub_code, ev_queue;
bool ev_failed;
if (!falcon_event_present(event))
break;

ev_code = EFX_QWORD_FIELD(*event, EV_CODE);
if (ev_code != DRIVER_EV_DECODE)
continue;

ev_sub_code = EFX_QWORD_FIELD(*event, DRIVER_EV_SUB_CODE);
switch (ev_sub_code) {
case TX_DESCQ_FLS_DONE_EV_DECODE:
ev_queue = EFX_QWORD_FIELD(*event,
DRIVER_EV_TX_DESCQ_ID);
if (ev_queue < EFX_TX_QUEUE_COUNT) {
tx_queue = efx->tx_queue + ev_queue;
tx_queue->flushed = true;
}
break;
case RX_DESCQ_FLS_DONE_EV_DECODE:
ev_queue = EFX_QWORD_FIELD(*event,
DRIVER_EV_RX_DESCQ_ID);
ev_failed = EFX_QWORD_FIELD(*event,
DRIVER_EV_RX_FLUSH_FAIL);
if (ev_queue < efx->n_rx_queues) {
rx_queue = efx->rx_queue + ev_queue;

/* retry the rx flush */
if (ev_failed)
falcon_flush_rx_queue(rx_queue);
else
rx_queue->flushed = true;
}
break;
}

read_ptr = (read_ptr + 1) & FALCON_EVQ_MASK;
}
}

/* Handle tx and rx flushes at the same time, since they run in
* parallel in the hardware and there's no reason for us to
* serialise them */
int falcon_flush_queues(struct efx_nic *efx)
{
struct efx_rx_queue *rx_queue;
struct efx_tx_queue *tx_queue;
int i;
bool outstanding;

/* Issue flush requests */
efx_for_each_tx_queue(tx_queue, efx) {
tx_queue->flushed = false;
falcon_flush_tx_queue(tx_queue);
}
efx_for_each_rx_queue(rx_queue, efx) {
rx_queue->flushed = false;
falcon_flush_rx_queue(rx_queue);
}

/* Poll the evq looking for flush completions. Since we're not pushing
* any more rx or tx descriptors at this point, we're in no danger of
* overflowing the evq whilst we wait */
for (i = 0; i < FALCON_FLUSH_POLL_COUNT; ++i) {
msleep(FALCON_FLUSH_INTERVAL);
falcon_poll_flush_events(efx);

/* Check if every queue has been succesfully flushed */
outstanding = false;
efx_for_each_tx_queue(tx_queue, efx)
outstanding |= !tx_queue->flushed;
efx_for_each_rx_queue(rx_queue, efx)
outstanding |= !rx_queue->flushed;
if (!outstanding)
return 0;
}

/* Mark the queues as all flushed. We're going to return failure
* leading to a reset, or fake up success anyway. "flushed" now
* indicates that we tried to flush. */
efx_for_each_tx_queue(tx_queue, efx) {
if (!tx_queue->flushed)
EFX_ERR(efx, "tx queue %d flush command timed out\n",
tx_queue->queue);
tx_queue->flushed = true;
}
efx_for_each_rx_queue(rx_queue, efx) {
if (!rx_queue->flushed)
EFX_ERR(efx, "rx queue %d flush command timed out\n",
rx_queue->queue);
rx_queue->flushed = true;
}

if (EFX_WORKAROUND_7803(efx))
return 0;

return -ETIMEDOUT;
}

/**************************************************************************
*
Expand Down
1 change: 1 addition & 0 deletions drivers/net/sfc/falcon.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -86,6 +86,7 @@ extern void falcon_fini_interrupt(struct efx_nic *efx);
extern int falcon_probe_nic(struct efx_nic *efx);
extern int falcon_probe_resources(struct efx_nic *efx);
extern int falcon_init_nic(struct efx_nic *efx);
extern int falcon_flush_queues(struct efx_nic *efx);
extern int falcon_reset_hw(struct efx_nic *efx, enum reset_type method);
extern void falcon_remove_resources(struct efx_nic *efx);
extern void falcon_remove_nic(struct efx_nic *efx);
Expand Down
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