2010-02-25 01:08:34

by Alban Browaeys

[permalink] [raw]
Subject: [PATCH 1/2] rt2x00 : hw support txdone implementation.

This is an implementation that support WCID being the key_index coming
from benoit and a change in the meaning of the tx fallback flag.

Signed-off-by: Benoit Papillault <[email protected]>
Signed-off-by: Alban Browaeys <[email protected]>
---
drivers/net/wireless/rt2x00/rt2800pci.c | 116 ++++++++++++++---------------
drivers/net/wireless/rt2x00/rt2x00dev.c | 51 +++++++++++--
drivers/net/wireless/rt2x00/rt2x00queue.h | 6 +-
3 files changed, 103 insertions(+), 70 deletions(-)

diff --git a/drivers/net/wireless/rt2x00/rt2800pci.c b/drivers/net/wireless/rt2x00/rt2800pci.c
index 7899789..3ac1df0 100644
--- a/drivers/net/wireless/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/rt2x00/rt2800pci.c
@@ -920,100 +920,96 @@ static void rt2800pci_txdone(struct rt2x00_dev *rt2x00dev)
{
struct data_queue *queue;
struct queue_entry *entry;
- struct queue_entry *entry_done;
- struct queue_entry_priv_pci *entry_priv;
+ __le32 *txwi;
struct txdone_entry_desc txdesc;
u32 word;
u32 reg;
- u32 old_reg;
- unsigned int type;
- unsigned int index;
- u16 mcs, real_mcs;
-
+ int i;
+ int wcid, ack, pid, tx_wcid, tx_ack, tx_pid;
+ u16 mcs, tx_mcs;
+
/*
- * During each loop we will compare the freshly read
- * TX_STA_FIFO register value with the value read from
- * the previous loop. If the 2 values are equal then
- * we should stop processing because the chance it
- * quite big that the device has been unplugged and
- * we risk going into an endless loop.
+ * To avoid an endlees loop, we only read the TX_STA_FIFO register up
+ * to 256 times (this is enought to get all values from the FIFO). In
+ * normal situation, the loop is terminated when we reach a value with
+ * TX_STA_FIFO_VALID bit is 0.
*/
- old_reg = 0;
-
- while (1) {
+
+ for (i=0; i<256; i++) {
rt2800_register_read(rt2x00dev, TX_STA_FIFO, &reg);
if (!rt2x00_get_field32(reg, TX_STA_FIFO_VALID))
break;

- if (old_reg == reg)
- break;
- old_reg = reg;
+ wcid = rt2x00_get_field32(reg, TX_STA_FIFO_WCID);
+ ack = rt2x00_get_field32(reg, TX_STA_FIFO_TX_ACK_REQUIRED);
+ pid = rt2x00_get_field32(reg, TX_STA_FIFO_PID_TYPE);

/*
* Skip this entry when it contains an invalid
* queue identication number.
*/
- type = rt2x00_get_field32(reg, TX_STA_FIFO_PID_TYPE) - 1;
- if (type >= QID_RX)
+ if (pid < 1)
continue;

- queue = rt2x00queue_get_queue(rt2x00dev, type);
+ queue = rt2x00queue_get_queue(rt2x00dev, pid - 1);
if (unlikely(!queue))
continue;

/*
- * Skip this entry when it contains an invalid
- * index number.
+ * Inside each queue, we process each entry in a chronological
+ * order. We first check that the queue is not empty.
*/
- index = rt2x00_get_field32(reg, TX_STA_FIFO_WCID) - 1;
- if (unlikely(index >= queue->limit))
+ if (queue->length == 0)
continue;
+ entry = rt2x00queue_get_entry(queue, Q_INDEX_DONE);

- entry = &queue->entries[index];
- entry_priv = entry->priv_data;
- rt2x00_desc_read((__le32 *)entry->skb->data, 0, &word);
+ /* Check if we got a match by looking at WCID/ACK/PID
+ * fields */
+ txwi = (__le32 *)(entry->skb->data -
+ rt2x00dev->hw->extra_tx_headroom);

- entry_done = rt2x00queue_get_entry(queue, Q_INDEX_DONE);
- while (entry != entry_done) {
- /*
- * Catch up.
- * Just report any entries we missed as failed.
- */
- WARNING(rt2x00dev,
- "TX status report missed for entry %d\n",
- entry_done->entry_idx);
-
- txdesc.flags = 0;
- __set_bit(TXDONE_UNKNOWN, &txdesc.flags);
- txdesc.retry = 0;
+ rt2x00_desc_read(txwi, 1, &word);
+ tx_wcid = rt2x00_get_field32(word, TXWI_W1_WIRELESS_CLI_ID);
+ tx_ack = rt2x00_get_field32(word, TXWI_W1_ACK);
+ tx_pid = rt2x00_get_field32(word, TXWI_W1_PACKETID);

- rt2x00lib_txdone(entry_done, &txdesc);
- entry_done = rt2x00queue_get_entry(queue, Q_INDEX_DONE);
- }
+ if ((wcid != tx_wcid) || (ack != tx_ack) || (pid != tx_pid))
+ WARNING(rt2x00dev, "invalid TX_STA_FIFO content\n");

/*
* Obtain the status about this packet.
*/
- txdesc.flags = 0;
- if (rt2x00_get_field32(reg, TX_STA_FIFO_TX_SUCCESS))
- __set_bit(TXDONE_SUCCESS, &txdesc.flags);
- else
- __set_bit(TXDONE_FAILURE, &txdesc.flags);
+ mcs = rt2x00_get_field32(reg, TX_STA_FIFO_MCS);
+ rt2x00_desc_read(txwi, 0, &word);
+ tx_mcs = rt2x00_get_field32(word, TXWI_W0_MCS);

/*
* Ralink has a retry mechanism using a global fallback
- * table. We setup this fallback table to try immediate
- * lower rate for all rates. In the TX_STA_FIFO,
- * the MCS field contains the MCS used for the successfull
- * transmission. If the first transmission succeed,
- * we have mcs == tx_mcs. On the second transmission,
- * we have mcs = tx_mcs - 1. So the number of
- * retry is (tx_mcs - mcs).
+ * table. We setup this fallback table to try the immediate
+ * lower rate for all rates. In the TX_STA_FIFO, the MCS field
+ * always contains the MCS used for the last transmission, be
+ * it successful or not.
*/
- mcs = rt2x00_get_field32(word, TXWI_W0_MCS);
- real_mcs = rt2x00_get_field32(reg, TX_STA_FIFO_MCS);
+
+ txdesc.flags = 0;
+ if (rt2x00_get_field32(reg, TX_STA_FIFO_TX_SUCCESS)) {
+ /*
+ * Transmission succeeded. The number of retries is
+ * tx_mcs - mcs
+ */
+ __set_bit(TXDONE_SUCCESS, &txdesc.flags);
+ txdesc.retry = ((tx_mcs > mcs) ? tx_mcs - mcs : 0);
+ } else {
+ /*
+ * Transmission failed. The number of retries is
+ * always 7 in this case (for a total number of 8
+ * frames sent).
+ */
+ __set_bit(TXDONE_FAILURE, &txdesc.flags);
+ txdesc.retry = 7;
+ }
+
__set_bit(TXDONE_FALLBACK, &txdesc.flags);
- txdesc.retry = mcs - min(mcs, real_mcs);

rt2x00lib_txdone(entry, &txdesc);
}
diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c
index b93731b..506b052 100644
--- a/drivers/net/wireless/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/rt2x00/rt2x00dev.c
@@ -251,8 +251,7 @@ void rt2x00lib_txdone(struct queue_entry *entry,

rate_idx = skbdesc->tx_rate_idx;
rate_flags = skbdesc->tx_rate_flags;
- retry_rates = test_bit(TXDONE_FALLBACK, &txdesc->flags) ?
- (txdesc->retry + 1) : 1;
+ retry_rates = txdesc->retry + 1;

/*
* Initialize TX status
@@ -265,13 +264,49 @@ void rt2x00lib_txdone(struct queue_entry *entry,
* different rates to send out the frame, at each
* retry it lowered the rate 1 step.
*/
- for (i = 0; i < retry_rates && i < IEEE80211_TX_MAX_RATES; i++) {
- tx_info->status.rates[i].idx = rate_idx - i;
- tx_info->status.rates[i].flags = rate_flags;
- tx_info->status.rates[i].count = 1;
+ if (test_bit(TXDONE_FALLBACK, &txdesc->flags)) {
+ /*
+ * Fill in a multiple rate entries, ie frame was sent once at
+ * each rates. We use rate_idx as an index into
+ * rt2x00_supported_rates array. Since we can have up to 8
+ * transmissions at different rates and since
+ * IEEE80211_TX_MAX_RATES is only 5, the array can be
+ * truncated.
+ */
+ for (i=0; (i < retry_rates) && (i < IEEE80211_TX_MAX_RATES); i++) {
+ /*
+ * check if we reach the lowest rates for this
+ * modulation ie 1 Mbits for CCK and 6 Mbits for
+ * OFDM.
+ *
+ * FIXME : This code needs to be checked for MCS
+ */
+
+ int idx = rate_idx - i;
+ if ((idx == 0) /* 1 Mbits CCK rate index */ ||
+ (idx == 4) /* 6 Mbits OFDM rate index */) {
+ tx_info->status.rates[i].idx = idx;
+ tx_info->status.rates[i].flags = rate_flags;
+ tx_info->status.rates[i].count = retry_rates - i;
+ /* move to the next entry */
+ i++;
+ break;
+ } else {
+ tx_info->status.rates[i].idx = idx;
+ tx_info->status.rates[i].flags = rate_flags;
+ tx_info->status.rates[i].count = 1;
+ }
+ }
+ if (i < IEEE80211_TX_MAX_RATES)
+ tx_info->status.rates[i].idx = -1; /* terminate */
+ } else {
+ /* Fill in a single rate entry, ie frame was sent
+ * (txdesc->retry+1) times at the same rate */
+ tx_info->status.rates[0].idx = rate_idx;
+ tx_info->status.rates[0].flags = rate_flags;
+ tx_info->status.rates[0].count = retry_rates;
+ tx_info->status.rates[1].idx = -1; /* terminate */
}
- if (i < (IEEE80211_TX_MAX_RATES - 1))
- tx_info->status.rates[i].idx = -1; /* terminate */

if (!(tx_info->flags & IEEE80211_TX_CTL_NO_ACK)) {
if (success)
diff --git a/drivers/net/wireless/rt2x00/rt2x00queue.h b/drivers/net/wireless/rt2x00/rt2x00queue.h
index c1e482b..4e801c3 100644
--- a/drivers/net/wireless/rt2x00/rt2x00queue.h
+++ b/drivers/net/wireless/rt2x00/rt2x00queue.h
@@ -214,7 +214,7 @@ struct rxdone_entry_desc {
*
* @TXDONE_UNKNOWN: Hardware could not determine success of transmission.
* @TXDONE_SUCCESS: Frame was successfully send
- * @TXDONE_FALLBACK: Frame was successfully send using a fallback rate.
+ * @TXDONE_FALLBACK: Frame was sent using a fallback rate table.
* @TXDONE_FAILURE: Frame was not successfully send
* @TXDONE_EXCESSIVE_RETRY: In addition to &TXDONE_FAILURE, the
* frame transmission failed due to excessive retries.
@@ -234,7 +234,9 @@ enum txdone_entry_desc_flags {
* after the device is done with transmission.
*
* @flags: TX done flags (See &enum txdone_entry_desc_flags).
- * @retry: Retry count.
+ * @retry: Retry count. If TXDONE_FALLBACK is not set, the frame was sent
+ * (retry+1) times at the same rate. If TXDONE_FALLBACK is set, the frame was
+ * sent once for each lower rates, up to (retry+1) times in total.
*/
struct txdone_entry_desc {
unsigned long flags;
--
1.7.0