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iwlwifi: pcie: get rid of q->n_bd
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This variable always tracks a constant value (256) so there's
no need to have it. Removing it simplifies code generation,
reducing the .text size (by about 240 bytes on x86-64.)

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
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Johannes Berg authored and Emmanuel Grumbach committed May 6, 2014
1 parent 6d6e68f commit 83f32a4
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Showing 4 changed files with 45 additions and 53 deletions.
17 changes: 7 additions & 10 deletions drivers/net/wireless/iwlwifi/pcie/internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -117,21 +117,19 @@ struct iwl_dma_ptr {
/**
* iwl_queue_inc_wrap - increment queue index, wrap back to beginning
* @index -- current index
* @n_bd -- total number of entries in queue (must be power of 2)
*/
static inline int iwl_queue_inc_wrap(int index, int n_bd)
static inline int iwl_queue_inc_wrap(int index)
{
return ++index & (n_bd - 1);
return ++index & (TFD_QUEUE_SIZE_MAX - 1);
}

/**
* iwl_queue_dec_wrap - decrement queue index, wrap back to end
* @index -- current index
* @n_bd -- total number of entries in queue (must be power of 2)
*/
static inline int iwl_queue_dec_wrap(int index, int n_bd)
static inline int iwl_queue_dec_wrap(int index)
{
return --index & (n_bd - 1);
return --index & (TFD_QUEUE_SIZE_MAX - 1);
}

struct iwl_cmd_meta {
Expand All @@ -145,13 +143,13 @@ struct iwl_cmd_meta {
*
* Contains common data for Rx and Tx queues.
*
* Note the difference between n_bd and n_window: the hardware
* always assumes 256 descriptors, so n_bd is always 256 (unless
* Note the difference between TFD_QUEUE_SIZE_MAX and n_window: the hardware
* always assumes 256 descriptors, so TFD_QUEUE_SIZE_MAX is always 256 (unless
* there might be HW changes in the future). For the normal TX
* queues, n_window, which is the size of the software queue data
* is also 256; however, for the command queue, n_window is only
* 32 since we don't need so many commands pending. Since the HW
* still uses 256 BDs for DMA though, n_bd stays 256. As a result,
* still uses 256 BDs for DMA though, TFD_QUEUE_SIZE_MAX stays 256. As a result,
* the software buffers (in the variables @meta, @txb in struct
* iwl_txq) only have 32 entries, while the HW buffers (@tfds in
* the same struct) have 256.
Expand All @@ -162,7 +160,6 @@ struct iwl_cmd_meta {
* data is a window overlayed over the HW queue.
*/
struct iwl_queue {
int n_bd; /* number of BDs in this queue */
int write_ptr; /* 1-st empty entry (index) host_w*/
int read_ptr; /* last used entry (index) host_r*/
/* use for monitoring and recovering the stuck queue */
Expand Down
2 changes: 1 addition & 1 deletion drivers/net/wireless/iwlwifi/pcie/rx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -850,7 +850,7 @@ static u32 iwl_pcie_int_cause_ict(struct iwl_trans *trans)
trans_pcie->ict_index, read);
trans_pcie->ict_tbl[trans_pcie->ict_index] = 0;
trans_pcie->ict_index =
iwl_queue_inc_wrap(trans_pcie->ict_index, ICT_COUNT);
((trans_pcie->ict_index + 1) & (ICT_COUNT - 1));

read = le32_to_cpu(trans_pcie->ict_tbl[trans_pcie->ict_index]);
trace_iwlwifi_dev_ict_read(trans->dev, trans_pcie->ict_index,
Expand Down
4 changes: 2 additions & 2 deletions drivers/net/wireless/iwlwifi/pcie/trans.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1337,8 +1337,8 @@ static int iwl_trans_pcie_wait_txq_empty(struct iwl_trans *trans, u32 txq_bm)
IWL_ERR(trans,
"Q %d is %sactive and mapped to fifo %d ra_tid 0x%04x [%d,%d]\n",
cnt, active ? "" : "in", fifo, tbl_dw,
iwl_read_prph(trans,
SCD_QUEUE_RDPTR(cnt)) & (txq->q.n_bd - 1),
iwl_read_prph(trans, SCD_QUEUE_RDPTR(cnt)) &
(TFD_QUEUE_SIZE_MAX - 1),
iwl_read_prph(trans, SCD_QUEUE_WRPTR(cnt)));
}

Expand Down
75 changes: 35 additions & 40 deletions drivers/net/wireless/iwlwifi/pcie/tx.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -70,20 +70,20 @@ static int iwl_queue_space(const struct iwl_queue *q)

/*
* To avoid ambiguity between empty and completely full queues, there
* should always be less than q->n_bd elements in the queue.
* If q->n_window is smaller than q->n_bd, there is no need to reserve
* any queue entries for this purpose.
* should always be less than TFD_QUEUE_SIZE_MAX elements in the queue.
* If q->n_window is smaller than TFD_QUEUE_SIZE_MAX, there is no need
* to reserve any queue entries for this purpose.
*/
if (q->n_window < q->n_bd)
if (q->n_window < TFD_QUEUE_SIZE_MAX)
max = q->n_window;
else
max = q->n_bd - 1;
max = TFD_QUEUE_SIZE_MAX - 1;

/*
* q->n_bd is a power of 2, so the following is equivalent to modulo by
* q->n_bd and is well defined for negative dividends.
* TFD_QUEUE_SIZE_MAX is a power of 2, so the following is equivalent to
* modulo by TFD_QUEUE_SIZE_MAX and is well defined.
*/
used = (q->write_ptr - q->read_ptr) & (q->n_bd - 1);
used = (q->write_ptr - q->read_ptr) & (TFD_QUEUE_SIZE_MAX - 1);

if (WARN_ON(used > max))
return 0;
Expand All @@ -94,17 +94,11 @@ static int iwl_queue_space(const struct iwl_queue *q)
/*
* iwl_queue_init - Initialize queue's high/low-water and read/write indexes
*/
static int iwl_queue_init(struct iwl_queue *q, int count, int slots_num, u32 id)
static int iwl_queue_init(struct iwl_queue *q, int slots_num, u32 id)
{
q->n_bd = count;
q->n_window = slots_num;
q->id = id;

/* count must be power-of-two size, otherwise iwl_queue_inc_wrap
* and iwl_queue_dec_wrap are broken. */
if (WARN_ON(!is_power_of_2(count)))
return -EINVAL;

/* slots_num must be power-of-two size, otherwise
* get_cmd_index is broken. */
if (WARN_ON(!is_power_of_2(slots_num)))
Expand Down Expand Up @@ -197,13 +191,13 @@ static void iwl_pcie_txq_stuck_timer(unsigned long data)
IWL_ERR(trans,
"Q %d is %sactive and mapped to fifo %d ra_tid 0x%04x [%d,%d]\n",
i, active ? "" : "in", fifo, tbl_dw,
iwl_read_prph(trans,
SCD_QUEUE_RDPTR(i)) & (txq->q.n_bd - 1),
iwl_read_prph(trans, SCD_QUEUE_RDPTR(i)) &
(TFD_QUEUE_SIZE_MAX - 1),
iwl_read_prph(trans, SCD_QUEUE_WRPTR(i)));
}

for (i = q->read_ptr; i != q->write_ptr;
i = iwl_queue_inc_wrap(i, q->n_bd))
i = iwl_queue_inc_wrap(i))
IWL_ERR(trans, "scratch %d = 0x%08x\n", i,
le32_to_cpu(txq->scratchbufs[i].scratch));

Expand Down Expand Up @@ -425,13 +419,17 @@ static void iwl_pcie_txq_free_tfd(struct iwl_trans *trans, struct iwl_txq *txq)
{
struct iwl_tfd *tfd_tmp = txq->tfds;

/* rd_ptr is bounded by n_bd and idx is bounded by n_window */
/* rd_ptr is bounded by TFD_QUEUE_SIZE_MAX and
* idx is bounded by n_window
*/
int rd_ptr = txq->q.read_ptr;
int idx = get_cmd_index(&txq->q, rd_ptr);

lockdep_assert_held(&txq->lock);

/* We have only q->n_window txq->entries, but we use q->n_bd tfds */
/* We have only q->n_window txq->entries, but we use
* TFD_QUEUE_SIZE_MAX tfds
*/
iwl_pcie_tfd_unmap(trans, &txq->entries[idx].meta, &tfd_tmp[rd_ptr]);

/* free SKB */
Expand Down Expand Up @@ -565,8 +563,7 @@ static int iwl_pcie_txq_init(struct iwl_trans *trans, struct iwl_txq *txq,
BUILD_BUG_ON(TFD_QUEUE_SIZE_MAX & (TFD_QUEUE_SIZE_MAX - 1));

/* Initialize queue's high/low-water marks, and head/tail indexes */
ret = iwl_queue_init(&txq->q, TFD_QUEUE_SIZE_MAX, slots_num,
txq_id);
ret = iwl_queue_init(&txq->q, slots_num, txq_id);
if (ret)
return ret;

Expand All @@ -591,15 +588,12 @@ static void iwl_pcie_txq_unmap(struct iwl_trans *trans, int txq_id)
struct iwl_txq *txq = &trans_pcie->txq[txq_id];
struct iwl_queue *q = &txq->q;

if (!q->n_bd)
return;

spin_lock_bh(&txq->lock);
while (q->write_ptr != q->read_ptr) {
IWL_DEBUG_TX_REPLY(trans, "Q %d Free %d\n",
txq_id, q->read_ptr);
iwl_pcie_txq_free_tfd(trans, txq);
q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd);
q->read_ptr = iwl_queue_inc_wrap(q->read_ptr);
}
txq->active = false;
spin_unlock_bh(&txq->lock);
Expand Down Expand Up @@ -636,10 +630,12 @@ static void iwl_pcie_txq_free(struct iwl_trans *trans, int txq_id)
}

/* De-alloc circular buffer of TFDs */
if (txq->q.n_bd) {
dma_free_coherent(dev, sizeof(struct iwl_tfd) *
txq->q.n_bd, txq->tfds, txq->q.dma_addr);
if (txq->tfds) {
dma_free_coherent(dev,
sizeof(struct iwl_tfd) * TFD_QUEUE_SIZE_MAX,
txq->tfds, txq->q.dma_addr);
txq->q.dma_addr = 0;
txq->tfds = NULL;

dma_free_coherent(dev,
sizeof(*txq->scratchbufs) * txq->q.n_window,
Expand Down Expand Up @@ -948,8 +944,7 @@ void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,
{
struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
struct iwl_txq *txq = &trans_pcie->txq[txq_id];
/* n_bd is usually 256 => n_bd - 1 = 0xff */
int tfd_num = ssn & (txq->q.n_bd - 1);
int tfd_num = ssn & (TFD_QUEUE_SIZE_MAX - 1);
struct iwl_queue *q = &txq->q;
int last_to_free;

Expand All @@ -973,12 +968,12 @@ void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,

/*Since we free until index _not_ inclusive, the one before index is
* the last we will free. This one must be used */
last_to_free = iwl_queue_dec_wrap(tfd_num, q->n_bd);
last_to_free = iwl_queue_dec_wrap(tfd_num);

if (!iwl_queue_used(q, last_to_free)) {
IWL_ERR(trans,
"%s: Read index for DMA queue txq id (%d), last_to_free %d is out of range [0-%d] %d %d.\n",
__func__, txq_id, last_to_free, q->n_bd,
__func__, txq_id, last_to_free, TFD_QUEUE_SIZE_MAX,
q->write_ptr, q->read_ptr);
goto out;
}
Expand All @@ -988,7 +983,7 @@ void iwl_trans_pcie_reclaim(struct iwl_trans *trans, int txq_id, int ssn,

for (;
q->read_ptr != tfd_num;
q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {
q->read_ptr = iwl_queue_inc_wrap(q->read_ptr)) {

if (WARN_ON_ONCE(txq->entries[txq->q.read_ptr].skb == NULL))
continue;
Expand Down Expand Up @@ -1027,16 +1022,16 @@ static void iwl_pcie_cmdq_reclaim(struct iwl_trans *trans, int txq_id, int idx)

lockdep_assert_held(&txq->lock);

if ((idx >= q->n_bd) || (!iwl_queue_used(q, idx))) {
if ((idx >= TFD_QUEUE_SIZE_MAX) || (!iwl_queue_used(q, idx))) {
IWL_ERR(trans,
"%s: Read index for DMA queue txq id (%d), index %d is out of range [0-%d] %d %d.\n",
__func__, txq_id, idx, q->n_bd,
__func__, txq_id, idx, TFD_QUEUE_SIZE_MAX,
q->write_ptr, q->read_ptr);
return;
}

for (idx = iwl_queue_inc_wrap(idx, q->n_bd); q->read_ptr != idx;
q->read_ptr = iwl_queue_inc_wrap(q->read_ptr, q->n_bd)) {
for (idx = iwl_queue_inc_wrap(idx); q->read_ptr != idx;
q->read_ptr = iwl_queue_inc_wrap(q->read_ptr)) {

if (nfreed++ > 0) {
IWL_ERR(trans, "HCMD skipped: index (%d) %d %d\n",
Expand Down Expand Up @@ -1445,7 +1440,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
}

/* Increment and update queue's write index */
q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
q->write_ptr = iwl_queue_inc_wrap(q->write_ptr);
iwl_pcie_txq_inc_wr_ptr(trans, txq);

spin_unlock_irqrestore(&trans_pcie->reg_lock, flags);
Expand Down Expand Up @@ -1788,7 +1783,7 @@ int iwl_trans_pcie_tx(struct iwl_trans *trans, struct sk_buff *skb,
mod_timer(&txq->stuck_timer, jiffies + trans_pcie->wd_timeout);

/* Tell device the write index *just past* this latest filled TFD */
q->write_ptr = iwl_queue_inc_wrap(q->write_ptr, q->n_bd);
q->write_ptr = iwl_queue_inc_wrap(q->write_ptr);
if (!wait_write_ptr)
iwl_pcie_txq_inc_wr_ptr(trans, txq);

Expand Down

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