Skip to content

Commit

Permalink
dmaengine: mv_xor: improve descriptors list handling and reduce locking
Browse files Browse the repository at this point in the history 
This patch change the way free descriptors are marked.

Instead of having a field for descriptor in use, all the descriptors in the
all_slots list are free for use.

This simplify the allocation method and reduce the locking needed.

Signed-off-by: Lior Amsalem <alior@marvell.com>
Reviewed-by: Ofer Heifetz <oferh@marvell.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
  • Loading branch information
Lior Amsalem authored and Vinod Koul committed Jun 10, 2015
1 parent f1d25e0 commit fbea28a
Show file tree
Hide file tree
Showing 2 changed files with 53 additions and 105 deletions.
141 changes: 47 additions & 94 deletions drivers/dma/mv_xor.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -88,12 +88,6 @@ static void mv_desc_set_next_desc(struct mv_xor_desc_slot *desc,
hw_desc->phy_next_desc = next_desc_addr;
}

static void mv_desc_clear_next_desc(struct mv_xor_desc_slot *desc)
{
struct mv_xor_desc *hw_desc = desc->hw_desc;
hw_desc->phy_next_desc = 0;
}

static void mv_desc_set_src_addr(struct mv_xor_desc_slot *desc,
int index, dma_addr_t addr)
{
Expand Down Expand Up @@ -213,21 +207,6 @@ static char mv_chan_is_busy(struct mv_xor_chan *chan)
return (state == 1) ? 1 : 0;
}

/**
* mv_chan_free_slots - flags descriptor slots for reuse
* @slot: Slot to free
* Caller must hold &mv_chan->lock while calling this function
*/
static void mv_chan_free_slots(struct mv_xor_chan *mv_chan,
struct mv_xor_desc_slot *slot)
{
dev_dbg(mv_chan_to_devp(mv_chan), "%s %d slot %p\n",
__func__, __LINE__, slot);

slot->slot_used = 0;

}

/*
* mv_chan_start_new_chain - program the engine to operate on new
* chain headed by sw_desc
Expand Down Expand Up @@ -279,12 +258,10 @@ mv_chan_clean_completed_slots(struct mv_xor_chan *mv_chan)

dev_dbg(mv_chan_to_devp(mv_chan), "%s %d\n", __func__, __LINE__);
list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,
completed_node) {
node) {

if (async_tx_test_ack(&iter->async_tx)) {
list_del(&iter->completed_node);
mv_chan_free_slots(mv_chan, iter);
}
if (async_tx_test_ack(&iter->async_tx))
list_move_tail(&iter->node, &mv_chan->free_slots);
}
return 0;
}
Expand All @@ -295,17 +272,16 @@ mv_desc_clean_slot(struct mv_xor_desc_slot *desc,
{
dev_dbg(mv_chan_to_devp(mv_chan), "%s %d: desc %p flags %d\n",
__func__, __LINE__, desc, desc->async_tx.flags);
list_del(&desc->chain_node);

/* the client is allowed to attach dependent operations
* until 'ack' is set
*/
if (!async_tx_test_ack(&desc->async_tx)) {
if (!async_tx_test_ack(&desc->async_tx))
/* move this slot to the completed_slots */
list_add_tail(&desc->completed_node, &mv_chan->completed_slots);
return 0;
}
list_move_tail(&desc->node, &mv_chan->completed_slots);
else
list_move_tail(&desc->node, &mv_chan->free_slots);

mv_chan_free_slots(mv_chan, desc);
return 0;
}

Expand All @@ -328,7 +304,7 @@ static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan)
*/

list_for_each_entry_safe(iter, _iter, &mv_chan->chain,
chain_node) {
node) {

/* clean finished descriptors */
hw_desc = iter->hw_desc;
Expand Down Expand Up @@ -360,17 +336,17 @@ static void mv_chan_slot_cleanup(struct mv_xor_chan *mv_chan)
*/
iter = list_entry(mv_chan->chain.next,
struct mv_xor_desc_slot,
chain_node);
node);
mv_chan_start_new_chain(mv_chan, iter);
} else {
if (!list_is_last(&iter->chain_node, &mv_chan->chain)) {
if (!list_is_last(&iter->node, &mv_chan->chain)) {
/*
* descriptors are still waiting after
* current, trigger them
*/
iter = list_entry(iter->chain_node.next,
iter = list_entry(iter->node.next,
struct mv_xor_desc_slot,
chain_node);
node);
mv_chan_start_new_chain(mv_chan, iter);
} else {
/*
Expand Down Expand Up @@ -398,49 +374,28 @@ static void mv_xor_tasklet(unsigned long data)
static struct mv_xor_desc_slot *
mv_chan_alloc_slot(struct mv_xor_chan *mv_chan)
{
struct mv_xor_desc_slot *iter, *_iter;
int retry = 0;
struct mv_xor_desc_slot *iter;

/* start search from the last allocated descrtiptor
* if a contiguous allocation can not be found start searching
* from the beginning of the list
*/
retry:
if (retry == 0)
iter = mv_chan->last_used;
else
iter = list_entry(&mv_chan->all_slots,
struct mv_xor_desc_slot,
slot_node);

list_for_each_entry_safe_continue(
iter, _iter, &mv_chan->all_slots, slot_node) {

prefetch(_iter);
prefetch(&_iter->async_tx);
if (iter->slot_used) {
/* give up after finding the first busy slot
* on the second pass through the list
*/
if (retry)
break;
continue;
}
spin_lock_bh(&mv_chan->lock);

if (!list_empty(&mv_chan->free_slots)) {
iter = list_first_entry(&mv_chan->free_slots,
struct mv_xor_desc_slot,
node);

list_move_tail(&iter->node, &mv_chan->allocated_slots);

spin_unlock_bh(&mv_chan->lock);

/* pre-ack descriptor */
async_tx_ack(&iter->async_tx);

iter->slot_used = 1;
INIT_LIST_HEAD(&iter->chain_node);
iter->async_tx.cookie = -EBUSY;
mv_chan->last_used = iter;
mv_desc_clear_next_desc(iter);

return iter;

}
if (!retry++)
goto retry;

spin_unlock_bh(&mv_chan->lock);

/* try to free some slots if the allocation fails */
tasklet_schedule(&mv_chan->irq_tasklet);
Expand All @@ -466,14 +421,14 @@ mv_xor_tx_submit(struct dma_async_tx_descriptor *tx)
cookie = dma_cookie_assign(tx);

if (list_empty(&mv_chan->chain))
list_add_tail(&sw_desc->chain_node, &mv_chan->chain);
list_move_tail(&sw_desc->node, &mv_chan->chain);
else {
new_hw_chain = 0;

old_chain_tail = list_entry(mv_chan->chain.prev,
struct mv_xor_desc_slot,
chain_node);
list_add_tail(&sw_desc->chain_node, &mv_chan->chain);
node);
list_move_tail(&sw_desc->node, &mv_chan->chain);

dev_dbg(mv_chan_to_devp(mv_chan), "Append to last desc %pa\n",
&old_chain_tail->async_tx.phys);
Expand Down Expand Up @@ -526,26 +481,20 @@ static int mv_xor_alloc_chan_resources(struct dma_chan *chan)

dma_async_tx_descriptor_init(&slot->async_tx, chan);
slot->async_tx.tx_submit = mv_xor_tx_submit;
INIT_LIST_HEAD(&slot->chain_node);
INIT_LIST_HEAD(&slot->slot_node);
INIT_LIST_HEAD(&slot->node);
dma_desc = mv_chan->dma_desc_pool;
slot->async_tx.phys = dma_desc + idx * MV_XOR_SLOT_SIZE;
slot->idx = idx++;

spin_lock_bh(&mv_chan->lock);
mv_chan->slots_allocated = idx;
list_add_tail(&slot->slot_node, &mv_chan->all_slots);
list_add_tail(&slot->node, &mv_chan->free_slots);
spin_unlock_bh(&mv_chan->lock);
}

if (mv_chan->slots_allocated && !mv_chan->last_used)
mv_chan->last_used = list_entry(mv_chan->all_slots.next,
struct mv_xor_desc_slot,
slot_node);

dev_dbg(mv_chan_to_devp(mv_chan),
"allocated %d descriptor slots last_used: %p\n",
mv_chan->slots_allocated, mv_chan->last_used);
"allocated %d descriptor slots\n",
mv_chan->slots_allocated);

return mv_chan->slots_allocated ? : -ENOMEM;
}
Expand All @@ -566,7 +515,6 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
"%s src_cnt: %d len: %u dest %pad flags: %ld\n",
__func__, src_cnt, len, &dest, flags);

spin_lock_bh(&mv_chan->lock);
sw_desc = mv_chan_alloc_slot(mv_chan);
if (sw_desc) {
sw_desc->type = DMA_XOR;
Expand All @@ -577,7 +525,7 @@ mv_xor_prep_dma_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
while (src_cnt--)
mv_desc_set_src_addr(sw_desc, src_cnt, src[src_cnt]);
}
spin_unlock_bh(&mv_chan->lock);

dev_dbg(mv_chan_to_devp(mv_chan),
"%s sw_desc %p async_tx %p \n",
__func__, sw_desc, &sw_desc->async_tx);
Expand Down Expand Up @@ -624,22 +572,26 @@ static void mv_xor_free_chan_resources(struct dma_chan *chan)
mv_chan_slot_cleanup(mv_chan);

list_for_each_entry_safe(iter, _iter, &mv_chan->chain,
chain_node) {
node) {
in_use_descs++;
list_del(&iter->chain_node);
list_move_tail(&iter->node, &mv_chan->free_slots);
}
list_for_each_entry_safe(iter, _iter, &mv_chan->completed_slots,
completed_node) {
node) {
in_use_descs++;
list_move_tail(&iter->node, &mv_chan->free_slots);
}
list_for_each_entry_safe(iter, _iter, &mv_chan->allocated_slots,
node) {
in_use_descs++;
list_del(&iter->completed_node);
list_move_tail(&iter->node, &mv_chan->free_slots);
}
list_for_each_entry_safe_reverse(
iter, _iter, &mv_chan->all_slots, slot_node) {
list_del(&iter->slot_node);
iter, _iter, &mv_chan->free_slots, node) {
list_del(&iter->node);
kfree(iter);
mv_chan->slots_allocated--;
}
mv_chan->last_used = NULL;

dev_dbg(mv_chan_to_devp(mv_chan), "%s slots_allocated %d\n",
__func__, mv_chan->slots_allocated);
Expand Down Expand Up @@ -1097,7 +1049,8 @@ mv_xor_channel_add(struct mv_xor_device *xordev,
spin_lock_init(&mv_chan->lock);
INIT_LIST_HEAD(&mv_chan->chain);
INIT_LIST_HEAD(&mv_chan->completed_slots);
INIT_LIST_HEAD(&mv_chan->all_slots);
INIT_LIST_HEAD(&mv_chan->free_slots);
INIT_LIST_HEAD(&mv_chan->allocated_slots);
mv_chan->dmachan.device = dma_dev;
dma_cookie_init(&mv_chan->dmachan);

Expand Down
17 changes: 6 additions & 11 deletions drivers/dma/mv_xor.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -94,11 +94,11 @@ struct mv_xor_device {
* @mmr_base: memory mapped register base
* @idx: the index of the xor channel
* @chain: device chain view of the descriptors
* @free_slots: free slots usable by the channel
* @allocated_slots: slots allocated by the driver
* @completed_slots: slots completed by HW but still need to be acked
* @device: parent device
* @common: common dmaengine channel object members
* @last_used: place holder for allocation to continue from where it left off
* @all_slots: complete domain of slots usable by the channel
* @slots_allocated: records the actual size of the descriptor slot pool
* @irq_tasklet: bottom half where mv_xor_slot_cleanup runs
* @op_in_desc: new mode of driver, each op is writen to descriptor.
Expand All @@ -112,14 +112,14 @@ struct mv_xor_chan {
int irq;
enum dma_transaction_type current_type;
struct list_head chain;
struct list_head free_slots;
struct list_head allocated_slots;
struct list_head completed_slots;
dma_addr_t dma_desc_pool;
void *dma_desc_pool_virt;
size_t pool_size;
struct dma_device dmadev;
struct dma_chan dmachan;
struct mv_xor_desc_slot *last_used;
struct list_head all_slots;
int slots_allocated;
struct tasklet_struct irq_tasklet;
int op_in_desc;
Expand All @@ -130,9 +130,7 @@ struct mv_xor_chan {

/**
* struct mv_xor_desc_slot - software descriptor
* @slot_node: node on the mv_xor_chan.all_slots list
* @chain_node: node on the mv_xor_chan.chain list
* @completed_node: node on the mv_xor_chan.completed_slots list
* @node: node on the mv_xor_chan lists
* @hw_desc: virtual address of the hardware descriptor chain
* @phys: hardware address of the hardware descriptor chain
* @slot_used: slot in use or not
Expand All @@ -141,12 +139,9 @@ struct mv_xor_chan {
* @async_tx: support for the async_tx api
*/
struct mv_xor_desc_slot {
struct list_head slot_node;
struct list_head chain_node;
struct list_head completed_node;
struct list_head node;
enum dma_transaction_type type;
void *hw_desc;
u16 slot_used;
u16 idx;
struct dma_async_tx_descriptor async_tx;
};
Expand Down

0 comments on commit fbea28a

Please sign in to comment.