From: Per Forlin <per.forlin@xxxxxxxxxx>
Skip the use of work queue and call musb_dma_completion() directly from
DMA callback context.
Here follows measurements on a Snowball board with ondemand governor active.
Performance using work queue:
(105 MB) copied, 6.23758 s, 16.8 MB/s
(105 MB) copied, 5.7151 s, 18.3 MB/s
(105 MB) copied, 5.83583 s, 18.0 MB/s
(105 MB) copied, 5.93611 s, 17.7 MB/s
Performance without work queue
(105 MB) copied, 5.62173 s, 18.7 MB/s
(105 MB) copied, 5.61811 s, 18.7 MB/s
(105 MB) copied, 5.57817 s, 18.8 MB/s
(105 MB) copied, 5.58549 s, 18.8 MB/s
Signed-off-by: Per Forlin <per.forlin@xxxxxxxxxx>
Acked-by: Mian Yousaf Kaukab <mian.yousaf.kaukab@xxxxxxxxxxxxxx>
---
Change log.
v2: remove cast for void pointer
v3: rebase patch on top of a pure 3.1-rc1
drivers/usb/musb/ux500_dma.c | 38 +++-----------------------------------
1 files changed, 3 insertions(+), 35 deletions(-)
diff --git a/drivers/usb/musb/ux500_dma.c b/drivers/usb/musb/ux500_dma.c
index cecace4..6f10bba 100644
--- a/drivers/usb/musb/ux500_dma.c
+++ b/drivers/usb/musb/ux500_dma.c
@@ -37,7 +37,6 @@ struct ux500_dma_channel {
struct dma_channel channel;
struct ux500_dma_controller *controller;
struct musb_hw_ep *hw_ep;
- struct work_struct channel_work;
struct dma_chan *dma_chan;
unsigned int cur_len;
dma_cookie_t cookie;
@@ -56,30 +55,11 @@ struct ux500_dma_controller {
dma_addr_t phy_base;
};
-/* Work function invoked from DMA callback to handle tx transfers. */
-static void ux500_tx_work(struct work_struct *data)
-{
- struct ux500_dma_channel *ux500_channel = container_of(data,
- struct ux500_dma_channel, channel_work);
- struct musb_hw_ep *hw_ep = ux500_channel->hw_ep;
- struct musb *musb = hw_ep->musb;
- unsigned long flags;
-
- DBG(4, "DMA tx transfer done on hw_ep=%d\n", hw_ep->epnum);
-
- spin_lock_irqsave(&musb->lock, flags);
- ux500_channel->channel.actual_len = ux500_channel->cur_len;
- ux500_channel->channel.status = MUSB_DMA_STATUS_FREE;
- musb_dma_completion(musb, hw_ep->epnum,
- ux500_channel->is_tx);
- spin_unlock_irqrestore(&musb->lock, flags);
-}
-
/* Work function invoked from DMA callback to handle rx transfers. */
-static void ux500_rx_work(struct work_struct *data)
+void ux500_dma_callback(void *private_data)
{
- struct ux500_dma_channel *ux500_channel = container_of(data,
- struct ux500_dma_channel, channel_work);
+ struct dma_channel *channel = private_data;
+ struct ux500_dma_channel *ux500_channel = channel->private_data;
struct musb_hw_ep *hw_ep = ux500_channel->hw_ep;
struct musb *musb = hw_ep->musb;
unsigned long flags;
@@ -92,14 +72,7 @@ static void ux500_rx_work(struct work_struct *data)
musb_dma_completion(musb, hw_ep->epnum,
ux500_channel->is_tx);
spin_unlock_irqrestore(&musb->lock, flags);
-}
-
-void ux500_dma_callback(void *private_data)
-{
- struct dma_channel *channel = (struct dma_channel *)private_data;
- struct ux500_dma_channel *ux500_channel = channel->private_data;
- schedule_work(&ux500_channel->channel_work);
}
static bool ux500_configure_channel(struct dma_channel *channel,
@@ -326,7 +299,6 @@ static int ux500_dma_controller_start(struct dma_controller *c)
void **param_array;
struct ux500_dma_channel *channel_array;
u32 ch_count;
- void (*musb_channel_work)(struct work_struct *);
dma_cap_mask_t mask;
if ((data->num_rx_channels > UX500_MUSB_DMA_NUM_RX_CHANNELS) ||
@@ -343,7 +315,6 @@ static int ux500_dma_controller_start(struct dma_controller *c)
channel_array = controller->rx_channel;
ch_count = data->num_rx_channels;
param_array = data->dma_rx_param_array;
- musb_channel_work = ux500_rx_work;
for (dir = 0; dir < 2; dir++) {
for (ch_num = 0; ch_num < ch_count; ch_num++) {
@@ -370,15 +341,12 @@ static int ux500_dma_controller_start(struct dma_controller *c)
return -EBUSY;
}
- INIT_WORK(&ux500_channel->channel_work,
- musb_channel_work);
}
/* Prepare the loop for TX channels */
channel_array = controller->tx_channel;
ch_count = data->num_tx_channels;
param_array = data->dma_tx_param_array;
- musb_channel_work = ux500_tx_work;
is_tx = 1;
}
--
1.7.4.1
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