leverage the performance gain by change in low level
read/write batch operations
Signed-off-by: Alek Du <alek...@intel.com>
Signed-off-by: Feng Tang <feng.t...@intel.com>
---
drivers/spi/dw_spi.c | 63 ++++++++++++-------------------------------------
1 files changed, 16 insertions(+), 47 deletions(-)
diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c
index ba8b394..a063019 100644
--- a/drivers/spi/dw_spi.c
+++ b/drivers/spi/dw_spi.c
@@ -190,21 +190,7 @@ static inline u32 rx_max(struct dw_spi *dws)
return min(rx_left, (u32)dw_readw(dws, rxflr));
}
-
-static void wait_till_not_busy(struct dw_spi *dws)
-{
- unsigned long end = jiffies + 1 + usecs_to_jiffies(5000);
-
- while (time_before(jiffies, end)) {
- if (!(dw_readw(dws, sr) & SR_BUSY))
- return;
- cpu_relax();
- }
- dev_err(&dws->master->dev,
- "DW SPI: Status keeps busy for 5000us after a read/write!\n");
-}
-
-static int dw_writer(struct dw_spi *dws)
+static void dw_writer(struct dw_spi *dws)
{
u32 max = tx_max(dws);
u16 txw = 0;
@@ -220,11 +206,9 @@ static int dw_writer(struct dw_spi *dws)
dw_writew(dws, dr, txw);
dws->tx += dws->n_bytes;
}
-
- return 1;
}
-static int dw_reader(struct dw_spi *dws)
+static void dw_reader(struct dw_spi *dws)
{
u32 max = rx_max(dws);
u16 rxw;
@@ -240,8 +224,6 @@ static int dw_reader(struct dw_spi *dws)
}
dws->rx += dws->n_bytes;
}
-
- return dws->rx == dws->rx_end;
}
static void *next_transfer(struct dw_spi *dws)
@@ -340,35 +322,28 @@ EXPORT_SYMBOL_GPL(dw_spi_xfer_done);
static irqreturn_t interrupt_transfer(struct dw_spi *dws)
{
- u16 irq_status, irq_mask = 0x3f;
- u32 int_level = dws->fifo_len / 2;
- u32 left;
+ u16 irq_status = dw_readw(dws, isr);
- irq_status = dw_readw(dws, isr) & irq_mask;
/* Error handling */
if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
dw_readw(dws, txoicr);
dw_readw(dws, rxoicr);
dw_readw(dws, rxuicr);
- int_error_stop(dws, "interrupt_transfer: fifo overrun");
+ int_error_stop(dws, "interrupt_transfer: fifo
overrun/underrun");
return IRQ_HANDLED;
}
+ dw_reader(dws);
+ if (dws->rx_end == dws->rx) {
+ spi_mask_intr(dws, SPI_INT_TXEI);
+ dw_spi_xfer_done(dws);
+ return IRQ_HANDLED;
+ }
if (irq_status & SPI_INT_TXEI) {
spi_mask_intr(dws, SPI_INT_TXEI);
-
- left = (dws->tx_end - dws->tx) / dws->n_bytes;
- left = (left > int_level) ? int_level : left;
-
- while (left--)
- dw_writer(dws);
- dw_reader(dws);
-
- /* Re-enable the IRQ if there is still data left to tx */
- if (dws->tx_end > dws->tx)
- spi_umask_intr(dws, SPI_INT_TXEI);
- else
- dw_spi_xfer_done(dws);
+ dw_writer(dws);
+ /* Enable TX irq always, it will be disabled when RX finished */
+ spi_umask_intr(dws, SPI_INT_TXEI);
}
return IRQ_HANDLED;
@@ -377,15 +352,13 @@ static irqreturn_t interrupt_transfer(struct dw_spi *dws)
static irqreturn_t dw_spi_irq(int irq, void *dev_id)
{
struct dw_spi *dws = dev_id;
- u16 irq_status, irq_mask = 0x3f;
+ u16 irq_status = dw_readw(dws, isr) & 0x3f;
- irq_status = dw_readw(dws, isr) & irq_mask;
if (!irq_status)
return IRQ_NONE;
if (!dws->cur_msg) {
spi_mask_intr(dws, SPI_INT_TXEI);
- /* Never fail */
return IRQ_HANDLED;
}
@@ -492,12 +465,8 @@ static void pump_transfers(unsigned long data)
switch (bits) {
case 8:
- dws->n_bytes = 1;
- dws->dma_width = 1;
- break;
case 16:
- dws->n_bytes = 2;
- dws->dma_width = 2;
+ dws->n_bytes = dws->dma_width = bits >> 3;
break;
default:
printk(KERN_ERR "MRST SPI0: unsupported bits:"
@@ -541,7 +510,7 @@ static void pump_transfers(unsigned long data)
txint_level = dws->fifo_len / 2;
txint_level = (templen > txint_level) ? txint_level : templen;
- imask |= SPI_INT_TXEI;
+ imask |= SPI_INT_TXEI | SPI_INT_TXOI | SPI_INT_RXUI |
SPI_INT_RXOI;
dws->transfer_handler = interrupt_transfer;
}
--
1.7.0.4
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