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spi/dw_spi: improve the interrupt mode with the batch ops 

leverage the performance gain by change in low level
read/write batch operations

Signed-off-by: Alek Du <alek.du@intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Alek Du 2011-03-30 23:09:55 +08:00 committed by Grant Likely
parent 2ff271bf65
commit 3b8a4dd3eb
1 changed files with 16 additions and 47 deletions
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63
drivers/spi/dw_spi.c
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@ -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;
}