From 3b8a4dd3ebfcc647260ad5c39ef4f73eb3a6b155 Mon Sep 17 00:00:00 2001 From: Alek Du Date: Wed, 30 Mar 2011 23:09:55 +0800 Subject: 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 Signed-off-by: Feng Tang Signed-off-by: Grant Likely --- drivers/spi/dw_spi.c | 63 +++++++++++++--------------------------------------- 1 file changed, 16 insertions(+), 47 deletions(-) (limited to 'drivers/spi') diff --git a/drivers/spi/dw_spi.c b/drivers/spi/dw_spi.c index 7a2a722..855ac4a 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; } -- cgit v1.1