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spi: sirf: decrease the interrupt count and latency of PIO mode 

current PIO tranfer method be described as follows:
1. fill as much as bytes but no more than 256 bytes(fifo size)
2. enable oflow/uflow/txfifo_empty interrupt
3. isr process 3 interrupt signal, do complete works.
4. after isr done, if there are left bytes go into 1 else go into 5
5. transfer end

by current PIO transfer method:
1. reduce interrupt counts in spi interrupt line.
2. reduce interrupt latency because no do data fill/fetch in isr.

Signed-off-by: Qipan Li <Qipan.Li@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
hifive-unleashed-5.1
Qipan Li 2014-05-04 14:32:36 +08:00 committed by Mark Brown
parent c908ef345d
commit 41148c3a72
1 changed files with 54 additions and 47 deletions
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101
drivers/spi/spi-sirf.c
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@ -86,6 +86,7 @@
#define SIRFSOC_SPI_TX_DONE BIT(1)
#define SIRFSOC_SPI_RX_OFLOW BIT(2)
#define SIRFSOC_SPI_TX_UFLOW BIT(3)
#define SIRFSOC_SPI_RX_IO_DMA BIT(4)
#define SIRFSOC_SPI_RX_FIFO_FULL BIT(6)
#define SIRFSOC_SPI_TXFIFO_EMPTY BIT(7)
#define SIRFSOC_SPI_RXFIFO_THD_REACH BIT(8)
@ -265,41 +266,34 @@ static irqreturn_t spi_sirfsoc_irq(int irq, void *dev_id)
{
struct sirfsoc_spi *sspi = dev_id;
u32 spi_stat = readl(sspi->base + SIRFSOC_SPI_INT_STATUS);
writel(spi_stat, sspi->base + SIRFSOC_SPI_INT_STATUS);
if (sspi->tx_by_cmd && (spi_stat & SIRFSOC_SPI_FRM_END)) {
complete(&sspi->tx_done);
writel(0x0, sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_INT_MASK_ALL,
sspi->base + SIRFSOC_SPI_INT_STATUS);
return IRQ_HANDLED;
}
/* Error Conditions */
if (spi_stat & SIRFSOC_SPI_RX_OFLOW ||
spi_stat & SIRFSOC_SPI_TX_UFLOW) {
complete(&sspi->tx_done);
complete(&sspi->rx_done);
writel(0x0, sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_INT_MASK_ALL,
sspi->base + SIRFSOC_SPI_INT_STATUS);
return IRQ_HANDLED;
}
if (spi_stat & SIRFSOC_SPI_TXFIFO_EMPTY)
complete(&sspi->tx_done);
while (!(readl(sspi->base + SIRFSOC_SPI_INT_STATUS) &
SIRFSOC_SPI_RX_IO_DMA))
cpu_relax();
complete(&sspi->rx_done);
writel(0x0, sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_INT_MASK_ALL,
sspi->base + SIRFSOC_SPI_INT_STATUS);
if (spi_stat & (SIRFSOC_SPI_FRM_END
| SIRFSOC_SPI_RXFIFO_THD_REACH))
while (!((readl(sspi->base + SIRFSOC_SPI_RXFIFO_STATUS)
& SIRFSOC_SPI_FIFO_EMPTY)) &&
sspi->left_rx_word)
sspi->rx_word(sspi);
if (spi_stat & (SIRFSOC_SPI_TXFIFO_EMPTY |
SIRFSOC_SPI_TXFIFO_THD_REACH))
while (!((readl(sspi->base + SIRFSOC_SPI_TXFIFO_STATUS)
& SIRFSOC_SPI_FIFO_FULL)) &&
sspi->left_tx_word)
sspi->tx_word(sspi);
/* Received all words */
if ((sspi->left_rx_word == 0) && (sspi->left_tx_word == 0)) {
complete(&sspi->rx_done);
writel(0x0, sspi->base + SIRFSOC_SPI_INT_EN);
}
return IRQ_HANDLED;
}
@ -420,32 +414,45 @@ static void spi_sirfsoc_pio_transfer(struct spi_device *spi,
int timeout = t->len * 10;
sspi = spi_master_get_devdata(spi->master);
writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + SIRFSOC_SPI_RXFIFO_OP);
writel(SIRFSOC_SPI_FIFO_RESET, sspi->base + SIRFSOC_SPI_TXFIFO_OP);
writel(SIRFSOC_SPI_FIFO_START, sspi->base + SIRFSOC_SPI_RXFIFO_OP);
writel(SIRFSOC_SPI_FIFO_START, sspi->base + SIRFSOC_SPI_TXFIFO_OP);
writel(0, sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_INT_MASK_ALL, sspi->base + SIRFSOC_SPI_INT_STATUS);
writel(readl(sspi->base + SIRFSOC_SPI_CTRL) | SIRFSOC_SPI_MUL_DAT_MODE |
SIRFSOC_SPI_ENA_AUTO_CLR, sspi->base + SIRFSOC_SPI_CTRL);
writel(sspi->left_tx_word - 1,
sspi->base + SIRFSOC_SPI_TX_DMA_IO_LEN);
writel(sspi->left_rx_word - 1,
sspi->base + SIRFSOC_SPI_RX_DMA_IO_LEN);
sspi->tx_word(sspi);
writel(SIRFSOC_SPI_TXFIFO_EMPTY_INT_EN | SIRFSOC_SPI_TX_UFLOW_INT_EN |
SIRFSOC_SPI_RX_OFLOW_INT_EN | SIRFSOC_SPI_RXFIFO_THD_INT_EN |
SIRFSOC_SPI_TXFIFO_THD_INT_EN | SIRFSOC_SPI_FRM_END_INT_EN|
SIRFSOC_SPI_RXFIFO_FULL_INT_EN,
sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_RX_EN | SIRFSOC_SPI_TX_EN,
do {
writel(SIRFSOC_SPI_FIFO_RESET,
sspi->base + SIRFSOC_SPI_RXFIFO_OP);
writel(SIRFSOC_SPI_FIFO_RESET,
sspi->base + SIRFSOC_SPI_TXFIFO_OP);
writel(SIRFSOC_SPI_FIFO_START,
sspi->base + SIRFSOC_SPI_RXFIFO_OP);
writel(SIRFSOC_SPI_FIFO_START,
sspi->base + SIRFSOC_SPI_TXFIFO_OP);
writel(0, sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_INT_MASK_ALL,
sspi->base + SIRFSOC_SPI_INT_STATUS);
writel(readl(sspi->base + SIRFSOC_SPI_CTRL) |
SIRFSOC_SPI_MUL_DAT_MODE | SIRFSOC_SPI_ENA_AUTO_CLR,
sspi->base + SIRFSOC_SPI_CTRL);
writel(min(sspi->left_tx_word, (u32)(256 / sspi->word_width))
- 1, sspi->base + SIRFSOC_SPI_TX_DMA_IO_LEN);
writel(min(sspi->left_rx_word, (u32)(256 / sspi->word_width))
- 1, sspi->base + SIRFSOC_SPI_RX_DMA_IO_LEN);
while (!((readl(sspi->base + SIRFSOC_SPI_TXFIFO_STATUS)
& SIRFSOC_SPI_FIFO_FULL)) && sspi->left_tx_word)
sspi->tx_word(sspi);
writel(SIRFSOC_SPI_TXFIFO_EMPTY_INT_EN |
SIRFSOC_SPI_TX_UFLOW_INT_EN |
SIRFSOC_SPI_RX_OFLOW_INT_EN,
sspi->base + SIRFSOC_SPI_INT_EN);
writel(SIRFSOC_SPI_RX_EN | SIRFSOC_SPI_TX_EN,
sspi->base + SIRFSOC_SPI_TX_RX_EN);
if (wait_for_completion_timeout(&sspi->rx_done, timeout) == 0)
dev_err(&spi->dev, "transfer timeout\n");
writel(0, sspi->base + SIRFSOC_SPI_RXFIFO_OP);
writel(0, sspi->base + SIRFSOC_SPI_TXFIFO_OP);
writel(0, sspi->base + SIRFSOC_SPI_TX_RX_EN);
writel(0, sspi->base + SIRFSOC_SPI_INT_EN);
if (!wait_for_completion_timeout(&sspi->tx_done, timeout) ||
!wait_for_completion_timeout(&sspi->rx_done, timeout)) {
dev_err(&spi->dev, "transfer timeout\n");
break;
}
while (!((readl(sspi->base + SIRFSOC_SPI_RXFIFO_STATUS)
& SIRFSOC_SPI_FIFO_EMPTY)) && sspi->left_rx_word)
sspi->rx_word(sspi);
writel(0, sspi->base + SIRFSOC_SPI_RXFIFO_OP);
writel(0, sspi->base + SIRFSOC_SPI_TXFIFO_OP);
} while (sspi->left_tx_word != 0 || sspi->left_rx_word != 0);
}
static int spi_sirfsoc_transfer(struct spi_device *spi, struct spi_transfer *t)