diff options
author | Qipan Li <Qipan.Li@csr.com> | 2014-05-04 10:32:36 +0400 |
---|---|---|
committer | Mark Brown <broonie@linaro.org> | 2014-05-21 02:24:20 +0400 |
commit | 41148c3a728222a885bc2f3ba3ce66831de0b244 (patch) | |
tree | e98c1efb42481caa47f2c256b73aef131812e079 /drivers/spi/spi-sirf.c | |
parent | c908ef345d2c314ec25cfac113a8f9bb2b6b3a25 (diff) | |
download | linux-41148c3a728222a885bc2f3ba3ce66831de0b244.tar.xz |
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>
Diffstat (limited to 'drivers/spi/spi-sirf.c')
-rw-r--r-- | drivers/spi/spi-sirf.c | 101 |
1 files changed, 54 insertions, 47 deletions
diff --git a/drivers/spi/spi-sirf.c b/drivers/spi/spi-sirf.c index 2d238990115c..95ac276eaafe 100644 --- a/drivers/spi/spi-sirf.c +++ b/drivers/spi/spi-sirf.c @@ -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) |