From: Qipan Li <[email protected]> The old codes use the below flow to do TX: send one word at first, after this word is finished and TX empty interrupt is generated, send more words. This causes redundant interrupt overhead at least for the 1st word.
This patch moves to send as many as possible words at the beginning and handle TX empty interrupt to send another bundle of words. so interrupt overhead is decreased. Signed-off-by: Qipan Li <[email protected]> Signed-off-by: Barry Song <[email protected]> --- drivers/spi/spi-sirf.c | 101 ++++++++++++++++++++++++++----------------------- 1 file changed, 54 insertions(+), 47 deletions(-) diff --git a/drivers/spi/spi-sirf.c b/drivers/spi/spi-sirf.c index 2d23899..95ac276 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) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
