From e0d205e9914476e96596c5339fa440fb314ef03b Mon Sep 17 00:00:00 2001 From: Brian Niebuhr Date: Thu, 2 Sep 2010 16:52:06 +0530 Subject: spi: davinci: add support for interrupt mode Add support for SPI interrupt mode operation. Define a per chip-select "io type" variable which specifies if the transfers on this chip-select should happen in interrupt mode or polled mode. Introduce a new function davinci_spi_process_events() to help consolidate the code between interrupt mode processing and polled mode processing. Signed-off-by: Brian Niebuhr Tested-By: Michael Williamson Signed-off-by: Sekhar Nori --- drivers/spi/davinci_spi.c | 145 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 115 insertions(+), 30 deletions(-) (limited to 'drivers/spi/davinci_spi.c') diff --git a/drivers/spi/davinci_spi.c b/drivers/spi/davinci_spi.c index cd37697850c..45cc1a77a51 100644 --- a/drivers/spi/davinci_spi.c +++ b/drivers/spi/davinci_spi.c @@ -59,6 +59,9 @@ #define SPIPC0_SPIENA_MASK BIT(8) /* nREADY */ #define SPIINT_MASKALL 0x0101035F +#define SPIINT_MASKINT 0x0000015F +#define SPI_INTLVL_1 0x000001FF +#define SPI_INTLVL_0 0x00000000 /* SPIDAT1 (upper 16 bit defines) */ #define SPIDAT1_CSHOLD_MASK BIT(12) @@ -132,10 +135,14 @@ struct davinci_spi { resource_size_t pbase; void __iomem *base; size_t region_size; + u32 irq; + struct completion done; const void *tx; void *rx; u8 *tmp_buf; + int rcount; + int wcount; struct davinci_spi_dma *dma_channels; struct davinci_spi_platform_data *pdata; @@ -593,6 +600,43 @@ static int davinci_spi_check_error(struct davinci_spi *davinci_spi, return 0; } +/** + * davinci_spi_process_events - check for and handle any SPI controller events + * @davinci_spi: the controller data + * + * This function will check the SPIFLG register and handle any events that are + * detected there + */ +static int davinci_spi_process_events(struct davinci_spi *davinci_spi) +{ + u32 buf, status, errors = 0, data1_reg_val; + + buf = ioread32(davinci_spi->base + SPIBUF); + + if (davinci_spi->rcount > 0 && !(buf & SPIBUF_RXEMPTY_MASK)) { + davinci_spi->get_rx(buf & 0xFFFF, davinci_spi); + davinci_spi->rcount--; + } + + status = ioread32(davinci_spi->base + SPIFLG); + + if (unlikely(status & SPIFLG_ERROR_MASK)) { + errors = status & SPIFLG_ERROR_MASK; + goto out; + } + + if (davinci_spi->wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) { + data1_reg_val = ioread32(davinci_spi->base + SPIDAT1); + davinci_spi->wcount--; + data1_reg_val &= ~0xFFFF; + data1_reg_val |= 0xFFFF & davinci_spi->get_tx(davinci_spi); + iowrite32(data1_reg_val, davinci_spi->base + SPIDAT1); + } + +out: + return errors; +} + /** * davinci_spi_bufs - functions which will handle transfer data * @spi: spi device on which data transfer to be done @@ -606,18 +650,22 @@ static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t) { struct davinci_spi *davinci_spi; int ret; - int rcount, wcount; u32 tx_data, data1_reg_val; u32 errors = 0; + struct davinci_spi_config *spicfg; struct davinci_spi_platform_data *pdata; davinci_spi = spi_master_get_devdata(spi->master); pdata = davinci_spi->pdata; + spicfg = (struct davinci_spi_config *)spi->controller_data; + if (!spicfg) + spicfg = &davinci_spi_default_cfg; davinci_spi->tx = t->tx_buf; davinci_spi->rx = t->rx_buf; - wcount = t->len / davinci_spi->bytes_per_word[spi->chip_select]; - rcount = wcount; + davinci_spi->wcount = t->len / + davinci_spi->bytes_per_word[spi->chip_select]; + davinci_spi->rcount = davinci_spi->wcount; ret = davinci_spi_bufs_prep(spi, davinci_spi); if (ret) @@ -628,42 +676,32 @@ static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t) /* Enable SPI */ set_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_SPIENA_MASK); - clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKALL); + if (spicfg->io_type == SPI_IO_TYPE_INTR) { + set_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKINT); + INIT_COMPLETION(davinci_spi->done); + } /* start the transfer */ - wcount--; + davinci_spi->wcount--; tx_data = davinci_spi->get_tx(davinci_spi); data1_reg_val &= 0xFFFF0000; data1_reg_val |= tx_data & 0xFFFF; iowrite32(data1_reg_val, davinci_spi->base + SPIDAT1); - while (rcount > 0 || wcount > 0) { - - u32 buf, status; - - buf = ioread32(davinci_spi->base + SPIBUF); - - if (!(buf & SPIBUF_RXEMPTY_MASK)) { - davinci_spi->get_rx(buf & 0xFFFF, davinci_spi); - rcount--; - } - - status = ioread32(davinci_spi->base + SPIFLG); - - if (unlikely(status & SPIFLG_ERROR_MASK)) { - errors = status & SPIFLG_ERROR_MASK; - break; - } - - if (wcount > 0 && !(buf & SPIBUF_TXFULL_MASK)) { - wcount--; - tx_data = davinci_spi->get_tx(davinci_spi); - data1_reg_val &= ~0xFFFF; - data1_reg_val |= 0xFFFF & tx_data; - iowrite32(data1_reg_val, davinci_spi->base + SPIDAT1); + /* Wait for the transfer to complete */ + if (spicfg->io_type == SPI_IO_TYPE_INTR) { + wait_for_completion_interruptible(&(davinci_spi->done)); + } else { + while (davinci_spi->rcount > 0 || davinci_spi->wcount > 0) { + errors = davinci_spi_process_events(davinci_spi); + if (errors) + break; + cpu_relax(); } } + clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKALL); + /* * Check for bit error, desync error,parity error,timeout error and * receive overflow errors @@ -678,6 +716,32 @@ static int davinci_spi_bufs_pio(struct spi_device *spi, struct spi_transfer *t) return t->len; } +/** + * davinci_spi_irq - Interrupt handler for SPI Master Controller + * @irq: IRQ number for this SPI Master + * @context_data: structure for SPI Master controller davinci_spi + * + * ISR will determine that interrupt arrives either for READ or WRITE command. + * According to command it will do the appropriate action. It will check + * transfer length and if it is not zero then dispatch transfer command again. + * If transfer length is zero then it will indicate the COMPLETION so that + * davinci_spi_bufs function can go ahead. + */ +static irqreturn_t davinci_spi_irq(s32 irq, void *context_data) +{ + struct davinci_spi *davinci_spi = context_data; + int status; + + status = davinci_spi_process_events(davinci_spi); + if (unlikely(status != 0)) + clear_io_bits(davinci_spi->base + SPIINT, SPIINT_MASKINT); + + if ((!davinci_spi->rcount && !davinci_spi->wcount) || status) + complete(&davinci_spi->done); + + return IRQ_HANDLED; +} + static int davinci_spi_bufs_dma(struct spi_device *spi, struct spi_transfer *t) { struct davinci_spi *davinci_spi; @@ -866,11 +930,22 @@ static int davinci_spi_probe(struct platform_device *pdev) goto release_region; } + davinci_spi->irq = platform_get_irq(pdev, 0); + if (davinci_spi->irq <= 0) { + ret = -EINVAL; + goto unmap_io; + } + + ret = request_irq(davinci_spi->irq, davinci_spi_irq, 0, + dev_name(&pdev->dev), davinci_spi); + if (ret) + goto unmap_io; + /* Allocate tmp_buf for tx_buf */ davinci_spi->tmp_buf = kzalloc(SPI_BUFSIZ, GFP_KERNEL); if (davinci_spi->tmp_buf == NULL) { ret = -ENOMEM; - goto unmap_io; + goto irq_free; } davinci_spi->bitbang.master = spi_master_get(master); @@ -946,6 +1021,8 @@ static int davinci_spi_probe(struct platform_device *pdev) davinci_spi->get_rx = davinci_spi_rx_buf_u8; davinci_spi->get_tx = davinci_spi_tx_buf_u8; + init_completion(&davinci_spi->done); + /* Reset In/OUT SPI module */ iowrite32(0, davinci_spi->base + SPIGCR0); udelay(100); @@ -967,6 +1044,11 @@ static int davinci_spi_probe(struct platform_device *pdev) clear_io_bits(davinci_spi->base + SPIGCR1, SPIGCR1_CLKMOD_MASK); + if (pdata->intr_line) + iowrite32(SPI_INTLVL_1, davinci_spi->base + SPILVL); + else + iowrite32(SPI_INTLVL_0, davinci_spi->base + SPILVL); + iowrite32(CS_DEFAULT, davinci_spi->base + SPIDEF); /* master mode default */ @@ -987,6 +1069,8 @@ put_master: spi_master_put(master); free_tmp_buf: kfree(davinci_spi->tmp_buf); +irq_free: + free_irq(davinci_spi->irq, davinci_spi); unmap_io: iounmap(davinci_spi->base); release_region: @@ -1020,6 +1104,7 @@ static int __exit davinci_spi_remove(struct platform_device *pdev) clk_put(davinci_spi->clk); spi_master_put(master); kfree(davinci_spi->tmp_buf); + free_irq(davinci_spi->irq, davinci_spi); iounmap(davinci_spi->base); release_mem_region(davinci_spi->pbase, davinci_spi->region_size); -- cgit v1.2.3-70-g09d2