diff options
| -rw-r--r-- | drivers/spi/spi-s3c64xx.c | 153 |
1 files changed, 104 insertions, 49 deletions
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c index 5000586..0a80692 100644 --- a/drivers/spi/spi-s3c64xx.c +++ b/drivers/spi/spi-s3c64xx.c @@ -39,6 +39,7 @@ #endif #define MAX_SPI_PORTS 3 +#define S3C64XX_SPI_QUIRK_POLL (1 << 0) /* Registers and bit-fields */ @@ -130,6 +131,7 @@ #define S3C64XX_SPI_TRAILCNT S3C64XX_SPI_MAX_TRAILCNT #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t) +#define is_polling(x) (x->port_conf->quirks & S3C64XX_SPI_QUIRK_POLL) #define RXBUSY (1<<2) #define TXBUSY (1<<3) @@ -158,6 +160,7 @@ struct s3c64xx_spi_port_config { int fifo_lvl_mask[MAX_SPI_PORTS]; int rx_lvl_offset; int tx_st_done; + int quirks; bool high_speed; bool clk_from_cmu; }; @@ -344,8 +347,12 @@ static int s3c64xx_spi_prepare_transfer(struct spi_master *spi) { struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi); - /* Acquire DMA channels */ - while (!acquire_dma(sdd)) + /* + * If DMA resource was not available during + * probe, no need to continue with dma requests + * else Acquire DMA channels + */ + while (!is_polling(sdd) && !acquire_dma(sdd)) usleep_range(10000, 11000); pm_runtime_get_sync(&sdd->pdev->dev); @@ -358,9 +365,12 @@ static int s3c64xx_spi_unprepare_transfer(struct spi_master *spi) struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi); /* Free DMA channels */ - sdd->ops->release((enum dma_ch)sdd->rx_dma.ch, &s3c64xx_spi_dma_client); - sdd->ops->release((enum dma_ch)sdd->tx_dma.ch, &s3c64xx_spi_dma_client); - + if (!is_polling(sdd)) { + sdd->ops->release((enum dma_ch)sdd->rx_dma.ch, + &s3c64xx_spi_dma_client); + sdd->ops->release((enum dma_ch)sdd->tx_dma.ch, + &s3c64xx_spi_dma_client); + } pm_runtime_put(&sdd->pdev->dev); return 0; @@ -464,8 +474,10 @@ static int s3c64xx_spi_unprepare_transfer(struct spi_master *spi) struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(spi); /* Free DMA channels */ - dma_release_channel(sdd->rx_dma.ch); - dma_release_channel(sdd->tx_dma.ch); + if (!is_polling(sdd)) { + dma_release_channel(sdd->rx_dma.ch); + dma_release_channel(sdd->tx_dma.ch); + } pm_runtime_put(&sdd->pdev->dev); return 0; @@ -566,6 +578,30 @@ static inline void enable_cs(struct s3c64xx_spi_driver_data *sdd, cs = spi->controller_data; gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 1 : 0); + + /* Start the signals */ + writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL); +} + +static u32 wait_for_timeout(struct s3c64xx_spi_driver_data *sdd, + int timeout_ms) +{ + void __iomem *regs = sdd->regs; + unsigned long val = 1; + u32 status; + + /* max fifo depth available */ + u32 max_fifo = (FIFO_LVL_MASK(sdd) >> 1) + 1; + + if (timeout_ms) + val = msecs_to_loops(timeout_ms); + + do { + status = readl(regs + S3C64XX_SPI_STATUS); + } while (RX_FIFO_LVL(status, sdd) < max_fifo && --val); + + /* return the actual received data length */ + return RX_FIFO_LVL(status, sdd); } static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd, @@ -590,20 +626,19 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd, } while (RX_FIFO_LVL(status, sdd) < xfer->len && --val); } - if (!val) - return -EIO; - if (dma_mode) { u32 status; /* + * If the previous xfer was completed within timeout, then + * proceed further else return -EIO. * DmaTx returns after simply writing data in the FIFO, * w/o waiting for real transmission on the bus to finish. * DmaRx returns only after Dma read data from FIFO which * needs bus transmission to finish, so we don't worry if * Xfer involved Rx(with or without Tx). */ - if (xfer->rx_buf == NULL) { + if (val && !xfer->rx_buf) { val = msecs_to_loops(10); status = readl(regs + S3C64XX_SPI_STATUS); while ((TX_FIFO_LVL(status, sdd) @@ -613,30 +648,53 @@ static int wait_for_xfer(struct s3c64xx_spi_driver_data *sdd, status = readl(regs + S3C64XX_SPI_STATUS); } - if (!val) - return -EIO; } + + /* If timed out while checking rx/tx status return error */ + if (!val) + return -EIO; } else { + int loops; + u32 cpy_len; + u8 *buf; + /* If it was only Tx */ - if (xfer->rx_buf == NULL) { + if (!xfer->rx_buf) { sdd->state &= ~TXBUSY; return 0; } - switch (sdd->cur_bpw) { - case 32: - ioread32_rep(regs + S3C64XX_SPI_RX_DATA, - xfer->rx_buf, xfer->len / 4); - break; - case 16: - ioread16_rep(regs + S3C64XX_SPI_RX_DATA, - xfer->rx_buf, xfer->len / 2); - break; - default: - ioread8_rep(regs + S3C64XX_SPI_RX_DATA, - xfer->rx_buf, xfer->len); - break; - } + /* + * If the receive length is bigger than the controller fifo + * size, calculate the loops and read the fifo as many times. + * loops = length / max fifo size (calculated by using the + * fifo mask). + * For any size less than the fifo size the below code is + * executed atleast once. + */ + loops = xfer->len / ((FIFO_LVL_MASK(sdd) >> 1) + 1); + buf = xfer->rx_buf; + do { + /* wait for data to be received in the fifo */ + cpy_len = wait_for_timeout(sdd, (loops ? ms : 0)); + + switch (sdd->cur_bpw) { + case 32: + ioread32_rep(regs + S3C64XX_SPI_RX_DATA, + buf, cpy_len / 4); + break; + case 16: + ioread16_rep(regs + S3C64XX_SPI_RX_DATA, + buf, cpy_len / 2); + break; + default: + ioread8_rep(regs + S3C64XX_SPI_RX_DATA, + buf, cpy_len); + break; + } + + buf = buf + cpy_len; + } while (loops--); sdd->state &= ~RXBUSY; } @@ -652,6 +710,9 @@ static inline void disable_cs(struct s3c64xx_spi_driver_data *sdd, sdd->tgl_spi = NULL; gpio_set_value(cs->line, spi->mode & SPI_CS_HIGH ? 0 : 1); + + /* Quiese the signals */ + writel(S3C64XX_SPI_SLAVE_SIG_INACT, sdd->regs + S3C64XX_SPI_SLAVE_SEL); } static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd) @@ -733,7 +794,7 @@ static int s3c64xx_spi_map_mssg(struct s3c64xx_spi_driver_data *sdd, struct device *dev = &sdd->pdev->dev; struct spi_transfer *xfer; - if (msg->is_dma_mapped) + if (is_polling(sdd) || msg->is_dma_mapped) return 0; /* First mark all xfer unmapped */ @@ -782,7 +843,7 @@ static void s3c64xx_spi_unmap_mssg(struct s3c64xx_spi_driver_data *sdd, struct device *dev = &sdd->pdev->dev; struct spi_transfer *xfer; - if (msg->is_dma_mapped) + if (is_polling(sdd) || msg->is_dma_mapped) return; list_for_each_entry(xfer, &msg->transfers, transfer_list) { @@ -861,8 +922,9 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master, /* Polling method for xfers not bigger than FIFO capacity */ use_dma = 0; - if (sdd->rx_dma.ch && sdd->tx_dma.ch && - (xfer->len > ((FIFO_LVL_MASK(sdd) >> 1) + 1))) + if (!is_polling(sdd) && + (sdd->rx_dma.ch && sdd->tx_dma.ch && + (xfer->len > ((FIFO_LVL_MASK(sdd) >> 1) + 1)))) use_dma = 1; spin_lock_irqsave(&sdd->lock, flags); @@ -876,17 +938,10 @@ static int s3c64xx_spi_transfer_one_message(struct spi_master *master, /* Slave Select */ enable_cs(sdd, spi); - /* Start the signals */ - writel(0, sdd->regs + S3C64XX_SPI_SLAVE_SEL); - spin_unlock_irqrestore(&sdd->lock, flags); status = wait_for_xfer(sdd, xfer, use_dma); - /* Quiese the signals */ - writel(S3C64XX_SPI_SLAVE_SIG_INACT, - sdd->regs + S3C64XX_SPI_SLAVE_SEL); - if (status) { dev_err(&spi->dev, "I/O Error: rx-%d tx-%d res:rx-%c tx-%c len-%d\n", xfer->rx_buf ? 1 : 0, xfer->tx_buf ? 1 : 0, @@ -1287,19 +1342,19 @@ static int s3c64xx_spi_probe(struct platform_device *pdev) if (!sdd->pdev->dev.of_node) { res = platform_get_resource(pdev, IORESOURCE_DMA, 0); if (!res) { - dev_err(&pdev->dev, "Unable to get SPI tx dma " - "resource\n"); - return -ENXIO; - } - sdd->tx_dma.dmach = res->start; + dev_warn(&pdev->dev, "Unable to get SPI tx dma " + "resource. Switching to poll mode\n"); + sdd->port_conf->quirks = S3C64XX_SPI_QUIRK_POLL; + } else + sdd->tx_dma.dmach = res->start; res = platform_get_resource(pdev, IORESOURCE_DMA, 1); if (!res) { - dev_err(&pdev->dev, "Unable to get SPI rx dma " - "resource\n"); - return -ENXIO; - } - sdd->rx_dma.dmach = res->start; + dev_warn(&pdev->dev, "Unable to get SPI rx dma " + "resource. Switching to poll mode\n"); + sdd->port_conf->quirks = S3C64XX_SPI_QUIRK_POLL; + } else + sdd->rx_dma.dmach = res->start; } sdd->tx_dma.direction = DMA_MEM_TO_DEV; |
