diff options
Diffstat (limited to 'drivers/spi/spi-atmel.c')
| -rw-r--r-- | drivers/spi/spi-atmel.c | 255 |
1 files changed, 245 insertions, 10 deletions
diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c index aa7d202d6905..c9eca347787d 100644 --- a/drivers/spi/spi-atmel.c +++ b/drivers/spi/spi-atmel.c @@ -41,6 +41,8 @@ #define SPI_CSR1 0x0034 #define SPI_CSR2 0x0038 #define SPI_CSR3 0x003c +#define SPI_FMR 0x0040 +#define SPI_FLR 0x0044 #define SPI_VERSION 0x00fc #define SPI_RPR 0x0100 #define SPI_RCR 0x0104 @@ -62,6 +64,14 @@ #define SPI_SWRST_SIZE 1 #define SPI_LASTXFER_OFFSET 24 #define SPI_LASTXFER_SIZE 1 +#define SPI_TXFCLR_OFFSET 16 +#define SPI_TXFCLR_SIZE 1 +#define SPI_RXFCLR_OFFSET 17 +#define SPI_RXFCLR_SIZE 1 +#define SPI_FIFOEN_OFFSET 30 +#define SPI_FIFOEN_SIZE 1 +#define SPI_FIFODIS_OFFSET 31 +#define SPI_FIFODIS_SIZE 1 /* Bitfields in MR */ #define SPI_MSTR_OFFSET 0 @@ -114,6 +124,22 @@ #define SPI_TXEMPTY_SIZE 1 #define SPI_SPIENS_OFFSET 16 #define SPI_SPIENS_SIZE 1 +#define SPI_TXFEF_OFFSET 24 +#define SPI_TXFEF_SIZE 1 +#define SPI_TXFFF_OFFSET 25 +#define SPI_TXFFF_SIZE 1 +#define SPI_TXFTHF_OFFSET 26 +#define SPI_TXFTHF_SIZE 1 +#define SPI_RXFEF_OFFSET 27 +#define SPI_RXFEF_SIZE 1 +#define SPI_RXFFF_OFFSET 28 +#define SPI_RXFFF_SIZE 1 +#define SPI_RXFTHF_OFFSET 29 +#define SPI_RXFTHF_SIZE 1 +#define SPI_TXFPTEF_OFFSET 30 +#define SPI_TXFPTEF_SIZE 1 +#define SPI_RXFPTEF_OFFSET 31 +#define SPI_RXFPTEF_SIZE 1 /* Bitfields in CSR0 */ #define SPI_CPOL_OFFSET 0 @@ -157,6 +183,22 @@ #define SPI_TXTDIS_OFFSET 9 #define SPI_TXTDIS_SIZE 1 +/* Bitfields in FMR */ +#define SPI_TXRDYM_OFFSET 0 +#define SPI_TXRDYM_SIZE 2 +#define SPI_RXRDYM_OFFSET 4 +#define SPI_RXRDYM_SIZE 2 +#define SPI_TXFTHRES_OFFSET 16 +#define SPI_TXFTHRES_SIZE 6 +#define SPI_RXFTHRES_OFFSET 24 +#define SPI_RXFTHRES_SIZE 6 + +/* Bitfields in FLR */ +#define SPI_TXFL_OFFSET 0 +#define SPI_TXFL_SIZE 6 +#define SPI_RXFL_OFFSET 16 +#define SPI_RXFL_SIZE 6 + /* Constants for BITS */ #define SPI_BITS_8_BPT 0 #define SPI_BITS_9_BPT 1 @@ -167,6 +209,9 @@ #define SPI_BITS_14_BPT 6 #define SPI_BITS_15_BPT 7 #define SPI_BITS_16_BPT 8 +#define SPI_ONE_DATA 0 +#define SPI_TWO_DATA 1 +#define SPI_FOUR_DATA 2 /* Bit manipulation macros */ #define SPI_BIT(name) \ @@ -185,11 +230,31 @@ __raw_readl((port)->regs + SPI_##reg) #define spi_writel(port, reg, value) \ __raw_writel((value), (port)->regs + SPI_##reg) + +#define spi_readw(port, reg) \ + __raw_readw((port)->regs + SPI_##reg) +#define spi_writew(port, reg, value) \ + __raw_writew((value), (port)->regs + SPI_##reg) + +#define spi_readb(port, reg) \ + __raw_readb((port)->regs + SPI_##reg) +#define spi_writeb(port, reg, value) \ + __raw_writeb((value), (port)->regs + SPI_##reg) #else #define spi_readl(port, reg) \ readl_relaxed((port)->regs + SPI_##reg) #define spi_writel(port, reg, value) \ writel_relaxed((value), (port)->regs + SPI_##reg) + +#define spi_readw(port, reg) \ + readw_relaxed((port)->regs + SPI_##reg) +#define spi_writew(port, reg, value) \ + writew_relaxed((value), (port)->regs + SPI_##reg) + +#define spi_readb(port, reg) \ + readb_relaxed((port)->regs + SPI_##reg) +#define spi_writeb(port, reg, value) \ + writeb_relaxed((value), (port)->regs + SPI_##reg) #endif /* use PIO for small transfers, avoiding DMA setup/teardown overhead and * cache operations; better heuristics consider wordsize and bitrate. @@ -252,6 +317,8 @@ struct atmel_spi { bool keep_cs; bool cs_active; + + u32 fifo_size; }; /* Controller-specific per-slave state */ @@ -410,6 +477,20 @@ static int atmel_spi_dma_slave_config(struct atmel_spi *as, slave_config->dst_maxburst = 1; slave_config->device_fc = false; + /* + * This driver uses fixed peripheral select mode (PS bit set to '0' in + * the Mode Register). + * So according to the datasheet, when FIFOs are available (and + * enabled), the Transmit FIFO operates in Multiple Data Mode. + * In this mode, up to 2 data, not 4, can be written into the Transmit + * Data Register in a single access. + * However, the first data has to be written into the lowest 16 bits and + * the second data into the highest 16 bits of the Transmit + * Data Register. For 8bit data (the most frequent case), it would + * require to rework tx_buf so each data would actualy fit 16 bits. + * So we'd rather write only one data at the time. Hence the transmit + * path works the same whether FIFOs are available (and enabled) or not. + */ slave_config->direction = DMA_MEM_TO_DEV; if (dmaengine_slave_config(as->dma.chan_tx, slave_config)) { dev_err(&as->pdev->dev, @@ -417,6 +498,14 @@ static int atmel_spi_dma_slave_config(struct atmel_spi *as, err = -EINVAL; } + /* + * This driver configures the spi controller for master mode (MSTR bit + * set to '1' in the Mode Register). + * So according to the datasheet, when FIFOs are available (and + * enabled), the Receive FIFO operates in Single Data Mode. + * So the receive path works the same whether FIFOs are available (and + * enabled) or not. + */ slave_config->direction = DMA_DEV_TO_MEM; if (dmaengine_slave_config(as->dma.chan_rx, slave_config)) { dev_err(&as->pdev->dev, @@ -506,10 +595,10 @@ static void dma_callback(void *data) } /* - * Next transfer using PIO. + * Next transfer using PIO without FIFO. */ -static void atmel_spi_next_xfer_pio(struct spi_master *master, - struct spi_transfer *xfer) +static void atmel_spi_next_xfer_single(struct spi_master *master, + struct spi_transfer *xfer) { struct atmel_spi *as = spi_master_get_devdata(master); unsigned long xfer_pos = xfer->len - as->current_remaining_bytes; @@ -542,6 +631,99 @@ static void atmel_spi_next_xfer_pio(struct spi_master *master, } /* + * Next transfer using PIO with FIFO. + */ +static void atmel_spi_next_xfer_fifo(struct spi_master *master, + struct spi_transfer *xfer) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + u32 current_remaining_data, num_data; + u32 offset = xfer->len - as->current_remaining_bytes; + const u16 *words = (const u16 *)((u8 *)xfer->tx_buf + offset); + const u8 *bytes = (const u8 *)((u8 *)xfer->tx_buf + offset); + u16 td0, td1; + u32 fifomr; + + dev_vdbg(master->dev.parent, "atmel_spi_next_xfer_fifo\n"); + + /* Compute the number of data to transfer in the current iteration */ + current_remaining_data = ((xfer->bits_per_word > 8) ? + ((u32)as->current_remaining_bytes >> 1) : + (u32)as->current_remaining_bytes); + num_data = min(current_remaining_data, as->fifo_size); + + /* Flush RX and TX FIFOs */ + spi_writel(as, CR, SPI_BIT(RXFCLR) | SPI_BIT(TXFCLR)); + while (spi_readl(as, FLR)) + cpu_relax(); + + /* Set RX FIFO Threshold to the number of data to transfer */ + fifomr = spi_readl(as, FMR); + spi_writel(as, FMR, SPI_BFINS(RXFTHRES, num_data, fifomr)); + + /* Clear FIFO flags in the Status Register, especially RXFTHF */ + (void)spi_readl(as, SR); + + /* Fill TX FIFO */ + while (num_data >= 2) { + if (xfer->tx_buf) { + if (xfer->bits_per_word > 8) { + td0 = *words++; + td1 = *words++; + } else { + td0 = *bytes++; + td1 = *bytes++; + } + } else { + td0 = 0; + td1 = 0; + } + + spi_writel(as, TDR, (td1 << 16) | td0); + num_data -= 2; + } + + if (num_data) { + if (xfer->tx_buf) { + if (xfer->bits_per_word > 8) + td0 = *words++; + else + td0 = *bytes++; + } else { + td0 = 0; + } + + spi_writew(as, TDR, td0); + num_data--; + } + + dev_dbg(master->dev.parent, + " start fifo xfer %p: len %u tx %p rx %p bitpw %d\n", + xfer, xfer->len, xfer->tx_buf, xfer->rx_buf, + xfer->bits_per_word); + + /* + * Enable RX FIFO Threshold Flag interrupt to be notified about + * transfer completion. + */ + spi_writel(as, IER, SPI_BIT(RXFTHF) | SPI_BIT(OVRES)); +} + +/* + * Next transfer using PIO. + */ +static void atmel_spi_next_xfer_pio(struct spi_master *master, + struct spi_transfer *xfer) +{ + struct atmel_spi *as = spi_master_get_devdata(master); + + if (as->fifo_size) + atmel_spi_next_xfer_fifo(master, xfer); + else + atmel_spi_next_xfer_single(master, xfer); +} + +/* * Submit next transfer for DMA. */ static int atmel_spi_next_xfer_dma_submit(struct spi_master *master, @@ -843,13 +1025,8 @@ static void atmel_spi_disable_pdc_transfer(struct atmel_spi *as) spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); } -/* Called from IRQ - * - * Must update "current_remaining_bytes" to keep track of data - * to transfer. - */ static void -atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) +atmel_spi_pump_single_data(struct atmel_spi *as, struct spi_transfer *xfer) { u8 *rxp; u16 *rxp16; @@ -876,6 +1053,57 @@ atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) } } +static void +atmel_spi_pump_fifo_data(struct atmel_spi *as, struct spi_transfer *xfer) +{ + u32 fifolr = spi_readl(as, FLR); + u32 num_bytes, num_data = SPI_BFEXT(RXFL, fifolr); + u32 offset = xfer->len - as->current_remaining_bytes; + u16 *words = (u16 *)((u8 *)xfer->rx_buf + offset); + u8 *bytes = (u8 *)((u8 *)xfer->rx_buf + offset); + u16 rd; /* RD field is the lowest 16 bits of RDR */ + + /* Update the number of remaining bytes to transfer */ + num_bytes = ((xfer->bits_per_word > 8) ? + (num_data << 1) : + num_data); + + if (as->current_remaining_bytes > num_bytes) + as->current_remaining_bytes -= num_bytes; + else + as->current_remaining_bytes = 0; + + /* Handle odd number of bytes when data are more than 8bit width */ + if (xfer->bits_per_word > 8) + as->current_remaining_bytes &= ~0x1; + + /* Read data */ + while (num_data) { + rd = spi_readl(as, RDR); + if (xfer->rx_buf) { + if (xfer->bits_per_word > 8) + *words++ = rd; + else + *bytes++ = rd; + } + num_data--; + } +} + +/* Called from IRQ + * + * Must update "current_remaining_bytes" to keep track of data + * to transfer. + */ +static void +atmel_spi_pump_pio_data(struct atmel_spi *as, struct spi_transfer *xfer) +{ + if (as->fifo_size) + atmel_spi_pump_fifo_data(as, xfer); + else + atmel_spi_pump_single_data(as, xfer); +} + /* Interrupt * * No need for locking in this Interrupt handler: done_status is the @@ -916,7 +1144,7 @@ atmel_spi_pio_interrupt(int irq, void *dev_id) complete(&as->xfer_completion); - } else if (pending & SPI_BIT(RDRF)) { + } else if (pending & (SPI_BIT(RDRF) | SPI_BIT(RXFTHF))) { atmel_spi_lock(as); if (as->current_remaining_bytes) { @@ -1399,6 +1627,13 @@ static int atmel_spi_probe(struct platform_device *pdev) spi_writel(as, PTCR, SPI_BIT(RXTDIS) | SPI_BIT(TXTDIS)); spi_writel(as, CR, SPI_BIT(SPIEN)); + as->fifo_size = 0; + if (!of_property_read_u32(pdev->dev.of_node, "atmel,fifo-size", + &as->fifo_size)) { + dev_info(&pdev->dev, "Using FIFO (%u data)\n", as->fifo_size); + spi_writel(as, CR, SPI_BIT(FIFOEN)); + } + /* go! */ dev_info(&pdev->dev, "Atmel SPI Controller at 0x%08lx (irq %d)\n", (unsigned long)regs->start, irq); |