diff options
Diffstat (limited to 'drivers')
-rw-r--r-- | drivers/spi/spi-xilinx.c | 298 |
1 files changed, 163 insertions, 135 deletions
diff --git a/drivers/spi/spi-xilinx.c b/drivers/spi/spi-xilinx.c index 79bd84f43430..133f53a9c1d4 100644 --- a/drivers/spi/spi-xilinx.c +++ b/drivers/spi/spi-xilinx.c @@ -22,6 +22,8 @@ #include <linux/spi/xilinx_spi.h> #include <linux/io.h> +#define XILINX_SPI_MAX_CS 32 + #define XILINX_SPI_NAME "xilinx_spi" /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e) @@ -34,7 +36,8 @@ #define XSPI_CR_MASTER_MODE 0x04 #define XSPI_CR_CPOL 0x08 #define XSPI_CR_CPHA 0x10 -#define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL) +#define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL | \ + XSPI_CR_LSB_FIRST | XSPI_CR_LOOP) #define XSPI_CR_TXFIFO_RESET 0x20 #define XSPI_CR_RXFIFO_RESET 0x40 #define XSPI_CR_MANUAL_SSELECT 0x80 @@ -85,12 +88,11 @@ struct xilinx_spi { u8 *rx_ptr; /* pointer in the Tx buffer */ const u8 *tx_ptr; /* pointer in the Rx buffer */ - int remaining_bytes; /* the number of bytes left to transfer */ - u8 bits_per_word; + u8 bytes_per_word; + int buffer_size; /* buffer size in words */ + u32 cs_inactive; /* Level of the CS pins when inactive*/ unsigned int (*read_fn)(void __iomem *); void (*write_fn)(u32, void __iomem *); - void (*tx_fn)(struct xilinx_spi *); - void (*rx_fn)(struct xilinx_spi *); }; static void xspi_write32(u32 val, void __iomem *addr) @@ -113,49 +115,51 @@ static unsigned int xspi_read32_be(void __iomem *addr) return ioread32be(addr); } -static void xspi_tx8(struct xilinx_spi *xspi) +static void xilinx_spi_tx(struct xilinx_spi *xspi) { - xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET); - xspi->tx_ptr++; -} - -static void xspi_tx16(struct xilinx_spi *xspi) -{ - xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET); - xspi->tx_ptr += 2; -} + u32 data = 0; -static void xspi_tx32(struct xilinx_spi *xspi) -{ - xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET); - xspi->tx_ptr += 4; -} - -static void xspi_rx8(struct xilinx_spi *xspi) -{ - u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); - if (xspi->rx_ptr) { - *xspi->rx_ptr = data & 0xff; - xspi->rx_ptr++; + if (!xspi->tx_ptr) { + xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); + return; } -} -static void xspi_rx16(struct xilinx_spi *xspi) -{ - u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); - if (xspi->rx_ptr) { - *(u16 *)(xspi->rx_ptr) = data & 0xffff; - xspi->rx_ptr += 2; + switch (xspi->bytes_per_word) { + case 1: + data = *(u8 *)(xspi->tx_ptr); + break; + case 2: + data = *(u16 *)(xspi->tx_ptr); + break; + case 4: + data = *(u32 *)(xspi->tx_ptr); + break; } + + xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET); + xspi->tx_ptr += xspi->bytes_per_word; } -static void xspi_rx32(struct xilinx_spi *xspi) +static void xilinx_spi_rx(struct xilinx_spi *xspi) { u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET); - if (xspi->rx_ptr) { + + if (!xspi->rx_ptr) + return; + + switch (xspi->bytes_per_word) { + case 1: + *(u8 *)(xspi->rx_ptr) = data; + break; + case 2: + *(u16 *)(xspi->rx_ptr) = data; + break; + case 4: *(u32 *)(xspi->rx_ptr) = data; - xspi->rx_ptr += 4; + break; } + + xspi->rx_ptr += xspi->bytes_per_word; } static void xspi_init_hw(struct xilinx_spi *xspi) @@ -165,46 +169,56 @@ static void xspi_init_hw(struct xilinx_spi *xspi) /* Reset the SPI device */ xspi->write_fn(XIPIF_V123B_RESET_MASK, regs_base + XIPIF_V123B_RESETR_OFFSET); - /* Disable all the interrupts just in case */ - xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET); - /* Enable the global IPIF interrupt */ - xspi->write_fn(XIPIF_V123B_GINTR_ENABLE, - regs_base + XIPIF_V123B_DGIER_OFFSET); + /* Enable the transmit empty interrupt, which we use to determine + * progress on the transmission. + */ + xspi->write_fn(XSPI_INTR_TX_EMPTY, + regs_base + XIPIF_V123B_IIER_OFFSET); + /* Disable the global IPIF interrupt */ + xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET); /* Deselect the slave on the SPI bus */ xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET); /* Disable the transmitter, enable Manual Slave Select Assertion, * put SPI controller into master mode, and enable it */ - xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT | - XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | - XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET); + xspi->write_fn(XSPI_CR_MANUAL_SSELECT | XSPI_CR_MASTER_MODE | + XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | XSPI_CR_RXFIFO_RESET, + regs_base + XSPI_CR_OFFSET); } static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) { struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); + u16 cr; + u32 cs; if (is_on == BITBANG_CS_INACTIVE) { /* Deselect the slave on the SPI bus */ - xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET); - } else if (is_on == BITBANG_CS_ACTIVE) { - /* Set the SPI clock phase and polarity */ - u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) - & ~XSPI_CR_MODE_MASK; - if (spi->mode & SPI_CPHA) - cr |= XSPI_CR_CPHA; - if (spi->mode & SPI_CPOL) - cr |= XSPI_CR_CPOL; - xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET); - - /* We do not check spi->max_speed_hz here as the SPI clock - * frequency is not software programmable (the IP block design - * parameter) - */ - - /* Activate the chip select */ - xspi->write_fn(~(0x0001 << spi->chip_select), - xspi->regs + XSPI_SSR_OFFSET); + xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET); + return; } + + /* Set the SPI clock phase and polarity */ + cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_MODE_MASK; + if (spi->mode & SPI_CPHA) + cr |= XSPI_CR_CPHA; + if (spi->mode & SPI_CPOL) + cr |= XSPI_CR_CPOL; + if (spi->mode & SPI_LSB_FIRST) + cr |= XSPI_CR_LSB_FIRST; + if (spi->mode & SPI_LOOP) + cr |= XSPI_CR_LOOP; + xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET); + + /* We do not check spi->max_speed_hz here as the SPI clock + * frequency is not software programmable (the IP block design + * parameter) + */ + + cs = xspi->cs_inactive; + cs ^= BIT(spi->chip_select); + + /* Activate the chip select */ + xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET); } /* spi_bitbang requires custom setup_transfer() to be defined if there is a @@ -213,85 +227,85 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on) static int xilinx_spi_setup_transfer(struct spi_device *spi, struct spi_transfer *t) { - return 0; -} + struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); -static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi) -{ - u8 sr; + if (spi->mode & SPI_CS_HIGH) + xspi->cs_inactive &= ~BIT(spi->chip_select); + else + xspi->cs_inactive |= BIT(spi->chip_select); - /* Fill the Tx FIFO with as many bytes as possible */ - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) { - if (xspi->tx_ptr) - xspi->tx_fn(xspi); - else - xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); - xspi->remaining_bytes -= xspi->bits_per_word / 8; - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - } + return 0; } static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t) { struct xilinx_spi *xspi = spi_master_get_devdata(spi->master); - u32 ipif_ier; + int remaining_words; /* the number of words left to transfer */ + bool use_irq = false; + u16 cr = 0; /* We get here with transmitter inhibited */ xspi->tx_ptr = t->tx_buf; xspi->rx_ptr = t->rx_buf; - xspi->remaining_bytes = t->len; + remaining_words = t->len / xspi->bytes_per_word; reinit_completion(&xspi->done); + if (xspi->irq >= 0 && remaining_words > xspi->buffer_size) { + use_irq = true; + xspi->write_fn(XSPI_INTR_TX_EMPTY, + xspi->regs + XIPIF_V123B_IISR_OFFSET); + /* Enable the global IPIF interrupt */ + xspi->write_fn(XIPIF_V123B_GINTR_ENABLE, + xspi->regs + XIPIF_V123B_DGIER_OFFSET); + /* Inhibit irq to avoid spurious irqs on tx_empty*/ + cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET); + xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT, + xspi->regs + XSPI_CR_OFFSET); + } - /* Enable the transmit empty interrupt, which we use to determine - * progress on the transmission. - */ - ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET); - xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY, - xspi->regs + XIPIF_V123B_IIER_OFFSET); + while (remaining_words) { + int n_words, tx_words, rx_words; - for (;;) { - u16 cr; - u8 sr; + n_words = min(remaining_words, xspi->buffer_size); - xilinx_spi_fill_tx_fifo(xspi); + tx_words = n_words; + while (tx_words--) + xilinx_spi_tx(xspi); /* Start the transfer by not inhibiting the transmitter any * longer */ - cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) & - ~XSPI_CR_TRANS_INHIBIT; - xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET); - wait_for_completion(&xspi->done); + if (use_irq) { + xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET); + wait_for_completion(&xspi->done); + } else + while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) & + XSPI_SR_TX_EMPTY_MASK)) + ; /* A transmit has just completed. Process received data and * check for more data to transmit. Always inhibit the * transmitter while the Isr refills the transmit register/FIFO, * or make sure it is stopped if we're done. */ - cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET); - xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT, + if (use_irq) + xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT, xspi->regs + XSPI_CR_OFFSET); /* Read out all the data from the Rx FIFO */ - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) { - xspi->rx_fn(xspi); - sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); - } - - /* See if there is more data to send */ - if (xspi->remaining_bytes <= 0) - break; + rx_words = n_words; + while (rx_words--) + xilinx_spi_rx(xspi); + + remaining_words -= n_words; } - /* Disable the transmit empty interrupt */ - xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET); + if (use_irq) + xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET); - return t->len - xspi->remaining_bytes; + return t->len; } @@ -316,6 +330,28 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id) return IRQ_HANDLED; } +static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi) +{ + u8 sr; + int n_words = 0; + + /* + * Before the buffer_size detection we reset the core + * to make sure we start with a clean state. + */ + xspi->write_fn(XIPIF_V123B_RESET_MASK, + xspi->regs + XIPIF_V123B_RESETR_OFFSET); + + /* Fill the Tx FIFO with as many words as possible */ + do { + xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET); + sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET); + n_words++; + } while (!(sr & XSPI_SR_TX_FULL_MASK)); + + return n_words; +} + static const struct of_device_id xilinx_spi_of_match[] = { { .compatible = "xlnx,xps-spi-2.00.a", }, { .compatible = "xlnx,xps-spi-2.00.b", }, @@ -348,14 +384,21 @@ static int xilinx_spi_probe(struct platform_device *pdev) return -EINVAL; } + if (num_cs > XILINX_SPI_MAX_CS) { + dev_err(&pdev->dev, "Invalid number of spi slaves\n"); + return -EINVAL; + } + master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi)); if (!master) return -ENODEV; /* the spi->mode bits understood by this driver: */ - master->mode_bits = SPI_CPOL | SPI_CPHA; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP | + SPI_CS_HIGH; xspi = spi_master_get_devdata(master); + xspi->cs_inactive = 0xffffffff; xspi->bitbang.master = master; xspi->bitbang.chipselect = xilinx_spi_chipselect; xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer; @@ -392,35 +435,20 @@ static int xilinx_spi_probe(struct platform_device *pdev) } master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word); - xspi->bits_per_word = bits_per_word; - if (xspi->bits_per_word == 8) { - xspi->tx_fn = xspi_tx8; - xspi->rx_fn = xspi_rx8; - } else if (xspi->bits_per_word == 16) { - xspi->tx_fn = xspi_tx16; - xspi->rx_fn = xspi_rx16; - } else if (xspi->bits_per_word == 32) { - xspi->tx_fn = xspi_tx32; - xspi->rx_fn = xspi_rx32; - } else { - ret = -EINVAL; - goto put_master; - } - - /* SPI controller initializations */ - xspi_init_hw(xspi); + xspi->bytes_per_word = bits_per_word / 8; + xspi->buffer_size = xilinx_spi_find_buffer_size(xspi); xspi->irq = platform_get_irq(pdev, 0); - if (xspi->irq < 0) { - ret = xspi->irq; - goto put_master; + if (xspi->irq >= 0) { + /* Register for SPI Interrupt */ + ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0, + dev_name(&pdev->dev), xspi); + if (ret) + goto put_master; } - /* Register for SPI Interrupt */ - ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0, - dev_name(&pdev->dev), xspi); - if (ret) - goto put_master; + /* SPI controller initializations */ + xspi_init_hw(xspi); ret = spi_bitbang_start(&xspi->bitbang); if (ret) { |