diff options
Diffstat (limited to 'drivers/spi/xilinx_spi.c')
| -rw-r--r-- | drivers/spi/xilinx_spi.c | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c new file mode 100644 index 0000000..e563c19 --- /dev/null +++ b/drivers/spi/xilinx_spi.c @@ -0,0 +1,214 @@ +/* + * Xilinx SPI driver + * + * supports 8 bit SPI transfers only, with or w/o FIFO + * + * based on bfin_spi.c, by way of altera_spi.c + * Copyright (c) 2005-2008 Analog Devices Inc. + * Copyright (c) 2010 Thomas Chou <thomas@wytron.com.tw> + * Copyright (c) 2010 Graeme Smecher <graeme.smecher@mail.mcgill.ca> + * Copyright (c) 2012 Stephan Linz <linz@li-pro.net> + * + * Licensed under the GPL-2 or later. + * + * [0]: http://www.xilinx.com/support/documentation + * + * [S]: [0]/ip_documentation/xps_spi.pdf + * [0]/ip_documentation/axi_spi_ds742.pdf + */ +#include <config.h> +#include <common.h> +#include <malloc.h> +#include <spi.h> + +#include "xilinx_spi.h" + +#ifndef CONFIG_SYS_XILINX_SPI_LIST +#define CONFIG_SYS_XILINX_SPI_LIST { CONFIG_SYS_SPI_BASE } +#endif + +#ifndef CONFIG_XILINX_SPI_IDLE_VAL +#define CONFIG_XILINX_SPI_IDLE_VAL 0xff +#endif + +#define XILSPI_SPICR_DFLT_ON (SPICR_MANUAL_SS | \ + SPICR_MASTER_MODE | \ + SPICR_SPE) + +#define XILSPI_SPICR_DFLT_OFF (SPICR_MASTER_INHIBIT | \ + SPICR_MANUAL_SS) + +#define XILSPI_MAX_XFER_BITS 8 + +static unsigned long xilinx_spi_base_list[] = CONFIG_SYS_XILINX_SPI_LIST; + +__attribute__((weak)) +int spi_cs_is_valid(unsigned int bus, unsigned int cs) +{ + return bus < ARRAY_SIZE(xilinx_spi_base_list) && cs < 32; +} + +__attribute__((weak)) +void spi_cs_activate(struct spi_slave *slave) +{ + struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave); + + writel(SPISSR_ACT(slave->cs), &xilspi->regs->spissr); +} + +__attribute__((weak)) +void spi_cs_deactivate(struct spi_slave *slave) +{ + struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave); + + writel(SPISSR_OFF, &xilspi->regs->spissr); +} + +void spi_init(void) +{ + /* do nothing */ +} + +void spi_set_speed(struct spi_slave *slave, uint hz) +{ + /* xilinx spi core does not support programmable speed */ +} + +struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs, + unsigned int max_hz, unsigned int mode) +{ + struct xilinx_spi_slave *xilspi; + struct xilinx_spi_reg *regs; + + if (!spi_cs_is_valid(bus, cs)) { + printf("XILSPI error: %s: unsupported bus %d / cs %d\n", + __func__, bus, cs); + return NULL; + } + + xilspi = malloc(sizeof(*xilspi)); + if (!xilspi) { + printf("XILSPI error: %s: malloc of SPI structure failed\n", + __func__); + return NULL; + } + xilspi->slave.bus = bus; + xilspi->slave.cs = cs; + xilspi->regs = (struct xilinx_spi_reg *)xilinx_spi_base_list[bus]; + xilspi->freq = max_hz; + xilspi->mode = mode; + debug("%s: bus:%i cs:%i base:%p mode:%x max_hz:%d\n", __func__, + bus, cs, xilspi->regs, xilspi->mode, xilspi->freq); + + return &xilspi->slave; +} + +void spi_free_slave(struct spi_slave *slave) +{ + struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave); + + free(xilspi); +} + +int spi_claim_bus(struct spi_slave *slave) +{ + struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave); + u32 spicr; + + debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs); + writel(SPISSR_OFF, &xilspi->regs->spissr); + + spicr = XILSPI_SPICR_DFLT_ON; + if (xilspi->mode & SPI_LSB_FIRST) + spicr |= SPICR_LSB_FIRST; + if (xilspi->mode & SPI_CPHA) + spicr |= SPICR_CPHA; + if (xilspi->mode & SPI_CPOL) + spicr |= SPICR_CPOL; + if (xilspi->mode & SPI_LOOP) + spicr |= SPICR_LOOP; + + writel(spicr, &xilspi->regs->spicr); + return 0; +} + +void spi_release_bus(struct spi_slave *slave) +{ + struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave); + + debug("%s: bus:%i cs:%i\n", __func__, slave->bus, slave->cs); + writel(SPISSR_OFF, &xilspi->regs->spissr); + writel(XILSPI_SPICR_DFLT_OFF, &xilspi->regs->spicr); +} + +int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout, + void *din, unsigned long flags) +{ + struct xilinx_spi_slave *xilspi = to_xilinx_spi_slave(slave); + /* assume spi core configured to do 8 bit transfers */ + unsigned int bytes = bitlen / XILSPI_MAX_XFER_BITS; + const unsigned char *txp = dout; + unsigned char *rxp = din; + unsigned rxecount = 17; /* max. 16 elements in FIFO, leftover 1 */ + + debug("%s: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n", __func__, + slave->bus, slave->cs, bitlen, bytes, flags); + if (bitlen == 0) + goto done; + + if (bitlen % XILSPI_MAX_XFER_BITS) { + printf("XILSPI warning: %s: Not a multiple of %d bits\n", + __func__, XILSPI_MAX_XFER_BITS); + flags |= SPI_XFER_END; + goto done; + } + + /* empty read buffer */ + while (rxecount && !(readl(&xilspi->regs->spisr) & SPISR_RX_EMPTY)) { + readl(&xilspi->regs->spidrr); + rxecount--; + } + + if (!rxecount) { + printf("XILSPI error: %s: Rx buffer not empty\n", __func__); + return -1; + } + + if (flags & SPI_XFER_BEGIN) + spi_cs_activate(slave); + + while (bytes--) { + unsigned timeout = /* at least 1usec or greater, leftover 1 */ + xilspi->freq > XILSPI_MAX_XFER_BITS * 1000000 ? 2 : + (XILSPI_MAX_XFER_BITS * 1000000 / xilspi->freq) + 1; + + /* get Tx element from data out buffer and count up */ + unsigned char d = txp ? *txp++ : CONFIG_XILINX_SPI_IDLE_VAL; + debug("%s: tx:%x ", __func__, d); + + /* write out and wait for processing (receive data) */ + writel(d & SPIDTR_8BIT_MASK, &xilspi->regs->spidtr); + while (timeout && readl(&xilspi->regs->spisr) + & SPISR_RX_EMPTY) { + timeout--; + udelay(1); + } + + if (!timeout) { + printf("XILSPI error: %s: Xfer timeout\n", __func__); + return -1; + } + + /* read Rx element and push into data in buffer */ + d = readl(&xilspi->regs->spidrr) & SPIDRR_8BIT_MASK; + if (rxp) + *rxp++ = d; + debug("rx:%x\n", d); + } + + done: + if (flags & SPI_XFER_END) + spi_cs_deactivate(slave); + + return 0; +} |