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/*
* 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;
}
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