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/*
* Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
*
* Driver for SPI controller on DaVinci. Based on atmel_spi.c
* by Atmel Corporation
*
* Copyright (C) 2007 Atmel Corporation
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <spi.h>
#include <malloc.h>
#include <asm/io.h>
#include <asm/arch/hardware.h>
#include "davinci_spi.h"
void spi_init()
{
/* do nothing */
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct davinci_spi_slave *ds;
if (!spi_cs_is_valid(bus, cs))
return NULL;
ds = spi_alloc_slave(struct davinci_spi_slave, bus, cs);
if (!ds)
return NULL;
ds->regs = (struct davinci_spi_regs *)CONFIG_SYS_SPI_BASE;
ds->freq = max_hz;
return &ds->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct davinci_spi_slave *ds = to_davinci_spi(slave);
free(ds);
}
int spi_claim_bus(struct spi_slave *slave)
{
struct davinci_spi_slave *ds = to_davinci_spi(slave);
unsigned int scalar;
/* Enable the SPI hardware */
writel(SPIGCR0_SPIRST_MASK, &ds->regs->gcr0);
udelay(1000);
writel(SPIGCR0_SPIENA_MASK, &ds->regs->gcr0);
/* Set master mode, powered up and not activated */
writel(SPIGCR1_MASTER_MASK | SPIGCR1_CLKMOD_MASK, &ds->regs->gcr1);
/* CS, CLK, SIMO and SOMI are functional pins */
writel((SPIPC0_EN0FUN_MASK | SPIPC0_CLKFUN_MASK |
SPIPC0_DOFUN_MASK | SPIPC0_DIFUN_MASK), &ds->regs->pc0);
/* setup format */
scalar = ((CONFIG_SYS_SPI_CLK / ds->freq) - 1) & 0xFF;
/*
* Use following format:
* character length = 8,
* clock signal delayed by half clk cycle,
* clock low in idle state - Mode 0,
* MSB shifted out first
*/
writel(8 | (scalar << SPIFMT_PRESCALE_SHIFT) |
(1 << SPIFMT_PHASE_SHIFT), &ds->regs->fmt0);
/*
* Including a minor delay. No science here. Should be good even with
* no delay
*/
writel((50 << SPI_C2TDELAY_SHIFT) |
(50 << SPI_T2CDELAY_SHIFT), &ds->regs->delay);
/* default chip select register */
writel(SPIDEF_CSDEF0_MASK, &ds->regs->def);
/* no interrupts */
writel(0, &ds->regs->int0);
writel(0, &ds->regs->lvl);
/* enable SPI */
writel((readl(&ds->regs->gcr1) | SPIGCR1_SPIENA_MASK), &ds->regs->gcr1);
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
struct davinci_spi_slave *ds = to_davinci_spi(slave);
/* Disable the SPI hardware */
writel(SPIGCR0_SPIRST_MASK, &ds->regs->gcr0);
}
/*
* This functions needs to act like a macro to avoid pipeline reloads in the
* loops below. Use always_inline. This gains us about 160KiB/s and the bloat
* appears to be zero bytes (da830).
*/
__attribute__((always_inline))
static inline u32 davinci_spi_xfer_data(struct davinci_spi_slave *ds, u32 data)
{
u32 buf_reg_val;
/* send out data */
writel(data, &ds->regs->dat1);
/* wait for the data to clock in/out */
while ((buf_reg_val = readl(&ds->regs->buf)) & SPIBUF_RXEMPTY_MASK)
;
return buf_reg_val;
}
static int davinci_spi_read(struct spi_slave *slave, unsigned int len,
u8 *rxp, unsigned long flags)
{
struct davinci_spi_slave *ds = to_davinci_spi(slave);
unsigned int data1_reg_val;
/* enable CS hold, CS[n] and clear the data bits */
data1_reg_val = ((1 << SPIDAT1_CSHOLD_SHIFT) |
(slave->cs << SPIDAT1_CSNR_SHIFT));
/* wait till TXFULL is deasserted */
while (readl(&ds->regs->buf) & SPIBUF_TXFULL_MASK)
;
/* preload the TX buffer to avoid clock starvation */
writel(data1_reg_val, &ds->regs->dat1);
/* keep reading 1 byte until only 1 byte left */
while ((len--) > 1)
*rxp++ = davinci_spi_xfer_data(ds, data1_reg_val);
/* clear CS hold when we reach the end */
if (flags & SPI_XFER_END)
data1_reg_val &= ~(1 << SPIDAT1_CSHOLD_SHIFT);
/* read the last byte */
*rxp = davinci_spi_xfer_data(ds, data1_reg_val);
return 0;
}
static int davinci_spi_write(struct spi_slave *slave, unsigned int len,
const u8 *txp, unsigned long flags)
{
struct davinci_spi_slave *ds = to_davinci_spi(slave);
unsigned int data1_reg_val;
/* enable CS hold and clear the data bits */
data1_reg_val = ((1 << SPIDAT1_CSHOLD_SHIFT) |
(slave->cs << SPIDAT1_CSNR_SHIFT));
/* wait till TXFULL is deasserted */
while (readl(&ds->regs->buf) & SPIBUF_TXFULL_MASK)
;
/* preload the TX buffer to avoid clock starvation */
if (len > 2) {
writel(data1_reg_val | *txp++, &ds->regs->dat1);
len--;
}
/* keep writing 1 byte until only 1 byte left */
while ((len--) > 1)
davinci_spi_xfer_data(ds, data1_reg_val | *txp++);
/* clear CS hold when we reach the end */
if (flags & SPI_XFER_END)
data1_reg_val &= ~(1 << SPIDAT1_CSHOLD_SHIFT);
/* write the last byte */
davinci_spi_xfer_data(ds, data1_reg_val | *txp);
return 0;
}
#ifndef CONFIG_SPI_HALF_DUPLEX
static int davinci_spi_read_write(struct spi_slave *slave, unsigned int len,
u8 *rxp, const u8 *txp, unsigned long flags)
{
struct davinci_spi_slave *ds = to_davinci_spi(slave);
unsigned int data1_reg_val;
/* enable CS hold and clear the data bits */
data1_reg_val = ((1 << SPIDAT1_CSHOLD_SHIFT) |
(slave->cs << SPIDAT1_CSNR_SHIFT));
/* wait till TXFULL is deasserted */
while (readl(&ds->regs->buf) & SPIBUF_TXFULL_MASK)
;
/* keep reading and writing 1 byte until only 1 byte left */
while ((len--) > 1)
*rxp++ = davinci_spi_xfer_data(ds, data1_reg_val | *txp++);
/* clear CS hold when we reach the end */
if (flags & SPI_XFER_END)
data1_reg_val &= ~(1 << SPIDAT1_CSHOLD_SHIFT);
/* read and write the last byte */
*rxp = davinci_spi_xfer_data(ds, data1_reg_val | *txp);
return 0;
}
#endif
int spi_xfer(struct spi_slave *slave, unsigned int bitlen,
const void *dout, void *din, unsigned long flags)
{
unsigned int len;
if (bitlen == 0)
/* Finish any previously submitted transfers */
goto out;
/*
* It's not clear how non-8-bit-aligned transfers are supposed to be
* represented as a stream of bytes...this is a limitation of
* the current SPI interface - here we terminate on receiving such a
* transfer request.
*/
if (bitlen % 8) {
/* Errors always terminate an ongoing transfer */
flags |= SPI_XFER_END;
goto out;
}
len = bitlen / 8;
if (!dout)
return davinci_spi_read(slave, len, din, flags);
else if (!din)
return davinci_spi_write(slave, len, dout, flags);
#ifndef CONFIG_SPI_HALF_DUPLEX
else
return davinci_spi_read_write(slave, len, din, dout, flags);
#else
printf("SPI full duplex transaction requested with "
"CONFIG_SPI_HALF_DUPLEX defined.\n");
flags |= SPI_XFER_END;
#endif
out:
if (flags & SPI_XFER_END) {
u8 dummy = 0;
davinci_spi_write(slave, 1, &dummy, flags);
}
return 0;
}
int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
return bus == 0 && cs == 0;
}
void spi_cs_activate(struct spi_slave *slave)
{
/* do nothing */
}
void spi_cs_deactivate(struct spi_slave *slave)
{
/* do nothing */
}
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