u-boot/drivers/spi/davinci_spi.c
Jagan Teki ff6e31d3a1 spi: davinci_spi: Driver cleanup
Arrange driver code in more readable format[1] for easy accessing
and readable.
[1] http://patchwork.ozlabs.org/patch/265683/

Signed-off-by: Jagan Teki <jteki@openedev.com>
Cc: Rex Chang <rchang@ti.com>
Cc: Murali Karicheri <m-karicheri2@ti.com>
2015-07-01 21:15:03 +05:30

430 lines
10 KiB
C

/*
* 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>
#define BIT(x) (1 << (x))
/* SPIGCR0 */
#define SPIGCR0_SPIENA_MASK 0x1
#define SPIGCR0_SPIRST_MASK 0x0
/* SPIGCR0 */
#define SPIGCR1_CLKMOD_MASK BIT(1)
#define SPIGCR1_MASTER_MASK BIT(0)
#define SPIGCR1_SPIENA_MASK BIT(24)
/* SPIPC0 */
#define SPIPC0_DIFUN_MASK BIT(11) /* SIMO */
#define SPIPC0_DOFUN_MASK BIT(10) /* SOMI */
#define SPIPC0_CLKFUN_MASK BIT(9) /* CLK */
#define SPIPC0_EN0FUN_MASK BIT(0)
/* SPIFMT0 */
#define SPIFMT_SHIFTDIR_SHIFT 20
#define SPIFMT_POLARITY_SHIFT 17
#define SPIFMT_PHASE_SHIFT 16
#define SPIFMT_PRESCALE_SHIFT 8
/* SPIDAT1 */
#define SPIDAT1_CSHOLD_SHIFT 28
#define SPIDAT1_CSNR_SHIFT 16
/* SPIDELAY */
#define SPI_C2TDELAY_SHIFT 24
#define SPI_T2CDELAY_SHIFT 16
/* SPIBUF */
#define SPIBUF_RXEMPTY_MASK BIT(31)
#define SPIBUF_TXFULL_MASK BIT(29)
/* SPIDEF */
#define SPIDEF_CSDEF0_MASK BIT(0)
#define SPI0_BUS 0
#define SPI0_BASE CONFIG_SYS_SPI_BASE
/*
* Define default SPI0_NUM_CS as 1 for existing platforms that uses this
* driver. Platform can configure number of CS using CONFIG_SYS_SPI0_NUM_CS
* if more than one CS is supported and by defining CONFIG_SYS_SPI0.
*/
#ifndef CONFIG_SYS_SPI0
#define SPI0_NUM_CS 1
#else
#define SPI0_NUM_CS CONFIG_SYS_SPI0_NUM_CS
#endif
/*
* define CONFIG_SYS_SPI1 when platform has spi-1 device (bus #1) and
* CONFIG_SYS_SPI1_NUM_CS defines number of CS on this bus
*/
#ifdef CONFIG_SYS_SPI1
#define SPI1_BUS 1
#define SPI1_NUM_CS CONFIG_SYS_SPI1_NUM_CS
#define SPI1_BASE CONFIG_SYS_SPI1_BASE
#endif
/*
* define CONFIG_SYS_SPI2 when platform has spi-2 device (bus #2) and
* CONFIG_SYS_SPI2_NUM_CS defines number of CS on this bus
*/
#ifdef CONFIG_SYS_SPI2
#define SPI2_BUS 2
#define SPI2_NUM_CS CONFIG_SYS_SPI2_NUM_CS
#define SPI2_BASE CONFIG_SYS_SPI2_BASE
#endif
/* davinci spi register set */
struct davinci_spi_regs {
dv_reg gcr0; /* 0x00 */
dv_reg gcr1; /* 0x04 */
dv_reg int0; /* 0x08 */
dv_reg lvl; /* 0x0c */
dv_reg flg; /* 0x10 */
dv_reg pc0; /* 0x14 */
dv_reg pc1; /* 0x18 */
dv_reg pc2; /* 0x1c */
dv_reg pc3; /* 0x20 */
dv_reg pc4; /* 0x24 */
dv_reg pc5; /* 0x28 */
dv_reg rsvd[3];
dv_reg dat0; /* 0x38 */
dv_reg dat1; /* 0x3c */
dv_reg buf; /* 0x40 */
dv_reg emu; /* 0x44 */
dv_reg delay; /* 0x48 */
dv_reg def; /* 0x4c */
dv_reg fmt0; /* 0x50 */
dv_reg fmt1; /* 0x54 */
dv_reg fmt2; /* 0x58 */
dv_reg fmt3; /* 0x5c */
dv_reg intvec0; /* 0x60 */
dv_reg intvec1; /* 0x64 */
};
/* davinci spi slave */
struct davinci_spi_slave {
struct spi_slave slave;
struct davinci_spi_regs *regs;
unsigned int freq;
};
static inline struct davinci_spi_slave *to_davinci_spi(struct spi_slave *slave)
{
return container_of(slave, struct davinci_spi_slave, slave);
}
/*
* 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_cs_is_valid(unsigned int bus, unsigned int cs)
{
int ret = 0;
switch (bus) {
case SPI0_BUS:
if (cs < SPI0_NUM_CS)
ret = 1;
break;
#ifdef CONFIG_SYS_SPI1
case SPI1_BUS:
if (cs < SPI1_NUM_CS)
ret = 1;
break;
#endif
#ifdef CONFIG_SYS_SPI2
case SPI2_BUS:
if (cs < SPI2_NUM_CS)
ret = 1;
break;
#endif
default:
/* Invalid bus number. Do nothing */
break;
}
return ret;
}
void spi_cs_activate(struct spi_slave *slave)
{
/* do nothing */
}
void spi_cs_deactivate(struct spi_slave *slave)
{
/* do nothing */
}
void spi_init(void)
{
/* 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;
switch (bus) {
case SPI0_BUS:
ds->regs = (struct davinci_spi_regs *)SPI0_BASE;
break;
#ifdef CONFIG_SYS_SPI1
case SPI1_BUS:
ds->regs = (struct davinci_spi_regs *)SPI1_BASE;
break;
#endif
#ifdef CONFIG_SYS_SPI2
case SPI2_BUS:
ds->regs = (struct davinci_spi_regs *)SPI2_BASE;
break;
#endif
default: /* Invalid bus number */
return NULL;
}
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(((1 << slave->cs) | 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);
}
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;
}