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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (c) 2006 Ben Warren, Qstreams Networks Inc.
* With help from the common/soft_spi and arch/powerpc/cpu/mpc8260 drivers
*/
#include <common.h>
#include <malloc.h>
#include <spi.h>
#include <asm/mpc8xxx_spi.h>
enum {
SPI_EV_NE = BIT(31 - 22), /* Receiver Not Empty */
SPI_EV_NF = BIT(31 - 23), /* Transmitter Not Full */
};
enum {
SPI_MODE_LOOP = BIT(31 - 1), /* Loopback mode */
SPI_MODE_CI = BIT(31 - 2), /* Clock invert */
SPI_MODE_CP = BIT(31 - 3), /* Clock phase */
SPI_MODE_DIV16 = BIT(31 - 4), /* Divide clock source by 16 */
SPI_MODE_REV = BIT(31 - 5), /* Reverse mode - MSB first */
SPI_MODE_MS = BIT(31 - 6), /* Always master */
SPI_MODE_EN = BIT(31 - 7), /* Enable interface */
SPI_MODE_LEN_MASK = 0xf00000,
SPI_MODE_PM_MASK = 0xf0000,
SPI_COM_LST = BIT(31 - 9),
};
static inline u32 to_prescale_mod(u32 val)
{
return (min(val, (u32)15) << 16);
}
static void set_char_len(spi8xxx_t *spi, u32 val)
{
clrsetbits_be32(&spi->mode, SPI_MODE_LEN_MASK, (val << 20));
}
#define SPI_TIMEOUT 1000
struct spi_slave *spi_setup_slave(uint bus, uint cs, uint max_hz, uint mode)
{
struct spi_slave *slave;
if (!spi_cs_is_valid(bus, cs))
return NULL;
slave = spi_alloc_slave_base(bus, cs);
if (!slave)
return NULL;
/*
* TODO: Some of the code in spi_init() should probably move
* here, or into spi_claim_bus() below.
*/
return slave;
}
void spi_free_slave(struct spi_slave *slave)
{
free(slave);
}
void spi_init(void)
{
spi8xxx_t *spi = &((immap_t *)(CONFIG_SYS_IMMR))->spi;
/*
* SPI pins on the MPC83xx are not muxed, so all we do is initialize
* some registers
*/
out_be32(&spi->mode, SPI_MODE_REV | SPI_MODE_MS | SPI_MODE_EN);
/* Use SYSCLK / 8 (16.67MHz typ.) */
clrsetbits_be32(&spi->mode, SPI_MODE_PM_MASK, to_prescale_mod(1));
/* Clear all SPI events */
setbits_be32(&spi->event, 0xffffffff);
/* Mask all SPI interrupts */
clrbits_be32(&spi->mask, 0xffffffff);
/* LST bit doesn't do anything, so disregard */
out_be32(&spi->com, 0);
}
int spi_claim_bus(struct spi_slave *slave)
{
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
}
int spi_xfer(struct spi_slave *slave, uint bitlen, const void *dout, void *din,
ulong flags)
{
spi8xxx_t *spi = &((immap_t *)(CONFIG_SYS_IMMR))->spi;
u32 tmpdin;
int num_blks = DIV_ROUND_UP(bitlen, 32);
debug("%s: slave %u:%u dout %08X din %08X bitlen %u\n", __func__,
slave->bus, slave->cs, *(uint *)dout, *(uint *)din, bitlen);
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(slave);
/* Clear all SPI events */
setbits_be32(&spi->event, 0xffffffff);
/* Handle data in 32-bit chunks */
while (num_blks--) {
u32 tmpdout = 0;
uchar xfer_bitlen = (bitlen >= 32 ? 32 : bitlen);
ulong start;
clrbits_be32(&spi->mode, SPI_MODE_EN);
/* Set up length for this transfer */
if (bitlen <= 4) /* 4 bits or less */
set_char_len(spi, 3);
else if (bitlen <= 16) /* at most 16 bits */
set_char_len(spi, bitlen - 1);
else /* more than 16 bits -> full 32 bit transfer */
set_char_len(spi, 0);
setbits_be32(&spi->mode, SPI_MODE_EN);
/* Shift data so it's msb-justified */
tmpdout = *(u32 *)dout >> (32 - xfer_bitlen);
if (bitlen > 32) {
/* Set up the next iteration if sending > 32 bits */
bitlen -= 32;
dout += 4;
}
/* Write the data out */
out_be32(&spi->tx, tmpdout);
debug("*** %s: ... %08x written\n", __func__, tmpdout);
/*
* Wait for SPI transmit to get out
* or time out (1 second = 1000 ms)
* The NE event must be read and cleared first
*/
start = get_timer(0);
do {
u32 event = in_be32(&spi->event);
bool have_ne = event & SPI_EV_NE;
bool have_nf = event & SPI_EV_NF;
if (!have_ne)
continue;
tmpdin = in_be32(&spi->rx);
setbits_be32(&spi->event, SPI_EV_NE);
*(u32 *)din = (tmpdin << (32 - xfer_bitlen));
if (xfer_bitlen == 32) {
/* Advance output buffer by 32 bits */
din += 4;
}
/*
* Only bail when we've had both NE and NF events.
* This will cause timeouts on RO devices, so maybe
* in the future put an arbitrary delay after writing
* the device. Arbitrary delays suck, though...
*/
if (have_nf)
break;
mdelay(1);
} while (get_timer(start) < SPI_TIMEOUT);
if (get_timer(start) >= SPI_TIMEOUT)
debug("*** %s: Time out during SPI transfer\n",
__func__);
debug("*** %s: transfer ended. Value=%08x\n", __func__, tmpdin);
}
if (flags & SPI_XFER_END)
spi_cs_deactivate(slave);
return 0;
}
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