sandbox_spi.c
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/*
* Simulate a SPI port
*
* Copyright (c) 2011-2013 The Chromium OS Authors.
* See file CREDITS for list of people who contributed to this
* project.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <malloc.h>
#include <spi.h>
#include <os.h>
#include <asm/errno.h>
#include <asm/spi.h>
#include <asm/state.h>
#ifndef CONFIG_SPI_IDLE_VAL
# define CONFIG_SPI_IDLE_VAL 0xFF
#endif
struct sandbox_spi_slave {
struct spi_slave slave;
const struct sandbox_spi_emu_ops *ops;
void *priv;
};
#define to_sandbox_spi_slave(s) container_of(s, struct sandbox_spi_slave, slave)
const char *sandbox_spi_parse_spec(const char *arg, unsigned long *bus,
unsigned long *cs)
{
char *endp;
*bus = simple_strtoul(arg, &endp, 0);
if (*endp != ':' || *bus >= CONFIG_SANDBOX_SPI_MAX_BUS)
return NULL;
*cs = simple_strtoul(endp + 1, &endp, 0);
if (*endp != ':' || *cs >= CONFIG_SANDBOX_SPI_MAX_CS)
return NULL;
return endp + 1;
}
int spi_cs_is_valid(unsigned int bus, unsigned int cs)
{
return bus < CONFIG_SANDBOX_SPI_MAX_BUS &&
cs < CONFIG_SANDBOX_SPI_MAX_CS;
}
void spi_cs_activate(struct spi_slave *slave)
{
struct sandbox_spi_slave *sss = to_sandbox_spi_slave(slave);
debug("sandbox_spi: activating CS\n");
if (sss->ops->cs_activate)
sss->ops->cs_activate(sss->priv);
}
void spi_cs_deactivate(struct spi_slave *slave)
{
struct sandbox_spi_slave *sss = to_sandbox_spi_slave(slave);
debug("sandbox_spi: deactivating CS\n");
if (sss->ops->cs_deactivate)
sss->ops->cs_deactivate(sss->priv);
}
void spi_init(void)
{
}
void spi_set_speed(struct spi_slave *slave, uint hz)
{
}
struct spi_slave *spi_setup_slave(unsigned int bus, unsigned int cs,
unsigned int max_hz, unsigned int mode)
{
struct sandbox_spi_slave *sss;
struct sandbox_state *state = state_get_current();
const char *spec;
if (!spi_cs_is_valid(bus, cs)) {
debug("sandbox_spi: Invalid SPI bus/cs\n");
return NULL;
}
sss = spi_alloc_slave(struct sandbox_spi_slave, bus, cs);
if (!sss) {
debug("sandbox_spi: Out of memory\n");
return NULL;
}
spec = state->spi[bus][cs].spec;
sss->ops = state->spi[bus][cs].ops;
if (!spec || !sss->ops || sss->ops->setup(&sss->priv, spec)) {
free(sss);
printf("sandbox_spi: unable to locate a slave client\n");
return NULL;
}
return &sss->slave;
}
void spi_free_slave(struct spi_slave *slave)
{
struct sandbox_spi_slave *sss = to_sandbox_spi_slave(slave);
debug("sandbox_spi: releasing slave\n");
if (sss->ops->free)
sss->ops->free(sss->priv);
free(sss);
}
static int spi_bus_claim_cnt[CONFIG_SANDBOX_SPI_MAX_BUS];
int spi_claim_bus(struct spi_slave *slave)
{
if (spi_bus_claim_cnt[slave->bus]++) {
printf("sandbox_spi: error: bus already claimed: %d!\n",
spi_bus_claim_cnt[slave->bus]);
}
return 0;
}
void spi_release_bus(struct spi_slave *slave)
{
if (--spi_bus_claim_cnt[slave->bus]) {
printf("sandbox_spi: error: bus freed too often: %d!\n",
spi_bus_claim_cnt[slave->bus]);
}
}
int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
void *din, unsigned long flags)
{
struct sandbox_spi_slave *sss = to_sandbox_spi_slave(slave);
uint bytes = bitlen / 8, i;
int ret = 0;
u8 *tx = (void *)dout, *rx = din;
if (bitlen == 0)
goto done;
/* we can only do 8 bit transfers */
if (bitlen % 8) {
printf("sandbox_spi: xfer: invalid bitlen size %u; needs to be 8bit\n",
bitlen);
flags |= SPI_XFER_END;
goto done;
}
if (flags & SPI_XFER_BEGIN)
spi_cs_activate(slave);
/* make sure rx/tx buffers are full so clients can assume */
if (!tx) {
debug("sandbox_spi: xfer: auto-allocating tx scratch buffer\n");
tx = malloc(bytes);
if (!tx) {
debug("sandbox_spi: Out of memory\n");
return -ENOMEM;
}
}
if (!rx) {
debug("sandbox_spi: xfer: auto-allocating rx scratch buffer\n");
rx = malloc(bytes);
if (!rx) {
debug("sandbox_spi: Out of memory\n");
return -ENOMEM;
}
}
debug("sandbox_spi: xfer: bytes = %u\n tx:", bytes);
for (i = 0; i < bytes; ++i)
debug(" %u:%02x", i, tx[i]);
debug("\n");
ret = sss->ops->xfer(sss->priv, tx, rx, bytes);
debug("sandbox_spi: xfer: got back %i (that's %s)\n rx:",
ret, ret ? "bad" : "good");
for (i = 0; i < bytes; ++i)
debug(" %u:%02x", i, rx[i]);
debug("\n");
if (tx != dout)
free(tx);
if (rx != din)
free(rx);
done:
if (flags & SPI_XFER_END)
spi_cs_deactivate(slave);
return ret;
}