drivers/spi/sandbox_spi.c

/*
 * 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 <dm.h>
#include <malloc.h>
#include <spi.h>
#include <spi_flash.h>
#include <os.h>

#include <asm/errno.h>
#include <asm/spi.h>
#include <asm/state.h>
#include <dm/device-internal.h>

DECLARE_GLOBAL_DATA_PTR;

#ifndef CONFIG_SPI_IDLE_VAL
# define CONFIG_SPI_IDLE_VAL 0xFF
#endif

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;
}

__weak int sandbox_spi_get_emul(struct sandbox_state *state,
				struct udevice *bus, struct udevice *slave,
				struct udevice **emulp)
{
	return -ENOENT;
}

static int sandbox_spi_xfer(struct udevice *slave, unsigned int bitlen,
			    const void *dout, void *din, unsigned long flags)
{
	struct udevice *bus = slave->parent;
	struct sandbox_state *state = state_get_current();
	struct dm_spi_emul_ops *ops;
	struct udevice *emul;
	uint bytes = bitlen / 8, i;
	int ret;
	u8 *tx = (void *)dout, *rx = din;
	uint busnum, cs;

	if (bitlen == 0)
		return 0;

	/* we can only do 8 bit transfers */
	if (bitlen % 8) {
		printf("sandbox_spi: xfer: invalid bitlen size %u; needs to be 8bit\n",
		       bitlen);
		return -EINVAL;
	}

	busnum = bus->seq;
	cs = spi_chip_select(slave);
	if (busnum >= CONFIG_SANDBOX_SPI_MAX_BUS ||
	    cs >= CONFIG_SANDBOX_SPI_MAX_CS) {
		printf("%s: busnum=%u, cs=%u: out of range\n", __func__,
		       busnum, cs);
		return -ENOENT;
	}
	ret = sandbox_spi_get_emul(state, bus, slave, &emul);
	if (ret) {
		printf("%s: busnum=%u, cs=%u: no emulation available (err=%d)\n",
		       __func__, busnum, cs, ret);
		return -ENOENT;
	}
	ret = device_probe(emul);
	if (ret)
		return ret;

	/* 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;
		}
	}

	ops = spi_emul_get_ops(emul);
	ret = ops->xfer(emul, bitlen, dout, din, flags);

	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);

	return ret;
}

static int sandbox_spi_set_speed(struct udevice *bus, uint speed)
{
	return 0;
}

static int sandbox_spi_set_mode(struct udevice *bus, uint mode)
{
	return 0;
}

static int sandbox_cs_info(struct udevice *bus, uint cs,
			   struct spi_cs_info *info)
{
	/* Always allow activity on CS 0 */
	if (cs >= 1)
		return -ENODEV;

	return 0;
}

static const struct dm_spi_ops sandbox_spi_ops = {
	.xfer		= sandbox_spi_xfer,
	.set_speed	= sandbox_spi_set_speed,
	.set_mode	= sandbox_spi_set_mode,
	.cs_info	= sandbox_cs_info,
};

static const struct udevice_id sandbox_spi_ids[] = {
	{ .compatible = "sandbox,spi" },
	{ }
};

U_BOOT_DRIVER(spi_sandbox) = {
	.name	= "spi_sandbox",
	.id	= UCLASS_SPI,
	.of_match = sandbox_spi_ids,
	.per_child_auto_alloc_size	= sizeof(struct spi_slave),
	.ops	= &sandbox_spi_ops,
};