sandbox: spi: Add SPI emulation bus

This adds a SPI framework for people to hook up simulated SPI clients.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 205 insertions, 0 deletions

diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 27902fe..ed4ecd7 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -27,6 +27,7 @@ obj-$(CONFIG_MXC_SPI) += mxc_spi.o
 obj-$(CONFIG_MXS_SPI) += mxs_spi.o
 obj-$(CONFIG_OC_TINY_SPI) += oc_tiny_spi.o
 obj-$(CONFIG_OMAP3_SPI) += omap3_spi.o
+obj-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
 obj-$(CONFIG_SOFT_SPI) += soft_spi.o
 obj-$(CONFIG_SH_SPI) += sh_spi.o
 obj-$(CONFIG_FSL_ESPI) += fsl_espi.o
diff --git a/drivers/spi/sandbox_spi.c b/drivers/spi/sandbox_spi.c
new file mode 100644
index 0000000..7895305
--- /dev/null
+++ b/drivers/spi/sandbox_spi.c
@@ -0,0 +1,204 @@
+/*
+ * 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;
+}