This adds a SPI framework for people to hook up simulated SPI clients.
Signed-off-by: Mike Frysinger <vap...@gentoo.org>
---
arch/sandbox/include/asm/spi.h | 48 ++++++++++
drivers/spi/Makefile | 1 +
drivers/spi/sandbox_spi.c | 198 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 247 insertions(+), 0 deletions(-)
create mode 100644 arch/sandbox/include/asm/spi.h
create mode 100644 drivers/spi/sandbox_spi.c
diff --git a/arch/sandbox/include/asm/spi.h b/arch/sandbox/include/asm/spi.h
new file mode 100644
index 0000000..8de19c4
--- /dev/null
+++ b/arch/sandbox/include/asm/spi.h
@@ -0,0 +1,48 @@
+/*
+ * Simulate a SPI port and clients
+ *
+ * Copyright (c) 2011-2012 The Chromium OS Authors.
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#ifndef __ASM_SPI_H__
+#define __ASM_SPI_H__
+
+#include <linux/types.h>
+
+/*
+ * The interface between the SPI bus and the SPI client. The bus will
+ * instantiate a client, and that then call into it via these entry
+ * points. These should be enough for the client to emulate the SPI
+ * device just like the real hardware.
+ */
+struct sb_spi_emu_ops {
+ /* The bus wants to instantiate a new client, so setup everything */
+ int (*setup)(void **priv, const char *spec);
+ /* The bus is done with us, so break things down */
+ void (*free)(void *priv);
+ /* The CS has been "activated" -- we won't worry about low/high */
+ void (*cs_activate)(void *priv);
+ /* The CS has been "deactivated" -- we won't worry about low/high */
+ void (*cs_deactivate)(void *priv);
+ /* The client is rx-ing bytes from the bus, so it should tx some */
+ int (*xfer)(void *priv, const u8 *rx, u8 *tx, uint bytes);
+};
+
+/*
+ * There are times when the data lines are allowed to tristate. What
+ * is actually sensed on the line depends on the hardware. It could
+ * always be 0xFF/0x00 (if there are pull ups/downs), or things could
+ * float and so we'd get garbage back. This func encapsulates that
+ * scenario so we can worry about the details here.
+ */
+static inline void sb_spi_tristate(u8 *buf, uint len)
+{
+ /* XXX: make this into a user config option ? */
+ memset(buf, 0xff, len);
+}
+
+#endif
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index c967d87..d80ff8b 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -40,6 +40,7 @@ COBJS-$(CONFIG_MXC_SPI) += mxc_spi.o
COBJS-$(CONFIG_MXS_SPI) += mxs_spi.o
COBJS-$(CONFIG_OC_TINY_SPI) += oc_tiny_spi.o
COBJS-$(CONFIG_OMAP3_SPI) += omap3_spi.o
+COBJS-$(CONFIG_SANDBOX_SPI) += sandbox_spi.o
COBJS-$(CONFIG_SOFT_SPI) += soft_spi.o
COBJS-$(CONFIG_SH_SPI) += sh_spi.o
COBJS-$(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..d0cba76
--- /dev/null
+++ b/drivers/spi/sandbox_spi.c
@@ -0,0 +1,198 @@
+/*
+ * Simulate a SPI port
+ *
+ * Copyright (c) 2011-2012 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/spi.h>
+
+#ifndef CONFIG_SPI_IDLE_VAL
+# define CONFIG_SPI_IDLE_VAL 0xFF
+#endif
+
+struct sb_spi_slave {
+ struct spi_slave slave;
+ const char *spec;
+ const struct sb_spi_emu_ops *ops;
+ void *priv;
+};
+
+#define to_sb_spi_slave(s) container_of(s, struct sb_spi_slave, slave)
+
+static const char *sb_lookup_arg(unsigned int bus, unsigned int cs)
+{
+ char sf_arg[20];
+ sprintf(sf_arg, "--spi-%u-%u", bus, cs);
+ return os_getopt(sf_arg, 1);
+}
+
+static const struct {
+ const char *spec;
+ const struct sb_spi_emu_ops *ops;
+} sb_emu_map[] = {
+};
+
+static int sb_parse_type(struct sb_spi_slave *sss)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(sb_emu_map); ++i) {
+ size_t len = strlen(sb_emu_map[i].spec);
+ const char *sub_spec = sss->spec + len;
+
+ sss->ops = sb_emu_map[i].ops;
+ if (!memcmp(sss->spec, sb_emu_map[i].spec, len) &&
+ sss->spec[len] == ':')
+ return sss->ops->setup(&sss->priv, sub_spec + 1);
+ }
+
+ return 1;
+}
+
+int spi_cs_is_valid(unsigned int bus, unsigned int cs)
+{
+ return sb_lookup_arg(bus, cs) ? 1 : 0;
+}
+
+void spi_cs_activate(struct spi_slave *slave)
+{
+ struct sb_spi_slave *sss = to_sb_spi_slave(slave);
+
+ debug("sb_spi: activating CS\n");
+ if (sss->ops->cs_activate)
+ sss->ops->cs_activate(sss->priv);
+}
+
+void spi_cs_deactivate(struct spi_slave *slave)
+{
+ struct sb_spi_slave *sss = to_sb_spi_slave(slave);
+
+ debug("sb_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 sb_spi_slave *sss;
+
+ if (!spi_cs_is_valid(bus, cs))
+ return NULL;
+
+ sss = malloc(sizeof(*sss));
+ if (!sss)
+ return NULL;
+
+ sss->spec = sb_lookup_arg(bus, cs);
+ if (sb_parse_type(sss)) {
+ free(sss);
+ printf("sb_spi: unable to locate a slave client\n");
+ return NULL;
+ }
+
+ return &sss->slave;
+}
+
+void spi_free_slave(struct spi_slave *slave)
+{
+ struct sb_spi_slave *sss = to_sb_spi_slave(slave);
+
+ debug("sb_spi: releasing slave\n");
+
+ if (sss->ops->free)
+ sss->ops->free(sss->priv);
+
+ free(sss);
+}
+
+static int spi_bus_claim_cnt;
+
+int spi_claim_bus(struct spi_slave *slave)
+{
+ if (spi_bus_claim_cnt++)
+ printf("sb_spi: error: bus already claimed!\n");
+ return 0;
+}
+
+void spi_release_bus(struct spi_slave *slave)
+{
+ if (--spi_bus_claim_cnt)
+ printf("sb_spi: error: bus freed too often!\n");
+}
+
+int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
+ void *din, unsigned long flags)
+{
+ struct sb_spi_slave *sss = to_sb_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("sb_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("sb_spi: xfer: auto-allocating tx scratch buffer\n");
+ tx = malloc(bytes);
+ if (tx)
+ memset(tx, CONFIG_SPI_IDLE_VAL, bytes);
+ }
+ if (!rx) {
+ debug("sb_spi: xfer: auto-allocating rx scratch buffer\n");
+ rx = malloc(bytes);
+ }
+ if (tx && rx) {
+ debug("sb_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("sb_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;
+}
--
1.7.8.4
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