This adds a SPI framework for people to hook up simulated SPI clients.
Signed-off-by: Mike Frysinger vapier@gentoo.org --- v3 - rearchitected on top of state/getopt support
arch/sandbox/include/asm/config.h | 8 ++ arch/sandbox/include/asm/spi.h | 58 ++++++++++++ arch/sandbox/include/asm/state.h | 1 + drivers/spi/Makefile | 1 + drivers/spi/sandbox_spi.c | 186 +++++++++++++++++++++++++++++++++++++ 5 files changed, 254 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/config.h b/arch/sandbox/include/asm/config.h index 2ef0564..a9590bc 100644 --- a/arch/sandbox/include/asm/config.h +++ b/arch/sandbox/include/asm/config.h @@ -23,4 +23,12 @@
#define CONFIG_SANDBOX_ARCH
+/* Used by drivers/spi/sandbox_spi.c */ +#ifndef CONFIG_SANDBOX_SPI_MAX_BUS +#define CONFIG_SANDBOX_SPI_MAX_BUS 1 +#endif +#ifndef CONFIG_SANDBOX_SPI_MAX_CS +#define CONFIG_SANDBOX_SPI_MAX_CS 10 +#endif + #endif diff --git a/arch/sandbox/include/asm/spi.h b/arch/sandbox/include/asm/spi.h new file mode 100644 index 0000000..f96a926 --- /dev/null +++ b/arch/sandbox/include/asm/spi.h @@ -0,0 +1,58 @@ +/* + * 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); +} + +/* + * Extract the bus/cs from the spi spec and return the start of the spi + * client spec. If the bus/cs are invalid for the current config, then + * it returns NULL. + * + * Example: arg="0:1:foo" will set bus to 0, cs to 1, and return "foo" + */ +const char *sb_spi_parse_spec(const char *arg, unsigned long *bus, + unsigned long *cs); + +#endif diff --git a/arch/sandbox/include/asm/state.h b/arch/sandbox/include/asm/state.h index 2b62b46..ea5fbe0 100644 --- a/arch/sandbox/include/asm/state.h +++ b/arch/sandbox/include/asm/state.h @@ -38,6 +38,7 @@ struct sandbox_state { const char *parse_err; /* Error to report from parsing */ int argc; /* Program arguments */ char **argv; + const void *spi[CONFIG_SANDBOX_SPI_MAX_BUS][CONFIG_SANDBOX_SPI_MAX_CS][2]; };
/** 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..bb89c7a --- /dev/null +++ b/drivers/spi/sandbox_spi.c @@ -0,0 +1,186 @@ +/* + * 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> +#include <asm/state.h> + +#ifndef CONFIG_SPI_IDLE_VAL +# define CONFIG_SPI_IDLE_VAL 0xFF +#endif + +struct sb_spi_slave { + struct spi_slave slave; + const struct sb_spi_emu_ops *ops; + void *priv; +}; + +#define to_sb_spi_slave(s) container_of(s, struct sb_spi_slave, slave) + +const char *sb_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 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; + struct sandbox_state *state = state_get_current(); + const char *spec; + + if (!spi_cs_is_valid(bus, cs)) + return NULL; + + sss = malloc(sizeof(*sss)); + if (!sss) + return NULL; + + spec = state->spi[bus][cs][1]; + sss->ops = state->spi[bus][cs][0]; + if (!spec || !sss->ops || sss->ops->setup(&sss->priv, spec)) { + 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[CONFIG_SANDBOX_SPI_MAX_BUS]; + +int spi_claim_bus(struct spi_slave *slave) +{ + if (spi_bus_claim_cnt[slave->bus]++) + printf("sb_spi: error: bus already claimed!\n"); + return 0; +} + +void spi_release_bus(struct spi_slave *slave) +{ + if (--spi_bus_claim_cnt[slave->bus]) + 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; +}