[U-Boot,3/6] sandbox: SPI emulation bus

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

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
---
 arch/sandbox/include/asm/spi.h |   33 +++++++
 drivers/spi/Makefile           |    1 +
 drivers/spi/sandbox_spi.c      |  183 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 217 insertions(+), 0 deletions(-)
 create mode 100644 arch/sandbox/include/asm/spi.h
 create mode 100644 drivers/spi/sandbox_spi.c

Hi Mike,

On Sun, Jan 22, 2012 at 10:30 PM, Mike Frysinger <vapier@gentoo.org> wrote:
> This adds a SPI framework for people to hook up simulated SPI clients.
>
> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
> ---
>  arch/sandbox/include/asm/spi.h |   33 +++++++
>  drivers/spi/Makefile           |    1 +
>  drivers/spi/sandbox_spi.c      |  183 ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 217 insertions(+), 0 deletions(-)
>  create mode 100644 arch/sandbox/include/asm/spi.h
>  create mode 100644 drivers/spi/sandbox_spi.c

I don't know the SPI interface as well as use - might be useful to
have a few comments and debug() things when things go wrong I think.
Please see below for some ideas.

>
> diff --git a/arch/sandbox/include/asm/spi.h b/arch/sandbox/include/asm/spi.h
> new file mode 100644
> index 0000000..082df37
> --- /dev/null
> +++ b/arch/sandbox/include/asm/spi.h
> @@ -0,0 +1,33 @@
> +/*
> + * 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>
> +
> +struct sb_spi_emu_ops {
> +       int (*setup)(void **priv, const char *spec);
> +       void (*free)(void *priv);
> +       void (*cs_activate)(void *priv);
> +       void (*cs_deactivate)(void *priv);
> +       int (*xfer)(void *priv, const u8 *tx, u8 *rx, uint bytes);
> +};

I think this could do with some comments.

> +
> +static inline void sb_spi_tristate(u8 *buf, uint len)

What does this do - comments?

> +{
> +       /*
> +        * XXX: make this into a user config option ?  let them pick
> +        *      whether this is pulled low, or high, or tristates.
> +        */
> +       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..eda0f3e
> --- /dev/null
> +++ b/drivers/spi/sandbox_spi.c
> @@ -0,0 +1,183 @@
> +/*
> + * 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];

blank line?

> +       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);
> +
> +       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);
> +
> +       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)
> +{

Should this store the value somewhere?

> +}
> +
> +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;

Do we want a debug() message for this?

> +
> +       sss->spec = sb_lookup_arg(bus, cs);
> +       if (sb_parse_type(sss)) {
> +               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 sb_spi_slave *sss = to_sb_spi_slave(slave);
> +
> +       if (sss->ops->free)
> +               sss->ops->free(sss->priv);
> +
> +       free(sss);
> +}
> +
> +int spi_claim_bus(struct spi_slave *slave)
> +{

Should we track claim/release for debugging purposes?

> +       return 0;
> +}
> +
> +void spi_release_bus(struct spi_slave *slave)
> +{
> +}
> +
> +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) {
> +               flags |= SPI_XFER_END;
> +               goto done;
> +       }

debug() on these perhaps?

> +
> +       if (flags & SPI_XFER_BEGIN)
> +               spi_cs_activate(slave);
> +
> +       /* make sure rx/tx buffers are full so clients can assume */
> +       if (!tx) {
> +               tx = malloc(bytes);
> +               if (tx)
> +                       memset(tx, CONFIG_SPI_IDLE_VAL, bytes);
> +       }
> +       if (!rx)
> +               rx = malloc(bytes);
> +       if (tx && rx) {
> +               debug("sb_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_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");
> +       }

debug() message if rx / tx is NULL?

> +       if (tx != dout)
> +               free(tx);
> +       if (rx != din)
> +               free(rx);
> +
> + done:
> +       if (flags & SPI_XFER_END)
> +               spi_cs_deactivate(slave);
> +
> +       return ret;
> +}
> --
> 1.7.8.3
>

On Monday 23 January 2012 19:31:23 Simon Glass wrote:
> On Sun, Jan 22, 2012 at 10:30 PM, Mike Frysinger wrote:
> > This adds a SPI framework for people to hook up simulated SPI clients.
> 
> I don't know the SPI interface as well as use - might be useful to
> have a few comments and debug() things when things go wrong I think.
> Please see below for some ideas.

i can add some more

> > +void spi_set_speed(struct spi_slave *slave, uint hz)
> > +{
> 
> Should this store the value somewhere?

it could, but i'm not sure where it'd be used ... i don't want to get into 
simulating the actual line transitions :).  the SID project is for that level 
of craziness:
	http://sourceware.org/sid/

> > +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;
> 
> Do we want a debug() message for this?

for memory failures, i don't generally think so.  for other probe type 
failures, sure.

> > +int spi_claim_bus(struct spi_slave *slave)
> > +{
> 
> Should we track claim/release for debugging purposes?

ah, that'd be good
-mike