Re: [Qemu-devel] [PATCH 06/14] stellaris: Removed SSI mux

[Peter Maydell <peter.maydell@linaro.org>]

On 5 October 2012 01:08, Peter Crosthwaite
<peter.crosthwaite@petalogix.com> wrote:
> From: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
>
> Removed the explicit SSI mux and wired the CS line directly up to the SSI
> devices.
>
> Signed-off-by: Peter A. G. Crosthwaite <peter.crosthwaite@petalogix.com>
> ---
>  hw/ssd0323.c   |    1 +
>  hw/ssi-sd.c    |    1 +
>  hw/stellaris.c |   98 ++++++++++----------------------------------------------
>  3 files changed, 19 insertions(+), 81 deletions(-)
>
> diff --git a/hw/ssd0323.c b/hw/ssd0323.c
> index 5d05a35..9c42d64 100644
> --- a/hw/ssd0323.c
> +++ b/hw/ssd0323.c
> @@ -354,6 +354,7 @@ static void ssd0323_class_init(ObjectClass *klass, void *data)
>
>      k->init = ssd0323_init;
>      k->transfer = ssd0323_transfer;
> +    k->cs_polarity = SSI_CS_HIGH;
>  }
>
>  static TypeInfo ssd0323_info = {
> diff --git a/hw/ssi-sd.c b/hw/ssi-sd.c
> index cbbc645..c5505ee 100644
> --- a/hw/ssi-sd.c
> +++ b/hw/ssi-sd.c
> @@ -256,6 +256,7 @@ static void ssi_sd_class_init(ObjectClass *klass, void *data)
>
>      k->init = ssi_sd_init;
>      k->transfer = ssi_sd_transfer;
> +    k->cs_polarity = SSI_CS_LOW;
>  }
>
>  static TypeInfo ssi_sd_info = {
> diff --git a/hw/stellaris.c b/hw/stellaris.c
> index a7b68f4..acb297b 100644
> --- a/hw/stellaris.c
> +++ b/hw/stellaris.c
> @@ -1154,58 +1154,6 @@ static int stellaris_adc_init(SysBusDevice *dev)
>      return 0;
>  }
>
> -/* Some boards have both an OLED controller and SD card connected to
> -   the same SSI port, with the SD card chip select connected to a
> -   GPIO pin.  Technically the OLED chip select is connected to the SSI
> -   Fss pin.  We do not bother emulating that as both devices should
> -   never be selected simultaneously, and our OLED controller ignores stray
> -   0xff commands that occur when deselecting the SD card.  */
> -
> -typedef struct {
> -    SSISlave ssidev;
> -    qemu_irq irq;
> -    int current_dev;
> -    SSIBus *bus[2];
> -} stellaris_ssi_bus_state;
> -
> -static void stellaris_ssi_bus_select(void *opaque, int irq, int level)
> -{
> -    stellaris_ssi_bus_state *s = (stellaris_ssi_bus_state *)opaque;
> -
> -    s->current_dev = level;
> -}
> -
> -static uint32_t stellaris_ssi_bus_transfer(SSISlave *dev, uint32_t val)
> -{
> -    stellaris_ssi_bus_state *s = FROM_SSI_SLAVE(stellaris_ssi_bus_state, dev);
> -
> -    return ssi_transfer(s->bus[s->current_dev], val);
> -}
> -
> -static const VMStateDescription vmstate_stellaris_ssi_bus = {
> -    .name = "stellaris_ssi_bus",
> -    .version_id = 2,
> -    .minimum_version_id = 2,
> -    .minimum_version_id_old = 2,
> -    .fields      = (VMStateField[]) {
> -        VMSTATE_SSI_SLAVE(ssidev, stellaris_ssi_bus_state),
> -        VMSTATE_INT32(current_dev, stellaris_ssi_bus_state),
> -        VMSTATE_END_OF_LIST()
> -    }
> -};
> -
> -static int stellaris_ssi_bus_init(SSISlave *dev)
> -{
> -    stellaris_ssi_bus_state *s = FROM_SSI_SLAVE(stellaris_ssi_bus_state, dev);
> -
> -    s->bus[0] = ssi_create_bus(&dev->qdev, "ssi0");
> -    s->bus[1] = ssi_create_bus(&dev->qdev, "ssi1");
> -    qdev_init_gpio_in(&dev->qdev, stellaris_ssi_bus_select, 1);
> -
> -    vmstate_register(&dev->qdev, -1, &vmstate_stellaris_ssi_bus, s);
> -    return 0;
> -}
> -
>  /* Board init.  */
>  static stellaris_board_info stellaris_boards[] = {
>    { "LM3S811EVB",
> @@ -1306,29 +1254,33 @@ static void stellaris_init(const char *kernel_filename, const char *cpu_model,
>      if (board->dc2 & (1 << 4)) {
>          dev = sysbus_create_simple("pl022", 0x40008000, pic[7]);
>          if (board->peripherals & BP_OLED_SSI) {
> -            DeviceState *mux;
>              void *bus;
> -            qemu_irq select_pin;
>
> +            /* Some boards have both an OLED controller and SD card connected to
> +             * the same SSI port, with the SD card chip select connected to a
> +             * GPIO pin.  Technically the OLED chip select is connected to the
> +             * SSI Fss pin.  We do not bother emulating that as both devices
> +             * should never be selected simultaneously, and our OLED controller
> +             * ignores stray 0xff commands that occur when deselecting the SD
> +             * card.
> +             */
>              bus = qdev_get_child_bus(dev, "ssi");
> -            mux = ssi_create_slave(bus, "evb6965-ssi");
> -            select_pin = qdev_get_gpio_in(mux, 0);
> +
> +            dev = ssi_create_slave(bus, "ssi-sd");
>              if (gpio_dev[GPIO_D]) {
> -                qdev_connect_gpio_out(gpio_dev[GPIO_D], 0, select_pin);
> +                qdev_connect_gpio_out(gpio_dev[GPIO_D], 0,
> +                                        qdev_get_gpio_in(dev, 0));
>              }
>
> -            bus = qdev_get_child_bus(mux, "ssi0");
> -            ssi_create_slave(bus, "ssi-sd");
> -
> -            bus = qdev_get_child_bus(mux, "ssi1");
>              dev = ssi_create_slave(bus, "ssd0323");
> +            if (gpio_dev[GPIO_D]) {
> +                qdev_connect_gpio_out(gpio_dev[GPIO_D], 0,
> +                                        qdev_get_gpio_in(dev, 0));
> +            }

...this seems to be trying to wire up two devices to the same
GPIO output ?

-- PMM