From 66530953319427d7c67a723076acd68075dc7db2 Mon Sep 17 00:00:00 2001 From: "Peter A. G. Crosthwaite" Date: Tue, 24 Jul 2012 12:23:22 +1000 Subject: ssi: Implemented CS behaviour Added default CS behaviour for SSI slaves. SSI devices can set a property to enable CS behaviour which will create a GPIO on the device which is the CS. Tristating of the bus on SSI transfers is implemented. Signed-off-by: Peter A. G. Crosthwaite Acked-by: Peter Maydell --- hw/ssi.h | 37 +++++++++++++++++++++++++++++++++++++ 1 file changed, 37 insertions(+) (limited to 'hw/ssi.h') diff --git a/hw/ssi.h b/hw/ssi.h index 06657d7..65b159d 100644 --- a/hw/ssi.h +++ b/hw/ssi.h @@ -23,21 +23,58 @@ typedef struct SSISlave SSISlave; #define SSI_SLAVE_GET_CLASS(obj) \ OBJECT_GET_CLASS(SSISlaveClass, (obj), TYPE_SSI_SLAVE) +typedef enum { + SSI_CS_NONE = 0, + SSI_CS_LOW, + SSI_CS_HIGH, +} SSICSMode; + /* Slave devices. */ typedef struct SSISlaveClass { DeviceClass parent_class; int (*init)(SSISlave *dev); + + /* if you have standard or no CS behaviour, just override transfer. + * This is called when the device cs is active (true by default). + */ uint32_t (*transfer)(SSISlave *dev, uint32_t val); + /* called when the CS line changes. Optional, devices only need to implement + * this if they have side effects associated with the cs line (beyond + * tristating the txrx lines). + */ + int (*set_cs)(SSISlave *dev, bool select); + /* define whether or not CS exists and is active low/high */ + SSICSMode cs_polarity; + + /* if you have non-standard CS behaviour override this to take control + * of the CS behaviour at the device level. transfer, set_cs, and + * cs_polarity are unused if this is overwritten. Transfer_raw will + * always be called for the device for every txrx access to the parent bus + */ + uint32_t (*transfer_raw)(SSISlave *dev, uint32_t val); } SSISlaveClass; struct SSISlave { DeviceState qdev; + + /* Chip select state */ + bool cs; }; #define SSI_SLAVE_FROM_QDEV(dev) DO_UPCAST(SSISlave, qdev, dev) #define FROM_SSI_SLAVE(type, dev) DO_UPCAST(type, ssidev, dev) +extern const VMStateDescription vmstate_ssi_slave; + +#define VMSTATE_SSI_SLAVE(_field, _state) { \ + .name = (stringify(_field)), \ + .size = sizeof(SSISlave), \ + .vmsd = &vmstate_ssi_slave, \ + .flags = VMS_STRUCT, \ + .offset = vmstate_offset_value(_state, _field, SSISlave), \ +} + DeviceState *ssi_create_slave(SSIBus *bus, const char *name); /* Master interface. */ -- cgit v1.1