LXR qemu/include/hw/ssi.h

   1/* QEMU Synchronous Serial Interface support.  */
   2
   3/* In principle SSI is a point-point interface.  As such the qemu
   4   implementation has a single slave device on a "bus".
   5   However it is fairly common for boards to have multiple slaves
   6   connected to a single master, and select devices with an external
   7   chip select.  This is implemented in qemu by having an explicit mux device.
   8   It is assumed that master and slave are both using the same transfer width.
   9   */
  10
  11#ifndef QEMU_SSI_H
  12#define QEMU_SSI_H
  13
  14#include "hw/qdev.h"
  15
  16typedef struct SSISlave SSISlave;
  17
  18#define TYPE_SSI_SLAVE "ssi-slave"
  19#define SSI_SLAVE(obj) \
  20     OBJECT_CHECK(SSISlave, (obj), TYPE_SSI_SLAVE)
  21#define SSI_SLAVE_CLASS(klass) \
  22     OBJECT_CLASS_CHECK(SSISlaveClass, (klass), TYPE_SSI_SLAVE)
  23#define SSI_SLAVE_GET_CLASS(obj) \
  24     OBJECT_GET_CLASS(SSISlaveClass, (obj), TYPE_SSI_SLAVE)
  25
  26#define SSI_GPIO_CS "ssi-gpio-cs"
  27
  28typedef enum {
  29    SSI_CS_NONE = 0,
  30    SSI_CS_LOW,
  31    SSI_CS_HIGH,
  32} SSICSMode;
  33
  34/* Slave devices.  */
  35typedef struct SSISlaveClass {
  36    DeviceClass parent_class;
  37
  38    int (*init)(SSISlave *dev);
  39
  40    /* if you have standard or no CS behaviour, just override transfer.
  41     * This is called when the device cs is active (true by default).
  42     */
  43    uint32_t (*transfer)(SSISlave *dev, uint32_t val);
  44    /* called when the CS line changes. Optional, devices only need to implement
  45     * this if they have side effects associated with the cs line (beyond
  46     * tristating the txrx lines).
  47     */
  48    int (*set_cs)(SSISlave *dev, bool select);
  49    /* define whether or not CS exists and is active low/high */
  50    SSICSMode cs_polarity;
  51
  52    /* if you have non-standard CS behaviour override this to take control
  53     * of the CS behaviour at the device level. transfer, set_cs, and
  54     * cs_polarity are unused if this is overwritten. Transfer_raw will
  55     * always be called for the device for every txrx access to the parent bus
  56     */
  57    uint32_t (*transfer_raw)(SSISlave *dev, uint32_t val);
  58} SSISlaveClass;
  59
  60struct SSISlave {
  61    DeviceState parent_obj;
  62
  63    /* Chip select state */
  64    bool cs;
  65};
  66
  67#define FROM_SSI_SLAVE(type, dev) DO_UPCAST(type, ssidev, dev)
  68
  69extern const VMStateDescription vmstate_ssi_slave;
  70
  71#define VMSTATE_SSI_SLAVE(_field, _state) {                          \
  72    .name       = (stringify(_field)),                               \
  73    .size       = sizeof(SSISlave),                                  \
  74    .vmsd       = &vmstate_ssi_slave,                                \
  75    .flags      = VMS_STRUCT,                                        \
  76    .offset     = vmstate_offset_value(_state, _field, SSISlave),    \
  77}
  78
  79DeviceState *ssi_create_slave(SSIBus *bus, const char *name);
  80DeviceState *ssi_create_slave_no_init(SSIBus *bus, const char *name);
  81
  82/* Master interface.  */
  83SSIBus *ssi_create_bus(DeviceState *parent, const char *name);
  84
  85uint32_t ssi_transfer(SSIBus *bus, uint32_t val);
  86
  87/* Automatically connect all children nodes a spi controller as slaves */
  88void ssi_auto_connect_slaves(DeviceState *parent, qemu_irq *cs_lines,
  89                             SSIBus *bus);
  90
  91/* max111x.c */
  92void max111x_set_input(DeviceState *dev, int line, uint8_t value);
  93
  94#endif
  95