1 files changed, 93 insertions, 0 deletions
diff --git a/include/hw/ssi.h b/include/hw/ssi.h
new file mode 100644
index 0000000..fdae317
--- /dev/null
+++ b/include/hw/ssi.h
@@ -0,0 +1,93 @@
+/* QEMU Synchronous Serial Interface support.  */
+
+/* In principle SSI is a point-point interface.  As such the qemu
+   implementation has a single slave device on a "bus".
+   However it is fairly common for boards to have multiple slaves
+   connected to a single master, and select devices with an external
+   chip select.  This is implemented in qemu by having an explicit mux device.
+   It is assumed that master and slave are both using the same transfer width.
+   */
+
+#ifndef QEMU_SSI_H
+#define QEMU_SSI_H
+
+#include "hw/qdev.h"
+
+typedef struct SSISlave SSISlave;
+
+#define TYPE_SSI_SLAVE "ssi-slave"
+#define SSI_SLAVE(obj) \
+     OBJECT_CHECK(SSISlave, (obj), TYPE_SSI_SLAVE)
+#define SSI_SLAVE_CLASS(klass) \
+     OBJECT_CLASS_CHECK(SSISlaveClass, (klass), TYPE_SSI_SLAVE)
+#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);
+DeviceState *ssi_create_slave_no_init(SSIBus *bus, const char *name);
+
+/* Master interface.  */
+SSIBus *ssi_create_bus(DeviceState *parent, const char *name);
+
+uint32_t ssi_transfer(SSIBus *bus, uint32_t val);
+
+/* Automatically connect all children nodes a spi controller as slaves */
+void ssi_auto_connect_slaves(DeviceState *parent, qemu_irq *cs_lines,
+                             SSIBus *bus);
+
+/* max111x.c */
+void max111x_set_input(DeviceState *dev, int line, uint8_t value);
+
+#endif