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-core.h"
15
16typedef struct SSISlave SSISlave;
17typedef struct SSISlaveClass SSISlaveClass;
18typedef enum SSICSMode SSICSMode;
19
20#define TYPE_SSI_SLAVE "ssi-slave"
21#define SSI_SLAVE(obj) \
22 OBJECT_CHECK(SSISlave, (obj), TYPE_SSI_SLAVE)
23#define SSI_SLAVE_CLASS(klass) \
24 OBJECT_CLASS_CHECK(SSISlaveClass, (klass), TYPE_SSI_SLAVE)
25#define SSI_SLAVE_GET_CLASS(obj) \
26 OBJECT_GET_CLASS(SSISlaveClass, (obj), TYPE_SSI_SLAVE)
27
28#define SSI_GPIO_CS "ssi-gpio-cs"
29
30enum SSICSMode {
31 SSI_CS_NONE = 0,
32 SSI_CS_LOW,
33 SSI_CS_HIGH,
34};
35
36/* Slave devices. */
37struct SSISlaveClass {
38 DeviceClass parent_class;
39
40 void (*realize)(SSISlave *dev, Error **errp);
41
42 /* if you have standard or no CS behaviour, just override transfer.
43 * This is called when the device cs is active (true by default).
44 */
45 uint32_t (*transfer)(SSISlave *dev, uint32_t val);
46 /* called when the CS line changes. Optional, devices only need to implement
47 * this if they have side effects associated with the cs line (beyond
48 * tristating the txrx lines).
49 */
50 int (*set_cs)(SSISlave *dev, bool select);
51 /* define whether or not CS exists and is active low/high */
52 SSICSMode cs_polarity;
53
54 /* if you have non-standard CS behaviour override this to take control
55 * of the CS behaviour at the device level. transfer, set_cs, and
56 * cs_polarity are unused if this is overwritten. Transfer_raw will
57 * always be called for the device for every txrx access to the parent bus
58 */
59 uint32_t (*transfer_raw)(SSISlave *dev, uint32_t val);
60};
61
62struct SSISlave {
63 DeviceState parent_obj;
64
65 /* Chip select state */
66 bool cs;
67};
68
69#define FROM_SSI_SLAVE(type, dev) DO_UPCAST(type, ssidev, dev)
70
71extern const VMStateDescription vmstate_ssi_slave;
72
73#define VMSTATE_SSI_SLAVE(_field, _state) { \
74 .name = (stringify(_field)), \
75 .size = sizeof(SSISlave), \
76 .vmsd = &vmstate_ssi_slave, \
77 .flags = VMS_STRUCT, \
78 .offset = vmstate_offset_value(_state, _field, SSISlave), \
79}
80
81DeviceState *ssi_create_slave(SSIBus *bus, const char *name);
82DeviceState *ssi_create_slave_no_init(SSIBus *bus, const char *name);
83
84/* Master interface. */
85SSIBus *ssi_create_bus(DeviceState *parent, const char *name);
86
87uint32_t ssi_transfer(SSIBus *bus, uint32_t val);
88
89/* Automatically connect all children nodes a spi controller as slaves */
90void ssi_auto_connect_slaves(DeviceState *parent, qemu_irq *cs_lines,
91 SSIBus *bus);
92
93/* max111x.c */
94void max111x_set_input(DeviceState *dev, int line, uint8_t value);
95
96#endif
97