[Qemu-devel] [PATCH 1/8] Introduce AUX bus.

[fred.konrad@greensocs.com]

From: KONRAD Frederic <fred.konrad@greensocs.com>

This introduces a new bus: aux-bus.

It contains an address space for aux slaves devices and a bridge to an I2C bus
for I2C through AUX transactions.

Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
---
 hw/misc/Makefile.objs |   1 +
 hw/misc/aux.c         | 421 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/aux.h      | 127 +++++++++++++++
 3 files changed, 549 insertions(+)
 create mode 100644 hw/misc/aux.c
 create mode 100644 include/hw/aux.h

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index 4aa76ff..61eb59b 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -40,3 +40,4 @@ obj-$(CONFIG_STM32F2XX_SYSCFG) += stm32f2xx_syscfg.o
 
 obj-$(CONFIG_PVPANIC) += pvpanic.o
 obj-$(CONFIG_EDU) += edu.o
+obj-y += aux.o
diff --git a/hw/misc/aux.c b/hw/misc/aux.c
new file mode 100644
index 0000000..ad64acd
--- /dev/null
+++ b/hw/misc/aux.c
@@ -0,0 +1,421 @@
+/*
+ * aux.c
+ *
+ *  Copyright 2015 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Developed by :
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option)any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+/*
+ * This is an implementation of the AUX bus for VESA Display Port v1.1a.
+ */
+
+#include "hw/aux.h"
+#include "hw/i2c/i2c.h"
+#include "monitor/monitor.h"
+
+/* #define DEBUG_AUX */
+
+#ifdef DEBUG_AUX
+#define DPRINTF(fmt, ...)\
+do { printf("aux: " fmt , ## __VA_ARGS__); } while (0)
+#else
+#define DPRINTF(fmt, ...)do {} while (0)
+#endif
+
+#define TYPE_AUXTOI2C "aux-to-i2c-bridge"
+#define AUXTOI2C(obj) OBJECT_CHECK(AUXTOI2CState, (obj), TYPE_AUXTOI2C)
+
+typedef struct AUXTOI2CState AUXTOI2CState;
+
+struct AUXBus {
+    BusState qbus;
+    AUXSlave *current_dev;
+    AUXSlave *dev;
+    uint32_t last_i2c_address;
+    aux_command last_transaction;
+
+    AUXTOI2CState *bridge;
+
+    MemoryRegion *aux_io;
+    AddressSpace aux_addr_space;
+};
+
+static Property aux_props[] = {
+    DEFINE_PROP_UINT64("address", struct AUXSlave, address, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+#define TYPE_AUX_BUS "aux-bus"
+#define AUX_BUS(obj) OBJECT_CHECK(AUXBus, (obj), TYPE_AUX_BUS)
+
+static void aux_slave_dev_print(Monitor *mon, DeviceState *dev, int indent);
+
+static void aux_bus_class_init(ObjectClass *klass, void *data)
+{
+    /*
+     * AUXSlave has an mmio so we need to change the way we print information
+     * in monitor.
+     */
+    BusClass *k = BUS_CLASS(klass);
+    k->print_dev = aux_slave_dev_print;
+}
+
+static const TypeInfo aux_bus_info = {
+    .name = TYPE_AUX_BUS,
+    .parent = TYPE_BUS,
+    .instance_size = sizeof(AUXBus),
+    .class_init = aux_bus_class_init
+};
+
+AUXBus *aux_init_bus(DeviceState *parent, const char *name)
+{
+    AUXBus *bus;
+
+    bus = AUX_BUS(qbus_create(TYPE_AUX_BUS, parent, name));
+
+    /*
+     * Create the bridge.
+     */
+    bus->bridge = AUXTOI2C(qdev_create(BUS(bus), TYPE_AUXTOI2C));
+
+    /*
+     * Memory related.
+     */
+    bus->aux_io = g_malloc(sizeof(*bus->aux_io));
+    memory_region_init(bus->aux_io, OBJECT(bus), "aux-io", (1 << 20));
+    address_space_init(&bus->aux_addr_space, bus->aux_io, "aux-io");
+    return bus;
+}
+
+static void aux_bus_map_device(AUXBus *bus, AUXSlave *dev)
+{
+    memory_region_add_subregion(bus->aux_io, dev->address, dev->mmio);
+}
+
+void aux_set_slave_address(AUXSlave *dev, uint32_t address)
+{
+    qdev_prop_set_uint64(DEVICE(dev), "address", address);
+}
+
+static bool aux_bus_is_bridge(AUXBus *bus, DeviceState *dev)
+{
+    return (dev == DEVICE(bus->bridge));
+}
+
+/*
+ * Make a native request on the AUX bus.
+ */
+static aux_reply aux_native_request(AUXBus *bus, aux_command cmd,
+                                    uint32_t address, uint8_t len,
+                                    uint8_t *data)
+{
+    /*
+     * Transactions on aux address map are 1bytes len time.
+     */
+    aux_reply ret = AUX_NACK;
+    size_t i;
+
+    switch (cmd) {
+    case READ_AUX:
+        for (i = 0; i < len; i++) {
+            if (!address_space_rw(&bus->aux_addr_space, address++,
+                                  MEMTXATTRS_UNSPECIFIED, data++, 1, false)) {
+                ret = AUX_I2C_ACK;
+            } else {
+                ret = AUX_NACK;
+                break;
+            }
+        }
+    break;
+    case WRITE_AUX:
+        for (i = 0; i < len; i++) {
+            if (!address_space_rw(&bus->aux_addr_space, address++,
+                                  MEMTXATTRS_UNSPECIFIED, data++, 1, true)) {
+                ret = AUX_I2C_ACK;
+            } else {
+                ret = AUX_NACK;
+                break;
+            }
+        }
+    break;
+    default:
+        abort();
+    break;
+    }
+
+    return ret;
+}
+
+aux_reply aux_request(AUXBus *bus, aux_command cmd, uint32_t address,
+                      uint8_t len, uint8_t *data)
+{
+    DPRINTF("request at address 0x%5.5X, command %u, len %u\n", address, cmd,
+            len);
+
+    int temp;
+    aux_reply ret = AUX_NACK;
+    I2CBus *i2c_bus = aux_get_i2c_bus(bus);
+
+    switch (cmd) {
+    /*
+     * Forward the request on the AUX bus..
+     */
+    case WRITE_AUX:
+    case READ_AUX:
+        ret = aux_native_request(bus, cmd, address, len, data);
+    break;
+    /*
+     * Classic I2C transactions..
+     */
+    case READ_I2C:
+        if (i2c_bus_busy(i2c_bus)) {
+            i2c_end_transfer(i2c_bus);
+        }
+
+        if (i2c_start_transfer(i2c_bus, address, 1)) {
+            ret = AUX_I2C_NACK;
+            break;
+        }
+
+        while (len > 0) {
+            temp = i2c_recv(i2c_bus);
+
+            if (temp < 0) {
+                ret = AUX_I2C_NACK;
+                i2c_end_transfer(i2c_bus);
+                break;
+            }
+
+            *data++ = temp;
+            len--;
+        }
+        i2c_end_transfer(i2c_bus);
+        ret = AUX_I2C_ACK;
+    break;
+    case WRITE_I2C:
+        if (i2c_bus_busy(i2c_bus)) {
+            i2c_end_transfer(i2c_bus);
+        }
+
+        if (i2c_start_transfer(i2c_bus, address, 0)) {
+            ret = AUX_I2C_NACK;
+            break;
+        }
+
+        while (len > 0) {
+            if (!i2c_send(i2c_bus, *data++)) {
+                ret = AUX_I2C_NACK;
+                i2c_end_transfer(i2c_bus);
+                break;
+            }
+            len--;
+        }
+        i2c_end_transfer(i2c_bus);
+        ret = AUX_I2C_ACK;
+    break;
+    /*
+     * I2C MOT transactions.
+     *
+     * Here we send a start when:
+     *  - We didn't start transaction yet.
+     *  - We had a READ and we do a WRITE.
+     *  - We change the address.
+     */
+    case WRITE_I2C_MOT:
+        if (!i2c_bus_busy(i2c_bus)) {
+            /*
+             * No transactions started..
+             */
+            if (i2c_start_transfer(i2c_bus, address, 0)) {
+                ret = AUX_I2C_NACK;
+                break;
+            }
+        } else if ((address != bus->last_i2c_address) ||
+                   (bus->last_transaction == READ_I2C_MOT)) {
+            /*
+             * Transaction started but we need to restart..
+             */
+            i2c_end_transfer(i2c_bus);
+            if (i2c_start_transfer(i2c_bus, address, 0)) {
+                ret = AUX_I2C_NACK;
+                break;
+            }
+        }
+
+        while (len > 0) {
+            if (!i2c_send(i2c_bus, *data++)) {
+                ret = AUX_I2C_NACK;
+                i2c_end_transfer(i2c_bus);
+                break;
+            }
+            len--;
+        }
+        bus->last_transaction = WRITE_I2C_MOT;
+        bus->last_i2c_address = address;
+        ret = AUX_I2C_ACK;
+    break;
+    case READ_I2C_MOT:
+        if (!i2c_bus_busy(i2c_bus)) {
+            /*
+             * No transactions started..
+             */
+            if (i2c_start_transfer(i2c_bus, address, 0)) {
+                ret = AUX_I2C_NACK;
+                break;
+            }
+        } else if (address != bus->last_i2c_address) {
+            /*
+             * Transaction started but we need to restart..
+             */
+            i2c_end_transfer(i2c_bus);
+            if (i2c_start_transfer(i2c_bus, address, 0)) {
+                ret = AUX_I2C_NACK;
+                break;
+            }
+        }
+
+        while (len > 0) {
+            temp = i2c_recv(i2c_bus);
+
+            if (temp < 0) {
+                ret = AUX_I2C_NACK;
+                i2c_end_transfer(i2c_bus);
+                break;
+            }
+
+            *data++ = temp;
+            len--;
+        }
+        bus->last_transaction = READ_I2C_MOT;
+        bus->last_i2c_address = address;
+        ret = AUX_I2C_ACK;
+    break;
+    default:
+        DPRINTF("Not implemented!\n");
+        ret = AUX_NACK;
+    break;
+    }
+
+    DPRINTF("reply: %u\n", ret);
+    return ret;
+}
+
+/*
+ * AUX to I2C bridge.
+ */
+struct AUXTOI2CState {
+    DeviceState parent_obj;
+    I2CBus *i2c_bus;
+};
+
+I2CBus *aux_get_i2c_bus(AUXBus *bus)
+{
+    return bus->bridge->i2c_bus;
+}
+
+static void aux_bridge_init(Object *obj)
+{
+    AUXTOI2CState *s = AUXTOI2C(obj);
+    /*
+     * Create the I2C Bus.
+     */
+    s->i2c_bus = i2c_init_bus(DEVICE(obj), "aux-i2c");
+}
+
+static const TypeInfo aux_to_i2c_type_info = {
+    .name = TYPE_AUXTOI2C,
+    .parent = TYPE_DEVICE,
+    .instance_size = sizeof(AUXTOI2CState),
+    .instance_init = aux_bridge_init
+};
+
+/*
+ * AUX Slave.
+ */
+static void aux_slave_dev_print(Monitor *mon, DeviceState *dev, int indent)
+{
+    AUXBus *bus = AUX_BUS(qdev_get_parent_bus(dev));
+    hwaddr size;
+    AUXSlave *s;
+
+    /*
+     * Don't print anything if the device is I2C "bridge".
+     */
+    if (aux_bus_is_bridge(bus, dev)) {
+        return;
+    }
+
+    s = AUX_SLAVE(dev);
+
+    size = memory_region_size(s->mmio);
+    monitor_printf(mon, "%*smemory " TARGET_FMT_plx "/" TARGET_FMT_plx "\n",
+                   indent, "", s->address, size);
+}
+
+static int aux_slave_qdev_init(DeviceState *dev)
+{
+    AUXSlave *s = AUX_SLAVE(dev);
+    AUXSlaveClass *sc = AUX_SLAVE_GET_CLASS(s);
+
+    return sc->init(s);
+}
+
+DeviceState *aux_create_slave(AUXBus *bus, const char *name, uint32_t addr)
+{
+    DeviceState *dev;
+
+    dev = qdev_create(&bus->qbus, name);
+    qdev_prop_set_uint64(dev, "address", addr);
+    qdev_init_nofail(dev);
+    aux_bus_map_device(AUX_BUS(qdev_get_parent_bus(dev)), AUX_SLAVE(dev));
+    return dev;
+}
+
+void aux_init_mmio(AUXSlave *aux_slave, MemoryRegion *mmio)
+{
+    aux_slave->mmio = mmio;
+}
+
+static void aux_slave_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *k = DEVICE_CLASS(klass);
+    k->init = aux_slave_qdev_init;
+    set_bit(DEVICE_CATEGORY_MISC, k->categories);
+    k->bus_type = TYPE_AUX_BUS;
+    k->props = aux_props;
+}
+
+static const TypeInfo aux_slave_type_info = {
+    .name = TYPE_AUX_SLAVE,
+    .parent = TYPE_DEVICE,
+    .instance_size = sizeof(AUXSlave),
+    .abstract = true,
+    .class_size = sizeof(AUXSlaveClass),
+    .class_init = aux_slave_class_init,
+};
+
+static void aux_slave_register_types(void)
+{
+    type_register_static(&aux_bus_info);
+    type_register_static(&aux_slave_type_info);
+    type_register_static(&aux_to_i2c_type_info);
+}
+
+type_init(aux_slave_register_types)
diff --git a/include/hw/aux.h b/include/hw/aux.h
new file mode 100644
index 0000000..b9be4a4
--- /dev/null
+++ b/include/hw/aux.h
@@ -0,0 +1,127 @@
+/*
+ * aux.h
+ *
+ *  Copyright (C)2014 : GreenSocs Ltd
+ *      http://www.greensocs.com/ , email: info@greensocs.com
+ *
+ *  Developed by :
+ *  Frederic Konrad   <fred.konrad@greensocs.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 2 of the License, or
+ * (at your option)any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QEMU_AUX_H
+#define QEMU_AUX_H
+
+#include "hw/qdev.h"
+
+enum aux_command {
+    WRITE_I2C = 0,
+    READ_I2C = 1,
+    WRITE_I2C_STATUS = 2,
+    WRITE_I2C_MOT = 4,
+    READ_I2C_MOT = 5,
+    WRITE_AUX = 8,
+    READ_AUX = 9
+};
+
+enum aux_reply {
+    AUX_I2C_ACK = 0,
+    AUX_NACK = 1,
+    AUX_DEFER = 2,
+    AUX_I2C_NACK = 4,
+    AUX_I2C_DEFER = 8
+};
+
+typedef struct AUXBus AUXBus;
+typedef struct AUXSlave AUXSlave;
+typedef enum aux_command aux_command;
+typedef enum aux_reply aux_reply;
+
+#define TYPE_AUX_SLAVE "aux-slave"
+#define AUX_SLAVE(obj) \
+     OBJECT_CHECK(AUXSlave, (obj), TYPE_AUX_SLAVE)
+#define AUX_SLAVE_CLASS(klass) \
+     OBJECT_CLASS_CHECK(AUXSlaveClass, (klass), TYPE_AUX_SLAVE)
+#define AUX_SLAVE_GET_CLASS(obj) \
+     OBJECT_GET_CLASS(AUXSlaveClass, (obj), TYPE_AUX_SLAVE)
+
+struct AUXSlave {
+    /* < private > */
+    DeviceState parent_obj;
+
+    /* address of the device on the aux bus. */
+    hwaddr address;
+    /* memory region associated. */
+    MemoryRegion *mmio;
+};
+
+typedef struct AUXSlaveClass {
+    DeviceClass parent_class;
+
+    /* Callbacks provided by the device.  */
+    int (*init)(AUXSlave *dev);
+} AUXSlaveClass;
+
+/*
+ * \func aux_init_bus
+ * \brief Init an aux bus.
+ * \param parent The device where this bus is located.
+ * \param name The name of the bus.
+ * \return The new aux bus.
+ */
+AUXBus *aux_init_bus(DeviceState *parent, const char *name);
+
+/*
+ * \func aux_slave_set_address
+ * \brief Set the address of the slave on the aux bus.
+ * \param dev The aux slave device.
+ * \param address The address to give to the slave.
+ */
+void aux_set_slave_address(AUXSlave *dev, uint32_t address);
+
+/*
+ * \func aux_request
+ * \brief Make a request on the bus.
+ * \param bus Ths bus where the request happen.
+ * \param cmd The command requested.
+ * \param address The 20bits address of the slave.
+ * \param len The length of the read or write.
+ * \param data The data array which will be filled or read during transfer.
+ * \return Return the reply of the request.
+ */
+aux_reply aux_request(AUXBus *bus, aux_command cmd, uint32_t address,
+                              uint8_t len, uint8_t *data);
+
+/*
+ * \func aux_get_i2c_bus
+ * \brief Get the i2c bus for I2C over AUX command.
+ * \param bus The aux bus.
+ * \return Return the i2c bus associated.
+ */
+I2CBus *aux_get_i2c_bus(AUXBus *bus);
+
+/*
+ * \func aux_init_mmio
+ * \brief Init an mmio for an aux slave, must be called after
+ *        memory_region_init_io.
+ * \param aux_slave The aux slave.
+ * \param mmio The mmio to be registered.
+ */
+void aux_init_mmio(AUXSlave *aux_slave, MemoryRegion *mmio);
+
+DeviceState *aux_create_slave(AUXBus *bus, const char *name, uint32_t addr);
+
+#endif /* !QEMU_AUX_H */
-- 
1.9.0