[Qemu-devel] [PATCH 2/4] bcm2835_aux: add emulation of BCM2835 AUX (aka UART1) block

[Andrew Baumann <Andrew.Baumann@microsoft.com>]

Signed-off-by: Andrew Baumann <Andrew.Baumann@microsoft.com>
---
 hw/arm/bcm2835_peripherals.c         |  18 +++
 hw/char/Makefile.objs                |   1 +
 hw/char/bcm2835_aux.c                | 241 +++++++++++++++++++++++++++++++++++
 include/hw/arm/bcm2835_peripherals.h |   2 +
 include/hw/char/bcm2835_aux.h        |  31 +++++
 5 files changed, 293 insertions(+)
 create mode 100644 hw/char/bcm2835_aux.c
 create mode 100644 include/hw/char/bcm2835_aux.h

diff --git a/hw/arm/bcm2835_peripherals.c b/hw/arm/bcm2835_peripherals.c
index 6ce9cd1..103a330 100644
--- a/hw/arm/bcm2835_peripherals.c
+++ b/hw/arm/bcm2835_peripherals.c
@@ -48,6 +48,11 @@ static void bcm2835_peripherals_init(Object *obj)
     object_property_add_child(obj, "uart0", OBJECT(s->uart0), NULL);
     qdev_set_parent_bus(DEVICE(s->uart0), sysbus_get_default());
 
+    /* AUX / UART1 */
+    object_initialize(&s->aux, sizeof(s->aux), TYPE_BCM2835_AUX);
+    object_property_add_child(obj, "aux", OBJECT(&s->aux), NULL);
+    qdev_set_parent_bus(DEVICE(&s->aux), sysbus_get_default());
+
     /* Mailboxes */
     object_initialize(&s->mboxes, sizeof(s->mboxes), TYPE_BCM2835_MBOX);
     object_property_add_child(obj, "mbox", OBJECT(&s->mboxes), NULL);
@@ -131,6 +136,19 @@ static void bcm2835_peripherals_realize(DeviceState *dev, Error **errp)
         qdev_get_gpio_in_named(DEVICE(&s->ic), BCM2835_IC_GPU_IRQ,
                                INTERRUPT_UART));
 
+    /* AUX / UART1 */
+    object_property_set_bool(OBJECT(&s->aux), true, "realized", &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+
+    memory_region_add_subregion(&s->peri_mr, UART1_OFFSET,
+                sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->aux), 0));
+    sysbus_connect_irq(SYS_BUS_DEVICE(&s->aux), 0,
+        qdev_get_gpio_in_named(DEVICE(&s->ic), BCM2835_IC_GPU_IRQ,
+                               INTERRUPT_AUX));
+
     /* Mailboxes */
     object_property_set_bool(OBJECT(&s->mboxes), true, "realized", &err);
     if (err) {
diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs
index 5931cc8..69a553c 100644
--- a/hw/char/Makefile.objs
+++ b/hw/char/Makefile.objs
@@ -16,6 +16,7 @@ obj-$(CONFIG_SH4) += sh_serial.o
 obj-$(CONFIG_PSERIES) += spapr_vty.o
 obj-$(CONFIG_DIGIC) += digic-uart.o
 obj-$(CONFIG_STM32F2XX_USART) += stm32f2xx_usart.o
+obj-$(CONFIG_RASPI) += bcm2835_aux.o
 
 common-obj-$(CONFIG_ETRAXFS) += etraxfs_ser.o
 common-obj-$(CONFIG_ISA_DEBUG) += debugcon.o
diff --git a/hw/char/bcm2835_aux.c b/hw/char/bcm2835_aux.c
new file mode 100644
index 0000000..c2f71e5
--- /dev/null
+++ b/hw/char/bcm2835_aux.c
@@ -0,0 +1,241 @@
+/*
+ * BCM2835 (Raspberry Pi / Pi 2) Aux block (mini UART and SPI).
+ * Copyright (c) 2015, Microsoft
+ * Written by Andrew Baumann
+ * Based on pl011.c, copyright terms below:
+ *
+ * Arm PrimeCell PL011 UART
+ *
+ * Copyright (c) 2006 CodeSourcery.
+ * Written by Paul Brook
+ *
+ * This code is licensed under the GPL.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/char/bcm2835_aux.h"
+
+#define AUX_ENABLES     0x4
+#define AUX_MU_IO_REG   0x40
+#define AUX_MU_IER_REG  0x44
+#define AUX_MU_IIR_REG  0x48
+#define AUX_MU_LSR_REG  0x54
+#define AUX_MU_STAT_REG 0x64
+
+static void bcm2835_aux_update(BCM2835AuxState *s)
+{
+    bool status = (s->rx_int_enable && s->read_count != 0) || s->tx_int_enable;
+    qemu_set_irq(s->irq, status);
+}
+
+static uint64_t bcm2835_aux_read(void *opaque, hwaddr offset, unsigned size)
+{
+    BCM2835AuxState *s = opaque;
+    uint32_t c, res;
+
+    switch (offset) {
+    case AUX_ENABLES:
+        return 1; /* mini UART enabled */
+
+    case AUX_MU_IO_REG:
+        c = s->read_fifo[s->read_pos];
+        if (s->read_count > 0) {
+            s->read_count--;
+            if (++s->read_pos == 8) {
+                s->read_pos = 0;
+            }
+        }
+        if (s->chr) {
+            qemu_chr_accept_input(s->chr);
+        }
+        bcm2835_aux_update(s);
+        return c;
+
+    case AUX_MU_IER_REG:
+        res = 0;
+        if (s->rx_int_enable) {
+            res |= 0x2;
+        }
+        if (s->tx_int_enable) {
+            res |= 0x1;
+        }
+        return res;
+
+    case AUX_MU_IIR_REG:
+        res = 0xc0;
+        if (s->tx_int_enable) {
+            res |= 0x1;
+        } else if (s->rx_int_enable && s->read_count != 0) {
+            res |= 0x2;
+        }
+        return res;
+
+    case AUX_MU_LSR_REG:
+        res = 0x60; /* tx idle, empty */
+        if (s->read_count != 0) {
+            res |= 0x1;
+        }
+        return res;
+
+    case AUX_MU_STAT_REG:
+        res = 0x302; /* space in the output buffer, empty tx fifo */
+        if (s->read_count > 0) {
+            res |= 0x1; /* data in input buffer */
+            assert(s->read_count < 8);
+            res |= ((uint32_t)s->read_count) << 16; /* rx fifo fill level */
+        }
+        return res;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+                      __func__, offset);
+        return 0;
+    }
+}
+
+static void bcm2835_aux_write(void *opaque, hwaddr offset, uint64_t value,
+                              unsigned size)
+{
+    BCM2835AuxState *s = opaque;
+    unsigned char ch;
+
+    switch (offset) {
+    case AUX_ENABLES:
+        if (value != 1) {
+            qemu_log_mask(LOG_UNIMP, "%s: unsupported attempt to enable SPI "
+                          "or disable UART\n", __func__);
+        }
+        break;
+
+    case AUX_MU_IO_REG:
+        ch = value;
+        if (s->chr) {
+            qemu_chr_fe_write(s->chr, &ch, 1);
+        }
+        break;
+
+    case AUX_MU_IER_REG:
+        s->rx_int_enable = (value & 0x2) != 0;
+        s->tx_int_enable = (value & 0x1) != 0;
+        break;
+
+    case AUX_MU_IIR_REG:
+        if (value & 0x1) {
+            s->read_count = 0;
+        }
+        break;
+
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset %"HWADDR_PRIx"\n",
+                      __func__, offset);
+    }
+
+    bcm2835_aux_update(s);
+}
+
+static int bcm2835_aux_can_receive(void *opaque)
+{
+    BCM2835AuxState *s = opaque;
+
+    return s->read_count < 8;
+}
+
+static void bcm2835_aux_put_fifo(void *opaque, uint32_t value)
+{
+    BCM2835AuxState *s = opaque;
+    int slot;
+
+    slot = s->read_pos + s->read_count;
+    if (slot >= 8) {
+        slot -= 8;
+    }
+    s->read_fifo[slot] = value;
+    s->read_count++;
+    if (s->read_count == 8) {
+        /* buffer full */
+    }
+    bcm2835_aux_update(s);
+}
+
+static void bcm2835_aux_receive(void *opaque, const uint8_t *buf, int size)
+{
+    bcm2835_aux_put_fifo(opaque, *buf);
+}
+
+static void bcm2835_aux_event(void *opaque, int event)
+{
+    if (event == CHR_EVENT_BREAK) {
+        bcm2835_aux_put_fifo(opaque, 0x400);
+    }
+}
+
+static const MemoryRegionOps bcm2835_aux_ops = {
+    .read = bcm2835_aux_read,
+    .write = bcm2835_aux_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid.min_access_size = 4,
+    .valid.max_access_size = 4,
+};
+
+static const VMStateDescription vmstate_bcm2835_aux = {
+    .name = TYPE_BCM2835_AUX,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(read_fifo, BCM2835AuxState, 8),
+        VMSTATE_UINT8(read_pos, BCM2835AuxState),
+        VMSTATE_UINT8(read_count, BCM2835AuxState),
+        VMSTATE_BOOL(rx_int_enable, BCM2835AuxState),
+        VMSTATE_BOOL(tx_int_enable, BCM2835AuxState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void bcm2835_aux_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    BCM2835AuxState *s = BCM2835_AUX(obj);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &bcm2835_aux_ops, s,
+                          TYPE_BCM2835_AUX, 0x100);
+    sysbus_init_mmio(sbd, &s->iomem);
+    sysbus_init_irq(sbd, &s->irq);
+}
+
+static void bcm2835_aux_realize(DeviceState *dev, Error **errp)
+{
+    BCM2835AuxState *s = BCM2835_AUX(dev);
+
+    /* FIXME use a qdev chardev prop instead of qemu_char_get_next_serial() */
+    s->chr = qemu_char_get_next_serial();
+
+    if (s->chr) {
+        qemu_chr_add_handlers(s->chr, bcm2835_aux_can_receive,
+                              bcm2835_aux_receive, bcm2835_aux_event, s);
+    }
+}
+
+static void bcm2835_aux_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->realize = bcm2835_aux_realize;
+    dc->vmsd = &vmstate_bcm2835_aux;
+    /* Reason: realize() method uses qemu_char_get_next_serial() */
+    dc->cannot_instantiate_with_device_add_yet = true;
+}
+
+static const TypeInfo bcm2835_aux_info = {
+    .name          = TYPE_BCM2835_AUX,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(BCM2835AuxState),
+    .instance_init = bcm2835_aux_init,
+    .class_init    = bcm2835_aux_class_init,
+};
+
+static void bcm2835_aux_register_types(void)
+{
+    type_register_static(&bcm2835_aux_info);
+}
+
+type_init(bcm2835_aux_register_types)
diff --git a/include/hw/arm/bcm2835_peripherals.h b/include/hw/arm/bcm2835_peripherals.h
index 5d888dc..889adf5 100644
--- a/include/hw/arm/bcm2835_peripherals.h
+++ b/include/hw/arm/bcm2835_peripherals.h
@@ -14,6 +14,7 @@
 #include "qemu-common.h"
 #include "exec/address-spaces.h"
 #include "hw/sysbus.h"
+#include "hw/char/bcm2835_aux.h"
 #include "hw/intc/bcm2835_ic.h"
 #include "hw/misc/bcm2835_property.h"
 #include "hw/misc/bcm2835_mbox.h"
@@ -33,6 +34,7 @@ typedef struct BCM2835PeripheralState {
     qemu_irq irq, fiq;
 
     SysBusDevice *uart0;
+    BCM2835AuxState aux;
     BCM2835ICState ic;
     BCM2835PropertyState property;
     BCM2835MboxState mboxes;
diff --git a/include/hw/char/bcm2835_aux.h b/include/hw/char/bcm2835_aux.h
new file mode 100644
index 0000000..f917619
--- /dev/null
+++ b/include/hw/char/bcm2835_aux.h
@@ -0,0 +1,31 @@
+/*
+ * Rasperry Pi 2 emulation and refactoring Copyright (c) 2015, Microsoft
+ * Written by Andrew Baumann
+ *
+ * This code is licensed under the GNU GPLv2 and later.
+ */
+
+#ifndef BCM2835_AUX_H
+#define BCM2835_AUX_H
+
+#include "hw/sysbus.h"
+#include "sysemu/char.h"
+
+#define TYPE_BCM2835_AUX "bcm2835-aux"
+#define BCM2835_AUX(obj) OBJECT_CHECK(BCM2835AuxState, (obj), TYPE_BCM2835_AUX)
+
+typedef struct {
+    /*< private >*/
+    SysBusDevice parent_obj;
+    /*< public >*/
+
+    MemoryRegion iomem;
+    CharDriverState *chr;
+    qemu_irq irq;
+
+    uint32_t read_fifo[8];
+    uint8_t read_pos, read_count;
+    bool rx_int_enable, tx_int_enable;
+} BCM2835AuxState;
+
+#endif
-- 
2.5.3