[v5,2/7] stm32f205_USART: Add the stm32f205 USART Controller
diff mbox

Message ID 1ad3a23bc6f3ad0855234fca264082fd8e88c197.1413463862.git.alistair23@gmail.com
State New
Headers show

Commit Message

Alistair Francis Oct. 16, 2014, 12:53 p.m. UTC
This patch adds the stm32f205 USART controller
(UART also uses the same controller).

Signed-off-by: Alistair Francis <alistair23@gmail.com>
---
 default-configs/arm-softmmu.mak   |   1 +
 hw/char/Makefile.objs             |   1 +
 hw/char/stm32f205_usart.c         | 218 ++++++++++++++++++++++++++++++++++++++
 include/hw/char/stm32f205_usart.h |  69 ++++++++++++
 4 files changed, 289 insertions(+)
 create mode 100644 hw/char/stm32f205_usart.c
 create mode 100644 include/hw/char/stm32f205_usart.h

Comments

Peter Crosthwaite Oct. 20, 2014, 7:27 a.m. UTC | #1
On Thu, Oct 16, 2014 at 10:53 PM, Alistair Francis <alistair23@gmail.com> wrote:
> This patch adds the stm32f205 USART controller
> (UART also uses the same controller).
>
> Signed-off-by: Alistair Francis <alistair23@gmail.com>
> ---
>  default-configs/arm-softmmu.mak   |   1 +
>  hw/char/Makefile.objs             |   1 +
>  hw/char/stm32f205_usart.c         | 218 ++++++++++++++++++++++++++++++++++++++
>  include/hw/char/stm32f205_usart.h |  69 ++++++++++++
>  4 files changed, 289 insertions(+)
>  create mode 100644 hw/char/stm32f205_usart.c
>  create mode 100644 include/hw/char/stm32f205_usart.h
>
> diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
> index cf23b24..422dec0 100644
> --- a/default-configs/arm-softmmu.mak
> +++ b/default-configs/arm-softmmu.mak
> @@ -79,6 +79,7 @@ CONFIG_REALVIEW=y
>  CONFIG_ZAURUS=y
>  CONFIG_ZYNQ=y
>  CONFIG_STM32F205_TIMER=y
> +CONFIG_STM32F205_USART=y
>
>  CONFIG_VERSATILE_PCI=y
>  CONFIG_VERSATILE_I2C=y
> diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs
> index 317385d..c7b3ce4 100644
> --- a/hw/char/Makefile.objs
> +++ b/hw/char/Makefile.objs
> @@ -15,6 +15,7 @@ obj-$(CONFIG_OMAP) += omap_uart.o
>  obj-$(CONFIG_SH4) += sh_serial.o
>  obj-$(CONFIG_PSERIES) += spapr_vty.o
>  obj-$(CONFIG_DIGIC) += digic-uart.o
> +obj-$(CONFIG_STM32F205_USART) += stm32f205_usart.o
>
>  common-obj-$(CONFIG_ETRAXFS) += etraxfs_ser.o
>  common-obj-$(CONFIG_ISA_DEBUG) += debugcon.o
> diff --git a/hw/char/stm32f205_usart.c b/hw/char/stm32f205_usart.c
> new file mode 100644
> index 0000000..9d399b8
> --- /dev/null
> +++ b/hw/char/stm32f205_usart.c
> @@ -0,0 +1,218 @@
> +/*
> + * STM32F205 USART
> + *
> + * Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "hw/char/stm32f205_usart.h"
> +
> +#ifndef STM_USART_ERR_DEBUG
> +#define STM_USART_ERR_DEBUG 0
> +#endif
> +
> +#define DB_PRINT_L(lvl, fmt, args...) do { \
> +    if (STM_USART_ERR_DEBUG >= lvl) { \
> +        qemu_log("%s: " fmt, __func__, ## args); \
> +    } \
> +} while (0);
> +
> +#define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
> +
> +static int stm32f205_usart_can_receive(void *opaque)
> +{
> +    STM32f205UsartState *s = opaque;
> +
> +    if (!(s->usart_sr & USART_SR_RXNE)) {
> +        return 1;
> +    }
> +
> +    return 0;
> +}
> +
> +static void stm32f205_usart_receive(void *opaque, const uint8_t *buf, int size)
> +{
> +    STM32f205UsartState *s = opaque;
> +
> +    s->usart_dr = *buf;
> +
> +    if (!(s->usart_cr1 & USART_CR1_UE && s->usart_cr1 & USART_CR1_RE)) {
> +        /* USART not enabled - drop the chars */
> +        DB_PRINT("Dropping the chars\n");
> +        return;
> +    }
> +
> +    s->usart_sr |= USART_SR_RXNE;
> +
> +    if (s->usart_cr1 & USART_CR1_RXNEIE) {
> +        qemu_set_irq(s->irq, 1);
> +    }
> +
> +    DB_PRINT("Receiving: %c\n", s->usart_dr);
> +}
> +
> +static void stm32f205_usart_reset(DeviceState *dev)
> +{
> +    STM32f205UsartState *s = STM32F205_USART(dev);
> +
> +    s->usart_sr = USART_SR_RESET;
> +    s->usart_dr = 0x00000000;
> +    s->usart_brr = 0x00000000;
> +    s->usart_cr1 = 0x00000000;
> +    s->usart_cr2 = 0x00000000;
> +    s->usart_cr3 = 0x00000000;
> +    s->usart_gtpr = 0x00000000;
> +}
> +
> +static uint64_t stm32f205_usart_read(void *opaque, hwaddr addr,
> +                                       unsigned int size)
> +{
> +    STM32f205UsartState *s = opaque;
> +    uint64_t retvalue;
> +
> +    DB_PRINT("Read 0x%"HWADDR_PRIx"\n", addr);
> +
> +    switch (addr) {
> +    case USART_SR:
> +        retvalue = s->usart_sr;
> +        s->usart_sr &= ~USART_SR_TC;
> +        if (s->chr) {
> +            qemu_chr_accept_input(s->chr);
> +        }
> +        return retvalue;
> +    case USART_DR:
> +        DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
> +        s->usart_sr |= USART_SR_TXE;
> +        s->usart_sr &= ~USART_SR_RXNE;

Do you need to qemu_chr_accept_input here?

> +        return s->usart_dr & 0x3FF;
> +    case USART_BRR:
> +        return s->usart_brr;
> +    case USART_CR1:
> +        return s->usart_cr1;
> +    case USART_CR2:
> +        return s->usart_cr2;
> +    case USART_CR3:
> +        return s->usart_cr3;
> +    case USART_GTPR:
> +        return s->usart_gtpr;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "STM32F205_usart_read: Bad offset " \

Just use %s __func__ rather than STM32F205_usart_read.

> +                      "0x%"HWADDR_PRIx"\n", addr);
> +        return 0;
> +    }
> +
> +    return 0;
> +}
> +
> +static void stm32f205_usart_write(void *opaque, hwaddr addr,
> +                                  uint64_t val64, unsigned int size)
> +{
> +    STM32f205UsartState *s = opaque;
> +    uint32_t value = val64;
> +    unsigned char ch;
> +
> +    DB_PRINT("Write 0x%" PRIx32 ", 0x%"HWADDR_PRIx"\n", value, addr);
> +
> +    switch (addr) {
> +    case USART_SR:
> +        if (value <= 0x3FF) {
> +            s->usart_sr = value;
> +        } else {
> +            s->usart_sr &= value;
> +        }
> +        return;
> +    case USART_DR:
> +        if (value < 0xF000) {
> +            ch = value;
> +            if (s->chr) {
> +                qemu_chr_fe_write_all(s->chr, &ch, 1);
> +            }
> +            s->usart_sr |= USART_SR_TC;
> +            s->usart_sr &= ~USART_SR_TXE;
> +        }
> +        return;
> +    case USART_BRR:
> +        s->usart_brr = value;
> +        return;
> +    case USART_CR1:
> +        s->usart_cr1 = value;
> +        return;
> +    case USART_CR2:
> +        s->usart_cr2 = value;
> +        return;
> +    case USART_CR3:
> +        s->usart_cr3 = value;
> +        return;
> +    case USART_GTPR:
> +        s->usart_gtpr = value;
> +        return;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "STM32F205_usart_write: Bad offset " \

%s __func__

> +                      "0x%"HWADDR_PRIx"\n", addr);
> +    }
> +}
> +
> +static const MemoryRegionOps stm32f205_usart_ops = {
> +    .read = stm32f205_usart_read,
> +    .write = stm32f205_usart_write,
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static void stm32f205_usart_init(Object *obj)
> +{
> +    STM32f205UsartState *s = STM32F205_USART(obj);
> +
> +    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
> +
> +    memory_region_init_io(&s->mmio, obj, &stm32f205_usart_ops, s,
> +                          TYPE_STM32F205_USART, 0x2000);
> +    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
> +
> +    s->chr = qemu_char_get_next_serial();
> +
> +    if (s->chr) {
> +        qemu_chr_add_handlers(s->chr, stm32f205_usart_can_receive,
> +                              stm32f205_usart_receive, NULL, s);
> +    }
> +}
> +
> +static void stm32f205_usart_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->reset = stm32f205_usart_reset;
> +}
> +
> +static const TypeInfo stm32f205_usart_info = {
> +    .name          = TYPE_STM32F205_USART,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(STM32f205UsartState),
> +    .instance_init = stm32f205_usart_init,
> +    .class_init    = stm32f205_usart_class_init,
> +};
> +
> +static void stm32f205_usart_register_types(void)
> +{
> +    type_register_static(&stm32f205_usart_info);
> +}
> +
> +type_init(stm32f205_usart_register_types)
> diff --git a/include/hw/char/stm32f205_usart.h b/include/hw/char/stm32f205_usart.h
> new file mode 100644
> index 0000000..e121bf3
> --- /dev/null
> +++ b/include/hw/char/stm32f205_usart.h
> @@ -0,0 +1,69 @@
> +/*
> + * STM32F205 USART
> + *
> + * Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "hw/sysbus.h"
> +#include "sysemu/char.h"
> +#include "hw/hw.h"
> +
> +#define USART_SR   0x00
> +#define USART_DR   0x04
> +#define USART_BRR  0x08
> +#define USART_CR1  0x0C
> +#define USART_CR2  0x10
> +#define USART_CR3  0x14
> +#define USART_GTPR 0x18
> +
> +#define USART_SR_RESET 0x00C00000
> +
> +#define USART_SR_TXE  (1 << 7)
> +#define USART_SR_TC   (1 << 6)
> +#define USART_SR_RXNE (1 << 5)
> +
> +#define USART_CR1_UE  (1 << 13)
> +#define USART_CR1_RXNEIE  (1 << 5)
> +#define USART_CR1_TE  (1 << 3)
> +#define USART_CR1_RE  (1 << 2)
> +
> +#define TYPE_STM32F205_USART "stm32f205-usart"
> +#define STM32F205_USART(obj) \
> +    OBJECT_CHECK(STM32f205UsartState, (obj), TYPE_STM32F205_USART)
> +
> +typedef struct {
> +    /* <private> */
> +    SysBusDevice parent_obj;
> +
> +    /* <public> */
> +    MemoryRegion mmio;
> +
> +    uint32_t usart_sr;
> +    uint32_t usart_dr;
> +    uint32_t usart_brr;
> +    uint32_t usart_cr1;
> +    uint32_t usart_cr2;
> +    uint32_t usart_cr3;
> +    uint32_t usart_gtpr;
> +
> +    CharDriverState *chr;
> +    qemu_irq irq;
> +} STM32f205UsartState;

STM32F2XXUSARTState.

Note the big "F" too.

Regards,
Peter

> --
> 1.9.1
>
>

Patch
diff mbox

diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index cf23b24..422dec0 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -79,6 +79,7 @@  CONFIG_REALVIEW=y
 CONFIG_ZAURUS=y
 CONFIG_ZYNQ=y
 CONFIG_STM32F205_TIMER=y
+CONFIG_STM32F205_USART=y
 
 CONFIG_VERSATILE_PCI=y
 CONFIG_VERSATILE_I2C=y
diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs
index 317385d..c7b3ce4 100644
--- a/hw/char/Makefile.objs
+++ b/hw/char/Makefile.objs
@@ -15,6 +15,7 @@  obj-$(CONFIG_OMAP) += omap_uart.o
 obj-$(CONFIG_SH4) += sh_serial.o
 obj-$(CONFIG_PSERIES) += spapr_vty.o
 obj-$(CONFIG_DIGIC) += digic-uart.o
+obj-$(CONFIG_STM32F205_USART) += stm32f205_usart.o
 
 common-obj-$(CONFIG_ETRAXFS) += etraxfs_ser.o
 common-obj-$(CONFIG_ISA_DEBUG) += debugcon.o
diff --git a/hw/char/stm32f205_usart.c b/hw/char/stm32f205_usart.c
new file mode 100644
index 0000000..9d399b8
--- /dev/null
+++ b/hw/char/stm32f205_usart.c
@@ -0,0 +1,218 @@ 
+/*
+ * STM32F205 USART
+ *
+ * Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw/char/stm32f205_usart.h"
+
+#ifndef STM_USART_ERR_DEBUG
+#define STM_USART_ERR_DEBUG 0
+#endif
+
+#define DB_PRINT_L(lvl, fmt, args...) do { \
+    if (STM_USART_ERR_DEBUG >= lvl) { \
+        qemu_log("%s: " fmt, __func__, ## args); \
+    } \
+} while (0);
+
+#define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
+
+static int stm32f205_usart_can_receive(void *opaque)
+{
+    STM32f205UsartState *s = opaque;
+
+    if (!(s->usart_sr & USART_SR_RXNE)) {
+        return 1;
+    }
+
+    return 0;
+}
+
+static void stm32f205_usart_receive(void *opaque, const uint8_t *buf, int size)
+{
+    STM32f205UsartState *s = opaque;
+
+    s->usart_dr = *buf;
+
+    if (!(s->usart_cr1 & USART_CR1_UE && s->usart_cr1 & USART_CR1_RE)) {
+        /* USART not enabled - drop the chars */
+        DB_PRINT("Dropping the chars\n");
+        return;
+    }
+
+    s->usart_sr |= USART_SR_RXNE;
+
+    if (s->usart_cr1 & USART_CR1_RXNEIE) {
+        qemu_set_irq(s->irq, 1);
+    }
+
+    DB_PRINT("Receiving: %c\n", s->usart_dr);
+}
+
+static void stm32f205_usart_reset(DeviceState *dev)
+{
+    STM32f205UsartState *s = STM32F205_USART(dev);
+
+    s->usart_sr = USART_SR_RESET;
+    s->usart_dr = 0x00000000;
+    s->usart_brr = 0x00000000;
+    s->usart_cr1 = 0x00000000;
+    s->usart_cr2 = 0x00000000;
+    s->usart_cr3 = 0x00000000;
+    s->usart_gtpr = 0x00000000;
+}
+
+static uint64_t stm32f205_usart_read(void *opaque, hwaddr addr,
+                                       unsigned int size)
+{
+    STM32f205UsartState *s = opaque;
+    uint64_t retvalue;
+
+    DB_PRINT("Read 0x%"HWADDR_PRIx"\n", addr);
+
+    switch (addr) {
+    case USART_SR:
+        retvalue = s->usart_sr;
+        s->usart_sr &= ~USART_SR_TC;
+        if (s->chr) {
+            qemu_chr_accept_input(s->chr);
+        }
+        return retvalue;
+    case USART_DR:
+        DB_PRINT("Value: 0x%" PRIx32 ", %c\n", s->usart_dr, (char) s->usart_dr);
+        s->usart_sr |= USART_SR_TXE;
+        s->usart_sr &= ~USART_SR_RXNE;
+        return s->usart_dr & 0x3FF;
+    case USART_BRR:
+        return s->usart_brr;
+    case USART_CR1:
+        return s->usart_cr1;
+    case USART_CR2:
+        return s->usart_cr2;
+    case USART_CR3:
+        return s->usart_cr3;
+    case USART_GTPR:
+        return s->usart_gtpr;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "STM32F205_usart_read: Bad offset " \
+                      "0x%"HWADDR_PRIx"\n", addr);
+        return 0;
+    }
+
+    return 0;
+}
+
+static void stm32f205_usart_write(void *opaque, hwaddr addr,
+                                  uint64_t val64, unsigned int size)
+{
+    STM32f205UsartState *s = opaque;
+    uint32_t value = val64;
+    unsigned char ch;
+
+    DB_PRINT("Write 0x%" PRIx32 ", 0x%"HWADDR_PRIx"\n", value, addr);
+
+    switch (addr) {
+    case USART_SR:
+        if (value <= 0x3FF) {
+            s->usart_sr = value;
+        } else {
+            s->usart_sr &= value;
+        }
+        return;
+    case USART_DR:
+        if (value < 0xF000) {
+            ch = value;
+            if (s->chr) {
+                qemu_chr_fe_write_all(s->chr, &ch, 1);
+            }
+            s->usart_sr |= USART_SR_TC;
+            s->usart_sr &= ~USART_SR_TXE;
+        }
+        return;
+    case USART_BRR:
+        s->usart_brr = value;
+        return;
+    case USART_CR1:
+        s->usart_cr1 = value;
+        return;
+    case USART_CR2:
+        s->usart_cr2 = value;
+        return;
+    case USART_CR3:
+        s->usart_cr3 = value;
+        return;
+    case USART_GTPR:
+        s->usart_gtpr = value;
+        return;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "STM32F205_usart_write: Bad offset " \
+                      "0x%"HWADDR_PRIx"\n", addr);
+    }
+}
+
+static const MemoryRegionOps stm32f205_usart_ops = {
+    .read = stm32f205_usart_read,
+    .write = stm32f205_usart_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void stm32f205_usart_init(Object *obj)
+{
+    STM32f205UsartState *s = STM32F205_USART(obj);
+
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
+
+    memory_region_init_io(&s->mmio, obj, &stm32f205_usart_ops, s,
+                          TYPE_STM32F205_USART, 0x2000);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+
+    s->chr = qemu_char_get_next_serial();
+
+    if (s->chr) {
+        qemu_chr_add_handlers(s->chr, stm32f205_usart_can_receive,
+                              stm32f205_usart_receive, NULL, s);
+    }
+}
+
+static void stm32f205_usart_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = stm32f205_usart_reset;
+}
+
+static const TypeInfo stm32f205_usart_info = {
+    .name          = TYPE_STM32F205_USART,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(STM32f205UsartState),
+    .instance_init = stm32f205_usart_init,
+    .class_init    = stm32f205_usart_class_init,
+};
+
+static void stm32f205_usart_register_types(void)
+{
+    type_register_static(&stm32f205_usart_info);
+}
+
+type_init(stm32f205_usart_register_types)
diff --git a/include/hw/char/stm32f205_usart.h b/include/hw/char/stm32f205_usart.h
new file mode 100644
index 0000000..e121bf3
--- /dev/null
+++ b/include/hw/char/stm32f205_usart.h
@@ -0,0 +1,69 @@ 
+/*
+ * STM32F205 USART
+ *
+ * Copyright (c) 2014 Alistair Francis <alistair@alistair23.me>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw/sysbus.h"
+#include "sysemu/char.h"
+#include "hw/hw.h"
+
+#define USART_SR   0x00
+#define USART_DR   0x04
+#define USART_BRR  0x08
+#define USART_CR1  0x0C
+#define USART_CR2  0x10
+#define USART_CR3  0x14
+#define USART_GTPR 0x18
+
+#define USART_SR_RESET 0x00C00000
+
+#define USART_SR_TXE  (1 << 7)
+#define USART_SR_TC   (1 << 6)
+#define USART_SR_RXNE (1 << 5)
+
+#define USART_CR1_UE  (1 << 13)
+#define USART_CR1_RXNEIE  (1 << 5)
+#define USART_CR1_TE  (1 << 3)
+#define USART_CR1_RE  (1 << 2)
+
+#define TYPE_STM32F205_USART "stm32f205-usart"
+#define STM32F205_USART(obj) \
+    OBJECT_CHECK(STM32f205UsartState, (obj), TYPE_STM32F205_USART)
+
+typedef struct {
+    /* <private> */
+    SysBusDevice parent_obj;
+
+    /* <public> */
+    MemoryRegion mmio;
+
+    uint32_t usart_sr;
+    uint32_t usart_dr;
+    uint32_t usart_brr;
+    uint32_t usart_cr1;
+    uint32_t usart_cr2;
+    uint32_t usart_cr3;
+    uint32_t usart_gtpr;
+
+    CharDriverState *chr;
+    qemu_irq irq;
+} STM32f205UsartState;