stm32f2xx_USART: Add the stm32f2xx USART Controller

This patch adds the stm32f2xx USART controller
(UART also uses the same controller).

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Message-id: 762c6c0d2a41d574932bc4445ec9bfffe6da8798.1424175342.git.alistair@alistair23.me
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 230 insertions, 0 deletions

diff --git a/hw/char/Makefile.objs b/hw/char/Makefile.objs
index 317385d26f..5931cc8400 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_STM32F2XX_USART) += stm32f2xx_usart.o
 
 common-obj-$(CONFIG_ETRAXFS) += etraxfs_ser.o
 common-obj-$(CONFIG_ISA_DEBUG) += debugcon.o
diff --git a/hw/char/stm32f2xx_usart.c b/hw/char/stm32f2xx_usart.c
new file mode 100644
index 0000000000..260b053044
--- /dev/null
+++ b/hw/char/stm32f2xx_usart.c
@@ -0,0 +1,229 @@
+/*
+ * STM32F2XX 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/stm32f2xx_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 stm32f2xx_usart_can_receive(void *opaque)
+{
+    STM32F2XXUsartState *s = opaque;
+
+    if (!(s->usart_sr & USART_SR_RXNE)) {
+        return 1;
+    }
+
+    return 0;
+}
+
+static void stm32f2xx_usart_receive(void *opaque, const uint8_t *buf, int size)
+{
+    STM32F2XXUsartState *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 stm32f2xx_usart_reset(DeviceState *dev)
+{
+    STM32F2XXUsartState *s = STM32F2XX_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;
+
+    qemu_set_irq(s->irq, 0);
+}
+
+static uint64_t stm32f2xx_usart_read(void *opaque, hwaddr addr,
+                                       unsigned int size)
+{
+    STM32F2XXUsartState *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;
+        if (s->chr) {
+            qemu_chr_accept_input(s->chr);
+        }
+        qemu_set_irq(s->irq, 0);
+        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,
+                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
+        return 0;
+    }
+
+    return 0;
+}
+
+static void stm32f2xx_usart_write(void *opaque, hwaddr addr,
+                                  uint64_t val64, unsigned int size)
+{
+    STM32F2XXUsartState *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;
+        }
+        if (!(s->usart_sr & USART_SR_RXNE)) {
+            qemu_set_irq(s->irq, 0);
+        }
+        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;
+            if (s->usart_cr1 & USART_CR1_RXNEIE &&
+                s->usart_sr & USART_SR_RXNE) {
+                qemu_set_irq(s->irq, 1);
+            }
+        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,
+                      "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
+    }
+}
+
+static const MemoryRegionOps stm32f2xx_usart_ops = {
+    .read = stm32f2xx_usart_read,
+    .write = stm32f2xx_usart_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void stm32f2xx_usart_init(Object *obj)
+{
+    STM32F2XXUsartState *s = STM32F2XX_USART(obj);
+
+    sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
+
+    memory_region_init_io(&s->mmio, obj, &stm32f2xx_usart_ops, s,
+                          TYPE_STM32F2XX_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, stm32f2xx_usart_can_receive,
+                              stm32f2xx_usart_receive, NULL, s);
+    }
+}
+
+static void stm32f2xx_usart_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = stm32f2xx_usart_reset;
+}
+
+static const TypeInfo stm32f2xx_usart_info = {
+    .name          = TYPE_STM32F2XX_USART,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(STM32F2XXUsartState),
+    .instance_init = stm32f2xx_usart_init,
+    .class_init    = stm32f2xx_usart_class_init,
+};
+
+static void stm32f2xx_usart_register_types(void)
+{
+    type_register_static(&stm32f2xx_usart_info);
+}
+
+type_init(stm32f2xx_usart_register_types)