hw/char/cmsdk-apb-uart.c: Implement CMSDK APB UART

Implement a model of the simple "APB UART" provided in
the Cortex-M System Design Kit (CMSDK).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1500029487-14822-3-git-send-email-peter.maydell@linaro.org
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

1 files changed, 78 insertions, 0 deletions

diff --git a/include/hw/char/cmsdk-apb-uart.h b/include/hw/char/cmsdk-apb-uart.h
new file mode 100644
index 0000000000..c41fba9a27
--- /dev/null
+++ b/include/hw/char/cmsdk-apb-uart.h
@@ -0,0 +1,78 @@
+/*
+ * ARM CMSDK APB UART emulation
+ *
+ * Copyright (c) 2017 Linaro Limited
+ * Written by Peter Maydell
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+#ifndef CMSDK_APB_UART_H
+#define CMSDK_APB_UART_H
+
+#include "hw/sysbus.h"
+#include "chardev/char-fe.h"
+
+#define TYPE_CMSDK_APB_UART "cmsdk-apb-uart"
+#define CMSDK_APB_UART(obj) OBJECT_CHECK(CMSDKAPBUART, (obj), \
+                                         TYPE_CMSDK_APB_UART)
+
+typedef struct {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion iomem;
+    CharBackend chr;
+    qemu_irq txint;
+    qemu_irq rxint;
+    qemu_irq txovrint;
+    qemu_irq rxovrint;
+    qemu_irq uartint;
+    guint watch_tag;
+    uint32_t pclk_frq;
+
+    uint32_t state;
+    uint32_t ctrl;
+    uint32_t intstatus;
+    uint32_t bauddiv;
+    /* This UART has no FIFO, only a 1-character buffer for each of Tx and Rx */
+    uint8_t txbuf;
+    uint8_t rxbuf;
+} CMSDKAPBUART;
+
+/**
+ * cmsdk_apb_uart_create - convenience function to create TYPE_CMSDK_APB_UART
+ * @addr: location in system memory to map registers
+ * @chr: Chardev backend to connect UART to, or NULL if no backend
+ * @pclk_frq: frequency in Hz of the PCLK clock (used for calculating baud rate)
+ */
+static inline DeviceState *cmsdk_apb_uart_create(hwaddr addr,
+                                                 qemu_irq txint,
+                                                 qemu_irq rxint,
+                                                 qemu_irq txovrint,
+                                                 qemu_irq rxovrint,
+                                                 qemu_irq uartint,
+                                                 Chardev *chr,
+                                                 uint32_t pclk_frq)
+{
+    DeviceState *dev;
+    SysBusDevice *s;
+
+    dev = qdev_create(NULL, TYPE_CMSDK_APB_UART);
+    s = SYS_BUS_DEVICE(dev);
+    qdev_prop_set_chr(dev, "chardev", chr);
+    qdev_prop_set_uint32(dev, "pclk-frq", pclk_frq);
+    qdev_init_nofail(dev);
+    sysbus_mmio_map(s, 0, addr);
+    sysbus_connect_irq(s, 0, txint);
+    sysbus_connect_irq(s, 1, rxint);
+    sysbus_connect_irq(s, 2, txovrint);
+    sysbus_connect_irq(s, 3, rxovrint);
+    sysbus_connect_irq(s, 4, uartint);
+    return dev;
+}
+
+#endif