[PATCH v1 4/9] hw/dma: Add the DMA control interface

[Francisco Iglesias]

Add an interface for controlling DMA models that are reused with other
models. This allows a controlling model to start transfers through the
DMA while reusing the DMA's handling of transfer state and completion
signaling.

Signed-off-by: Francisco Iglesias <francisco.iglesias@xilinx.com>
---
 hw/dma/dma-ctrl.c         | 31 ++++++++++++++++++++
 hw/dma/meson.build        |  1 +
 include/hw/dma/dma-ctrl.h | 74 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+)
 create mode 100644 hw/dma/dma-ctrl.c
 create mode 100644 include/hw/dma/dma-ctrl.h

diff --git a/hw/dma/dma-ctrl.c b/hw/dma/dma-ctrl.c
new file mode 100644
index 0000000000..4a9b68dac1
--- /dev/null
+++ b/hw/dma/dma-ctrl.c
@@ -0,0 +1,31 @@
+/*
+ * DMA control interface.
+ *
+ * Copyright (c) 2021 Xilinx Inc.
+ * Written by Francisco Iglesias <francisco.iglesias@xilinx.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#include "qemu/osdep.h"
+#include "exec/hwaddr.h"
+#include "hw/dma/dma-ctrl.h"
+
+void dma_ctrl_read_with_notify(DmaCtrl *dma_ctrl, hwaddr addr, uint32_t len,
+                               DmaCtrlNotify *notify, bool start_dma)
+{
+    DmaCtrlClass *dcc =  DMA_CTRL_GET_CLASS(dma_ctrl);
+    dcc->read(dma_ctrl, addr, len, notify, start_dma);
+}
+
+static const TypeInfo dma_ctrl_info = {
+    .name          = TYPE_DMA_CTRL,
+    .parent        = TYPE_INTERFACE,
+    .class_size = sizeof(DmaCtrlClass),
+};
+
+static void dma_ctrl_register_types(void)
+{
+    type_register_static(&dma_ctrl_info);
+}
+
+type_init(dma_ctrl_register_types)
diff --git a/hw/dma/meson.build b/hw/dma/meson.build
index f3f0661bc3..c0bc134046 100644
--- a/hw/dma/meson.build
+++ b/hw/dma/meson.build
@@ -14,3 +14,4 @@ softmmu_ss.add(when: 'CONFIG_PXA2XX', if_true: 
files('pxa2xx_dma.c'))
 softmmu_ss.add(when: 'CONFIG_RASPI', if_true: files('bcm2835_dma.c'))
 softmmu_ss.add(when: 'CONFIG_SIFIVE_PDMA', if_true: files('sifive_pdma.c'))
 softmmu_ss.add(when: 'CONFIG_XLNX_CSU_DMA', if_true: files('xlnx_csu_dma.c'))
+common_ss.add(when: 'CONFIG_XILINX_AXI', if_true: files('dma-ctrl.c'))
diff --git a/include/hw/dma/dma-ctrl.h b/include/hw/dma/dma-ctrl.h
new file mode 100644
index 0000000000..498469395f
--- /dev/null
+++ b/include/hw/dma/dma-ctrl.h
@@ -0,0 +1,74 @@
+/*
+ * DMA control interface.
+ *
+ * Copyright (c) 2021 Xilinx Inc.
+ * Written by Francisco Iglesias <francisco.iglesias@xilinx.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+#ifndef HW_DMA_CTRL_H
+#define HW_DMA_CTRL_H
+
+#include "qemu-common.h"
+#include "hw/hw.h"
+#include "qom/object.h"
+
+#define TYPE_DMA_CTRL "dma-ctrl"
+
+#define DMA_CTRL_CLASS(klass) \
+     OBJECT_CLASS_CHECK(DmaCtrlClass, (klass), TYPE_DMA_CTRL)
+#define DMA_CTRL_GET_CLASS(obj) \
+    OBJECT_GET_CLASS(DmaCtrlClass, (obj), TYPE_DMA_CTRL)
+#define DMA_CTRL(obj) \
+     INTERFACE_CHECK(DmaCtrl, (obj), TYPE_DMA_CTRL)
+
+typedef void (*dmactrl_notify_fn)(void *opaque);
+
+typedef struct DmaCtrlNotify {
+    void *opaque;
+    dmactrl_notify_fn cb;
+} DmaCtrlNotify;
+
+typedef struct DmaCtrl {
+    Object Parent;
+} DmaCtrl;
+
+typedef struct DmaCtrlClass {
+    InterfaceClass parent;
+
+    /*
+     * read: Start a read transfer on the DMA implementing the DMA control
+     * interface
+     *
+     * @dma_ctrl: the DMA implementing this interface
+     * @addr: the address to read
+     * @len: the amount of bytes to read at 'addr'
+     * @notify: the structure containg a callback to call and opaque pointer
+     * to pass the callback when the transfer has been completed
+     * @start_dma: true for starting the DMA transfer and false for just
+     * refilling and proceding an already started transfer
+     */
+    void (*read)(DmaCtrl *dma_ctrl, hwaddr addr, uint32_t len,
+                 DmaCtrlNotify *notify, bool start_dma);
+} DmaCtrlClass;
+
+/*
+ * Start a read transfer on a DMA implementing the DMA control interface.
+ * The DMA will notify the caller that 'len' bytes have been read at 'addr'
+ * through the callback in the DmaCtrlNotify structure. For allowing refilling
+ * an already started transfer the DMA notifies the caller before considering
+ * the transfer done (e.g. before setting done flags, generating IRQs and
+ * modifying other relevant internal device state).
+ *
+ * @dma_ctrl: the DMA implementing this interface
+ * @addr: the address to read
+ * @len: the amount of bytes to read at 'addr'
+ * @notify: the structure containing a callback to call and opaque pointer
+ * to pass the callback when the transfer has been completed
+ * @start_dma: true for starting the DMA transfer and false for just
+ * refilling and proceding an already started transfer
+ */
+void dma_ctrl_read_with_notify(DmaCtrl *dma_ctrl, hwaddr addr, uint32_t len,
+                   DmaCtrlNotify *notify, bool start_dma);
+
+#endif /* HW_DMA_CTRL_H */
-- 
2.11.0