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

["Edgar E. Iglesias" <edgar.iglesias@xilinx.com>]

On Wed, Nov 17, 2021 at 02:18:36PM +0000, Francisco Iglesias wrote:
> 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.


Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>


> 
> 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
>