Re: [PATCH v2 4/9] hw/dma/xilinx_axidma: Add DMA memory-region property

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

Hi Edgar,

On 5/6/20 10:25 AM, Edgar E. Iglesias wrote:
> From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>
> 
> Add DMA memory-region property to externally control what
> address-space this DMA operates on.
> 
> Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
> Reviewed-by: Francisco Iglesias <frasse.iglesias@gmail.com>
> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> ---
>   hw/dma/xilinx_axidma.c | 30 +++++++++++++++++++++++-------
>   1 file changed, 23 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
> index 018f36991b..4540051448 100644
> --- a/hw/dma/xilinx_axidma.c
> +++ b/hw/dma/xilinx_axidma.c
> @@ -33,6 +33,7 @@
>   #include "qemu/log.h"
>   #include "qemu/module.h"
>   
> +#include "sysemu/dma.h"
>   #include "hw/stream.h"
>   
>   #define D(x)
> @@ -103,6 +104,7 @@ enum {
>   };
>   
>   struct Stream {
> +    struct XilinxAXIDMA *dma;
>       ptimer_state *ptimer;
>       qemu_irq irq;
>   
> @@ -125,6 +127,9 @@ struct XilinxAXIDMAStreamSlave {
>   struct XilinxAXIDMA {
>       SysBusDevice busdev;
>       MemoryRegion iomem;
> +    MemoryRegion *dma_mr;
> +    AddressSpace as;
> +
>       uint32_t freqhz;
>       StreamSlave *tx_data_dev;
>       StreamSlave *tx_control_dev;
> @@ -186,7 +191,7 @@ static void stream_desc_load(struct Stream *s, hwaddr addr)
>   {
>       struct SDesc *d = &s->desc;
>   
> -    cpu_physical_memory_read(addr, d, sizeof *d);
> +    address_space_read(&s->dma->as, addr, MEMTXATTRS_UNSPECIFIED, d, sizeof *d);
>   
>       /* Convert from LE into host endianness.  */
>       d->buffer_address = le64_to_cpu(d->buffer_address);
> @@ -204,7 +209,8 @@ static void stream_desc_store(struct Stream *s, hwaddr addr)
>       d->nxtdesc = cpu_to_le64(d->nxtdesc);
>       d->control = cpu_to_le32(d->control);
>       d->status = cpu_to_le32(d->status);
> -    cpu_physical_memory_write(addr, d, sizeof *d);
> +    address_space_write(&s->dma->as, addr, MEMTXATTRS_UNSPECIFIED,
> +                        d, sizeof *d);
>   }
>   
>   static void stream_update_irq(struct Stream *s)
> @@ -286,8 +292,9 @@ static void stream_process_mem2s(struct Stream *s, StreamSlave *tx_data_dev,
>                        txlen + s->pos);
>           }
>   
> -        cpu_physical_memory_read(s->desc.buffer_address,
> -                                 s->txbuf + s->pos, txlen);
> +        address_space_read(&s->dma->as, s->desc.buffer_address,
> +                           MEMTXATTRS_UNSPECIFIED,
> +                           s->txbuf + s->pos, txlen);
>           s->pos += txlen;
>   
>           if (stream_desc_eof(&s->desc)) {
> @@ -336,7 +343,8 @@ static size_t stream_process_s2mem(struct Stream *s, unsigned char *buf,
>               rxlen = len;
>           }
>   
> -        cpu_physical_memory_write(s->desc.buffer_address, buf + pos, rxlen);
> +        address_space_write(&s->dma->as, s->desc.buffer_address,
> +                            MEMTXATTRS_UNSPECIFIED, buf + pos, rxlen);
>           len -= rxlen;
>           pos += rxlen;
>   
> @@ -525,6 +533,7 @@ static void xilinx_axidma_realize(DeviceState *dev, Error **errp)
>       XilinxAXIDMAStreamSlave *cs = XILINX_AXI_DMA_CONTROL_STREAM(
>                                                               &s->rx_control_dev);
>       Error *local_err = NULL;
> +    int i;
>   
>       object_property_add_link(OBJECT(ds), "dma", TYPE_XILINX_AXI_DMA,
>                                (Object **)&ds->dma,
> @@ -545,17 +554,19 @@ static void xilinx_axidma_realize(DeviceState *dev, Error **errp)
>           goto xilinx_axidma_realize_fail;
>       }
>   
> -    int i;
> -
>       for (i = 0; i < 2; i++) {
>           struct Stream *st = &s->streams[i];
>   
> +        st->dma = s;
>           st->nr = i;
>           st->ptimer = ptimer_init(timer_hit, st, PTIMER_POLICY_DEFAULT);
>           ptimer_transaction_begin(st->ptimer);
>           ptimer_set_freq(st->ptimer, s->freqhz);
>           ptimer_transaction_commit(st->ptimer);
>       }
> +
> +    address_space_init(&s->as,
> +                       s->dma_mr ? s->dma_mr : get_system_memory(), "dma");

I'd instead return an error (earlier in this function) if dma_mr 
property is not set. If you ever respin...

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>


>       return;
>   
>   xilinx_axidma_realize_fail:
> @@ -575,6 +586,11 @@ static void xilinx_axidma_init(Object *obj)
>                               &s->rx_control_dev, sizeof(s->rx_control_dev),
>                               TYPE_XILINX_AXI_DMA_CONTROL_STREAM, &error_abort,
>                               NULL);
> +    object_property_add_link(obj, "dma", TYPE_MEMORY_REGION,
> +                             (Object **)&s->dma_mr,
> +                             qdev_prop_allow_set_link_before_realize,
> +                             OBJ_PROP_LINK_STRONG,
> +                             &error_abort);
>   
>       sysbus_init_irq(sbd, &s->streams[0].irq);
>       sysbus_init_irq(sbd, &s->streams[1].irq);
>