Re: [Qemu-devel] [PATCH] xilinx_spips: Make dma transactions as per dma_burst_size

[Sai Pavan Boddu]

Hi Edgar,

I got your suggestion below. Will be sending a V2 asap.

Thanks,
Sai Pavan

> -----Original Message-----
> From: Edgar E. Iglesias [mailto:address@hidden
> Sent: Thursday, June 14, 2018 4:55 PM
> To: Sai Pavan Boddu <address@hidden>
> Cc: address@hidden; Alistair Francis <address@hidden>; Peter
> Crosthwaite <address@hidden>; Peter Maydell
> <address@hidden>; Francisco Iglesias <address@hidden>
> Subject: Re: [PATCH] xilinx_spips: Make dma transactions as per dma_burst_size
> 
> On Thu, Jun 14, 2018 at 10:57:04AM +0530, Sai Pavan Boddu wrote:
> > Qspi dma has a burst length of 64 bytes, So limit transaction length
> > to
> > 64 max.
> 
> Hi Sai,
> 
> Is this a v2 or a resend?
> 
> >
> > Signed-off-by: Sai Pavan Boddu <address@hidden>
> > ---
> >  hw/ssi/xilinx_spips.c         | 18 +++++++++++++++---
> >  include/hw/ssi/xilinx_spips.h |  3 ++-
> >  2 files changed, 17 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c index
> > 03f5fae..ea006c4 100644
> > --- a/hw/ssi/xilinx_spips.c
> > +++ b/hw/ssi/xilinx_spips.c
> > @@ -851,12 +851,17 @@ static void xlnx_zynqmp_qspips_notify(void
> *opaque)
> >      {
> >          size_t ret;
> >          uint32_t num;
> > -        const void *rxd = pop_buf(recv_fifo, 4, &num);
> > +        const void *rxd;
> > +        int len;
> > +
> > +        len = recv_fifo->num >= rq->dma_burst_size ? rq->dma_burst_size :
> > +                                                   recv_fifo->num;
> > +        rxd = pop_buf(recv_fifo, len, &num);
> >
> >          memcpy(rq->dma_buf, rxd, num);
> >
> > -        ret = stream_push(rq->dma, rq->dma_buf, 4);
> > -        assert(ret == 4);
> > +        ret = stream_push(rq->dma, rq->dma_buf, num);
> > +        assert(ret == num);
> >          xlnx_zynqmp_qspips_check_flush(rq);
> >      }
> >  }
> > @@ -1337,6 +1342,7 @@ static void xlnx_zynqmp_qspips_realize(DeviceState
> *dev, Error **errp)
> >      fifo8_create(&s->rx_fifo_g, xsc->rx_fifo_size);
> >      fifo8_create(&s->tx_fifo_g, xsc->tx_fifo_size);
> >      fifo32_create(&s->fifo_g, 32);
> > +    s->dma_buf = g_new0(uint8_t, s->dma_burst_size);
> 
> 
> This would need to be free'd somewhere.
> But I think you should put a reasonably small limit on the burst size that 
> users
> can configure and then you can allocate this as an array in XlnxZynqMPQSPIPS.
> 
> 
> 
> >  }
> >
> >  static void xlnx_zynqmp_qspips_init(Object *obj) @@ -1411,6 +1417,11
> > @@ static const VMStateDescription vmstate_xlnx_zynqmp_qspips = {
> >      }
> >  };
> >
> > +static Property xilinx_zynqmp_qspips_properties[] = {
> > +    DEFINE_PROP_UINT32("dma-burst-size", XlnxZynqMPQSPIPS,
> > +dma_burst_size, 64),
> 
> You need to limit this so users dont pick 4G. Perhaps 2 or 4K max.
> 
> Cheers,
> Edgar
> 
> 
> > +    DEFINE_PROP_END_OF_LIST(),
> > +};
> > +
> >  static Property xilinx_qspips_properties[] = {
> >      /* We had to turn this off for 2.10 as it is not compatible with 
> > migration.
> >       * It can be enabled but will prevent the device to be migrated.
> > @@ -1463,6 +1474,7 @@ static void
> xlnx_zynqmp_qspips_class_init(ObjectClass *klass, void * data)
> >      dc->realize = xlnx_zynqmp_qspips_realize;
> >      dc->reset = xlnx_zynqmp_qspips_reset;
> >      dc->vmsd = &vmstate_xlnx_zynqmp_qspips;
> > +    dc->props = xilinx_zynqmp_qspips_properties;
> >      xsc->reg_ops = &xlnx_zynqmp_qspips_ops;
> >      xsc->rx_fifo_size = RXFF_A_Q;
> >      xsc->tx_fifo_size = TXFF_A_Q;
> > diff --git a/include/hw/ssi/xilinx_spips.h
> > b/include/hw/ssi/xilinx_spips.h index d398a4e..cca1813 100644
> > --- a/include/hw/ssi/xilinx_spips.h
> > +++ b/include/hw/ssi/xilinx_spips.h
> > @@ -95,7 +95,8 @@ typedef struct {
> >      XilinxQSPIPS parent_obj;
> >
> >      StreamSlave *dma;
> > -    uint8_t dma_buf[4];
> > +    uint8_t *dma_buf;
> > +    uint32_t dma_burst_size;
> >      int gqspi_irqline;
> >
> >      uint32_t regs[XLNX_ZYNQMP_SPIPS_R_MAX];
> > --
> > 2.7.4
> >