Re: [PATCH 3/3] hw/dma/xilinx_axidma.c: Switch to transaction-based ptimer API

[Philippe Mathieu-Daudé]

Hi Peter,

On 10/17/19 3:21 PM, Peter Maydell wrote:
> Switch the xilinx_axidma code away from bottom-half based ptimers to
> the new transaction-based ptimer API.  This just requires adding
> begin/commit calls around the various places that modify the ptimer
> state, and using the new ptimer_init() function to create the timer.
>
> Signed-off-by: Peter Maydell <address@hidden>
> ---
>   hw/dma/xilinx_axidma.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
> index e035d1f7504..fb3a978e282 100644
> --- a/hw/dma/xilinx_axidma.c
> +++ b/hw/dma/xilinx_axidma.c
> @@ -31,7 +31,6 @@
>   #include "hw/ptimer.h"
>   #include "hw/qdev-properties.h"
>   #include "qemu/log.h"
> -#include "qemu/main-loop.h"
>   #include "qemu/module.h"
>   
>   #include "hw/stream.h"
> @@ -104,7 +103,6 @@ enum {
>   };
>   
>   struct Stream {
> -    QEMUBH *bh;
>       ptimer_state *ptimer;
>       qemu_irq irq;
>   
> @@ -242,6 +240,7 @@ static void stream_complete(struct Stream *s)
>       unsigned int comp_delay;
>   
>       /* Start the delayed timer.  */
> +    ptimer_transaction_begin(s->ptimer);
>       comp_delay = s->regs[R_DMACR] >> 24;
>       if (comp_delay) {
>           ptimer_stop(s->ptimer);
> @@ -255,6 +254,7 @@ static void stream_complete(struct Stream *s)
>           s->regs[R_DMASR] |= DMASR_IOC_IRQ;
>           stream_reload_complete_cnt(s);
>       }
> +    ptimer_transaction_commit(s->ptimer);

I'd restrict the transaction here within the if() statement:

-- >8 --
@@ -244,9 +244,11 @@ static void stream_complete(struct Stream *s)
     /* Start the delayed timer.  */
     comp_delay = s->regs[R_DMACR] >> 24;
     if (comp_delay) {
+        ptimer_transaction_begin(s->ptimer);
         ptimer_stop(s->ptimer);
         ptimer_set_count(s->ptimer, comp_delay);
         ptimer_run(s->ptimer, 1);
+        ptimer_transaction_commit(s->ptimer);
     }

     s->complete_cnt--;
---

>   }
>   
>   static void stream_process_mem2s(struct Stream *s, StreamSlave *tx_data_dev,
> @@ -551,9 +551,10 @@ static void xilinx_axidma_realize(DeviceState *dev, Error 
> **errp)
>           struct Stream *st = &s->streams[i];
>   
>           st->nr = i;
> -        st->bh = qemu_bh_new(timer_hit, st);
> -        st->ptimer = ptimer_init_with_bh(st->bh, PTIMER_POLICY_DEFAULT);
> +        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);
>       }
>       return;
>