Re: [PATCH 2/3] hw/timer/xilinx_timer.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_timer 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/timer/xilinx_timer.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/hw/timer/xilinx_timer.c b/hw/timer/xilinx_timer.c
> index 92dbff304d9..7191ea54f58 100644
> --- a/hw/timer/xilinx_timer.c
> +++ b/hw/timer/xilinx_timer.c
> @@ -28,7 +28,6 @@
>   #include "hw/ptimer.h"
>   #include "hw/qdev-properties.h"
>   #include "qemu/log.h"
> -#include "qemu/main-loop.h"
>   #include "qemu/module.h"
>   
>   #define D(x)
> @@ -52,7 +51,6 @@
>   
>   struct xlx_timer
>   {
> -    QEMUBH *bh;
>       ptimer_state *ptimer;
>       void *parent;
>       int nr; /* for debug.  */
> @@ -134,6 +132,7 @@ timer_read(void *opaque, hwaddr addr, unsigned int size)
>       return r;
>   }
>   
> +/* Must be called inside ptimer transaction block */
>   static void timer_enable(struct xlx_timer *xt)
>   {
>       uint64_t count;
> @@ -174,8 +173,11 @@ timer_write(void *opaque, hwaddr addr,
>                   value &= ~TCSR_TINT;
>   
>               xt->regs[addr] = value & 0x7ff;
> -            if (value & TCSR_ENT)
> +            if (value & TCSR_ENT) {
> +                ptimer_transaction_begin(xt->ptimer);
>                   timer_enable(xt);
> +                ptimer_transaction_commit(xt->ptimer);

Why not move these inside timer_enable()?

> +            }
>               break;
>    
>           default:
> @@ -220,9 +222,10 @@ static void xilinx_timer_realize(DeviceState *dev, Error 
> **errp)
>   
>           xt->parent = t;
>           xt->nr = i;
> -        xt->bh = qemu_bh_new(timer_hit, xt);
> -        xt->ptimer = ptimer_init_with_bh(xt->bh, PTIMER_POLICY_DEFAULT);
> +        xt->ptimer = ptimer_init(timer_hit, xt, PTIMER_POLICY_DEFAULT);
> +        ptimer_transaction_begin(xt->ptimer);
>           ptimer_set_freq(xt->ptimer, t->freq_hz);
> +        ptimer_transaction_commit(xt->ptimer);
>       }
>   
>       memory_region_init_io(&t->mmio, OBJECT(t), &timer_ops, t, "xlnx.xps-timer",