Re: [Qemu-devel] [PATCH] opencores_eth: flush queue whenever can_receive can go from false to true

[Paolo Bonzini <pbonzini@redhat.com>]

Il 03/02/2014 05:20, Max Filippov ha scritto:
> The following registers control whether MAC can receive frames:
> - MODER.RXEN bit that enables/disables receiver;
> - TX_BD_NUM register that specifies number of RX descriptors.
> Notify QEMU networking core when the MAC is ready to receive frames.
> Discard frame and raise BUSY interrupt when the frame arrives but the
> current RX descriptor is not empty.
>
> Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
> ---
>  hw/net/opencores_eth.c | 33 +++++++++++++++++++++++++++++++--
>  1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/hw/net/opencores_eth.c b/hw/net/opencores_eth.c
> index 4118d54..4a44304 100644
> --- a/hw/net/opencores_eth.c
> +++ b/hw/net/opencores_eth.c
> @@ -169,6 +169,7 @@ enum {
>  };
>
>  enum {
> +    INT_SOURCE_BUSY = 0x10,
>      INT_SOURCE_RXB = 0x4,
>      INT_SOURCE_TXB = 0x1,
>  };
> @@ -351,8 +352,7 @@ static int open_eth_can_receive(NetClientState *nc)
>      OpenEthState *s = qemu_get_nic_opaque(nc);
>
>      return GET_REGBIT(s, MODER, RXEN) &&
> -        (s->regs[TX_BD_NUM] < 0x80) &&
> -        (rx_desc(s)->len_flags & RXD_E);
> +        (s->regs[TX_BD_NUM] < 0x80);
>  }
>
>  static ssize_t open_eth_receive(NetClientState *nc,
> @@ -402,6 +402,12 @@ static ssize_t open_eth_receive(NetClientState *nc,
>          desc *desc = rx_desc(s);
>          size_t copy_size = GET_REGBIT(s, MODER, HUGEN) ? 65536 : maxfl;
>
> +        if (!(desc->len_flags & RXD_E)) {
> +            open_eth_int_source_write(s,
> +                    s->regs[INT_SOURCE] | INT_SOURCE_BUSY);
> +            return size;
> +        }
> +
>          desc->len_flags &= ~(RXD_CF | RXD_M | RXD_OR |
>                  RXD_IS | RXD_DN | RXD_TL | RXD_SF | RXD_CRC | RXD_LC);
>
> @@ -551,6 +557,15 @@ static uint64_t open_eth_reg_read(void *opaque,
>      return v;
>  }
>
> +static void open_eth_notify_can_receive(OpenEthState *s)
> +{
> +    NetClientState *nc = qemu_get_queue(s->nic);
> +
> +    if (open_eth_can_receive(nc)) {
> +        qemu_flush_queued_packets(nc);
> +    }
> +}
> +
>  static void open_eth_ro(OpenEthState *s, uint32_t val)
>  {
>  }
> @@ -567,6 +582,7 @@ static void open_eth_moder_host_write(OpenEthState *s, uint32_t val)
>
>      if (set & MODER_RXEN) {
>          s->rx_desc = s->regs[TX_BD_NUM];
> +        open_eth_notify_can_receive(s);
>      }
>      if (set & MODER_TXEN) {
>          s->tx_desc = 0;
> @@ -592,6 +608,18 @@ static void open_eth_int_mask_host_write(OpenEthState *s, uint32_t val)
>              s->regs[INT_SOURCE] & s->regs[INT_MASK]);
>  }
>
> +static void open_eth_tx_bd_num_host_write(OpenEthState *s, uint32_t val)
> +{
> +    if (val < 0x80) {
> +        bool enable = s->regs[TX_BD_NUM] == 0x80;
> +
> +        s->regs[TX_BD_NUM] = val;
> +        if (enable) {
> +            open_eth_notify_can_receive(s);
> +        }
> +    }
> +}
> +
>  static void open_eth_mii_command_host_write(OpenEthState *s, uint32_t val)
>  {
>      unsigned fiad = GET_REGFIELD(s, MIIADDRESS, FIAD);
> @@ -630,6 +658,7 @@ static void open_eth_reg_write(void *opaque,
>          [MODER] = open_eth_moder_host_write,
>          [INT_SOURCE] = open_eth_int_source_host_write,
>          [INT_MASK] = open_eth_int_mask_host_write,
> +        [TX_BD_NUM] = open_eth_tx_bd_num_host_write,
>          [MIICOMMAND] = open_eth_mii_command_host_write,
>          [MIITX_DATA] = open_eth_mii_tx_host_write,
>          [MIISTATUS] = open_eth_ro,
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>