* Peter Maydell (peter.mayd...@linaro.org) wrote:
> The datasheet is clear that the frame length written to the DATA
> register is actually stored in the TX FIFO; this means we don't
> need to keep both tx_frame_len and tx_fifo_len state separately.
>
> Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
> ---
> hw/net/stellaris_enet.c | 119
> +++++++++++++++++++++++++++++++-----------------
> 1 file changed, 77 insertions(+), 42 deletions(-)
>
> diff --git a/hw/net/stellaris_enet.c b/hw/net/stellaris_enet.c
> index d0da819..b99f93e 100644
> --- a/hw/net/stellaris_enet.c
> +++ b/hw/net/stellaris_enet.c
> @@ -59,7 +59,6 @@ typedef struct {
> uint32_t mtxd;
> uint32_t mrxd;
> uint32_t np;
> - int tx_frame_len;
> int tx_fifo_len;
> uint8_t tx_fifo[2048];
> /* Real hardware has a 2k fifo, which works out to be at most 31 packets.
> @@ -82,6 +81,62 @@ static void stellaris_enet_update(stellaris_enet_state *s)
> qemu_set_irq(s->irq, (s->ris & s->im) != 0);
> }
>
> +/* Return the data length of the packet currently being assembled
> + * in the TX fifo.
> + */
> +static inline int stellaris_txpacket_datalen(stellaris_enet_state *s)
> +{
> + return s->tx_fifo[0] | (s->tx_fifo[1] << 8);
> +}
> +
> +/* Return true if the packet currently in the TX FIFO is complete,
> +* ie the FIFO holds enough bytes for the data length, ethernet header,
> +* payload and optionally CRC.
> +*/
> +static inline bool stellaris_txpacket_complete(stellaris_enet_state *s)
> +{
> + int framelen = stellaris_txpacket_datalen(s);
> + framelen += 16;
What's the magical 16? (It doesn't jump out from the data sheet).
> + if (!(s->tctl & SE_TCTL_CRC)) {
> + framelen += 4;
> + }
> + /* Cover the corner case of a 2032 byte payload with auto-CRC disabled:
> + * this requires more bytes than will fit in the FIFO. It's not totally
> + * clear how the h/w handles this, but if using threshold-based TX
> + * it will definitely try to transmit something.
> + */
> + framelen = MIN(framelen, ARRAY_SIZE(s->tx_fifo));
> + return s->tx_fifo_len >= framelen;
> +}
> +
> +/* Send the packet currently in the TX FIFO */
> +static void stellaris_enet_send(stellaris_enet_state *s)
> +{
> + int framelen = stellaris_txpacket_datalen(s);
> +
> + /* Ethernet header is in the FIFO but not in the datacount.
> + * We don't implement explicit CRC, so just ignore any
> + * CRC value in the FIFO.
> + */
> + framelen += 14;
> + if ((s->tctl & SE_TCTL_PADEN) && framelen < 60) {
> + memset(&s->tx_fifo[framelen + 2], 0, 60 - framelen);
> + framelen = 60;
> + }
> + /* This MIN will have no effect unless the FIFO data is corrupt
> + * (eg bad data from an incoming migration); otherwise the check
> + * on the datalen at the start of writing the data into the FIFO
> + * will have caught this. Silently write a corrupt half-packet,
> + * which is what the hardware does in FIFO underrun situations.
> + */
> + framelen = MIN(framelen, ARRAY_SIZE(s->tx_fifo) - 2);
> + qemu_send_packet(qemu_get_queue(s->nic), s->tx_fifo + 2, framelen);
> + s->tx_fifo_len = 0;
> + s->ris |= SE_INT_TXEMP;
> + stellaris_enet_update(s);
> + DPRINTF("Done TX\n");
> +}
> +
> /* TODO: Implement MAC address filtering. */
> static ssize_t stellaris_enet_receive(NetClientState *nc, const uint8_t
> *buf, size_t size)
> {
> @@ -215,8 +270,9 @@ static void stellaris_enet_write(void *opaque, hwaddr
> offset,
> DPRINTF("IRQ ack %02x/%02x\n", value, s->ris);
> stellaris_enet_update(s);
> /* Clearing TXER also resets the TX fifo. */
> - if (value & SE_INT_TXER)
> - s->tx_frame_len = -1;
> + if (value & SE_INT_TXER) {
> + s->tx_fifo_len = 0;
> + }
> break;
> case 0x04: /* IM */
> DPRINTF("IRQ mask %02x/%02x\n", value, s->ris);
> @@ -235,46 +291,27 @@ static void stellaris_enet_write(void *opaque, hwaddr
> offset,
> s->tctl = value;
> break;
> case 0x10: /* DATA */
> - if (s->tx_frame_len == -1) {
> - s->tx_frame_len = value & 0xffff;
> - if (s->tx_frame_len > 2032) {
> - DPRINTF("TX frame too long (%d)\n", s->tx_frame_len);
> - s->tx_frame_len = 0;
> + if (s->tx_fifo_len == 0) {
> + /* The first word is special, it contains the data length */
> + int framelen = value & 0xffff;
> + if (framelen > 2032) {
> + DPRINTF("TX frame too long (%d)\n", framelen);
> s->ris |= SE_INT_TXER;
> stellaris_enet_update(s);
> - } else {
> - DPRINTF("Start TX frame len=%d\n", s->tx_frame_len);
> - /* The value written does not include the ethernet header.
> */
> - s->tx_frame_len += 14;
> - if ((s->tctl & SE_TCTL_CRC) == 0)
> - s->tx_frame_len += 4;
> - s->tx_fifo_len = 0;
> - s->tx_fifo[s->tx_fifo_len++] = value >> 16;
> - s->tx_fifo[s->tx_fifo_len++] = value >> 24;
> - }
> - } else {
> - if (s->tx_fifo_len + 4 <= ARRAY_SIZE(s->tx_fifo)) {
> - s->tx_fifo[s->tx_fifo_len++] = value;
> - s->tx_fifo[s->tx_fifo_len++] = value >> 8;
> - s->tx_fifo[s->tx_fifo_len++] = value >> 16;
> - s->tx_fifo[s->tx_fifo_len++] = value >> 24;
> - }
> - if (s->tx_fifo_len >= s->tx_frame_len) {
> - /* We don't implement explicit CRC, so just chop it off. */
> - if ((s->tctl & SE_TCTL_CRC) == 0)
> - s->tx_frame_len -= 4;
> - if ((s->tctl & SE_TCTL_PADEN) && s->tx_frame_len < 60) {
> - memset(&s->tx_fifo[s->tx_frame_len], 0, 60 -
> s->tx_frame_len);
> - s->tx_frame_len = 60;
> - }
> - qemu_send_packet(qemu_get_queue(s->nic), s->tx_fifo,
> - s->tx_frame_len);
> - s->tx_frame_len = -1;
> - s->ris |= SE_INT_TXEMP;
> - stellaris_enet_update(s);
> - DPRINTF("Done TX\n");
> + break;
> }
> }
> +
> + if (s->tx_fifo_len + 4 <= ARRAY_SIZE(s->tx_fifo)) {
> + s->tx_fifo[s->tx_fifo_len++] = value;
> + s->tx_fifo[s->tx_fifo_len++] = value >> 8;
> + s->tx_fifo[s->tx_fifo_len++] = value >> 16;
> + s->tx_fifo[s->tx_fifo_len++] = value >> 24;
> + }
> +
> + if (stellaris_txpacket_complete(s)) {
> + stellaris_enet_send(s);
> + }
> break;
> case 0x14: /* IA0 */
> s->conf.macaddr.a[0] = value;
> @@ -326,7 +363,7 @@ static void stellaris_enet_reset(stellaris_enet_state *s)
> s->im = SE_INT_PHY | SE_INT_MD | SE_INT_RXER | SE_INT_FOV | SE_INT_TXEMP
> | SE_INT_TXER | SE_INT_RX;
> s->thr = 0x3f;
> - s->tx_frame_len = -1;
> + s->tx_fifo_len = 0;
> }
>
> static void stellaris_enet_save(QEMUFile *f, void *opaque)
> @@ -344,7 +381,6 @@ static void stellaris_enet_save(QEMUFile *f, void *opaque)
> qemu_put_be32(f, s->mtxd);
> qemu_put_be32(f, s->mrxd);
> qemu_put_be32(f, s->np);
> - qemu_put_be32(f, s->tx_frame_len);
> qemu_put_be32(f, s->tx_fifo_len);
> qemu_put_buffer(f, s->tx_fifo, sizeof(s->tx_fifo));
> for (i = 0; i < 31; i++) {
> @@ -375,7 +411,6 @@ static int stellaris_enet_load(QEMUFile *f, void *opaque,
> int version_id)
> s->mtxd = qemu_get_be32(f);
> s->mrxd = qemu_get_be32(f);
> s->np = qemu_get_be32(f);
> - s->tx_frame_len = qemu_get_be32(f);
> s->tx_fifo_len = qemu_get_be32(f);
> qemu_get_buffer(f, s->tx_fifo, sizeof(s->tx_fifo));
> for (i = 0; i < 31; i++) {
You should probably increment the migration state version number to 2.
Dave
> --
> 1.9.0
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
