From c2279bd0a19b35057f2e4c3b4df9a915717d1142 Mon Sep 17 00:00:00 2001 From: Finn Thain Date: Wed, 29 Jan 2020 20:27:49 +1100 Subject: [PATCH] dp8393x: Don't stop reception upon RBE interrupt assertion Section 3.4.7 of the datasheet explains that, The RBE bit in the Interrupt Status register is set when the SONIC finishes using the second to last receive buffer and reads the last RRA descriptor. Actually, the SONIC is not truly out of resources, but gives the system an early warning of an impending out of resources condition. RBE does not mean actual receive buffer exhaustion, and reception should not be stopped. This is important because Linux will not check and clear the RBE interrupt until it receives another packet. But that won't happen if can_receive returns false. This bug causes the SONIC to become deaf (until reset). Fix this with a new flag to indicate actual receive buffer exhaustion. Signed-off-by: Finn Thain Tested-by: Laurent Vivier Signed-off-by: Jason Wang --- hw/net/dp8393x.c | 37 +++++++++++++++++++++++-------------- 1 file changed, 23 insertions(+), 14 deletions(-) diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c index c2ac2a110e..8a3504d962 100644 --- a/hw/net/dp8393x.c +++ b/hw/net/dp8393x.c @@ -158,6 +158,7 @@ typedef struct dp8393xState { /* Hardware */ uint8_t it_shift; bool big_endian; + bool last_rba_is_full; qemu_irq irq; #ifdef DEBUG_SONIC int irq_level; @@ -347,12 +348,15 @@ static void dp8393x_do_read_rra(dp8393xState *s) s->regs[SONIC_RRP] = s->regs[SONIC_RSA]; } - /* Check resource exhaustion */ + /* Warn the host if CRBA now has the last available resource */ if (s->regs[SONIC_RRP] == s->regs[SONIC_RWP]) { s->regs[SONIC_ISR] |= SONIC_ISR_RBE; dp8393x_update_irq(s); } + + /* Allow packet reception */ + s->last_rba_is_full = false; } static void dp8393x_do_software_reset(dp8393xState *s) @@ -661,9 +665,6 @@ static void dp8393x_write(void *opaque, hwaddr addr, uint64_t data, dp8393x_do_read_rra(s); } dp8393x_update_irq(s); - if (dp8393x_can_receive(s->nic->ncs)) { - qemu_flush_queued_packets(qemu_get_queue(s->nic)); - } break; /* The guest is required to store aligned pointers here */ case SONIC_RSA: @@ -723,8 +724,6 @@ static int dp8393x_can_receive(NetClientState *nc) if (!(s->regs[SONIC_CR] & SONIC_CR_RXEN)) return 0; - if (s->regs[SONIC_ISR] & SONIC_ISR_RBE) - return 0; return 1; } @@ -775,6 +774,10 @@ static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf, s->regs[SONIC_RCR] &= ~(SONIC_RCR_PRX | SONIC_RCR_LBK | SONIC_RCR_FAER | SONIC_RCR_CRCR | SONIC_RCR_LPKT | SONIC_RCR_BC | SONIC_RCR_MC); + if (s->last_rba_is_full) { + return pkt_size; + } + rx_len = pkt_size + sizeof(checksum); if (s->regs[SONIC_DCR] & SONIC_DCR_DW) { width = 2; @@ -788,8 +791,8 @@ static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf, DPRINTF("oversize packet, pkt_size is %d\n", pkt_size); s->regs[SONIC_ISR] |= SONIC_ISR_RBAE; dp8393x_update_irq(s); - dp8393x_do_read_rra(s); - return pkt_size; + s->regs[SONIC_RCR] |= SONIC_RCR_LPKT; + goto done; } packet_type = dp8393x_receive_filter(s, buf, pkt_size); @@ -903,16 +906,22 @@ static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf, s->regs[SONIC_ISR] |= SONIC_ISR_PKTRX; } + dp8393x_update_irq(s); + s->regs[SONIC_RSC] = (s->regs[SONIC_RSC] & 0xff00) | ((s->regs[SONIC_RSC] + 1) & 0x00ff); - if (s->regs[SONIC_RCR] & SONIC_RCR_LPKT) { - /* Read next RRA */ - dp8393x_do_read_rra(s); - } +done: - /* Done */ - dp8393x_update_irq(s); + if (s->regs[SONIC_RCR] & SONIC_RCR_LPKT) { + if (s->regs[SONIC_RRP] == s->regs[SONIC_RWP]) { + /* Stop packet reception */ + s->last_rba_is_full = true; + } else { + /* Read next resource */ + dp8393x_do_read_rra(s); + } + } return pkt_size; }