Re: [PATCH 3/3] dp8393x: fix receiving buffer exhaustion

[Laurent Vivier]

Le 02/11/2019 à 18:15, Laurent Vivier a écrit :
> The card is not able to exit from exhaustion state, because
> while the drive consumes the buffers, the RRP is incremented
> (when the driver clears the ISR RBE bit), so it stays equal
> to RWP, and while RRP == RWP, the card thinks it is always
> in exhaustion state. So the driver consumes all the buffers,
> but the card cannot receive new ones.
> 
> This patch fixes the problem by not incrementing RRP when
> the driver clears the ISR RBE bit.
> 
> Signed-off-by: Laurent Vivier <laur...@vivier.eu>
> ---
>  hw/net/dp8393x.c | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)

For reviewers, this patch main changes (without indentation changes) can
be simplified to:

diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
index b8c4473f99..123d110f16 100644
--- a/hw/net/dp8393x.c
+++ b/hw/net/dp8393x.c
@@ -304,7 +304,7 @@ static void dp8393x_do_load_cam(dp8393xState *s)
     dp8393x_update_irq(s);
 }

-static void dp8393x_do_read_rra(dp8393xState *s)
+static void dp8393x_do_read_rra(dp8393xState *s, int next)
 {
     int width, size;

@@ -323,6 +323,7 @@ static void dp8393x_do_read_rra(dp8393xState *s)
         s->regs[SONIC_CRBA0], s->regs[SONIC_CRBA1],
         s->regs[SONIC_RBWC0], s->regs[SONIC_RBWC1]);

+    if (next) {
         /* Go to next entry */
         s->regs[SONIC_RRP] += size;

@@ -337,6 +338,7 @@ static void dp8393x_do_read_rra(dp8393xState *s)
             s->regs[SONIC_ISR] |= SONIC_ISR_RBE;
             dp8393x_update_irq(s);
         }
+    }

     /* Done */
     s->regs[SONIC_CR] &= ~SONIC_CR_RRRA;
@@ -549,7 +551,7 @@ static void dp8393x_do_command(dp8393xState *s,
uint16_t command)
     if (command & SONIC_CR_RST)
         dp8393x_do_software_reset(s);
     if (command & SONIC_CR_RRRA)
-        dp8393x_do_read_rra(s);
+        dp8393x_do_read_rra(s, 1);
     if (command & SONIC_CR_LCAM)
         dp8393x_do_load_cam(s);
 }
@@ -640,7 +642,7 @@ static void dp8393x_write(void *opaque, hwaddr addr,
uint64_t data,
             data &= s->regs[reg];
             s->regs[reg] &= ~data;
             if (data & SONIC_ISR_RBE) {
-                dp8393x_do_read_rra(s);
+                dp8393x_do_read_rra(s, 0);
             }
             dp8393x_update_irq(s);
             if (dp8393x_can_receive(s->nic->ncs)) {
@@ -840,7 +842,7 @@ static ssize_t dp8393x_receive(NetClientState *nc,
const uint8_t * buf,

         if (s->regs[SONIC_RCR] & SONIC_RCR_LPKT) {
             /* Read next RRA */
-            dp8393x_do_read_rra(s);
+            dp8393x_do_read_rra(s, 1);
         }
     }