hw/ssi/xilinx_spips: Fix flash erase assert in dual parallel configuration

Ensure that the FIFO is checked for emptiness before popping data
from it.  Previously, the code directly popped the data from the FIFO
without checking, which could cause an assertion failure:

../util/fifo8.c:67: fifo8_pop: Assertion `fifo->num > 0' failed.

Signed-off-by: Shiva sagar Myana <Shivasagar.Myana@amd.com>
Message-id: 20240924112035.1320865-1-Shivasagar.Myana@amd.com
Reviewed-by: Francisco Iglesias <francisco.iglesias@amd.com>
[PMM: tweaked commit message]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/hw/ssi/xilinx_spips.c b/hw/ssi/xilinx_spips.c
index 1595a887a1d3eda0b28c0ed8a77ad79129f962d8..aeb462c3cec7ce6394991570d85c6b36bc0062f7 100644 (file)
--- a/hw/ssi/xilinx_spips.c
+++ b/hw/ssi/xilinx_spips.c
@@ -620,7 +620,9 @@ static void xilinx_spips_flush_txfifo(XilinxSPIPS *s)
         } else if (s->snoop_state == SNOOP_STRIPING ||
                    s->snoop_state == SNOOP_NONE) {
             for (i = 0; i < num_effective_busses(s); ++i) {
-                tx_rx[i] = fifo8_pop(&s->tx_fifo);
+                if (!fifo8_is_empty(&s->tx_fifo)) {
+                    tx_rx[i] = fifo8_pop(&s->tx_fifo);
+                }
             }
             stripe8(tx_rx, num_effective_busses(s), false);
         } else if (s->snoop_state >= SNOOP_ADDR) {