[PULL 4/4] hw/ssi: Fix Linux driver init issue with xilinx_spi

[Peter Maydell <peter.maydell@linaro.org>]

From: Chris Rauer <crauer@google.com>

The problem is that the Linux driver expects the master transaction inhibit
bit(R_SPICR_MTI) to be set during driver initialization so that it can
detect the fifo size but QEMU defaults it to zero out of reset.  The
datasheet indicates this bit is active on reset.

See page 25, SPI Control Register section:
https://www.xilinx.com/content/dam/xilinx/support/documents/ip_documentation/axi_quad_spi/v3_2/pg153-axi-quad-spi.pdf

Signed-off-by: Chris Rauer <crauer@google.com>
Message-id: 20230323182811.2641044-1-crauer@google.com
Reviewed-by: Edgar E. Iglesias <edgar@zeroasic.com>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/ssi/xilinx_spi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/ssi/xilinx_spi.c b/hw/ssi/xilinx_spi.c
index 552927622f4..d4de2e7aabc 100644
--- a/hw/ssi/xilinx_spi.c
+++ b/hw/ssi/xilinx_spi.c
@@ -156,6 +156,7 @@ static void xlx_spi_do_reset(XilinxSPI *s)
     txfifo_reset(s);
 
     s->regs[R_SPISSR] = ~0;
+    s->regs[R_SPICR] = R_SPICR_MTI;
     xlx_spi_update_irq(s);
     xlx_spi_update_cs(s);
 }
-- 
2.34.1