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From: Chris Rauer <crauer@google.com>
To: alistair@alistair23.me, peter.maydell@linaro.org
Cc: qemu-devel@nongnu.org, Chris Rauer <crauer@google.com>
Subject: [PATCH] hw/ssi: Fix Linux driver init issue with xilinx_spi
Date: Thu, 23 Mar 2023 18:28:11 +0000	[thread overview]
Message-ID: <20230323182811.2641044-1-crauer@google.com> (raw)

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>
---
 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 552927622f..d4de2e7aab 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);
 }
-- 
2.40.0.348.gf938b09366-goog



             reply	other threads:[~2023-03-23 18:29 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-23 18:28 Chris Rauer [this message]
2023-03-30  9:51 ` [PATCH] hw/ssi: Fix Linux driver init issue with xilinx_spi Peter Maydell
2023-03-31 10:09 ` Edgar E. Iglesias
2023-03-31 10:11   ` Peter Maydell

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