diff mbox series

hw/ssi: Fix Linux driver init issue with xilinx_spi

Message ID 20230323182811.2641044-1-crauer@google.com (mailing list archive)
State New, archived
Headers show
Series hw/ssi: Fix Linux driver init issue with xilinx_spi | expand

Commit Message

Chris Rauer March 23, 2023, 6:28 p.m. UTC
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(+)

Comments

Peter Maydell March 30, 2023, 9:51 a.m. UTC | #1
Ping to the Xilinx folks, do you want to review this?

thanks
-- PMM

On Thu, 23 Mar 2023 at 18:28, Chris Rauer <crauer@google.com> wrote:
>
> 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
>
Edgar E. Iglesias March 31, 2023, 10:09 a.m. UTC | #2
On Thu, Mar 23, 2023 at 7:29 PM Chris Rauer <crauer@google.com> wrote:

> 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
>
>
Yes, MTI should be set when the device comes out of reset.

Reviewed-by: Edgar E. Iglesias <edgar@zeroasic.com>



> 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
>
>
>
Peter Maydell March 31, 2023, 10:11 a.m. UTC | #3
On Fri, 31 Mar 2023 at 11:09, Edgar E. Iglesias
<edgar.iglesias@gmail.com> wrote:
>
>
> On Thu, Mar 23, 2023 at 7:29 PM Chris Rauer <crauer@google.com> wrote:
>>
>> 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
>>
>
> Yes, MTI should be set when the device comes out of reset.
>
> Reviewed-by: Edgar E. Iglesias <edgar@zeroasic.com>

Thanks; applied to target-arm.next for 8.0.

-- PMM
diff mbox series

Patch

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);
 }