[v1] hw/dma: Add error handling for loading descriptions failing

[PATCH 1/4] hw/dma: Enhance error handling in loading description

Posted by Fea.Wang 5 months, 3 weeks ago

Loading a description from memory may cause a bus-error. In this
case, the DMA should stop working, set the error flag, and return
the error value.

Signed-off-by: Fea.Wang <fea.wang@sifive.com>
---
 hw/dma/xilinx_axidma.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
index 0ae056ed06..4b475e5484 100644
--- a/hw/dma/xilinx_axidma.c
+++ b/hw/dma/xilinx_axidma.c
@@ -71,8 +71,10 @@ enum {
 enum {
     DMASR_HALTED = 1,
     DMASR_IDLE  = 2,
+    DMASR_SLVERR = 1 << 5,
     DMASR_IOC_IRQ  = 1 << 12,
     DMASR_DLY_IRQ  = 1 << 13,
+    DMASR_ERR_IRQ  = 1 << 14,
 
     DMASR_IRQ_MASK = 7 << 12
 };
@@ -190,17 +192,27 @@ static inline int streamid_from_addr(hwaddr addr)
     return sid;
 }
 
-static void stream_desc_load(struct Stream *s, hwaddr addr)
+static MemTxResult stream_desc_load(struct Stream *s, hwaddr addr)
 {
     struct SDesc *d = &s->desc;
 
-    address_space_read(&s->dma->as, addr, MEMTXATTRS_UNSPECIFIED, d, sizeof *d);
+    MemTxResult result = address_space_read(&s->dma->as,
+                                            addr, MEMTXATTRS_UNSPECIFIED,
+                                            d, sizeof *d);
+    if (result != MEMTX_OK) {
+        s->regs[R_DMACR] &= ~DMACR_RUNSTOP;
+        s->regs[R_DMASR] |= DMASR_HALTED;
+        s->regs[R_DMASR] |= DMASR_SLVERR;
+        s->regs[R_DMASR] |= DMASR_ERR_IRQ;
+        return result;
+    }
 
     /* Convert from LE into host endianness.  */
     d->buffer_address = le64_to_cpu(d->buffer_address);
     d->nxtdesc = le64_to_cpu(d->nxtdesc);
     d->control = le32_to_cpu(d->control);
     d->status = le32_to_cpu(d->status);
+    return result;
 }
 
 static void stream_desc_store(struct Stream *s, hwaddr addr)
-- 
2.34.1

Re: [PATCH 1/4] hw/dma: Enhance error handling in loading description

Posted by Frank Chang 5 months, 3 weeks ago

Reviewed-by: Frank Chang <frank.chang@sifive.com>

Fea.Wang <fea.wang@sifive.com> 於 2024年6月3日 週一 下午1:48寫道：
>
> Loading a description from memory may cause a bus-error. In this
> case, the DMA should stop working, set the error flag, and return
> the error value.
>
> Signed-off-by: Fea.Wang <fea.wang@sifive.com>
> ---
>  hw/dma/xilinx_axidma.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
> index 0ae056ed06..4b475e5484 100644
> --- a/hw/dma/xilinx_axidma.c
> +++ b/hw/dma/xilinx_axidma.c
> @@ -71,8 +71,10 @@ enum {
>  enum {
>      DMASR_HALTED = 1,
>      DMASR_IDLE  = 2,
> +    DMASR_SLVERR = 1 << 5,
>      DMASR_IOC_IRQ  = 1 << 12,
>      DMASR_DLY_IRQ  = 1 << 13,
> +    DMASR_ERR_IRQ  = 1 << 14,
>
>      DMASR_IRQ_MASK = 7 << 12
>  };
> @@ -190,17 +192,27 @@ static inline int streamid_from_addr(hwaddr addr)
>      return sid;
>  }
>
> -static void stream_desc_load(struct Stream *s, hwaddr addr)
> +static MemTxResult stream_desc_load(struct Stream *s, hwaddr addr)
>  {
>      struct SDesc *d = &s->desc;
>
> -    address_space_read(&s->dma->as, addr, MEMTXATTRS_UNSPECIFIED, d, sizeof *d);
> +    MemTxResult result = address_space_read(&s->dma->as,
> +                                            addr, MEMTXATTRS_UNSPECIFIED,
> +                                            d, sizeof *d);
> +    if (result != MEMTX_OK) {
> +        s->regs[R_DMACR] &= ~DMACR_RUNSTOP;
> +        s->regs[R_DMASR] |= DMASR_HALTED;
> +        s->regs[R_DMASR] |= DMASR_SLVERR;
> +        s->regs[R_DMASR] |= DMASR_ERR_IRQ;
> +        return result;
> +    }
>
>      /* Convert from LE into host endianness.  */
>      d->buffer_address = le64_to_cpu(d->buffer_address);
>      d->nxtdesc = le64_to_cpu(d->nxtdesc);
>      d->control = le32_to_cpu(d->control);
>      d->status = le32_to_cpu(d->status);
> +    return result;
>  }
>
>  static void stream_desc_store(struct Stream *s, hwaddr addr)
> --
> 2.34.1
>
>

Re: [PATCH 1/4] hw/dma: Enhance error handling in loading description

Posted by Edgar E. Iglesias 5 months, 3 weeks ago

On Mon, Jun 3, 2024 at 7:47 AM Fea.Wang <fea.wang@sifive.com> wrote:

> Loading a description from memory may cause a bus-error. In this
> case, the DMA should stop working, set the error flag, and return
> the error value.
>
> Signed-off-by: Fea.Wang <fea.wang@sifive.com>
>


Hi Fea,

I've got a couple of small comments:


---
>  hw/dma/xilinx_axidma.c | 16 ++++++++++++++--
>  1 file changed, 14 insertions(+), 2 deletions(-)
>
> diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
> index 0ae056ed06..4b475e5484 100644
> --- a/hw/dma/xilinx_axidma.c
> +++ b/hw/dma/xilinx_axidma.c
> @@ -71,8 +71,10 @@ enum {
>  enum {
>      DMASR_HALTED = 1,
>      DMASR_IDLE  = 2,
> +    DMASR_SLVERR = 1 << 5,
>

We should also add DMASR_DECERR = 1 << 6


>      DMASR_IOC_IRQ  = 1 << 12,
>      DMASR_DLY_IRQ  = 1 << 13,
> +    DMASR_ERR_IRQ  = 1 << 14,
>
>      DMASR_IRQ_MASK = 7 << 12
>  };
> @@ -190,17 +192,27 @@ static inline int streamid_from_addr(hwaddr addr)
>      return sid;
>  }
>
> -static void stream_desc_load(struct Stream *s, hwaddr addr)
> +static MemTxResult stream_desc_load(struct Stream *s, hwaddr addr)
>  {
>      struct SDesc *d = &s->desc;
>
> -    address_space_read(&s->dma->as, addr, MEMTXATTRS_UNSPECIFIED, d,
> sizeof *d);
> +    MemTxResult result = address_space_read(&s->dma->as,
> +                                            addr, MEMTXATTRS_UNSPECIFIED,
> +                                            d, sizeof *d);
> +    if (result != MEMTX_OK) {
> +        s->regs[R_DMACR] &= ~DMACR_RUNSTOP;
> +        s->regs[R_DMASR] |= DMASR_HALTED;
> +        s->regs[R_DMASR] |= DMASR_SLVERR;
>

... and map MEMTX_DECODE_ERROR to DMASR_DECERR and everything else to
SLVERR, for example:
if (result == MEMTX_DECODE_ERROR) {
    s->regs[R_DMASR] |= DMASR_DECERR;
} else {
    s->regs[R_DMASR] |= DMASR_SLVERR;
}


> +        s->regs[R_DMASR] |= DMASR_ERR_IRQ;
> +        return result;
> +    }
>
>      /* Convert from LE into host endianness.  */
>      d->buffer_address = le64_to_cpu(d->buffer_address);
>      d->nxtdesc = le64_to_cpu(d->nxtdesc);
>      d->control = le32_to_cpu(d->control);
>      d->status = le32_to_cpu(d->status);
> +    return result;
>  }
>
>  static void stream_desc_store(struct Stream *s, hwaddr addr)
> --
> 2.34.1
>
>

Re: [PATCH 1/4] hw/dma: Enhance error handling in loading description

Posted by Fea Wang 5 months, 3 weeks ago

Hi Edgar,
Thank you for recommending to me. I will make the change in the next
version of the patch series.

Sincerely,
Fea

On Mon, Jun 3, 2024 at 6:19 PM Edgar E. Iglesias <edgar.iglesias@gmail.com>
wrote:

> On Mon, Jun 3, 2024 at 7:47 AM Fea.Wang <fea.wang@sifive.com> wrote:
>
>> Loading a description from memory may cause a bus-error. In this
>> case, the DMA should stop working, set the error flag, and return
>> the error value.
>>
>> Signed-off-by: Fea.Wang <fea.wang@sifive.com>
>>
>
>
> Hi Fea,
>
> I've got a couple of small comments:
>
>
> ---
>>  hw/dma/xilinx_axidma.c | 16 ++++++++++++++--
>>  1 file changed, 14 insertions(+), 2 deletions(-)
>>
>> diff --git a/hw/dma/xilinx_axidma.c b/hw/dma/xilinx_axidma.c
>> index 0ae056ed06..4b475e5484 100644
>> --- a/hw/dma/xilinx_axidma.c
>> +++ b/hw/dma/xilinx_axidma.c
>> @@ -71,8 +71,10 @@ enum {
>>  enum {
>>      DMASR_HALTED = 1,
>>      DMASR_IDLE  = 2,
>> +    DMASR_SLVERR = 1 << 5,
>>
>
> We should also add DMASR_DECERR = 1 << 6
>
>
>>      DMASR_IOC_IRQ  = 1 << 12,
>>      DMASR_DLY_IRQ  = 1 << 13,
>> +    DMASR_ERR_IRQ  = 1 << 14,
>>
>>      DMASR_IRQ_MASK = 7 << 12
>>  };
>> @@ -190,17 +192,27 @@ static inline int streamid_from_addr(hwaddr addr)
>>      return sid;
>>  }
>>
>> -static void stream_desc_load(struct Stream *s, hwaddr addr)
>> +static MemTxResult stream_desc_load(struct Stream *s, hwaddr addr)
>>  {
>>      struct SDesc *d = &s->desc;
>>
>> -    address_space_read(&s->dma->as, addr, MEMTXATTRS_UNSPECIFIED, d,
>> sizeof *d);
>> +    MemTxResult result = address_space_read(&s->dma->as,
>> +                                            addr, MEMTXATTRS_UNSPECIFIED,
>> +                                            d, sizeof *d);
>> +    if (result != MEMTX_OK) {
>> +        s->regs[R_DMACR] &= ~DMACR_RUNSTOP;
>> +        s->regs[R_DMASR] |= DMASR_HALTED;
>> +        s->regs[R_DMASR] |= DMASR_SLVERR;
>>
>
> ... and map MEMTX_DECODE_ERROR to DMASR_DECERR and everything else to
> SLVERR, for example:
> if (result == MEMTX_DECODE_ERROR) {
>     s->regs[R_DMASR] |= DMASR_DECERR;
> } else {
>     s->regs[R_DMASR] |= DMASR_SLVERR;
> }
>
>
>> +        s->regs[R_DMASR] |= DMASR_ERR_IRQ;
>> +        return result;
>> +    }
>>
>>      /* Convert from LE into host endianness.  */
>>      d->buffer_address = le64_to_cpu(d->buffer_address);
>>      d->nxtdesc = le64_to_cpu(d->nxtdesc);
>>      d->control = le32_to_cpu(d->control);
>>      d->status = le32_to_cpu(d->status);
>> +    return result;
>>  }
>>
>>  static void stream_desc_store(struct Stream *s, hwaddr addr)
>> --
>> 2.34.1
>>
>>