Re: [PATCH 3/4] remoteproc: add support for a new 64-bit trace version

Suman Anna
2020-05-22T16:54:49Z

On 5/21/20 2:42 PM, Suman Anna wrote:
> Hi Bjorn,
>
> On 5/21/20 1:04 PM, Bjorn Andersson wrote:
>> On Wed 25 Mar 13:47 PDT 2020, Suman Anna wrote:
>>
>>> Introduce a new trace entry resource structure that accommodates
>>> a 64-bit device address to support 64-bit processors. This is to
>>> be used using an overloaded version value of 1 in the upper 32-bits
>>> of the previous resource type field. The new resource still uses
>>> 32-bits for the length field (followed by a 32-bit reserved field,
>>> so can be updated in the future), which is a sufficiently large
>>> trace buffer size. A 32-bit padding field also had to be added
>>> to align the device address on a 64-bit boundary, and match the
>>> usage on the firmware side.
>>>
>>> The remoteproc debugfs logic also has been adjusted accordingly.
>>>
>>> Signed-off-by: Suman Anna <s-anna@ti.com>
>>> ---
>>>   drivers/remoteproc/remoteproc_core.c    | 40 ++++++++++++++++++++-----
>>>   drivers/remoteproc/remoteproc_debugfs.c | 37 ++++++++++++++++++-----
>>>   include/linux/remoteproc.h              | 26 ++++++++++++++++
>>>   3 files changed, 87 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/remoteproc/remoteproc_core.c
>>> b/drivers/remoteproc/remoteproc_core.c
>>> index 53bc37c508c6..b9a097990862 100644
>>> --- a/drivers/remoteproc/remoteproc_core.c
>>> +++ b/drivers/remoteproc/remoteproc_core.c
>>> @@ -609,21 +609,45 @@ void rproc_vdev_release(struct kref *ref)
>>>    *
>>>    * Returns 0 on success, or an appropriate error code otherwise
>>>    */
>>> -static int rproc_handle_trace(struct rproc *rproc, struct
>>> fw_rsc_trace *rsc,
>>> +static int rproc_handle_trace(struct rproc *rproc, void *rsc,
>>>                     int offset, int avail, u16 ver)
>>>   {
>>>       struct rproc_debug_trace *trace;
>>>       struct device *dev = &rproc->dev;
>>> +    struct fw_rsc_trace *rsc1;
>>> +    struct fw_rsc_trace2 *rsc2;
>>>       char name[15];
>>> +    size_t rsc_size;
>>> +    u32 reserved;
>>> +    u64 da;
>>> +    u32 len;
>>> +
>>> +    if (!ver) {
>>
>> This looks like a switch to me, but I also do think this looks rather
>> crude, if you spin off the tail of this function and call it from a
>> rproc_handle_trace() and rproc_handle_trace64() I believe this would be
>> cleaner.
>
> Yeah, ok. Will refactor for this in v2.
>
>>
>>> +        rsc1 = (struct fw_rsc_trace *)rsc;
>>> +        rsc_size = sizeof(*rsc1);
>>> +        reserved = rsc1->reserved;
>>> +        da = rsc1->da;
>>> +        len = rsc1->len;
>>> +    } else if (ver == 1) {
>>> +        rsc2 = (struct fw_rsc_trace2 *)rsc;
>>> +        rsc_size = sizeof(*rsc2);
>>> +        reserved = rsc2->reserved;
>>> +        da = rsc2->da;
>>> +        len = rsc2->len;
>>> +    } else {
>>> +        dev_err(dev, "unsupported trace rsc version %d\n", ver);
>>
>> If we use "type" to describe your 64-bit-da-trace then this sanity check
>> would have been taken care of by the core.
>>
>>> +        return -EINVAL;
>>> +    }
>>> -    if (sizeof(*rsc) > avail) {
>>> +    if (rsc_size > avail) {
>>>           dev_err(dev, "trace rsc is truncated\n");
>>>           return -EINVAL;
>>>       }
>>>       /* make sure reserved bytes are zeroes */
>>> -    if (rsc->reserved) {
>>> -        dev_err(dev, "trace rsc has non zero reserved bytes\n");
>>> +    if (reserved) {
>>> +        dev_err(dev, "trace rsc has non zero reserved bytes, value =
>>> 0x%x\n",
>>> +            reserved);
>>>           return -EINVAL;
>>>       }
>>> @@ -632,8 +656,8 @@ static int rproc_handle_trace(struct rproc
>>> *rproc, struct fw_rsc_trace *rsc,
>>>           return -ENOMEM;
>>>       /* set the trace buffer dma properties */
>>> -    trace->trace_mem.len = rsc->len;
>>> -    trace->trace_mem.da = rsc->da;
>>> +    trace->trace_mem.len = len;
>>> +    trace->trace_mem.da = da;
>>>       /* set pointer on rproc device */
>>>       trace->rproc = rproc;
>>> @@ -652,8 +676,8 @@ static int rproc_handle_trace(struct rproc
>>> *rproc, struct fw_rsc_trace *rsc,
>>>       rproc->num_traces++;
>>> -    dev_dbg(dev, "%s added: da 0x%x, len 0x%x\n",
>>> -        name, rsc->da, rsc->len);
>>> +    dev_dbg(dev, "%s added: da 0x%llx, len 0x%x\n",
>>> +        name, da, len);
>>>       return 0;
>>>   }
>>> diff --git a/drivers/remoteproc/remoteproc_debugfs.c
>>> b/drivers/remoteproc/remoteproc_debugfs.c
>>> index 3560eed7a360..ff43736db45a 100644
>>> --- a/drivers/remoteproc/remoteproc_debugfs.c
>>> +++ b/drivers/remoteproc/remoteproc_debugfs.c
>>> @@ -192,7 +192,8 @@ static int rproc_rsc_table_show(struct seq_file
>>> *seq, void *p)
>>>       struct resource_table *table = rproc->table_ptr;
>>>       struct fw_rsc_carveout *c;
>>>       struct fw_rsc_devmem *d;
>>> -    struct fw_rsc_trace *t;
>>> +    struct fw_rsc_trace *t1;
>>> +    struct fw_rsc_trace2 *t2;
>>>       struct fw_rsc_vdev *v;
>>>       int i, j;
>>> @@ -205,6 +206,7 @@ static int rproc_rsc_table_show(struct seq_file
>>> *seq, void *p)
>>>           int offset = table->offset[i];
>>>           struct fw_rsc_hdr *hdr = (void *)table + offset;
>>>           void *rsc = (void *)hdr + sizeof(*hdr);
>>> +        u16 ver = hdr->st.v;
>>>           switch (hdr->st.t) {
>>>           case RSC_CARVEOUT:
>>> @@ -230,13 +232,32 @@ static int rproc_rsc_table_show(struct seq_file
>>> *seq, void *p)
>>>               seq_printf(seq, "  Name %s\n\n", d->name);
>>>               break;
>>>           case RSC_TRACE:
>>> -            t = rsc;
>>> -            seq_printf(seq, "Entry %d is of type %s\n",
>>> -                   i, types[hdr->st.t]);
>>> -            seq_printf(seq, "  Device Address 0x%x\n", t->da);
>>> -            seq_printf(seq, "  Length 0x%x Bytes\n", t->len);
>>> -            seq_printf(seq, "  Reserved (should be zero) [%d]\n",
>>> t->reserved);
>>> -            seq_printf(seq, "  Name %s\n\n", t->name);
>>> +            if (ver == 0) {
>>
>> Again, this is a switch, here in a switch. Just defining a new
>> RSC_TRACE64 type would reduce the amount of code here...
>
> OK.
>
>>
>>> +                t1 = rsc;
>>> +                seq_printf(seq, "Entry %d is version %d of type %s\n",
>>> +                       i, ver, types[hdr->st.t]);
>>> +                seq_printf(seq, "  Device Address 0x%x\n",
>>> +                       t1->da);
>>> +                seq_printf(seq, "  Length 0x%x Bytes\n",
>>> +                       t1->len);
>>> +                seq_printf(seq, "  Reserved (should be zero) [%d]\n",
>>> +                       t1->reserved);
>>> +                seq_printf(seq, "  Name %s\n\n", t1->name);
>>> +            } else if (ver == 1) {
>>> +                t2 = rsc;
>>> +                seq_printf(seq, "Entry %d is version %d of type %s\n",
>>> +                       i, ver, types[hdr->st.t]);
>>> +                seq_printf(seq, "  Device Address 0x%llx\n",
>>> +                       t2->da);
>>> +                seq_printf(seq, "  Length 0x%x Bytes\n",
>>> +                       t2->len);
>>> +                seq_printf(seq, "  Reserved (should be zero) [%d]\n",
>>> +                       t2->reserved);
>>> +                seq_printf(seq, "  Name %s\n\n", t2->name);
>>> +            } else {
>>> +                seq_printf(seq, "Entry %d is an unsupported version
>>> %d of type %s\n",
>>> +                       i, ver, types[hdr->st.t]);
>>> +            }
>>>               break;
>>>           case RSC_VDEV:
>>>               v = rsc;
>>> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
>>> index 526d3cb45e37..3b3bea42f8b1 100644
>>> --- a/include/linux/remoteproc.h
>>> +++ b/include/linux/remoteproc.h
>>> @@ -243,6 +243,32 @@ struct fw_rsc_trace {
>>>       u8 name[32];
>>>   } __packed;
>>> +/**
>>> + * struct fw_rsc_trace2 - trace buffer declaration supporting 64-bits
>>> + * @padding: initial padding after type field for aligned 64-bit access
>>> + * @da: device address (64-bit)
>>> + * @len: length (in bytes)
>>> + * @reserved: reserved (must be zero)
>>> + * @name: human-readable name of the trace buffer
>>> + *
>>> + * This resource entry is an enhanced version of the fw_rsc_trace
>>> resourec entry
>>> + * and the provides equivalent functionality but designed for 64-bit
>>> remote
>>> + * processors.
>>> + *
>>> + * @da specifies the device address of the buffer, @len specifies
>>> + * its size, and @name may contain a human readable name of the
>>> trace buffer.
>>> + *
>>> + * After booting the remote processor, the trace buffers are exposed
>>> to the
>>> + * user via debugfs entries (called trace0, trace1, etc..).
>>> + */
>>> +struct fw_rsc_trace2 {
>>
>> Sounds more like fw_rsc_trace64 to me - in particular since the version
>> of trace2 is 1...
>
> Yeah, will rename this.
>
>>
>>> +    u32 padding;
>>> +    u64 da;
>>> +    u32 len;
>>> +    u32 reserved;
>>
>> What's the purpose of this reserved field?
>
> Partly to make sure the entire resource is aligned on an 8-byte, and
> partly copied over from fw_rsc_trace entry. I guess 32-bits is already
> large enough of a size for trace entries irrespective of 32-bit or
> 64-bit traces, so I doubt if we want to make the len field also a u64.

Looking at this again, I can drop both padding and reserved fields, if I
move the len field before da. Any preferences/comments?

regards
Suman

>
> regards
> Suman
>
>>
>> Regards,
>> Bjorn
>>
>>> +    u8 name[32];
>>> +} __packed;
>>> +
>>>   /**
>>>    * struct fw_rsc_vdev_vring - vring descriptor entry
>>>    * @da: device address
>>> --
>>> 2.23.0
>>>
>