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

Bjorn Andersson
2020-05-21T18:05:38Z

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.

> + 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...

> + 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...

> + u32 padding;
> + u64 da;
> + u32 len;
> + u32 reserved;

What's the purpose of this reserved field?

Regards,
Bjorn

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