Mathieu Poirier <[email protected]> writes:
> +static int stm_send(void *addr, const void *data, u32 size)
> +{
> + u32 len = size;
> +
> + if (((unsigned long)data & 0x1) && (size >= 1)) {
> + writeb_relaxed(*(u8 *)data, addr);
> + data++;
> + size--;
> + }
> + if (((unsigned long)data & 0x2) && (size >= 2)) {
> + writew_relaxed(*(u16 *)data, addr);
> + data += 2;
> + size -= 2;
> + }
> +
> + /* now we are 32bit aligned */
> + while (size >= 4) {
> + writel_relaxed(*(u32 *)data, addr);
> + data += 4;
> + size -= 4;
> + }
> +
> + if (size >= 2) {
> + writew_relaxed(*(u16 *)data, addr);
> + data += 2;
> + size -= 2;
> + }
> + if (size >= 1) {
> + writeb_relaxed(*(u8 *)data, addr);
> + data++;
> + size--;
> + }
> +
> + return len;
> +}
> +
> +static int stm_trace_data(unsigned long ch_addr, u32 options,
> + const void *data, u32 size)
> +{
> + void *addr;
> +
> + options &= ~STM_OPTION_TIMESTAMPED;
> + addr = (void *)(ch_addr | stm_channel_off(STM_PKT_TYPE_DATA, options));
> +
> + return stm_send(addr, data, size);
> +}
> +
> +static inline int stm_trace_hw(u32 options, u32 channel, u8 entity_id,
> + const void *data, u32 size)
> +{
> + int len = 0;
> + unsigned long ch_addr;
> + struct stm_drvdata *drvdata = stmdrvdata;
> +
> +
> + /* get the channel address */
> + ch_addr = (unsigned long)stm_channel_addr(drvdata, channel);
> +
> + if (drvdata->write_64bit)
> + len = stm_trace_data_64bit(ch_addr, options, data, size);
> + else
> + /* send the payload data */
> + len = stm_trace_data(ch_addr, options, data, size);
> +
> + return len;
> +}
As it looks from the above snippet, you're using a stream of DATA
packets for user's payload. I also noticed that you use an ioctl to
trigger timestamps.
Now, in the STP protocol there are, for example, marked data packets
that can be used to mark beginning of a higher-level message,
timestamped data packets that can be used to mean the same thing and
FLAG packets to mark message boundaries.
In my Intel TH code, I'm using D*TS packet for the beginning of a
message (or "frame") and FLAG packet for the the end of a message.
So my question is, is there any specific STP framing pattern that you
use with Coresight STM or should we perhaps figure out a generic framing
pattern and make it part of the stm class as well?
For example, we can replace stm's .write callback with something like
int (*packet)(struct stm_data *data,
unsigned int type, /* data, flag, trig etc */
unsigned int options, /* timestamped, marked */
u64 payload);
and let the stm core do the "framing", which, then, will be common and
consistent across different architectures/stm implementations.
> +static long stm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> + u32 options;
> + struct stm_node *node = file->private_data;
> +
> + switch (cmd) {
> + case STM_IOCTL_SET_OPTIONS:
> + if (copy_from_user(&options, (void __user *)arg, sizeof(u32)))
> + return -EFAULT;
> +
> + options &= (STM_OPTION_TIMESTAMPED | STM_OPTION_GUARANTEED);
> + node->options = options;
> + break;
> + case STM_IOCTL_GET_OPTIONS:
> + options = node->options;
> + if (copy_to_user((void __user *)arg, &options, sizeof(options)))
> + return -EFAULT;
> + break;
> + default:
> + return -EINVAL;
> + };
> +
> + return 0;
> +}
That way, we also won't need private ioctl()s, or at least, not for this
reason.
How do you feel about this?
Regards,
--
Alex
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