static ssize_t notrace sth_stm_packet()

in intel_th/sth.c [62:139]

• 63 lines of code
• 15 McCabe index (conditional complexity)

static ssize_t notrace sth_stm_packet(struct stm_data *stm_data,
				      unsigned int master,
				      unsigned int channel,
				      unsigned int packet,
				      unsigned int flags,
				      unsigned int size,
				      const unsigned char *payload)
{
	struct sth_device *sth = container_of(stm_data, struct sth_device, stm);
	struct intel_th_channel __iomem *out =
		sth_channel(sth, master, channel);
	u64 __iomem *outp = &out->Dn;
	unsigned long reg = REG_STH_TRIG;

#ifndef CONFIG_64BIT
	if (size > 4)
		size = 4;
#endif

	size = rounddown_pow_of_two(size);

	switch (packet) {
	/* Global packets (GERR, XSYNC, TRIG) are sent with register writes */
	case STP_PACKET_GERR:
		reg += 4;
		fallthrough;

	case STP_PACKET_XSYNC:
		reg += 8;
		fallthrough;

	case STP_PACKET_TRIG:
		if (flags & STP_PACKET_TIMESTAMPED)
			reg += 4;
		writeb_relaxed(*payload, sth->base + reg);
		break;

	case STP_PACKET_MERR:
		if (size > 4)
			size = 4;

		sth_iowrite(&out->MERR, payload, size);
		break;

	case STP_PACKET_FLAG:
		if (flags & STP_PACKET_TIMESTAMPED)
			outp = (u64 __iomem *)&out->FLAG_TS;
		else
			outp = (u64 __iomem *)&out->FLAG;

		size = 0;
		writeb_relaxed(0, outp);
		break;

	case STP_PACKET_USER:
		if (flags & STP_PACKET_TIMESTAMPED)
			outp = &out->USER_TS;
		else
			outp = &out->USER;
		sth_iowrite(outp, payload, size);
		break;

	case STP_PACKET_DATA:
		outp = &out->Dn;

		if (flags & STP_PACKET_TIMESTAMPED)
			outp += 2;
		if (flags & STP_PACKET_MARKED)
			outp++;

		sth_iowrite(outp, payload, size);
		break;
	default:
		return -ENOTSUPP;
	}

	return size;
}