static int __issue_avs_command()

in brcmstb-avs-cpufreq.c [224:314]

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

static int __issue_avs_command(struct private_data *priv, unsigned int cmd,
			       unsigned int num_in, unsigned int num_out,
			       u32 args[])
{
	void __iomem *base = priv->base;
	unsigned long time_left;
	unsigned int i;
	int ret;
	u32 val;

	ret = down_interruptible(&priv->sem);
	if (ret)
		return ret;

	/*
	 * Make sure no other command is currently running: cmd is 0 if AVS
	 * co-processor is idle. Due to the guard above, we should almost never
	 * have to wait here.
	 */
	for (i = 0, val = 1; val != 0 && i < AVS_LOOP_LIMIT; i++)
		val = readl(base + AVS_MBOX_COMMAND);

	/* Give the caller a chance to retry if AVS is busy. */
	if (i == AVS_LOOP_LIMIT) {
		ret = -EAGAIN;
		goto out;
	}

	/* Clear status before we begin. */
	writel(AVS_STATUS_CLEAR, base + AVS_MBOX_STATUS);

	/* Provide input parameters */
	for (i = 0; i < num_in; i++)
		writel(args[i], base + AVS_MBOX_PARAM(i));

	/* Protect from spurious interrupts. */
	reinit_completion(&priv->done);

	/* Now issue the command & tell firmware to wake up to process it. */
	writel(cmd, base + AVS_MBOX_COMMAND);
	writel(AVS_CPU_L2_INT_MASK, priv->avs_intr_base + AVS_CPU_L2_SET0);

	/* Wait for AVS co-processor to finish processing the command. */
	time_left = wait_for_avs_command(priv, AVS_TIMEOUT);

	/*
	 * If the AVS status is not in the expected range, it means AVS didn't
	 * complete our command in time, and we return an error. Also, if there
	 * is no "time left", we timed out waiting for the interrupt.
	 */
	val = readl(base + AVS_MBOX_STATUS);
	if (time_left == 0 || val == 0 || val > AVS_STATUS_MAX) {
		dev_err(priv->dev, "AVS command %#x didn't complete in time\n",
			cmd);
		dev_err(priv->dev, "    Time left: %u ms, AVS status: %#x\n",
			jiffies_to_msecs(time_left), val);
		ret = -ETIMEDOUT;
		goto out;
	}

	/* Process returned values */
	for (i = 0; i < num_out; i++)
		args[i] = readl(base + AVS_MBOX_PARAM(i));

	/* Clear status to tell AVS co-processor we are done. */
	writel(AVS_STATUS_CLEAR, base + AVS_MBOX_STATUS);

	/* Convert firmware errors to errno's as much as possible. */
	switch (val) {
	case AVS_STATUS_INVALID:
		ret = -EINVAL;
		break;
	case AVS_STATUS_NO_SUPP:
		ret = -ENOTSUPP;
		break;
	case AVS_STATUS_NO_MAP:
		ret = -ENOENT;
		break;
	case AVS_STATUS_MAP_SET:
		ret = -EEXIST;
		break;
	case AVS_STATUS_FAILURE:
		ret = -EIO;
		break;
	}

out:
	up(&priv->sem);

	return ret;
}