static int __mhi_download_rddm_in_panic()

in mhi/core/boot.c [57:152]

• 62 lines of code
• 9 McCabe index (conditional complexity)

static int __mhi_download_rddm_in_panic(struct mhi_controller *mhi_cntrl)
{
	int ret;
	u32 rx_status;
	enum mhi_ee_type ee;
	const u32 delayus = 2000;
	u32 retry = (mhi_cntrl->timeout_ms * 1000) / delayus;
	const u32 rddm_timeout_us = 200000;
	int rddm_retry = rddm_timeout_us / delayus;
	void __iomem *base = mhi_cntrl->bhie;
	struct device *dev = &mhi_cntrl->mhi_dev->dev;

	dev_dbg(dev, "Entered with pm_state:%s dev_state:%s ee:%s\n",
		to_mhi_pm_state_str(mhi_cntrl->pm_state),
		TO_MHI_STATE_STR(mhi_cntrl->dev_state),
		TO_MHI_EXEC_STR(mhi_cntrl->ee));

	/*
	 * This should only be executing during a kernel panic, we expect all
	 * other cores to shutdown while we're collecting RDDM buffer. After
	 * returning from this function, we expect the device to reset.
	 *
	 * Normaly, we read/write pm_state only after grabbing the
	 * pm_lock, since we're in a panic, skipping it. Also there is no
	 * gurantee that this state change would take effect since
	 * we're setting it w/o grabbing pm_lock
	 */
	mhi_cntrl->pm_state = MHI_PM_LD_ERR_FATAL_DETECT;
	/* update should take the effect immediately */
	smp_wmb();

	/*
	 * Make sure device is not already in RDDM. In case the device asserts
	 * and a kernel panic follows, device will already be in RDDM.
	 * Do not trigger SYS ERR again and proceed with waiting for
	 * image download completion.
	 */
	ee = mhi_get_exec_env(mhi_cntrl);
	if (ee == MHI_EE_MAX)
		goto error_exit_rddm;

	if (ee != MHI_EE_RDDM) {
		dev_dbg(dev, "Trigger device into RDDM mode using SYS ERR\n");
		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_SYS_ERR);

		dev_dbg(dev, "Waiting for device to enter RDDM\n");
		while (rddm_retry--) {
			ee = mhi_get_exec_env(mhi_cntrl);
			if (ee == MHI_EE_RDDM)
				break;

			udelay(delayus);
		}

		if (rddm_retry <= 0) {
			/* Hardware reset so force device to enter RDDM */
			dev_dbg(dev,
				"Did not enter RDDM, do a host req reset\n");
			mhi_write_reg(mhi_cntrl, mhi_cntrl->regs,
				      MHI_SOC_RESET_REQ_OFFSET,
				      MHI_SOC_RESET_REQ);
			udelay(delayus);
		}

		ee = mhi_get_exec_env(mhi_cntrl);
	}

	dev_dbg(dev,
		"Waiting for RDDM image download via BHIe, current EE:%s\n",
		TO_MHI_EXEC_STR(ee));

	while (retry--) {
		ret = mhi_read_reg_field(mhi_cntrl, base, BHIE_RXVECSTATUS_OFFS,
					 BHIE_RXVECSTATUS_STATUS_BMSK,
					 BHIE_RXVECSTATUS_STATUS_SHFT,
					 &rx_status);
		if (ret)
			return -EIO;

		if (rx_status == BHIE_RXVECSTATUS_STATUS_XFER_COMPL)
			return 0;

		udelay(delayus);
	}

	ee = mhi_get_exec_env(mhi_cntrl);
	ret = mhi_read_reg(mhi_cntrl, base, BHIE_RXVECSTATUS_OFFS, &rx_status);

	dev_err(dev, "RXVEC_STATUS: 0x%x\n", rx_status);

error_exit_rddm:
	dev_err(dev, "RDDM transfer failed. Current EE: %s\n",
		TO_MHI_EXEC_STR(ee));

	return -EIO;
}