static int mtk_cpufreq_voltage_tracking()

in mediatek-cpufreq.c [61:191]

• 96 lines of code
• 21 McCabe index (conditional complexity)

static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
					int new_vproc)
{
	struct regulator *proc_reg = info->proc_reg;
	struct regulator *sram_reg = info->sram_reg;
	int old_vproc, old_vsram, new_vsram, vsram, vproc, ret;

	old_vproc = regulator_get_voltage(proc_reg);
	if (old_vproc < 0) {
		pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
		return old_vproc;
	}
	/* Vsram should not exceed the maximum allowed voltage of SoC. */
	new_vsram = min(new_vproc + MIN_VOLT_SHIFT, MAX_VOLT_LIMIT);

	if (old_vproc < new_vproc) {
		/*
		 * When scaling up voltages, Vsram and Vproc scale up step
		 * by step. At each step, set Vsram to (Vproc + 200mV) first,
		 * then set Vproc to (Vsram - 100mV).
		 * Keep doing it until Vsram and Vproc hit target voltages.
		 */
		do {
			old_vsram = regulator_get_voltage(sram_reg);
			if (old_vsram < 0) {
				pr_err("%s: invalid Vsram value: %d\n",
				       __func__, old_vsram);
				return old_vsram;
			}
			old_vproc = regulator_get_voltage(proc_reg);
			if (old_vproc < 0) {
				pr_err("%s: invalid Vproc value: %d\n",
				       __func__, old_vproc);
				return old_vproc;
			}

			vsram = min(new_vsram, old_vproc + MAX_VOLT_SHIFT);

			if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
				vsram = MAX_VOLT_LIMIT;

				/*
				 * If the target Vsram hits the maximum voltage,
				 * try to set the exact voltage value first.
				 */
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram);
				if (ret)
					ret = regulator_set_voltage(sram_reg,
							vsram - VOLT_TOL,
							vsram);

				vproc = new_vproc;
			} else {
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram + VOLT_TOL);

				vproc = vsram - MIN_VOLT_SHIFT;
			}
			if (ret)
				return ret;

			ret = regulator_set_voltage(proc_reg, vproc,
						    vproc + VOLT_TOL);
			if (ret) {
				regulator_set_voltage(sram_reg, old_vsram,
						      old_vsram);
				return ret;
			}
		} while (vproc < new_vproc || vsram < new_vsram);
	} else if (old_vproc > new_vproc) {
		/*
		 * When scaling down voltages, Vsram and Vproc scale down step
		 * by step. At each step, set Vproc to (Vsram - 200mV) first,
		 * then set Vproc to (Vproc + 100mV).
		 * Keep doing it until Vsram and Vproc hit target voltages.
		 */
		do {
			old_vproc = regulator_get_voltage(proc_reg);
			if (old_vproc < 0) {
				pr_err("%s: invalid Vproc value: %d\n",
				       __func__, old_vproc);
				return old_vproc;
			}
			old_vsram = regulator_get_voltage(sram_reg);
			if (old_vsram < 0) {
				pr_err("%s: invalid Vsram value: %d\n",
				       __func__, old_vsram);
				return old_vsram;
			}

			vproc = max(new_vproc, old_vsram - MAX_VOLT_SHIFT);
			ret = regulator_set_voltage(proc_reg, vproc,
						    vproc + VOLT_TOL);
			if (ret)
				return ret;

			if (vproc == new_vproc)
				vsram = new_vsram;
			else
				vsram = max(new_vsram, vproc + MIN_VOLT_SHIFT);

			if (vsram + VOLT_TOL >= MAX_VOLT_LIMIT) {
				vsram = MAX_VOLT_LIMIT;

				/*
				 * If the target Vsram hits the maximum voltage,
				 * try to set the exact voltage value first.
				 */
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram);
				if (ret)
					ret = regulator_set_voltage(sram_reg,
							vsram - VOLT_TOL,
							vsram);
			} else {
				ret = regulator_set_voltage(sram_reg, vsram,
							    vsram + VOLT_TOL);
			}

			if (ret) {
				regulator_set_voltage(proc_reg, old_vproc,
						      old_vproc);
				return ret;
			}
		} while (vproc > new_vproc + VOLT_TOL ||
			 vsram > new_vsram + VOLT_TOL);
	}

	return 0;
}