on i.MX6Q, cpu freq change need to follow below flows:
1. each setpoint has different VDDARM, VDDSOC/PU voltage, get the setpoint
table from dts;
2. when cpu freq is scaling up, need to increase VDDSOC/PU voltage before
VDDARM, if VDDPU is off, no need to change it;
3. when cpu freq is scaling down, need to decrease VDDARM voltage before
VDDSOC/PU, if VDDPU is off, no need to change it;
normally dts will pass vddsoc/pu freq/volt info to kernel, if not, will
use fixed value for vddsoc/pu voltage setting.
Signed-off-by: Anson Huang <b20788@xxxxxxxxxxxxx>
---
drivers/cpufreq/imx6q-cpufreq.c | 106 ++++++++++++++++++++++++++++-----------
1 file changed, 77 insertions(+), 29 deletions(-)
diff --git a/drivers/cpufreq/imx6q-cpufreq.c b/drivers/cpufreq/imx6q-cpufreq.c
index 4b3f18e..c29198f 100644
--- a/drivers/cpufreq/imx6q-cpufreq.c
+++ b/drivers/cpufreq/imx6q-cpufreq.c
@@ -35,6 +35,9 @@ static struct device *cpu_dev;
static struct cpufreq_frequency_table *freq_table;
static unsigned int transition_latency;
+static u32 *imx6_soc_volt;
+static u32 soc_opp_count;
+
static unsigned int imx6q_get_speed(unsigned int cpu)
{
return clk_get_rate(arm_clk) / 1000;
@@ -69,23 +72,22 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
/* scaling up? scale voltage before frequency */
if (new_freq > old_freq) {
+ ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
+ if (ret) {
+ dev_err(cpu_dev, "failed to scale vddpu up: %d\n", ret);
+ return ret;
+ }
+ ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
+ if (ret) {
+ dev_err(cpu_dev, "failed to scale vddsoc up: %d\n", ret);
+ return ret;
+ }
ret = regulator_set_voltage_tol(arm_reg, volt, 0);
if (ret) {
dev_err(cpu_dev,
"failed to scale vddarm up: %d\n", ret);
return ret;
}
-
- /*
- * Need to increase vddpu and vddsoc for safety
- * if we are about to run at 1.2 GHz.
- */
- if (new_freq == FREQ_1P2_GHZ / 1000) {
- regulator_set_voltage_tol(pu_reg,
- PU_SOC_VOLTAGE_HIGH, 0);
- regulator_set_voltage_tol(soc_reg,
- PU_SOC_VOLTAGE_HIGH, 0);
- }
}
/*
@@ -120,12 +122,15 @@ static int imx6q_set_target(struct cpufreq_policy *policy, unsigned int index)
"failed to scale vddarm down: %d\n", ret);
ret = 0;
}
-
- if (old_freq == FREQ_1P2_GHZ / 1000) {
- regulator_set_voltage_tol(pu_reg,
- PU_SOC_VOLTAGE_NORMAL, 0);
- regulator_set_voltage_tol(soc_reg,
- PU_SOC_VOLTAGE_NORMAL, 0);
+ ret = regulator_set_voltage_tol(soc_reg, imx6_soc_volt[index], 0);
+ if (ret) {
+ dev_warn(cpu_dev, "failed to scale vddsoc down: %d\n", ret);
+ ret = 0;
+ }
+ ret = regulator_set_voltage_tol(pu_reg, imx6_soc_volt[index], 0);
+ if (ret) {
+ dev_warn(cpu_dev, "failed to scale vddpu down: %d\n", ret);
+ ret = 0;
}
}
@@ -153,6 +158,9 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
struct dev_pm_opp *opp;
unsigned long min_volt, max_volt;
int num, ret;
+ const struct property *prop;
+ const __be32 *val;
+ u32 nr, i, j;
cpu_dev = get_cpu_device(0);
if (!cpu_dev) {
@@ -201,10 +209,62 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
goto put_node;
}
+ /* Make imx6_soc_volt array's size same as arm opp number */
+ imx6_soc_volt = devm_kzalloc(cpu_dev, sizeof(*imx6_soc_volt) * num, GFP_KERNEL);
+ if (imx6_soc_volt == NULL) {
+ ret = -ENOMEM;
+ goto free_freq_table;
+ }
+
+ prop = of_find_property(np, "fsl,soc-operating-points", NULL);
+ if (!prop || !prop->value)
+ goto soc_opp_out;
+
+ /*
+ * Each OPP is a set of tuples consisting of frequency and
+ * voltage like <freq-kHz vol-uV>.
+ */
+ nr = prop->length / sizeof(u32);
+ if (nr % 2 || (nr / 2) < num)
+ goto soc_opp_out;
+
+ for (j = 0; j < num; j++) {
+ val = prop->value;
+ for (i = 0; i < nr / 2; i++) {
+ unsigned long freq = be32_to_cpup(val++);
+ unsigned long volt = be32_to_cpup(val++);
+ if (freq_table[j].frequency == freq) {
+ imx6_soc_volt[soc_opp_count++] = volt;
+ break;
+ }
+ }
+ }
+
+soc_opp_out:
+ /* use fixed soc opp volt if no valid soc opp info found in dtb */
+ if (soc_opp_count != num) {
+ dev_warn(cpu_dev, "can NOT find valid fsl,soc-operating-points property in dtb, use default value!\n");
+ for (j = 0; j < num; j++)
+ imx6_soc_volt[j] = PU_SOC_VOLTAGE_NORMAL;
+ if (freq_table[num - 1].frequency * 1000 == FREQ_1P2_GHZ)
+ imx6_soc_volt[num - 1] = PU_SOC_VOLTAGE_HIGH;
+ }
+
if (of_property_read_u32(np, "clock-latency", &transition_latency))
transition_latency = CPUFREQ_ETERNAL;
/*
+ * Calculate the ramp time for max voltage change in the
+ * VDDSOC and VDDPU regulators.
+ */
+ ret = regulator_set_voltage_time(soc_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
+ if (ret > 0)
+ transition_latency += ret * 1000;
+ ret = regulator_set_voltage_time(pu_reg, imx6_soc_volt[0], imx6_soc_volt[num - 1]);
+ if (ret > 0)
+ transition_latency += ret * 1000;
+
+ /*
* OPP is maintained in order of increasing frequency, and
* freq_table initialised from OPP is therefore sorted in the
* same order.
@@ -221,18 +281,6 @@ static int imx6q_cpufreq_probe(struct platform_device *pdev)
if (ret > 0)
transition_latency += ret * 1000;
- /* Count vddpu and vddsoc latency in for 1.2 GHz support */
- if (freq_table[num].frequency == FREQ_1P2_GHZ / 1000) {
- ret = regulator_set_voltage_time(pu_reg, PU_SOC_VOLTAGE_NORMAL,
- PU_SOC_VOLTAGE_HIGH);
- if (ret > 0)
- transition_latency += ret * 1000;
- ret = regulator_set_voltage_time(soc_reg, PU_SOC_VOLTAGE_NORMAL,
- PU_SOC_VOLTAGE_HIGH);
- if (ret > 0)
- transition_latency += ret * 1000;
- }
-
ret = cpufreq_register_driver(&imx6q_cpufreq_driver);
if (ret) {
dev_err(cpu_dev, "failed register driver: %d\n", ret);
--
1.7.9.5
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