diff --git a/drivers/platform/chrome/cros_ec_sensorhub_ring.c b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
index 71948dade0e2aedd0a1f1b4ea09dc954c6fb5b5e..1205219515d67c8ce999e5df4171c5dd1d1d28c7 100644
--- a/drivers/platform/chrome/cros_ec_sensorhub_ring.c
+++ b/drivers/platform/chrome/cros_ec_sensorhub_ring.c
@@ -103,7 +103,7 @@ EXPORT_SYMBOL_GPL(cros_ec_sensorhub_unregister_push_data);
* @sensorhub: Sensor Hub object
* @on: true when events are requested.
*
- * To be called before sleeping or when noone is listening.
+ * To be called before sleeping or when no one is listening.
* Return: 0 on success, or an error when we can not communicate with the EC.
*
*/
@@ -133,33 +133,61 @@ int cros_ec_sensorhub_ring_fifo_enable(struct cros_ec_sensorhub *sensorhub,
return ret;
}
-static int cros_ec_sensor_ring_median_cmp(const void *pv1, const void *pv2)
+static void cros_ec_sensor_ring_median_swap(s64 *a, s64 *b)
{
- s64 v1 = *(s64 *)pv1;
- s64 v2 = *(s64 *)pv2;
-
- if (v1 > v2)
- return 1;
- else if (v1 < v2)
- return -1;
- else
- return 0;
+ s64 tmp = *a;
+ *a = *b;
+ *b = tmp;
}
/*
* cros_ec_sensor_ring_median: Gets median of an array of numbers
*
- * For now it's implemented using an inefficient > O(n) sort then return
- * the middle element. A more optimal method would be something like
- * quickselect, but given that n = 64 we can probably live with it in the
- * name of clarity.
+ * It's implemented using the quickselect algorithm, which achieves an
+ * average time complexity of O(n) the middle element. In the worst case,
+ * the runtime of quickselect could regress to O(n^2). To mitigate this,
+ * algorithms like median-of-medians exist, which can guarantee O(n) even
+ * in the worst case. However, these algorithms come with a higher
+ * overhead and are more complex to implement, making quickselect a
+ * pragmatic choice for our use case.
*
- * Warning: the input array gets modified (sorted)!
+ * Warning: the input array gets modified!
*/
static s64 cros_ec_sensor_ring_median(s64 *array, size_t length)
{
- sort(array, length, sizeof(s64), cros_ec_sensor_ring_median_cmp, NULL);
- return array[length / 2];
+ int lo = 0;
+ int hi = length - 1;
+
+ while (lo <= hi) {
+ int mid = lo + (hi - lo) / 2;
+ int pivot, i;
+
+ if (array[lo] > array[mid])
+ cros_ec_sensor_ring_median_swap(&array[lo], &array[mid]);
+ if (array[lo] > array[hi])
+ cros_ec_sensor_ring_median_swap(&array[lo], &array[hi]);
+ if (array[mid] < array[hi])
+ cros_ec_sensor_ring_median_swap(&array[mid], &array[hi]);
+
+ pivot = array[hi];
+ i = lo - 1;
+
+ for (int j = lo; j < hi; j++)
+ if (array[j] < pivot)
+ cros_ec_sensor_ring_median_swap(&array[++i], &array[j]);
+
+ /* The pivot's index corresponds to i+1. */
+ cros_ec_sensor_ring_median_swap(&array[i + 1], &array[hi]);
+ if (i + 1 == length / 2)
+ return array[i + 1];
+ if (i + 1 > length / 2)
+ hi = i;
+ else
+ lo = i + 2;
+ }
+
+ /* Should never reach here. */
+ return -1;
}
/*
@@ -175,8 +203,8 @@ static s64 cros_ec_sensor_ring_median(s64 *array, size_t length)
*
* While a and b are recorded at accurate times (due to the EC real time
* nature); c is pretty untrustworthy, even though it's recorded the
- * first thing in ec_irq_handler(). There is a very good change we'll get
- * added lantency due to:
+ * first thing in ec_irq_handler(). There is a very good chance we'll get
+ * added latency due to:
* other irqs
* ddrfreq
* cpuidle
@@ -511,7 +539,7 @@ cros_ec_sensor_ring_process_event(struct cros_ec_sensorhub *sensorhub,
* ringbuffer.
*
* This is the new spreading code, assumes every sample's timestamp
- * preceeds the sample. Run if tight_timestamps == true.
+ * precedes the sample. Run if tight_timestamps == true.
*
* Sometimes the EC receives only one interrupt (hence timestamp) for
* a batch of samples. Only the first sample will have the correct
@@ -595,7 +623,7 @@ cros_ec_sensor_ring_spread_add(struct cros_ec_sensorhub *sensorhub,
} else {
/*
* Push first sample in the batch to the,
- * kifo, it's guaranteed to be correct, the
+ * kfifo, it's guaranteed to be correct, the
* rest will follow later on.
*/
sample_idx = 1;
@@ -701,7 +729,7 @@ cros_ec_sensor_ring_spread_add(struct cros_ec_sensorhub *sensorhub,
* last_out -->
*
*
- * We spread time for the samples using perod p = (current - TS1)/4.
+ * We spread time for the samples using period p = (current - TS1)/4.
* between TS1 and TS2: [TS1+p/4, TS1+2p/4, TS1+3p/4, current_timestamp].
*
*/
diff --git a/drivers/platform/chrome/cros_ec_vbc.c b/drivers/platform/chrome/cros_ec_vbc.c
index 2e4af10c76792e3efce87decd00bbfc98ddd5bbf..274ea0c64b33ba0992c3e6d5fd6503ed564fa96a 100644
--- a/drivers/platform/chrome/cros_ec_vbc.c
+++ b/drivers/platform/chrome/cros_ec_vbc.c
@@ -20,10 +20,14 @@ static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
struct device *dev = kobj_to_dev(kobj);
struct cros_ec_dev *ec = to_cros_ec_dev(dev);
struct cros_ec_device *ecdev = ec->ec_dev;
- struct ec_params_vbnvcontext *params;
struct cros_ec_command *msg;
+ /*
+ * This should be a pointer to the same type as op field in
+ * struct ec_params_vbnvcontext.
+ */
+ uint32_t *params_op;
int err;
- const size_t para_sz = sizeof(params->op);
+ const size_t para_sz = sizeof(*params_op);
const size_t resp_sz = sizeof(struct ec_response_vbnvcontext);
const size_t payload = max(para_sz, resp_sz);
@@ -32,8 +36,8 @@ static ssize_t vboot_context_read(struct file *filp, struct kobject *kobj,
return -ENOMEM;
/* NB: we only kmalloc()ated enough space for the op field */
- params = (struct ec_params_vbnvcontext *)msg->data;
- params->op = EC_VBNV_CONTEXT_OP_READ;
+ params_op = (uint32_t *)msg->data;
+ *params_op = EC_VBNV_CONTEXT_OP_READ;
msg->version = EC_VER_VBNV_CONTEXT;
msg->command = EC_CMD_VBNV_CONTEXT;
diff --git a/drivers/platform/chrome/wilco_ec/event.c b/drivers/platform/chrome/wilco_ec/event.c
index f80a7c83cfba02d29f3d464af4386c94f55c7026..13291fb4214e82bf78cb73e8b19916a5da68faa6 100644
--- a/drivers/platform/chrome/wilco_ec/event.c
+++ b/drivers/platform/chrome/wilco_ec/event.c
@@ -495,7 +495,7 @@ static int event_device_add(struct acpi_device *adev)
free_dev_data:
hangup_device(dev_data);
free_minor:
- ida_simple_remove(&event_ida, minor);
+ ida_free(&event_ida, minor);
return error;
}
@@ -504,7 +504,7 @@ static void event_device_remove(struct acpi_device *adev)
struct event_device_data *dev_data = adev->driver_data;
cdev_device_del(&dev_data->cdev, &dev_data->dev);
- ida_simple_remove(&event_ida, MINOR(dev_data->dev.devt));
+ ida_free(&event_ida, MINOR(dev_data->dev.devt));
hangup_device(dev_data);
}
diff --git a/drivers/platform/chrome/wilco_ec/telemetry.c b/drivers/platform/chrome/wilco_ec/telemetry.c
index 253098bace63e32192b8ef850913ab5a59daba44..b7c616f3d179bf669e4248944886cea6419efc1c 100644
--- a/drivers/platform/chrome/wilco_ec/telemetry.c
+++ b/drivers/platform/chrome/wilco_ec/telemetry.c
@@ -372,7 +372,7 @@ static int telem_device_probe(struct platform_device *pdev)
dev_data = kzalloc(sizeof(*dev_data), GFP_KERNEL);
if (!dev_data) {
- ida_simple_remove(&telem_ida, minor);
+ ida_free(&telem_ida, minor);
return -ENOMEM;
}
@@ -393,7 +393,7 @@ static int telem_device_probe(struct platform_device *pdev)
error = cdev_device_add(&dev_data->cdev, &dev_data->dev);
if (error) {
put_device(&dev_data->dev);
- ida_simple_remove(&telem_ida, minor);
+ ida_free(&telem_ida, minor);
return error;
}
@@ -405,7 +405,7 @@ static void telem_device_remove(struct platform_device *pdev)
struct telem_device_data *dev_data = platform_get_drvdata(pdev);
cdev_device_del(&dev_data->cdev, &dev_data->dev);
- ida_simple_remove(&telem_ida, MINOR(dev_data->dev.devt));
+ ida_free(&telem_ida, MINOR(dev_data->dev.devt));
put_device(&dev_data->dev);
}