[PATCH v2 03/12] HID: core: split data fetching from processing in hid_input_field()

From: Benjamin Tissoires
Date: Thu Feb 03 2022 - 09:33:11 EST


This is a preparatory patch for being able to process the usages
out of order. We split the retrieval of the data in a separate function
and also split out the processing of the usages depending if the field
is an array or a variable.

No functional changes from this patch.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@xxxxxxxxxx>
---
drivers/hid/hid-core.c | 96 +++++++++++++++++++++++++++++++++---------
include/linux/hid.h | 3 +-
2 files changed, 79 insertions(+), 20 deletions(-)

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index fad4dbdf6391..34188d7ac0f7 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -1544,13 +1544,12 @@ static inline int hid_array_value_is_valid(struct hid_field *field,
}

/*
- * Analyse a received field, and fetch the data from it. The field
- * content is stored for next report processing (we do differential
- * reporting to the layer).
+ * Fetch the field from the data. The field content is stored for next
+ * report processing (we do differential reporting to the layer).
*/
-
-static void hid_input_field(struct hid_device *hid, struct hid_field *field,
- __u8 *data, int interrupt)
+static void hid_input_fetch_field(struct hid_device *hid,
+ struct hid_field *field,
+ __u8 *data)
{
unsigned n;
unsigned count = field->report_count;
@@ -1561,6 +1560,7 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,

value = field->new_value;
memset(value, 0, count * sizeof(__s32));
+ field->ignored = false;

for (n = 0; n < count; n++) {

@@ -1572,21 +1572,56 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
/* Ignore report if ErrorRollOver */
if (!(field->flags & HID_MAIN_ITEM_VARIABLE) &&
hid_array_value_is_valid(field, value[n]) &&
- field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1)
+ field->usage[value[n] - min].hid == HID_UP_KEYBOARD + 1) {
+ field->ignored = true;
return;
+ }
}
+}

- for (n = 0; n < count; n++) {
+/*
+ * Process a received variable field.
+ */

- if (HID_MAIN_ITEM_VARIABLE & field->flags) {
- hid_process_event(hid,
- field,
- &field->usage[n],
- value[n],
- interrupt);
- continue;
- }
+static void hid_input_var_field(struct hid_device *hid,
+ struct hid_field *field,
+ int interrupt)
+{
+ unsigned int count = field->report_count;
+ __s32 *value = field->new_value;
+ unsigned int n;
+
+ for (n = 0; n < count; n++)
+ hid_process_event(hid,
+ field,
+ &field->usage[n],
+ value[n],
+ interrupt);
+
+ memcpy(field->value, value, count * sizeof(__s32));
+}

+/*
+ * Process a received array field. The field content is stored for
+ * next report processing (we do differential reporting to the layer).
+ */
+
+static void hid_input_array_field(struct hid_device *hid,
+ struct hid_field *field,
+ int interrupt)
+{
+ unsigned int n;
+ unsigned int count = field->report_count;
+ __s32 min = field->logical_minimum;
+ __s32 *value;
+
+ value = field->new_value;
+
+ /* ErrorRollOver */
+ if (field->ignored)
+ return;
+
+ for (n = 0; n < count; n++) {
if (hid_array_value_is_valid(field, field->value[n]) &&
search(value, field->value[n], count))
hid_process_event(hid,
@@ -1607,6 +1642,31 @@ static void hid_input_field(struct hid_device *hid, struct hid_field *field,
memcpy(field->value, value, count * sizeof(__s32));
}

+/*
+ * Analyse a received report, and fetch the data from it. The field
+ * content is stored for next report processing (we do differential
+ * reporting to the layer).
+ */
+static void hid_process_report(struct hid_device *hid,
+ struct hid_report *report,
+ __u8 *data,
+ int interrupt)
+{
+ unsigned int a;
+ struct hid_field *field;
+
+ for (a = 0; a < report->maxfield; a++) {
+ field = report->field[a];
+
+ hid_input_fetch_field(hid, field, data);
+
+ if (field->flags & HID_MAIN_ITEM_VARIABLE)
+ hid_input_var_field(hid, field, interrupt);
+ else
+ hid_input_array_field(hid, field, interrupt);
+ }
+}
+
/*
* Output the field into the report.
*/
@@ -1768,7 +1828,6 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
struct hid_report_enum *report_enum = hid->report_enum + type;
struct hid_report *report;
struct hid_driver *hdrv;
- unsigned int a;
u32 rsize, csize = size;
u8 *cdata = data;
int ret = 0;
@@ -1804,8 +1863,7 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, u32 size,
}

if (hid->claimed != HID_CLAIMED_HIDRAW && report->maxfield) {
- for (a = 0; a < report->maxfield; a++)
- hid_input_field(hid, report->field[a], cdata, interrupt);
+ hid_process_report(hid, report, cdata, interrupt);
hdrv = hid->driver;
if (hdrv && hdrv->report)
hdrv->report(hid, report);
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 3fbfe0986659..cf79eb3da465 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -342,7 +342,7 @@ struct hid_item {
* HID device quirks.
*/

-/*
+/*
* Increase this if you need to configure more HID quirks at module load time
*/
#define MAX_USBHID_BOOT_QUIRKS 4
@@ -483,6 +483,7 @@ struct hid_field {
__s32 physical_maximum;
__s32 unit_exponent;
unsigned unit;
+ bool ignored; /* this field is ignored in this event */
struct hid_report *report; /* associated report */
unsigned index; /* index into report->field[] */
/* hidinput data */
--
2.33.1