sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

1 files changed, 486 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
new file mode 100644
index 000000000..c2dcfce50
--- /dev/null
+++ b/drivers/input/touchscreen/st1232.c
@@ -0,0 +1,486 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ST1232 Touchscreen Controller Driver
+ *
+ * Copyright (C) 2010 Renesas Solutions Corp.
+ *	Tony SIM <chinyeow.sim.xt@renesas.com>
+ *
+ * Using code from:
+ *  - android.git.kernel.org: projects/kernel/common.git: synaptics_i2c_rmi.c
+ *	Copyright (C) 2007 Google, Inc.
+ */
+
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/input.h>
+#include <linux/input/mt.h>
+#include <linux/input/touch-overlay.h>
+#include <linux/input/touchscreen.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_qos.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+#define ST1232_TS_NAME	"st1232-ts"
+#define ST1633_TS_NAME	"st1633-ts"
+
+#define REG_FIRMWARE_VERSION	0x00
+#define REG_FIRMWARE_REVISION_3	0x0C
+
+#define REG_STATUS		0x01	/* Device Status | Error Code */
+
+#define STATUS_NORMAL		0x00
+#define STATUS_INIT		0x01
+#define STATUS_ERROR		0x02
+#define STATUS_AUTO_TUNING	0x03
+#define STATUS_IDLE		0x04
+#define STATUS_POWER_DOWN	0x05
+
+#define ERROR_NONE		0x00
+#define ERROR_INVALID_ADDRESS	0x10
+#define ERROR_INVALID_VALUE	0x20
+#define ERROR_INVALID_PLATFORM	0x30
+
+#define REG_XY_RESOLUTION	0x04
+#define REG_XY_COORDINATES	0x12
+#define ST_TS_MAX_FINGERS	10
+
+struct st_chip_info {
+	bool	have_z;
+	u16	max_area;
+	u16	max_fingers;
+};
+
+struct st1232_ts_data {
+	struct i2c_client *client;
+	struct input_dev *input_dev;
+	struct touchscreen_properties prop;
+	struct dev_pm_qos_request low_latency_req;
+	struct gpio_desc *reset_gpio;
+	const struct st_chip_info *chip_info;
+	struct list_head touch_overlay_list;
+	int read_buf_len;
+	u8 *read_buf;
+	u8 fw_version;
+	u32 fw_revision;
+};
+
+static ssize_t fw_version_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct st1232_ts_data *st1232_ts = i2c_get_clientdata(client);
+
+	return sysfs_emit(buf, "%u\n", st1232_ts->fw_version);
+}
+
+static ssize_t fw_revision_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct st1232_ts_data *st1232_ts = i2c_get_clientdata(client);
+
+	return sysfs_emit(buf, "%08x\n", st1232_ts->fw_revision);
+}
+
+static DEVICE_ATTR_RO(fw_version);
+static DEVICE_ATTR_RO(fw_revision);
+
+static struct attribute *st1232_attrs[] = {
+	&dev_attr_fw_version.attr,
+	&dev_attr_fw_revision.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(st1232);
+
+static int st1232_ts_read_data(struct st1232_ts_data *ts, u8 reg,
+			       unsigned int n)
+{
+	struct i2c_client *client = ts->client;
+	struct i2c_msg msg[] = {
+		{
+			.addr	= client->addr,
+			.len	= sizeof(reg),
+			.buf	= &reg,
+		},
+		{
+			.addr	= client->addr,
+			.flags	= I2C_M_RD | I2C_M_DMA_SAFE,
+			.len	= n,
+			.buf	= ts->read_buf,
+		}
+	};
+	int ret;
+
+	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+	if (ret != ARRAY_SIZE(msg))
+		return ret < 0 ? ret : -EIO;
+
+	return 0;
+}
+
+static int st1232_ts_wait_ready(struct st1232_ts_data *ts)
+{
+	unsigned int retries;
+	int error;
+
+	for (retries = 100; retries; retries--) {
+		error = st1232_ts_read_data(ts, REG_STATUS, 1);
+		if (!error) {
+			switch (ts->read_buf[0]) {
+			case STATUS_NORMAL | ERROR_NONE:
+			case STATUS_IDLE | ERROR_NONE:
+				return 0;
+			}
+		}
+
+		usleep_range(1000, 2000);
+	}
+
+	return -ENXIO;
+}
+
+static int st1232_ts_read_fw_version(struct st1232_ts_data *ts,
+				     u8 *fw_version, u32 *fw_revision)
+{
+	int error;
+
+	/* select firmware version register */
+	error = st1232_ts_read_data(ts, REG_FIRMWARE_VERSION, 1);
+	if (error)
+		return error;
+	*fw_version = ts->read_buf[0];
+
+	/* select firmware revision register */
+	error = st1232_ts_read_data(ts, REG_FIRMWARE_REVISION_3, 4);
+	if (error)
+		return error;
+	*fw_revision = le32_to_cpup((__le32 *)ts->read_buf);
+
+	return 0;
+}
+
+static int st1232_ts_read_resolution(struct st1232_ts_data *ts, u16 *max_x,
+				     u16 *max_y)
+{
+	u8 *buf;
+	int error;
+
+	/* select resolution register */
+	error = st1232_ts_read_data(ts, REG_XY_RESOLUTION, 3);
+	if (error)
+		return error;
+
+	buf = ts->read_buf;
+
+	*max_x = (((buf[0] & 0x0070) << 4) | buf[1]) - 1;
+	*max_y = (((buf[0] & 0x0007) << 8) | buf[2]) - 1;
+
+	return 0;
+}
+
+static int st1232_ts_parse_and_report(struct st1232_ts_data *ts)
+{
+	struct input_dev *input = ts->input_dev;
+	struct input_mt_pos pos[ST_TS_MAX_FINGERS];
+	u8 z[ST_TS_MAX_FINGERS];
+	int slots[ST_TS_MAX_FINGERS];
+	int n_contacts = 0;
+	int i;
+
+	for (i = 0; i < ts->chip_info->max_fingers; i++) {
+		u8 *buf = &ts->read_buf[i * 4];
+
+		if (buf[0] & BIT(7)) {
+			unsigned int x = ((buf[0] & 0x70) << 4) | buf[1];
+			unsigned int y = ((buf[0] & 0x07) << 8) | buf[2];
+
+			touchscreen_set_mt_pos(&pos[n_contacts],
+					       &ts->prop, x, y);
+
+			/* st1232 includes a z-axis / touch strength */
+			if (ts->chip_info->have_z)
+				z[n_contacts] = ts->read_buf[i + 6];
+
+			n_contacts++;
+		}
+	}
+
+	input_mt_assign_slots(input, slots, pos, n_contacts, 0);
+	for (i = 0; i < n_contacts; i++) {
+		if (touch_overlay_process_contact(&ts->touch_overlay_list,
+						  input, &pos[i], slots[i]))
+			continue;
+
+		input_mt_slot(input, slots[i]);
+		input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
+		input_report_abs(input, ABS_MT_POSITION_X, pos[i].x);
+		input_report_abs(input, ABS_MT_POSITION_Y, pos[i].y);
+		if (ts->chip_info->have_z)
+			input_report_abs(input, ABS_MT_TOUCH_MAJOR, z[i]);
+	}
+
+	touch_overlay_sync_frame(&ts->touch_overlay_list, input);
+	input_mt_sync_frame(input);
+	input_sync(input);
+
+	return n_contacts;
+}
+
+static irqreturn_t st1232_ts_irq_handler(int irq, void *dev_id)
+{
+	struct st1232_ts_data *ts = dev_id;
+	int count;
+	int error;
+
+	error = st1232_ts_read_data(ts, REG_XY_COORDINATES, ts->read_buf_len);
+	if (error)
+		goto out;
+
+	count = st1232_ts_parse_and_report(ts);
+	if (!count) {
+		if (ts->low_latency_req.dev) {
+			dev_pm_qos_remove_request(&ts->low_latency_req);
+			ts->low_latency_req.dev = NULL;
+		}
+	} else if (!ts->low_latency_req.dev) {
+		/* First contact, request 100 us latency. */
+		dev_pm_qos_add_ancestor_request(&ts->client->dev,
+						&ts->low_latency_req,
+						DEV_PM_QOS_RESUME_LATENCY, 100);
+	}
+
+out:
+	return IRQ_HANDLED;
+}
+
+static void st1232_ts_power(struct st1232_ts_data *ts, bool poweron)
+{
+	if (ts->reset_gpio)
+		gpiod_set_value_cansleep(ts->reset_gpio, !poweron);
+}
+
+static void st1232_ts_power_off(void *data)
+{
+	st1232_ts_power(data, false);
+}
+
+static const struct st_chip_info st1232_chip_info = {
+	.have_z		= true,
+	.max_area	= 0xff,
+	.max_fingers	= 2,
+};
+
+static const struct st_chip_info st1633_chip_info = {
+	.have_z		= false,
+	.max_area	= 0x00,
+	.max_fingers	= 5,
+};
+
+static int st1232_ts_probe(struct i2c_client *client)
+{
+	const struct i2c_device_id *id = i2c_client_get_device_id(client);
+	const struct st_chip_info *match;
+	struct st1232_ts_data *ts;
+	struct input_dev *input_dev;
+	u16 max_x, max_y;
+	int error;
+
+	match = device_get_match_data(&client->dev);
+	if (!match && id)
+		match = (const void *)id->driver_data;
+	if (!match) {
+		dev_err(&client->dev, "unknown device model\n");
+		return -ENODEV;
+	}
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev, "need I2C_FUNC_I2C\n");
+		return -EIO;
+	}
+
+	if (!client->irq) {
+		dev_err(&client->dev, "no IRQ?\n");
+		return -EINVAL;
+	}
+
+	ts = devm_kzalloc(&client->dev, sizeof(*ts), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	ts->chip_info = match;
+
+	/* allocate a buffer according to the number of registers to read */
+	ts->read_buf_len = ts->chip_info->max_fingers * 4;
+	ts->read_buf = devm_kzalloc(&client->dev, ts->read_buf_len, GFP_KERNEL);
+	if (!ts->read_buf)
+		return -ENOMEM;
+
+	input_dev = devm_input_allocate_device(&client->dev);
+	if (!input_dev)
+		return -ENOMEM;
+
+	ts->client = client;
+	ts->input_dev = input_dev;
+
+	ts->reset_gpio = devm_gpiod_get_optional(&client->dev, NULL,
+						 GPIOD_OUT_HIGH);
+	if (IS_ERR(ts->reset_gpio)) {
+		error = PTR_ERR(ts->reset_gpio);
+		dev_err(&client->dev, "Unable to request GPIO pin: %d.\n",
+			error);
+		return error;
+	}
+
+	st1232_ts_power(ts, true);
+
+	error = devm_add_action_or_reset(&client->dev, st1232_ts_power_off, ts);
+	if (error) {
+		dev_err(&client->dev,
+			"Failed to install power off action: %d\n", error);
+		return error;
+	}
+
+	input_dev->name = "st1232-touchscreen";
+	input_dev->id.bustype = BUS_I2C;
+
+	/* Wait until device is ready */
+	error = st1232_ts_wait_ready(ts);
+	if (error)
+		return error;
+
+	/* Read firmware version from the chip */
+	error = st1232_ts_read_fw_version(ts, &ts->fw_version, &ts->fw_revision);
+	if (error) {
+		dev_err(&client->dev,
+			"Failed to read firmware version: %d\n", error);
+		return error;
+	}
+	dev_dbg(&client->dev, "Detected firmware version %u, rev %08x\n",
+		ts->fw_version, ts->fw_revision);
+
+	if (ts->chip_info->have_z)
+		input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0,
+				     ts->chip_info->max_area, 0, 0);
+
+	/* map overlay objects if defined in the device tree */
+	INIT_LIST_HEAD(&ts->touch_overlay_list);
+	error = touch_overlay_map(&ts->touch_overlay_list, input_dev);
+	if (error)
+		return error;
+
+	if (touch_overlay_mapped_touchscreen(&ts->touch_overlay_list)) {
+		/* Read resolution from the overlay touchscreen if defined */
+		touch_overlay_get_touchscreen_abs(&ts->touch_overlay_list,
+						  &max_x, &max_y);
+	} else {
+		/* Read resolution from the chip */
+		error = st1232_ts_read_resolution(ts, &max_x, &max_y);
+		if (error) {
+			dev_err(&client->dev,
+				"Failed to read resolution: %d\n", error);
+			return error;
+		}
+	}
+
+	input_set_abs_params(input_dev, ABS_MT_POSITION_X,
+			     0, max_x, 0, 0);
+	input_set_abs_params(input_dev, ABS_MT_POSITION_Y,
+			     0, max_y, 0, 0);
+
+	touchscreen_parse_properties(input_dev, true, &ts->prop);
+
+	error = input_mt_init_slots(input_dev, ts->chip_info->max_fingers,
+				    INPUT_MT_DIRECT | INPUT_MT_TRACK |
+					INPUT_MT_DROP_UNUSED);
+	if (error) {
+		dev_err(&client->dev, "failed to initialize MT slots\n");
+		return error;
+	}
+
+	error = devm_request_threaded_irq(&client->dev, client->irq,
+					  NULL, st1232_ts_irq_handler,
+					  IRQF_ONESHOT,
+					  client->name, ts);
+	if (error) {
+		dev_err(&client->dev, "Failed to register interrupt\n");
+		return error;
+	}
+
+	error = input_register_device(ts->input_dev);
+	if (error) {
+		dev_err(&client->dev, "Unable to register %s input device\n",
+			input_dev->name);
+		return error;
+	}
+
+	i2c_set_clientdata(client, ts);
+
+	return 0;
+}
+
+static int st1232_ts_suspend(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct st1232_ts_data *ts = i2c_get_clientdata(client);
+
+	disable_irq(client->irq);
+
+	if (!device_may_wakeup(&client->dev))
+		st1232_ts_power(ts, false);
+
+	return 0;
+}
+
+static int st1232_ts_resume(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct st1232_ts_data *ts = i2c_get_clientdata(client);
+
+	if (!device_may_wakeup(&client->dev))
+		st1232_ts_power(ts, true);
+
+	enable_irq(client->irq);
+
+	return 0;
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(st1232_ts_pm_ops,
+				st1232_ts_suspend, st1232_ts_resume);
+
+static const struct i2c_device_id st1232_ts_id[] = {
+	{ .name = ST1232_TS_NAME, .driver_data = (unsigned long)&st1232_chip_info },
+	{ .name = ST1633_TS_NAME, .driver_data = (unsigned long)&st1633_chip_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, st1232_ts_id);
+
+static const struct of_device_id st1232_ts_dt_ids[] = {
+	{ .compatible = "sitronix,st1232", .data = &st1232_chip_info },
+	{ .compatible = "sitronix,st1633", .data = &st1633_chip_info },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, st1232_ts_dt_ids);
+
+static struct i2c_driver st1232_ts_driver = {
+	.probe		= st1232_ts_probe,
+	.id_table	= st1232_ts_id,
+	.driver = {
+		.name	= ST1232_TS_NAME,
+		.of_match_table = st1232_ts_dt_ids,
+		.dev_groups	= st1232_groups,
+		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
+		.pm	= pm_sleep_ptr(&st1232_ts_pm_ops),
+	},
+};
+
+module_i2c_driver(st1232_ts_driver);
+
+MODULE_AUTHOR("Tony SIM <chinyeow.sim.xt@renesas.com>");
+MODULE_AUTHOR("Martin Kepplinger <martin.kepplinger@ginzinger.com>");
+MODULE_DESCRIPTION("SITRONIX ST1232 Touchscreen Controller Driver");
+MODULE_LICENSE("GPL v2");