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Commit 3a97aabe authored by Alistair Delva's avatar Alistair Delva
Browse files

ANDROID: serdev: restrict claim of platform devices 



Make the fallback path for claiming platform devices trigger only if a
new module parameter is specified:

  serdev_ttyport.pdev_tty_port=ttyS2

Bug: 146517987
Change-Id: Ibf331ad6e6d8712a405921530f217f7122428b13
Signed-off-by: default avatarAlistair Delva <adelva@google.com>
parent 8d69223e

drivers/tty/serdev/core.c

+9 −6
Original line number Diff line number Diff line
@@ -679,16 +679,18 @@ static int platform_serdev_register_devices(struct serdev_controller *ctrl) 
	return err;

}





/**

 * serdev_controller_add() - Add an serdev controller

 * serdev_controller_add_platform() - Add an serdev controller

 * @ctrl:	controller to be registered.

 * @platform:	whether to permit fallthrough to platform device probe

 *

 * Register a controller previously allocated via serdev_controller_alloc() with

 * the serdev core.

 * the serdev core. Optionally permit probing via a platform device fallback.

 */

int serdev_controller_add(struct serdev_controller *ctrl)

int serdev_controller_add_platform(struct serdev_controller *ctrl, bool platform)

{

	int ret_of, ret_acpi, ret_platform, ret;

	int ret, ret_of, ret_acpi, ret_platform = -ENODEV;



	/* Can't register until after driver model init */

	if (WARN_ON(!is_registered))
@@ -702,6 +704,7 @@ int serdev_controller_add(struct serdev_controller *ctrl) 


	ret_of = of_serdev_register_devices(ctrl);

	ret_acpi = acpi_serdev_register_devices(ctrl);

	if (platform)

		ret_platform = platform_serdev_register_devices(ctrl);

	if (ret_of && ret_acpi && ret_platform) {

		dev_dbg(&ctrl->dev, "no devices registered: of:%d acpi:%d "
@@ -720,7 +723,7 @@ int serdev_controller_add(struct serdev_controller *ctrl) 
	device_del(&ctrl->dev);

	return ret;

};

EXPORT_SYMBOL_GPL(serdev_controller_add);

EXPORT_SYMBOL_GPL(serdev_controller_add_platform);



/* Remove a device associated with a controller */

static int serdev_remove_device(struct device *dev, void *data)

drivers/tty/serdev/serdev-ttyport.c

+25 −1
Original line number Diff line number Diff line
@@ -7,9 +7,15 @@ 
#include <linux/tty.h>

#include <linux/tty_driver.h>

#include <linux/poll.h>

#include <linux/platform_device.h>

#include <linux/module.h>



#define SERPORT_ACTIVE		1



static char *pdev_tty_port;

module_param(pdev_tty_port, charp, 0644);

MODULE_PARM_DESC(pdev_tty_port, "platform device tty port to claim");



struct serport {

	struct tty_port *port;

	struct tty_struct *tty;
@@ -267,6 +273,7 @@ struct device *serdev_tty_port_register(struct tty_port *port, 
{

	struct serdev_controller *ctrl;

	struct serport *serport;

	bool platform = false;

	int ret;



	if (!port || !drv || !parent)
@@ -291,7 +298,24 @@ struct device *serdev_tty_port_register(struct tty_port *port, 
	port->client_ops = &client_ops;

	port->client_data = ctrl;



	ret = serdev_controller_add(ctrl);

	/* There is not always a way to bind specific platform devices because

	 * they may be defined on platforms without DT or ACPI. When dealing

	 * with a platform devices, do not allow direct binding unless it is

	 * whitelisted by module parameter. If a platform device is otherwise

	 * described by DT or ACPI it will still be bound and this check will

	 * be ignored.

	 */

	if (parent->bus == &platform_bus_type) {

		char tty_port_name[7];



		sprintf(tty_port_name, "%s%d", drv->name, idx);

		if (pdev_tty_port &&

		    !strcmp(pdev_tty_port, tty_port_name)) {

			platform = true;

		}

	}



	ret = serdev_controller_add_platform(ctrl, platform);

	if (ret)

		goto err_reset_data;

include/linux/serdev.h

+13 −1
Original line number Diff line number Diff line
@@ -165,9 +165,21 @@ int serdev_device_add(struct serdev_device *); 
void serdev_device_remove(struct serdev_device *);



struct serdev_controller *serdev_controller_alloc(struct device *, size_t);

int serdev_controller_add(struct serdev_controller *);

int serdev_controller_add_platform(struct serdev_controller *, bool);

void serdev_controller_remove(struct serdev_controller *);



/**

 * serdev_controller_add() - Add an serdev controller

 * @ctrl:	controller to be registered.

 *

 * Register a controller previously allocated via serdev_controller_alloc() with

 * the serdev core.

 */

static inline int serdev_controller_add(struct serdev_controller *ctrl)

{

	return serdev_controller_add_platform(ctrl, false);

}



static inline void serdev_controller_write_wakeup(struct serdev_controller *ctrl)

{

	struct serdev_device *serdev = ctrl->serdev;