qdev: Document GPIO related functions (cd07d7f9) · Commits · SUMMER2020 / students / proj-2021291

include/hw/qdev-core.h

+189 −2

Original line number	Diff line number	Diff line
		@@ -424,13 +424,132 @@ void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev,
		void qdev_machine_creation_done(void);
		bool qdev_machine_modified(void);

		/**
		* qdev_get_gpio_in: Get one of a device's anonymous input GPIO lines
		* @dev: Device whose GPIO we want
		* @n: Number of the anonymous GPIO line (which must be in range)
		*
		* Returns the qemu_irq corresponding to an anonymous input GPIO line
		* (which the device has set up with qdev_init_gpio_in()). The index
		* @n of the GPIO line must be valid (i.e. be at least 0 and less than
		* the total number of anonymous input GPIOs the device has); this
		* function will assert() if passed an invalid index.
		*
		* This function is intended to be used by board code or SoC "container"
		* device models to wire up the GPIO lines; usually the return value
		* will be passed to qdev_connect_gpio_out() or a similar function to
		* connect another device's output GPIO line to this input.
		*
		* For named input GPIO lines, use qdev_get_gpio_in_named().
		*/
		qemu_irq qdev_get_gpio_in(DeviceState *dev, int n);
		/**
		* qdev_get_gpio_in_named: Get one of a device's named input GPIO lines
		* @dev: Device whose GPIO we want
		* @name: Name of the input GPIO array
		* @n: Number of the GPIO line in that array (which must be in range)
		*
		* Returns the qemu_irq corresponding to a named input GPIO line
		* (which the device has set up with qdev_init_gpio_in_named()).
		* The @name string must correspond to an input GPIO array which exists on
		* the device, and the index @n of the GPIO line must be valid (i.e.
		* be at least 0 and less than the total number of input GPIOs in that
		* array); this function will assert() if passed an invalid name or index.
		*
		* For anonymous input GPIO lines, use qdev_get_gpio_in().
		*/
		qemu_irq qdev_get_gpio_in_named(DeviceState dev, const char name, int n);

		/**
		* qdev_connect_gpio_out: Connect one of a device's anonymous output GPIO lines
		* @dev: Device whose GPIO to connect
		* @n: Number of the anonymous output GPIO line (which must be in range)
		* @pin: qemu_irq to connect the output line to
		*
		* This function connects an anonymous output GPIO line on a device
		* up to an arbitrary qemu_irq, so that when the device asserts that
		* output GPIO line, the qemu_irq's callback is invoked.
		* The index @n of the GPIO line must be valid (i.e. be at least 0 and
		* less than the total number of anonymous output GPIOs the device has
		* created with qdev_init_gpio_out()); otherwise this function will assert().
		*
		* Outbound GPIO lines can be connected to any qemu_irq, but the common
		* case is connecting them to another device's inbound GPIO line, using
		* the qemu_irq returned by qdev_get_gpio_in() or qdev_get_gpio_in_named().
		*
		* It is not valid to try to connect one outbound GPIO to multiple
		* qemu_irqs at once, or to connect multiple outbound GPIOs to the
		* same qemu_irq. (Warning: there is no assertion or other guard to
		* catch this error: the model will just not do the right thing.)
		* Instead, for fan-out you can use the TYPE_IRQ_SPLIT device: connect
		* a device's outbound GPIO to the splitter's input, and connect each
		* of the splitter's outputs to a different device. For fan-in you
		* can use the TYPE_OR_IRQ device, which is a model of a logical OR
		* gate with multiple inputs and one output.
		*
		* For named output GPIO lines, use qdev_connect_gpio_out_named().
		*/
		void qdev_connect_gpio_out(DeviceState *dev, int n, qemu_irq pin);
		/**
		* qdev_connect_gpio_out: Connect one of a device's anonymous output GPIO lines
		* @dev: Device whose GPIO to connect
		* @name: Name of the output GPIO array
		* @n: Number of the anonymous output GPIO line (which must be in range)
		* @pin: qemu_irq to connect the output line to
		*
		* This function connects an anonymous output GPIO line on a device
		* up to an arbitrary qemu_irq, so that when the device asserts that
		* output GPIO line, the qemu_irq's callback is invoked.
		* The @name string must correspond to an output GPIO array which exists on
		* the device, and the index @n of the GPIO line must be valid (i.e.
		* be at least 0 and less than the total number of input GPIOs in that
		* array); this function will assert() if passed an invalid name or index.
		*
		* Outbound GPIO lines can be connected to any qemu_irq, but the common
		* case is connecting them to another device's inbound GPIO line, using
		* the qemu_irq returned by qdev_get_gpio_in() or qdev_get_gpio_in_named().
		*
		* It is not valid to try to connect one outbound GPIO to multiple
		* qemu_irqs at once, or to connect multiple outbound GPIOs to the
		* same qemu_irq; see qdev_connect_gpio_out() for details.
		*
		* For named output GPIO lines, use qdev_connect_gpio_out_named().
		*/
		void qdev_connect_gpio_out_named(DeviceState dev, const char name, int n,
		qemu_irq pin);
		/**
		* qdev_get_gpio_out_connector: Get the qemu_irq connected to an output GPIO
		* @dev: Device whose output GPIO we are interested in
		* @name: Name of the output GPIO array
		* @n: Number of the output GPIO line within that array
		*
		* Returns whatever qemu_irq is currently connected to the specified
		* output GPIO line of @dev. This will be NULL if the output GPIO line
		* has never been wired up to the anything. Note that the qemu_irq
		* returned does not belong to @dev -- it will be the input GPIO or
		* IRQ of whichever device the board code has connected up to @dev's
		* output GPIO.
		*
		* You probably don't need to use this function -- it is used only
		* by the platform-bus subsystem.
		*/
		qemu_irq qdev_get_gpio_out_connector(DeviceState dev, const char name, int n);
		/**
		* qdev_intercept_gpio_out: Intercept an existing GPIO connection
		* @dev: Device to intercept the outbound GPIO line from
		* @icpt: New qemu_irq to connect instead
		* @name: Name of the output GPIO array
		* @n: Number of the GPIO line in the array
		*
		* This function is provided only for use by the qtest testing framework
		* and is not suitable for use in non-testing parts of QEMU.
		*
		* This function breaks an existing connection of an outbound GPIO
		* line from @dev, and replaces it with the new qemu_irq @icpt, as if
		* ``qdev_connect_gpio_out_named(dev, icpt, name, n)`` had been called.
		* The previously connected qemu_irq is returned, so it can be restored
		* by a second call to qdev_intercept_gpio_out() if desired.
		*/
		qemu_irq qdev_intercept_gpio_out(DeviceState *dev, qemu_irq icpt,
		const char *name, int n);

		@@ -438,10 +557,59 @@ BusState qdev_get_child_bus(DeviceState dev, const char *name);

		/* Device API. */

		/* Register device properties. */
		/* GPIO inputs also double as IRQ sinks. */
		/**
		* qdev_init_gpio_in: create an array of anonymous input GPIO lines
		* @dev: Device to create input GPIOs for
		* @handler: Function to call when GPIO line value is set
		* @n: Number of GPIO lines to create
		*
		* Devices should use functions in the qdev_init_gpio_in* family in
		* their instance_init or realize methods to create any input GPIO
		* lines they need. There is no functional difference between
		* anonymous and named GPIO lines. Stylistically, named GPIOs are
		* preferable (easier to understand at callsites) unless a device
		* has exactly one uniform kind of GPIO input whose purpose is obvious.
		* Note that input GPIO lines can serve as 'sinks' for IRQ lines.
		*
		* See qdev_get_gpio_in() for how code that uses such a device can get
		* hold of an input GPIO line to manipulate it.
		*/
		void qdev_init_gpio_in(DeviceState *dev, qemu_irq_handler handler, int n);
		/**
		* qdev_init_gpio_out: create an array of anonymous output GPIO lines
		* @dev: Device to create output GPIOs for
		* @pins: Pointer to qemu_irq or qemu_irq array for the GPIO lines
		* @n: Number of GPIO lines to create
		*
		* Devices should use functions in the qdev_init_gpio_out* family
		* in their instance_init or realize methods to create any output
		* GPIO lines they need. There is no functional difference between
		* anonymous and named GPIO lines. Stylistically, named GPIOs are
		* preferable (easier to understand at callsites) unless a device
		* has exactly one uniform kind of GPIO output whose purpose is obvious.
		*
		* The @pins argument should be a pointer to either a "qemu_irq"
		* (if @n == 1) or a "qemu_irq []" array (if @n > 1) in the device's
		* state structure. The device implementation can then raise and
		* lower the GPIO line by calling qemu_set_irq(). (If anything is
		* connected to the other end of the GPIO this will cause the handler
		* function for that input GPIO to be called.)
		*
		* See qdev_connect_gpio_out() for how code that uses such a device
		* can connect to one of its output GPIO lines.
		*/
		void qdev_init_gpio_out(DeviceState dev, qemu_irq pins, int n);
		/**
		* qdev_init_gpio_out: create an array of named output GPIO lines
		* @dev: Device to create output GPIOs for
		* @pins: Pointer to qemu_irq or qemu_irq array for the GPIO lines
		* @name: Name to give this array of GPIO lines
		* @n: Number of GPIO lines to create
		*
		* Like qdev_init_gpio_out(), but creates an array of GPIO output lines
		* with a name. Code using the device can then connect these GPIO lines
		* using qdev_connect_gpio_out_named().
		*/
		void qdev_init_gpio_out_named(DeviceState dev, qemu_irq pins,
		const char *name, int n);
		/**
		@@ -473,6 +641,25 @@ static inline void qdev_init_gpio_in_named(DeviceState *dev,
		qdev_init_gpio_in_named_with_opaque(dev, handler, dev, name, n);
		}

		/**
		* qdev_pass_gpios: create GPIO lines on container which pass through to device
		* @dev: Device which has GPIO lines
		* @container: Container device which needs to expose them
		* @name: Name of GPIO array to pass through (NULL for the anonymous GPIO array)
		*
		* In QEMU, complicated devices like SoCs are often modelled with a
		* "container" QOM device which itself contains other QOM devices and
		* which wires them up appropriately. This function allows the container
		* to create GPIO arrays on itself which simply pass through to a GPIO
		* array of one of its internal devices.
		*
		* If @dev has both input and output GPIOs named @name then both will
		* be passed through. It is not possible to pass a subset of the array
		* with this function.
		*
		* To users of the container device, the GPIO array created on @container
		* behaves exactly like any other.
		*/
		void qdev_pass_gpios(DeviceState dev, DeviceState container,
		const char *name);