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Commit 552c494a authored by Marc Zyngier's avatar Marc Zyngier
Browse files

platform-msi: Allow creation of a MSI-based stacked irq domain 



We almost have all the needed bits requiredable to create a irq domain
on top of a MSI domain.

For this, we enable a few things:
- the virq is stored in the msi_desc
- device, msi_alloc_info and domain-specific data
  are stored in the platform_priv_data structure
- we introduce a new API for platform-msi:

  /* Create a MSI-based domain */
  struct irq_domain *
  platform_msi_create_device_domain(struct device *dev,
                                    unsigned int nvec,
                                    irq_write_msi_msg_t write_msi_msg,
                                    const struct irq_domain_ops *ops,
                                    void *host_data);

  /* Allocate MSIs in an MSI domain */
  int platform_msi_domain_alloc(struct irq_domain *domain,
				unsigned int virq,
				unsigned int nr_irqs);

  /* Free MSIs from an MSI domain */
  void platform_msi_domain_free(struct irq_domain *domain,
				unsigned int virq,
				unsigned int nvec);

  /* Obtain the host data passed to platform_msi_create_device_domain */
  void *platform_msi_get_host_data(struct irq_domain *domain);

platform_msi_create_device_domain() is a hybrid of irqdomain creation
and interrupt allocation, creating a domain backed by the MSIs associated
to a device. IRQs can then be allocated in that domain using
platform_msi_domain_alloc().

This now allows a wired irq to MSI bridge to be created.

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent 2145ac93

drivers/base/platform-msi.c

+128 −2
Original line number Diff line number Diff line
@@ -32,6 +32,9 @@ 
 * and the callback to write the MSI message.

 */

struct platform_msi_priv_data {

	struct device		*dev;

	void 			*host_data;

	msi_alloc_info_t	arg;

	irq_write_msi_msg_t	write_msg;

	int			devid;

};
@@ -124,7 +127,8 @@ static void platform_msi_free_descs(struct device *dev, int base, int nvec) 
	}

}



static int platform_msi_alloc_descs(struct device *dev, int nvec,

static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq,

					     int nvec,

					     struct platform_msi_priv_data *data)



{
@@ -145,6 +149,7 @@ static int platform_msi_alloc_descs(struct device *dev, int nvec, 
		desc->platform.msi_priv_data = data;

		desc->platform.msi_index = base + i;

		desc->nvec_used = 1;

		desc->irq = virq ? virq + i : 0;



		list_add_tail(&desc->list, dev_to_msi_list(dev));

	}
@@ -159,6 +164,13 @@ static int platform_msi_alloc_descs(struct device *dev, int nvec, 
	return 0;

}



static int platform_msi_alloc_descs(struct device *dev, int nvec,

				    struct platform_msi_priv_data *data)



{

	return platform_msi_alloc_descs_with_irq(dev, 0, nvec, data);

}



/**

 * platform_msi_create_irq_domain - Create a platform MSI interrupt domain

 * @fwnode:		Optional fwnode of the interrupt controller
@@ -225,6 +237,7 @@ platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec, 
	}



	datap->write_msg = write_msi_msg;

	datap->dev = dev;



	return datap;

}
@@ -288,3 +301,116 @@ void platform_msi_domain_free_irqs(struct device *dev) 
	msi_domain_free_irqs(dev->msi_domain, dev);

	platform_msi_free_descs(dev, 0, MAX_DEV_MSIS);

}



/**

 * platform_msi_get_host_data - Query the private data associated with

 *                              a platform-msi domain

 * @domain:	The platform-msi domain

 *

 * Returns the private data provided when calling

 * platform_msi_create_device_domain.

 */

void *platform_msi_get_host_data(struct irq_domain *domain)

{

	struct platform_msi_priv_data *data = domain->host_data;

	return data->host_data;

}



/**

 * platform_msi_create_device_domain - Create a platform-msi domain

 *

 * @dev:		The device generating the MSIs

 * @nvec:		The number of MSIs that need to be allocated

 * @write_msi_msg:	Callback to write an interrupt message for @dev

 * @ops:		The hierarchy domain operations to use

 * @host_data:		Private data associated to this domain

 *

 * Returns an irqdomain for @nvec interrupts

 */

struct irq_domain *

platform_msi_create_device_domain(struct device *dev,

				  unsigned int nvec,

				  irq_write_msi_msg_t write_msi_msg,

				  const struct irq_domain_ops *ops,

				  void *host_data)

{

	struct platform_msi_priv_data *data;

	struct irq_domain *domain;

	int err;



	data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg);

	if (IS_ERR(data))

		return NULL;



	data->host_data = host_data;

	domain = irq_domain_create_hierarchy(dev->msi_domain, 0, nvec,

					     of_node_to_fwnode(dev->of_node),

					     ops, data);

	if (!domain)

		goto free_priv;



	err = msi_domain_prepare_irqs(domain->parent, dev, nvec, &data->arg);

	if (err)

		goto free_domain;



	return domain;



free_domain:

	irq_domain_remove(domain);

free_priv:

	platform_msi_free_priv_data(data);

	return NULL;

}



/**

 * platform_msi_domain_free - Free interrupts associated with a platform-msi

 *                            domain

 *

 * @domain:	The platform-msi domain

 * @virq:	The base irq from which to perform the free operation

 * @nvec:	How many interrupts to free from @virq

 */

void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,

			      unsigned int nvec)

{

	struct platform_msi_priv_data *data = domain->host_data;

	struct msi_desc *desc;

	for_each_msi_entry(desc, data->dev) {

		if (WARN_ON(!desc->irq || desc->nvec_used != 1))

			return;

		if (!(desc->irq >= virq && desc->irq < (virq + nvec)))

			continue;



		irq_domain_free_irqs_common(domain, desc->irq, 1);

	}

}



/**

 * platform_msi_domain_alloc - Allocate interrupts associated with

 *			       a platform-msi domain

 *

 * @domain:	The platform-msi domain

 * @virq:	The base irq from which to perform the allocate operation

 * @nvec:	How many interrupts to free from @virq

 *

 * Return 0 on success, or an error code on failure. Must be called

 * with irq_domain_mutex held (which can only be done as part of a

 * top-level interrupt allocation).

 */

int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,

			      unsigned int nr_irqs)

{

	struct platform_msi_priv_data *data = domain->host_data;

	int err;



	err = platform_msi_alloc_descs_with_irq(data->dev, virq, nr_irqs, data);

	if (err)

		return err;



	err = msi_domain_populate_irqs(domain->parent, data->dev,

				       virq, nr_irqs, &data->arg);

	if (err)

		platform_msi_domain_free(domain, virq, nr_irqs);



	return err;

}

include/linux/msi.h

+12 −0
Original line number Diff line number Diff line
@@ -174,6 +174,7 @@ struct msi_controller { 
#include <asm/msi.h>



struct irq_domain;

struct irq_domain_ops;

struct irq_chip;

struct device_node;

struct fwnode_handle;
@@ -285,6 +286,17 @@ int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev, 
			    int nvec, msi_alloc_info_t *args);

int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,

			     int virq, int nvec, msi_alloc_info_t *args);

struct irq_domain *

platform_msi_create_device_domain(struct device *dev,

				  unsigned int nvec,

				  irq_write_msi_msg_t write_msi_msg,

				  const struct irq_domain_ops *ops,

				  void *host_data);

int platform_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,

			      unsigned int nr_irqs);

void platform_msi_domain_free(struct irq_domain *domain, unsigned int virq,

			      unsigned int nvec);

void *platform_msi_get_host_data(struct irq_domain *domain);

#endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */



#ifdef CONFIG_PCI_MSI_IRQ_DOMAIN