From 552c494a7666c7fe490f179db1f52239a41fe734 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Mon, 23 Nov 2015 08:26:07 +0000 Subject: [PATCH] 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: Marc Zyngier --- drivers/base/platform-msi.c | 130 +++++++++++++++++++++++++++++++++++- include/linux/msi.h | 12 ++++ 2 files changed, 140 insertions(+), 2 deletions(-) diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c index 44b8c0d816fe..a203896f204f 100644 --- a/drivers/base/platform-msi.c +++ b/drivers/base/platform-msi.c @@ -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; }; @@ -124,8 +127,9 @@ static void platform_msi_free_descs(struct device *dev, int base, int nvec) } } -static int platform_msi_alloc_descs(struct device *dev, int nvec, - struct platform_msi_priv_data *data) +static int platform_msi_alloc_descs_with_irq(struct device *dev, int virq, + int nvec, + struct platform_msi_priv_data *data) { struct msi_desc *desc; @@ -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; +} diff --git a/include/linux/msi.h b/include/linux/msi.h index cee102b1916d..1c6342ab8c0e 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -174,6 +174,7 @@ struct msi_controller { #include 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 -- 2.20.1