diff options
Diffstat (limited to 'drivers/base/platform-msi.c')
| -rw-r--r-- | drivers/base/platform-msi.c | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/drivers/base/platform-msi.c b/drivers/base/platform-msi.c new file mode 100644 index 000000000..6d54905c6 --- /dev/null +++ b/drivers/base/platform-msi.c @@ -0,0 +1,410 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * MSI framework for platform devices + * + * Copyright (C) 2015 ARM Limited, All Rights Reserved. + * Author: Marc Zyngier <marc.zyngier@arm.com> + */ + +#include <linux/device.h> +#include <linux/idr.h> +#include <linux/irq.h> +#include <linux/irqdomain.h> +#include <linux/msi.h> +#include <linux/slab.h> + +#define DEV_ID_SHIFT 21 +#define MAX_DEV_MSIS (1 << (32 - DEV_ID_SHIFT)) + +/* + * Internal data structure containing a (made up, but unique) devid + * 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; +}; + +/* The devid allocator */ +static DEFINE_IDA(platform_msi_devid_ida); + +#ifdef GENERIC_MSI_DOMAIN_OPS +/* + * Convert an msi_desc to a globaly unique identifier (per-device + * devid + msi_desc position in the msi_list). + */ +static irq_hw_number_t platform_msi_calc_hwirq(struct msi_desc *desc) +{ + u32 devid; + + devid = desc->platform.msi_priv_data->devid; + + return (devid << (32 - DEV_ID_SHIFT)) | desc->platform.msi_index; +} + +static void platform_msi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc) +{ + arg->desc = desc; + arg->hwirq = platform_msi_calc_hwirq(desc); +} + +static int platform_msi_init(struct irq_domain *domain, + struct msi_domain_info *info, + unsigned int virq, irq_hw_number_t hwirq, + msi_alloc_info_t *arg) +{ + return irq_domain_set_hwirq_and_chip(domain, virq, hwirq, + info->chip, info->chip_data); +} +#else +#define platform_msi_set_desc NULL +#define platform_msi_init NULL +#endif + +static void platform_msi_update_dom_ops(struct msi_domain_info *info) +{ + struct msi_domain_ops *ops = info->ops; + + BUG_ON(!ops); + + if (ops->msi_init == NULL) + ops->msi_init = platform_msi_init; + if (ops->set_desc == NULL) + ops->set_desc = platform_msi_set_desc; +} + +static void platform_msi_write_msg(struct irq_data *data, struct msi_msg *msg) +{ + struct msi_desc *desc = irq_data_get_msi_desc(data); + struct platform_msi_priv_data *priv_data; + + priv_data = desc->platform.msi_priv_data; + + priv_data->write_msg(desc, msg); +} + +static void platform_msi_update_chip_ops(struct msi_domain_info *info) +{ + struct irq_chip *chip = info->chip; + + BUG_ON(!chip); + if (!chip->irq_mask) + chip->irq_mask = irq_chip_mask_parent; + if (!chip->irq_unmask) + chip->irq_unmask = irq_chip_unmask_parent; + if (!chip->irq_eoi) + chip->irq_eoi = irq_chip_eoi_parent; + if (!chip->irq_set_affinity) + chip->irq_set_affinity = msi_domain_set_affinity; + if (!chip->irq_write_msi_msg) + chip->irq_write_msi_msg = platform_msi_write_msg; + if (WARN_ON((info->flags & MSI_FLAG_LEVEL_CAPABLE) && + !(chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI))) + info->flags &= ~MSI_FLAG_LEVEL_CAPABLE; +} + +static void platform_msi_free_descs(struct device *dev, int base, int nvec) +{ + struct msi_desc *desc, *tmp; + + list_for_each_entry_safe(desc, tmp, dev_to_msi_list(dev), list) { + if (desc->platform.msi_index >= base && + desc->platform.msi_index < (base + nvec)) { + list_del(&desc->list); + free_msi_entry(desc); + } + } +} + +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; + int i, base = 0; + + if (!list_empty(dev_to_msi_list(dev))) { + desc = list_last_entry(dev_to_msi_list(dev), + struct msi_desc, list); + base = desc->platform.msi_index + 1; + } + + for (i = 0; i < nvec; i++) { + desc = alloc_msi_entry(dev, 1, NULL); + if (!desc) + break; + + desc->platform.msi_priv_data = data; + desc->platform.msi_index = base + i; + desc->irq = virq ? virq + i : 0; + + list_add_tail(&desc->list, dev_to_msi_list(dev)); + } + + if (i != nvec) { + /* Clean up the mess */ + platform_msi_free_descs(dev, base, nvec); + + return -ENOMEM; + } + + 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 + * @info: MSI domain info + * @parent: Parent irq domain + * + * Updates the domain and chip ops and creates a platform MSI + * interrupt domain. + * + * Returns: + * A domain pointer or NULL in case of failure. + */ +struct irq_domain *platform_msi_create_irq_domain(struct fwnode_handle *fwnode, + struct msi_domain_info *info, + struct irq_domain *parent) +{ + struct irq_domain *domain; + + if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS) + platform_msi_update_dom_ops(info); + if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS) + platform_msi_update_chip_ops(info); + + domain = msi_create_irq_domain(fwnode, info, parent); + if (domain) + irq_domain_update_bus_token(domain, DOMAIN_BUS_PLATFORM_MSI); + + return domain; +} + +static struct platform_msi_priv_data * +platform_msi_alloc_priv_data(struct device *dev, unsigned int nvec, + irq_write_msi_msg_t write_msi_msg) +{ + struct platform_msi_priv_data *datap; + /* + * Limit the number of interrupts to 2048 per device. Should we + * need to bump this up, DEV_ID_SHIFT should be adjusted + * accordingly (which would impact the max number of MSI + * capable devices). + */ + if (!dev->msi_domain || !write_msi_msg || !nvec || nvec > MAX_DEV_MSIS) + return ERR_PTR(-EINVAL); + + if (dev->msi_domain->bus_token != DOMAIN_BUS_PLATFORM_MSI) { + dev_err(dev, "Incompatible msi_domain, giving up\n"); + return ERR_PTR(-EINVAL); + } + + /* Already had a helping of MSI? Greed... */ + if (!list_empty(dev_to_msi_list(dev))) + return ERR_PTR(-EBUSY); + + datap = kzalloc(sizeof(*datap), GFP_KERNEL); + if (!datap) + return ERR_PTR(-ENOMEM); + + datap->devid = ida_simple_get(&platform_msi_devid_ida, + 0, 1 << DEV_ID_SHIFT, GFP_KERNEL); + if (datap->devid < 0) { + int err = datap->devid; + kfree(datap); + return ERR_PTR(err); + } + + datap->write_msg = write_msi_msg; + datap->dev = dev; + + return datap; +} + +static void platform_msi_free_priv_data(struct platform_msi_priv_data *data) +{ + ida_simple_remove(&platform_msi_devid_ida, data->devid); + kfree(data); +} + +/** + * platform_msi_domain_alloc_irqs - Allocate MSI interrupts for @dev + * @dev: The device for which to allocate interrupts + * @nvec: The number of interrupts to allocate + * @write_msi_msg: Callback to write an interrupt message for @dev + * + * Returns: + * Zero for success, or an error code in case of failure + */ +int platform_msi_domain_alloc_irqs(struct device *dev, unsigned int nvec, + irq_write_msi_msg_t write_msi_msg) +{ + struct platform_msi_priv_data *priv_data; + int err; + + priv_data = platform_msi_alloc_priv_data(dev, nvec, write_msi_msg); + if (IS_ERR(priv_data)) + return PTR_ERR(priv_data); + + err = platform_msi_alloc_descs(dev, nvec, priv_data); + if (err) + goto out_free_priv_data; + + err = msi_domain_alloc_irqs(dev->msi_domain, dev, nvec); + if (err) + goto out_free_desc; + + return 0; + +out_free_desc: + platform_msi_free_descs(dev, 0, nvec); +out_free_priv_data: + platform_msi_free_priv_data(priv_data); + + return err; +} +EXPORT_SYMBOL_GPL(platform_msi_domain_alloc_irqs); + +/** + * platform_msi_domain_free_irqs - Free MSI interrupts for @dev + * @dev: The device for which to free interrupts + */ +void platform_msi_domain_free_irqs(struct device *dev) +{ + if (!list_empty(dev_to_msi_list(dev))) { + struct msi_desc *desc; + + desc = first_msi_entry(dev); + platform_msi_free_priv_data(desc->platform.msi_priv_data); + } + + msi_domain_free_irqs(dev->msi_domain, dev); + platform_msi_free_descs(dev, 0, MAX_DEV_MSIS); +} +EXPORT_SYMBOL_GPL(platform_msi_domain_free_irqs); + +/** + * 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, + dev->fwnode, 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, *tmp; + for_each_msi_entry_safe(desc, tmp, 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); + list_del(&desc->list); + free_msi_entry(desc); + } +} + +/** + * 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; +} |