diff options
Diffstat (limited to 'drivers/irqchip/irq-gic-v3-its-msi-parent.c')
| -rw-r--r-- | drivers/irqchip/irq-gic-v3-its-msi-parent.c | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-gic-v3-its-msi-parent.c b/drivers/irqchip/irq-gic-v3-its-msi-parent.c new file mode 100644 index 000000000000..e150365fbe89 --- /dev/null +++ b/drivers/irqchip/irq-gic-v3-its-msi-parent.c @@ -0,0 +1,210 @@ +// SPDX-License-Identifier: GPL-2.0-only +// Copyright (C) 2013-2015 ARM Limited, All Rights Reserved. +// Author: Marc Zyngier <marc.zyngier@arm.com> +// Copyright (C) 2022 Linutronix GmbH +// Copyright (C) 2022 Intel + +#include <linux/acpi_iort.h> +#include <linux/pci.h> + +#include "irq-gic-common.h" +#include "irq-msi-lib.h" + +#define ITS_MSI_FLAGS_REQUIRED (MSI_FLAG_USE_DEF_DOM_OPS | \ + MSI_FLAG_USE_DEF_CHIP_OPS | \ + MSI_FLAG_PCI_MSI_MASK_PARENT) + +#define ITS_MSI_FLAGS_SUPPORTED (MSI_GENERIC_FLAGS_MASK | \ + MSI_FLAG_PCI_MSIX | \ + MSI_FLAG_MULTI_PCI_MSI) + +#ifdef CONFIG_PCI_MSI +static int its_pci_msi_vec_count(struct pci_dev *pdev, void *data) +{ + int msi, msix, *count = data; + + msi = max(pci_msi_vec_count(pdev), 0); + msix = max(pci_msix_vec_count(pdev), 0); + *count += max(msi, msix); + + return 0; +} + +static int its_get_pci_alias(struct pci_dev *pdev, u16 alias, void *data) +{ + struct pci_dev **alias_dev = data; + + *alias_dev = pdev; + + return 0; +} + +static int its_pci_msi_prepare(struct irq_domain *domain, struct device *dev, + int nvec, msi_alloc_info_t *info) +{ + struct pci_dev *pdev, *alias_dev; + struct msi_domain_info *msi_info; + int alias_count = 0, minnvec = 1; + + if (!dev_is_pci(dev)) + return -EINVAL; + + pdev = to_pci_dev(dev); + /* + * If pdev is downstream of any aliasing bridges, take an upper + * bound of how many other vectors could map to the same DevID. + * Also tell the ITS that the signalling will come from a proxy + * device, and that special allocation rules apply. + */ + pci_for_each_dma_alias(pdev, its_get_pci_alias, &alias_dev); + if (alias_dev != pdev) { + if (alias_dev->subordinate) + pci_walk_bus(alias_dev->subordinate, + its_pci_msi_vec_count, &alias_count); + info->flags |= MSI_ALLOC_FLAGS_PROXY_DEVICE; + } + + /* ITS specific DeviceID, as the core ITS ignores dev. */ + info->scratchpad[0].ul = pci_msi_domain_get_msi_rid(domain->parent, pdev); + + /* + * @domain->msi_domain_info->hwsize contains the size of the + * MSI[-X] domain, but vector allocation happens one by one. This + * needs some thought when MSI comes into play as the size of MSI + * might be unknown at domain creation time and therefore set to + * MSI_MAX_INDEX. + */ + msi_info = msi_get_domain_info(domain); + if (msi_info->hwsize > nvec) + nvec = msi_info->hwsize; + + /* + * Always allocate a power of 2, and special case device 0 for + * broken systems where the DevID is not wired (and all devices + * appear as DevID 0). For that reason, we generously allocate a + * minimum of 32 MSIs for DevID 0. If you want more because all + * your devices are aliasing to DevID 0, consider fixing your HW. + */ + nvec = max(nvec, alias_count); + if (!info->scratchpad[0].ul) + minnvec = 32; + nvec = max_t(int, minnvec, roundup_pow_of_two(nvec)); + + msi_info = msi_get_domain_info(domain->parent); + return msi_info->ops->msi_prepare(domain->parent, dev, nvec, info); +} +#else /* CONFIG_PCI_MSI */ +#define its_pci_msi_prepare NULL +#endif /* !CONFIG_PCI_MSI */ + +static int of_pmsi_get_dev_id(struct irq_domain *domain, struct device *dev, + u32 *dev_id) +{ + int ret, index = 0; + + /* Suck the DeviceID out of the msi-parent property */ + do { + struct of_phandle_args args; + + ret = of_parse_phandle_with_args(dev->of_node, + "msi-parent", "#msi-cells", + index, &args); + if (args.np == irq_domain_get_of_node(domain)) { + if (WARN_ON(args.args_count != 1)) + return -EINVAL; + *dev_id = args.args[0]; + break; + } + index++; + } while (!ret); + + return ret; +} + +int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id) +{ + return -1; +} + +static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev, + int nvec, msi_alloc_info_t *info) +{ + struct msi_domain_info *msi_info; + u32 dev_id; + int ret; + + if (dev->of_node) + ret = of_pmsi_get_dev_id(domain->parent, dev, &dev_id); + else + ret = iort_pmsi_get_dev_id(dev, &dev_id); + if (ret) + return ret; + + /* ITS specific DeviceID, as the core ITS ignores dev. */ + info->scratchpad[0].ul = dev_id; + + /* + * @domain->msi_domain_info->hwsize contains the size of the device + * domain, but vector allocation happens one by one. + */ + msi_info = msi_get_domain_info(domain); + if (msi_info->hwsize > nvec) + nvec = msi_info->hwsize; + + /* Allocate at least 32 MSIs, and always as a power of 2 */ + nvec = max_t(int, 32, roundup_pow_of_two(nvec)); + + msi_info = msi_get_domain_info(domain->parent); + return msi_info->ops->msi_prepare(domain->parent, + dev, nvec, info); +} + +static bool its_init_dev_msi_info(struct device *dev, struct irq_domain *domain, + struct irq_domain *real_parent, struct msi_domain_info *info) +{ + if (!msi_lib_init_dev_msi_info(dev, domain, real_parent, info)) + return false; + + switch(info->bus_token) { + case DOMAIN_BUS_PCI_DEVICE_MSI: + case DOMAIN_BUS_PCI_DEVICE_MSIX: + /* + * FIXME: This probably should be done after a (not yet + * existing) post domain creation callback once to make + * support for dynamic post-enable MSI-X allocations + * work without having to reevaluate the domain size + * over and over. It is known already at allocation + * time via info->hwsize. + * + * That should work perfectly fine for MSI/MSI-X but needs + * some thoughts for purely software managed MSI domains + * where the index space is only limited artificially via + * %MSI_MAX_INDEX. + */ + info->ops->msi_prepare = its_pci_msi_prepare; + break; + case DOMAIN_BUS_DEVICE_MSI: + case DOMAIN_BUS_WIRED_TO_MSI: + /* + * FIXME: See the above PCI prepare comment. The domain + * size is also known at domain creation time. + */ + info->ops->msi_prepare = its_pmsi_prepare; + break; + default: + /* Confused. How did the lib return true? */ + WARN_ON_ONCE(1); + return false; + } + + return true; +} + +const struct msi_parent_ops gic_v3_its_msi_parent_ops = { + .supported_flags = ITS_MSI_FLAGS_SUPPORTED, + .required_flags = ITS_MSI_FLAGS_REQUIRED, + .bus_select_token = DOMAIN_BUS_NEXUS, + .bus_select_mask = MATCH_PCI_MSI | MATCH_PLATFORM_MSI, + .prefix = "ITS-", + .init_dev_msi_info = its_init_dev_msi_info, +}; |