diff options
Diffstat (limited to 'drivers/pci/controller/pcie-altera-msi.c')
| -rw-r--r-- | drivers/pci/controller/pcie-altera-msi.c | 291 |
1 files changed, 291 insertions, 0 deletions
diff --git a/drivers/pci/controller/pcie-altera-msi.c b/drivers/pci/controller/pcie-altera-msi.c new file mode 100644 index 000000000..025ef7d9a --- /dev/null +++ b/drivers/pci/controller/pcie-altera-msi.c @@ -0,0 +1,291 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Altera PCIe MSI support + * + * Author: Ley Foon Tan <lftan@altera.com> + * + * Copyright Altera Corporation (C) 2013-2015. All rights reserved + */ + +#include <linux/interrupt.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/init.h> +#include <linux/msi.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/of_pci.h> +#include <linux/pci.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#define MSI_STATUS 0x0 +#define MSI_ERROR 0x4 +#define MSI_INTMASK 0x8 + +#define MAX_MSI_VECTORS 32 + +struct altera_msi { + DECLARE_BITMAP(used, MAX_MSI_VECTORS); + struct mutex lock; /* protect "used" bitmap */ + struct platform_device *pdev; + struct irq_domain *msi_domain; + struct irq_domain *inner_domain; + void __iomem *csr_base; + void __iomem *vector_base; + phys_addr_t vector_phy; + u32 num_of_vectors; + int irq; +}; + +static inline void msi_writel(struct altera_msi *msi, const u32 value, + const u32 reg) +{ + writel_relaxed(value, msi->csr_base + reg); +} + +static inline u32 msi_readl(struct altera_msi *msi, const u32 reg) +{ + return readl_relaxed(msi->csr_base + reg); +} + +static void altera_msi_isr(struct irq_desc *desc) +{ + struct irq_chip *chip = irq_desc_get_chip(desc); + struct altera_msi *msi; + unsigned long status; + u32 bit; + u32 virq; + + chained_irq_enter(chip, desc); + msi = irq_desc_get_handler_data(desc); + + while ((status = msi_readl(msi, MSI_STATUS)) != 0) { + for_each_set_bit(bit, &status, msi->num_of_vectors) { + /* Dummy read from vector to clear the interrupt */ + readl_relaxed(msi->vector_base + (bit * sizeof(u32))); + + virq = irq_find_mapping(msi->inner_domain, bit); + if (virq) + generic_handle_irq(virq); + else + dev_err(&msi->pdev->dev, "unexpected MSI\n"); + } + } + + chained_irq_exit(chip, desc); +} + +static struct irq_chip altera_msi_irq_chip = { + .name = "Altera PCIe MSI", + .irq_mask = pci_msi_mask_irq, + .irq_unmask = pci_msi_unmask_irq, +}; + +static struct msi_domain_info altera_msi_domain_info = { + .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | + MSI_FLAG_PCI_MSIX), + .chip = &altera_msi_irq_chip, +}; + +static void altera_compose_msi_msg(struct irq_data *data, struct msi_msg *msg) +{ + struct altera_msi *msi = irq_data_get_irq_chip_data(data); + phys_addr_t addr = msi->vector_phy + (data->hwirq * sizeof(u32)); + + msg->address_lo = lower_32_bits(addr); + msg->address_hi = upper_32_bits(addr); + msg->data = data->hwirq; + + dev_dbg(&msi->pdev->dev, "msi#%d address_hi %#x address_lo %#x\n", + (int)data->hwirq, msg->address_hi, msg->address_lo); +} + +static int altera_msi_set_affinity(struct irq_data *irq_data, + const struct cpumask *mask, bool force) +{ + return -EINVAL; +} + +static struct irq_chip altera_msi_bottom_irq_chip = { + .name = "Altera MSI", + .irq_compose_msi_msg = altera_compose_msi_msg, + .irq_set_affinity = altera_msi_set_affinity, +}; + +static int altera_irq_domain_alloc(struct irq_domain *domain, unsigned int virq, + unsigned int nr_irqs, void *args) +{ + struct altera_msi *msi = domain->host_data; + unsigned long bit; + u32 mask; + + WARN_ON(nr_irqs != 1); + mutex_lock(&msi->lock); + + bit = find_first_zero_bit(msi->used, msi->num_of_vectors); + if (bit >= msi->num_of_vectors) { + mutex_unlock(&msi->lock); + return -ENOSPC; + } + + set_bit(bit, msi->used); + + mutex_unlock(&msi->lock); + + irq_domain_set_info(domain, virq, bit, &altera_msi_bottom_irq_chip, + domain->host_data, handle_simple_irq, + NULL, NULL); + + mask = msi_readl(msi, MSI_INTMASK); + mask |= 1 << bit; + msi_writel(msi, mask, MSI_INTMASK); + + return 0; +} + +static void altera_irq_domain_free(struct irq_domain *domain, + unsigned int virq, unsigned int nr_irqs) +{ + struct irq_data *d = irq_domain_get_irq_data(domain, virq); + struct altera_msi *msi = irq_data_get_irq_chip_data(d); + u32 mask; + + mutex_lock(&msi->lock); + + if (!test_bit(d->hwirq, msi->used)) { + dev_err(&msi->pdev->dev, "trying to free unused MSI#%lu\n", + d->hwirq); + } else { + __clear_bit(d->hwirq, msi->used); + mask = msi_readl(msi, MSI_INTMASK); + mask &= ~(1 << d->hwirq); + msi_writel(msi, mask, MSI_INTMASK); + } + + mutex_unlock(&msi->lock); +} + +static const struct irq_domain_ops msi_domain_ops = { + .alloc = altera_irq_domain_alloc, + .free = altera_irq_domain_free, +}; + +static int altera_allocate_domains(struct altera_msi *msi) +{ + struct fwnode_handle *fwnode = of_node_to_fwnode(msi->pdev->dev.of_node); + + msi->inner_domain = irq_domain_add_linear(NULL, msi->num_of_vectors, + &msi_domain_ops, msi); + if (!msi->inner_domain) { + dev_err(&msi->pdev->dev, "failed to create IRQ domain\n"); + return -ENOMEM; + } + + msi->msi_domain = pci_msi_create_irq_domain(fwnode, + &altera_msi_domain_info, msi->inner_domain); + if (!msi->msi_domain) { + dev_err(&msi->pdev->dev, "failed to create MSI domain\n"); + irq_domain_remove(msi->inner_domain); + return -ENOMEM; + } + + return 0; +} + +static void altera_free_domains(struct altera_msi *msi) +{ + irq_domain_remove(msi->msi_domain); + irq_domain_remove(msi->inner_domain); +} + +static int altera_msi_remove(struct platform_device *pdev) +{ + struct altera_msi *msi = platform_get_drvdata(pdev); + + msi_writel(msi, 0, MSI_INTMASK); + irq_set_chained_handler(msi->irq, NULL); + irq_set_handler_data(msi->irq, NULL); + + altera_free_domains(msi); + + platform_set_drvdata(pdev, NULL); + return 0; +} + +static int altera_msi_probe(struct platform_device *pdev) +{ + struct altera_msi *msi; + struct device_node *np = pdev->dev.of_node; + struct resource *res; + int ret; + + msi = devm_kzalloc(&pdev->dev, sizeof(struct altera_msi), + GFP_KERNEL); + if (!msi) + return -ENOMEM; + + mutex_init(&msi->lock); + msi->pdev = pdev; + + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "csr"); + msi->csr_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(msi->csr_base)) { + dev_err(&pdev->dev, "failed to map csr memory\n"); + return PTR_ERR(msi->csr_base); + } + + res = platform_get_resource_byname(pdev, IORESOURCE_MEM, + "vector_slave"); + msi->vector_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(msi->vector_base)) { + dev_err(&pdev->dev, "failed to map vector_slave memory\n"); + return PTR_ERR(msi->vector_base); + } + + msi->vector_phy = res->start; + + if (of_property_read_u32(np, "num-vectors", &msi->num_of_vectors)) { + dev_err(&pdev->dev, "failed to parse the number of vectors\n"); + return -EINVAL; + } + + ret = altera_allocate_domains(msi); + if (ret) + return ret; + + msi->irq = platform_get_irq(pdev, 0); + if (msi->irq < 0) { + dev_err(&pdev->dev, "failed to map IRQ: %d\n", msi->irq); + ret = msi->irq; + goto err; + } + + irq_set_chained_handler_and_data(msi->irq, altera_msi_isr, msi); + platform_set_drvdata(pdev, msi); + + return 0; + +err: + altera_msi_remove(pdev); + return ret; +} + +static const struct of_device_id altera_msi_of_match[] = { + { .compatible = "altr,msi-1.0", NULL }, + { }, +}; + +static struct platform_driver altera_msi_driver = { + .driver = { + .name = "altera-msi", + .of_match_table = altera_msi_of_match, + }, + .probe = altera_msi_probe, + .remove = altera_msi_remove, +}; + +static int __init altera_msi_init(void) +{ + return platform_driver_register(&altera_msi_driver); +} +subsys_initcall(altera_msi_init); |