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Release 4.11 drivers/pci/host/pcie-altera-msi.c

Directory: drivers/pci/host
/*
 * Altera PCIe MSI support
 *
 * Author: Ley Foon Tan <lftan@altera.com>
 *
 * Copyright Altera Corporation (C) 2013-2015. All rights reserved
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#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); }

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static inline u32 msi_readl(struct altera_msi *msi, const u32 reg) { return readl_relaxed(msi->csr_base + reg); }

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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 num_of_vectors; u32 bit; u32 virq; chained_irq_enter(chip, desc); msi = irq_desc_get_handler_data(desc); num_of_vectors = msi->num_of_vectors; 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); }

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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); }

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static int altera_msi_set_affinity(struct irq_data *irq_data, const struct cpumask *mask, bool force) { return -EINVAL; }

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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; }

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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); }

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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; }

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static void altera_free_domains(struct altera_msi *msi) { irq_domain_remove(msi->msi_domain); irq_domain_remove(msi->inner_domain); }

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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; }

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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 = -ENODEV; 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; }

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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); }

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subsys_initcall(altera_msi_init);

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Directory: drivers/pci/host
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