linux/drivers/irqchip/irq-gic-v3-mbi.c
Marc Zyngier 3898535149 irqchip/gic-v3: Add PCI/MSI support to the GICv3 MBI sub-driver
You would hope that if you have a GICv3 in your system, you'd use the ITS,
as it provides a large interrupt ID space and device isolation. Sadly,
some SoC integrations are less than perfect, and the ITS is not usesable on
those.

The only solution for these systems is to use the MBI interface, and
rely on a very small number of possible vectors.

This patch thus adds minimal support for PCI/MSI on top of the GICv3
MBI driver. Please don't use it if you can avoid it.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lkml.kernel.org/r/20180508121438.11301-9-marc.zyngier@arm.com
2018-05-13 15:59:01 +02:00

332 lines
7.9 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2018 ARM Limited, All Rights Reserved.
* Author: Marc Zyngier <marc.zyngier@arm.com>
*/
#define pr_fmt(fmt) "GICv3: " fmt
#include <linux/dma-iommu.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/irqchip/arm-gic-v3.h>
struct mbi_range {
u32 spi_start;
u32 nr_spis;
unsigned long *bm;
};
static struct mutex mbi_lock;
static phys_addr_t mbi_phys_base;
static struct mbi_range *mbi_ranges;
static unsigned int mbi_range_nr;
static struct irq_chip mbi_irq_chip = {
.name = "MBI",
.irq_mask = irq_chip_mask_parent,
.irq_unmask = irq_chip_unmask_parent,
.irq_eoi = irq_chip_eoi_parent,
.irq_set_type = irq_chip_set_type_parent,
.irq_set_affinity = irq_chip_set_affinity_parent,
};
static int mbi_irq_gic_domain_alloc(struct irq_domain *domain,
unsigned int virq,
irq_hw_number_t hwirq)
{
struct irq_fwspec fwspec;
struct irq_data *d;
int err;
/*
* Using ACPI? There is no MBI support in the spec, you
* shouldn't even be here.
*/
if (!is_of_node(domain->parent->fwnode))
return -EINVAL;
/*
* Let's default to edge. This is consistent with traditional
* MSIs, and systems requiring level signaling will just
* enforce the trigger on their own.
*/
fwspec.fwnode = domain->parent->fwnode;
fwspec.param_count = 3;
fwspec.param[0] = 0;
fwspec.param[1] = hwirq - 32;
fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
if (err)
return err;
d = irq_domain_get_irq_data(domain->parent, virq);
return d->chip->irq_set_type(d, IRQ_TYPE_EDGE_RISING);
}
static void mbi_free_msi(struct mbi_range *mbi, unsigned int hwirq,
int nr_irqs)
{
mutex_lock(&mbi_lock);
bitmap_release_region(mbi->bm, hwirq - mbi->spi_start,
get_count_order(nr_irqs));
mutex_unlock(&mbi_lock);
}
static int mbi_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs, void *args)
{
struct mbi_range *mbi = NULL;
int hwirq, offset, i, err = 0;
mutex_lock(&mbi_lock);
for (i = 0; i < mbi_range_nr; i++) {
offset = bitmap_find_free_region(mbi_ranges[i].bm,
mbi_ranges[i].nr_spis,
get_count_order(nr_irqs));
if (offset >= 0) {
mbi = &mbi_ranges[i];
break;
}
}
mutex_unlock(&mbi_lock);
if (!mbi)
return -ENOSPC;
hwirq = mbi->spi_start + offset;
for (i = 0; i < nr_irqs; i++) {
err = mbi_irq_gic_domain_alloc(domain, virq + i, hwirq + i);
if (err)
goto fail;
irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
&mbi_irq_chip, mbi);
}
return 0;
fail:
irq_domain_free_irqs_parent(domain, virq, nr_irqs);
mbi_free_msi(mbi, hwirq, nr_irqs);
return err;
}
static void mbi_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 mbi_range *mbi = irq_data_get_irq_chip_data(d);
mbi_free_msi(mbi, d->hwirq, nr_irqs);
irq_domain_free_irqs_parent(domain, virq, nr_irqs);
}
static const struct irq_domain_ops mbi_domain_ops = {
.alloc = mbi_irq_domain_alloc,
.free = mbi_irq_domain_free,
};
static void mbi_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
{
msg[0].address_hi = upper_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
msg[0].address_lo = lower_32_bits(mbi_phys_base + GICD_SETSPI_NSR);
msg[0].data = data->parent_data->hwirq;
iommu_dma_map_msi_msg(data->irq, msg);
}
#ifdef CONFIG_PCI_MSI
/* PCI-specific irqchip */
static void mbi_mask_msi_irq(struct irq_data *d)
{
pci_msi_mask_irq(d);
irq_chip_mask_parent(d);
}
static void mbi_unmask_msi_irq(struct irq_data *d)
{
pci_msi_unmask_irq(d);
irq_chip_unmask_parent(d);
}
static struct irq_chip mbi_msi_irq_chip = {
.name = "MSI",
.irq_mask = mbi_mask_msi_irq,
.irq_unmask = mbi_unmask_msi_irq,
.irq_eoi = irq_chip_eoi_parent,
.irq_compose_msi_msg = mbi_compose_msi_msg,
.irq_write_msi_msg = pci_msi_domain_write_msg,
};
static struct msi_domain_info mbi_msi_domain_info = {
.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
MSI_FLAG_PCI_MSIX | MSI_FLAG_MULTI_PCI_MSI),
.chip = &mbi_msi_irq_chip,
};
static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
struct irq_domain **pci_domain)
{
*pci_domain = pci_msi_create_irq_domain(nexus_domain->parent->fwnode,
&mbi_msi_domain_info,
nexus_domain);
if (!*pci_domain)
return -ENOMEM;
return 0;
}
#else
static int mbi_allocate_pci_domain(struct irq_domain *nexus_domain,
struct irq_domain **pci_domain)
{
*pci_domain = NULL;
return 0;
}
#endif
static void mbi_compose_mbi_msg(struct irq_data *data, struct msi_msg *msg)
{
mbi_compose_msi_msg(data, msg);
msg[1].address_hi = upper_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
msg[1].address_lo = lower_32_bits(mbi_phys_base + GICD_CLRSPI_NSR);
msg[1].data = data->parent_data->hwirq;
iommu_dma_map_msi_msg(data->irq, &msg[1]);
}
/* Platform-MSI specific irqchip */
static struct irq_chip mbi_pmsi_irq_chip = {
.name = "pMSI",
.irq_set_type = irq_chip_set_type_parent,
.irq_compose_msi_msg = mbi_compose_mbi_msg,
.flags = IRQCHIP_SUPPORTS_LEVEL_MSI,
};
static struct msi_domain_ops mbi_pmsi_ops = {
};
static struct msi_domain_info mbi_pmsi_domain_info = {
.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
MSI_FLAG_LEVEL_CAPABLE),
.ops = &mbi_pmsi_ops,
.chip = &mbi_pmsi_irq_chip,
};
static int mbi_allocate_domains(struct irq_domain *parent)
{
struct irq_domain *nexus_domain, *pci_domain, *plat_domain;
int err;
nexus_domain = irq_domain_create_tree(parent->fwnode,
&mbi_domain_ops, NULL);
if (!nexus_domain)
return -ENOMEM;
irq_domain_update_bus_token(nexus_domain, DOMAIN_BUS_NEXUS);
nexus_domain->parent = parent;
err = mbi_allocate_pci_domain(nexus_domain, &pci_domain);
plat_domain = platform_msi_create_irq_domain(parent->fwnode,
&mbi_pmsi_domain_info,
nexus_domain);
if (err || !plat_domain) {
if (plat_domain)
irq_domain_remove(plat_domain);
if (pci_domain)
irq_domain_remove(pci_domain);
irq_domain_remove(nexus_domain);
return -ENOMEM;
}
return 0;
}
int __init mbi_init(struct fwnode_handle *fwnode, struct irq_domain *parent)
{
struct device_node *np;
const __be32 *reg;
int ret, n;
np = to_of_node(fwnode);
if (!of_property_read_bool(np, "msi-controller"))
return 0;
n = of_property_count_elems_of_size(np, "mbi-ranges", sizeof(u32));
if (n <= 0 || n % 2)
return -EINVAL;
mbi_range_nr = n / 2;
mbi_ranges = kcalloc(mbi_range_nr, sizeof(*mbi_ranges), GFP_KERNEL);
if (!mbi_ranges)
return -ENOMEM;
for (n = 0; n < mbi_range_nr; n++) {
ret = of_property_read_u32_index(np, "mbi-ranges", n * 2,
&mbi_ranges[n].spi_start);
if (ret)
goto err_free_mbi;
ret = of_property_read_u32_index(np, "mbi-ranges", n * 2 + 1,
&mbi_ranges[n].nr_spis);
if (ret)
goto err_free_mbi;
mbi_ranges[n].bm = kcalloc(BITS_TO_LONGS(mbi_ranges[n].nr_spis),
sizeof(long), GFP_KERNEL);
if (!mbi_ranges[n].bm) {
ret = -ENOMEM;
goto err_free_mbi;
}
pr_info("MBI range [%d:%d]\n", mbi_ranges[n].spi_start,
mbi_ranges[n].spi_start + mbi_ranges[n].nr_spis - 1);
}
reg = of_get_property(np, "mbi-alias", NULL);
if (reg) {
mbi_phys_base = of_translate_address(np, reg);
if (mbi_phys_base == OF_BAD_ADDR) {
ret = -ENXIO;
goto err_free_mbi;
}
} else {
struct resource res;
if (of_address_to_resource(np, 0, &res)) {
ret = -ENXIO;
goto err_free_mbi;
}
mbi_phys_base = res.start;
}
pr_info("Using MBI frame %pa\n", &mbi_phys_base);
ret = mbi_allocate_domains(parent);
if (ret)
goto err_free_mbi;
return 0;
err_free_mbi:
if (mbi_ranges) {
for (n = 0; n < mbi_range_nr; n++)
kfree(mbi_ranges[n].bm);
kfree(mbi_ranges);
}
return ret;
}