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PCI: apple: Implement MSI support
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Probe for the 'msi-ranges' property, and implement the MSI support in the
form of the usual two-level hierarchy.

Note that contrary to the wired interrupts, MSIs are shared among all the
ports.

Link: https://lore.kernel.org/r/20210929163847.2807812-8-maz@kernel.org
Tested-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
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@bjorn-helgaas
Marc Zyngier authored and bjorn-helgaas committed Nov 4, 2021
1 parent d8fcbe5 commit 476c41e
Showing 1 changed file with 168 additions and 1 deletion.
169 changes: 168 additions & 1 deletion drivers/pci/controller/pcie-apple.c
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Original file line number Diff line number Diff line change
Expand Up @@ -116,10 +116,22 @@
#define PORT_TUNSTAT_PERST_ACK_PEND BIT(1)
#define PORT_PREFMEM_ENABLE 0x00994

/*
* The doorbell address is set to 0xfffff000, which by convention
* matches what MacOS does, and it is possible to use any other
* address (in the bottom 4GB, as the base register is only 32bit).
*/
#define DOORBELL_ADDR 0xfffff000

struct apple_pcie {
struct mutex lock;
struct device *dev;
void __iomem *base;
struct irq_domain *domain;
unsigned long *bitmap;
struct completion event;
struct irq_fwspec fwspec;
u32 nvecs;
};

struct apple_pcie_port {
Expand All @@ -140,6 +152,101 @@ static void rmw_clear(u32 clr, void __iomem *addr)
writel_relaxed(readl_relaxed(addr) & ~clr, addr);
}

static void apple_msi_top_irq_mask(struct irq_data *d)
{
pci_msi_mask_irq(d);
irq_chip_mask_parent(d);
}

static void apple_msi_top_irq_unmask(struct irq_data *d)
{
pci_msi_unmask_irq(d);
irq_chip_unmask_parent(d);
}

static struct irq_chip apple_msi_top_chip = {
.name = "PCIe MSI",
.irq_mask = apple_msi_top_irq_mask,
.irq_unmask = apple_msi_top_irq_unmask,
.irq_eoi = irq_chip_eoi_parent,
.irq_set_affinity = irq_chip_set_affinity_parent,
.irq_set_type = irq_chip_set_type_parent,
};

static void apple_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
{
msg->address_hi = upper_32_bits(DOORBELL_ADDR);
msg->address_lo = lower_32_bits(DOORBELL_ADDR);
msg->data = data->hwirq;
}

static struct irq_chip apple_msi_bottom_chip = {
.name = "MSI",
.irq_mask = irq_chip_mask_parent,
.irq_unmask = irq_chip_unmask_parent,
.irq_eoi = irq_chip_eoi_parent,
.irq_set_affinity = irq_chip_set_affinity_parent,
.irq_set_type = irq_chip_set_type_parent,
.irq_compose_msi_msg = apple_msi_compose_msg,
};

static int apple_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
unsigned int nr_irqs, void *args)
{
struct apple_pcie *pcie = domain->host_data;
struct irq_fwspec fwspec = pcie->fwspec;
unsigned int i;
int ret, hwirq;

mutex_lock(&pcie->lock);

hwirq = bitmap_find_free_region(pcie->bitmap, pcie->nvecs,
order_base_2(nr_irqs));

mutex_unlock(&pcie->lock);

if (hwirq < 0)
return -ENOSPC;

fwspec.param[1] += hwirq;

ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &fwspec);
if (ret)
return ret;

for (i = 0; i < nr_irqs; i++) {
irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
&apple_msi_bottom_chip,
domain->host_data);
}

return 0;
}

static void apple_msi_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 apple_pcie *pcie = domain->host_data;

mutex_lock(&pcie->lock);

bitmap_release_region(pcie->bitmap, d->hwirq, order_base_2(nr_irqs));

mutex_unlock(&pcie->lock);
}

static const struct irq_domain_ops apple_msi_domain_ops = {
.alloc = apple_msi_domain_alloc,
.free = apple_msi_domain_free,
};

static struct msi_domain_info apple_msi_info = {
.flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX),
.chip = &apple_msi_top_chip,
};

static void apple_port_irq_mask(struct irq_data *data)
{
struct apple_pcie_port *port = irq_data_get_irq_chip_data(data);
Expand Down Expand Up @@ -275,6 +382,15 @@ static int apple_pcie_port_setup_irq(struct apple_pcie_port *port)

irq_set_chained_handler_and_data(irq, apple_port_irq_handler, port);

/* Configure MSI base address */
BUILD_BUG_ON(upper_32_bits(DOORBELL_ADDR));
writel_relaxed(lower_32_bits(DOORBELL_ADDR), port->base + PORT_MSIADDR);

/* Enable MSIs, shared between all ports */
writel_relaxed(0, port->base + PORT_MSIBASE);
writel_relaxed((ilog2(port->pcie->nvecs) << PORT_MSICFG_L2MSINUM_SHIFT) |
PORT_MSICFG_EN, port->base + PORT_MSICFG);

return 0;
}

Expand Down Expand Up @@ -436,6 +552,55 @@ static int apple_pcie_setup_port(struct apple_pcie *pcie,
return 0;
}

static int apple_msi_init(struct apple_pcie *pcie)
{
struct fwnode_handle *fwnode = dev_fwnode(pcie->dev);
struct of_phandle_args args = {};
struct irq_domain *parent;
int ret;

ret = of_parse_phandle_with_args(to_of_node(fwnode), "msi-ranges",
"#interrupt-cells", 0, &args);
if (ret)
return ret;

ret = of_property_read_u32_index(to_of_node(fwnode), "msi-ranges",
args.args_count + 1, &pcie->nvecs);
if (ret)
return ret;

of_phandle_args_to_fwspec(args.np, args.args, args.args_count,
&pcie->fwspec);

pcie->bitmap = devm_bitmap_zalloc(pcie->dev, pcie->nvecs, GFP_KERNEL);
if (!pcie->bitmap)
return -ENOMEM;

parent = irq_find_matching_fwspec(&pcie->fwspec, DOMAIN_BUS_WIRED);
if (!parent) {
dev_err(pcie->dev, "failed to find parent domain\n");
return -ENXIO;
}

parent = irq_domain_create_hierarchy(parent, 0, pcie->nvecs, fwnode,
&apple_msi_domain_ops, pcie);
if (!parent) {
dev_err(pcie->dev, "failed to create IRQ domain\n");
return -ENOMEM;
}
irq_domain_update_bus_token(parent, DOMAIN_BUS_NEXUS);

pcie->domain = pci_msi_create_irq_domain(fwnode, &apple_msi_info,
parent);
if (!pcie->domain) {
dev_err(pcie->dev, "failed to create MSI domain\n");
irq_domain_remove(parent);
return -ENOMEM;
}

return 0;
}

static int apple_pcie_init(struct pci_config_window *cfg)
{
struct device *dev = cfg->parent;
Expand All @@ -450,6 +615,8 @@ static int apple_pcie_init(struct pci_config_window *cfg)

pcie->dev = dev;

mutex_init(&pcie->lock);

pcie->base = devm_platform_ioremap_resource(platform, 1);
if (IS_ERR(pcie->base))
return PTR_ERR(pcie->base);
Expand All @@ -463,7 +630,7 @@ static int apple_pcie_init(struct pci_config_window *cfg)
}
}

return 0;
return apple_msi_init(pcie);
}

static const struct pci_ecam_ops apple_pcie_cfg_ecam_ops = {
Expand Down

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