Commit d76bdce3 authored by Marc Gonzalez's avatar Marc Gonzalez Committed by Bjorn Helgaas
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PCI: tango: Add MSI controller support 



Add support for the MSI controller in Tango, which supports 256
message-signaled interrupts and a single doorbell address.

Signed-off-by: default avatarMarc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 1e61a57c

drivers/pci/host/pcie-tango.c

+202 −3
Original line number Diff line number Diff line 
#include <linux/irqchip/chained_irq.h>

#include <linux/irqdomain.h>

#include <linux/pci-ecam.h>

#include <linux/delay.h>

#include <linux/of.h>

#include <linux/msi.h>

#include <linux/of_address.h>



#define MSI_MAX			256



#define SMP8759_MUX		0x48

#define SMP8759_TEST_OUT	0x74

#define SMP8759_DOORBELL	0x7c

#define SMP8759_STATUS		0x80

#define SMP8759_ENABLE		0xa0



struct tango_pcie {

	DECLARE_BITMAP(used_msi, MSI_MAX);

	u64			msi_doorbell;

	spinlock_t		used_msi_lock;

	void __iomem		*base;

	struct irq_domain	*dom;

};



static void tango_msi_isr(struct irq_desc *desc)

{

	struct irq_chip *chip = irq_desc_get_chip(desc);

	struct tango_pcie *pcie = irq_desc_get_handler_data(desc);

	unsigned long status, base, virq, idx, pos = 0;



	chained_irq_enter(chip, desc);

	spin_lock(&pcie->used_msi_lock);



	while ((pos = find_next_bit(pcie->used_msi, MSI_MAX, pos)) < MSI_MAX) {

		base = round_down(pos, 32);

		status = readl_relaxed(pcie->base + SMP8759_STATUS + base / 8);

		for_each_set_bit(idx, &status, 32) {

			virq = irq_find_mapping(pcie->dom, base + idx);

			generic_handle_irq(virq);

		}

		pos = base + 32;

	}



	spin_unlock(&pcie->used_msi_lock);

	chained_irq_exit(chip, desc);

}



static void tango_ack(struct irq_data *d)

{

	struct tango_pcie *pcie = d->chip_data;

	u32 offset = (d->hwirq / 32) * 4;

	u32 bit = BIT(d->hwirq % 32);



	writel_relaxed(bit, pcie->base + SMP8759_STATUS + offset);

}



static void update_msi_enable(struct irq_data *d, bool unmask)

{

	unsigned long flags;

	struct tango_pcie *pcie = d->chip_data;

	u32 offset = (d->hwirq / 32) * 4;

	u32 bit = BIT(d->hwirq % 32);

	u32 val;



	spin_lock_irqsave(&pcie->used_msi_lock, flags);

	val = readl_relaxed(pcie->base + SMP8759_ENABLE + offset);

	val = unmask ? val | bit : val & ~bit;

	writel_relaxed(val, pcie->base + SMP8759_ENABLE + offset);

	spin_unlock_irqrestore(&pcie->used_msi_lock, flags);

}



static void tango_mask(struct irq_data *d)

{

	update_msi_enable(d, false);

}



static void tango_unmask(struct irq_data *d)

{

	update_msi_enable(d, true);

}



static int tango_set_affinity(struct irq_data *d, const struct cpumask *mask,

			      bool force)

{

	return -EINVAL;

}



static void tango_compose_msi_msg(struct irq_data *d, struct msi_msg *msg)

{

	struct tango_pcie *pcie = d->chip_data;

	msg->address_lo = lower_32_bits(pcie->msi_doorbell);

	msg->address_hi = upper_32_bits(pcie->msi_doorbell);

	msg->data = d->hwirq;

}



static struct irq_chip tango_chip = {

	.irq_ack		= tango_ack,

	.irq_mask		= tango_mask,

	.irq_unmask		= tango_unmask,

	.irq_set_affinity	= tango_set_affinity,

	.irq_compose_msi_msg	= tango_compose_msi_msg,

};



static void msi_ack(struct irq_data *d)

{

	irq_chip_ack_parent(d);

}



static void msi_mask(struct irq_data *d)

{

	pci_msi_mask_irq(d);

	irq_chip_mask_parent(d);

}



static void msi_unmask(struct irq_data *d)

{

	pci_msi_unmask_irq(d);

	irq_chip_unmask_parent(d);

}



static struct irq_chip msi_chip = {

	.name = "MSI",

	.irq_ack = msi_ack,

	.irq_mask = msi_mask,

	.irq_unmask = msi_unmask,

};



static struct msi_domain_info msi_dom_info = {

	.flags	= MSI_FLAG_PCI_MSIX

		| MSI_FLAG_USE_DEF_DOM_OPS

		| MSI_FLAG_USE_DEF_CHIP_OPS,

	.chip	= &msi_chip,

};



static int tango_irq_domain_alloc(struct irq_domain *dom, unsigned int virq,

				  unsigned int nr_irqs, void *args)

{

	struct tango_pcie *pcie = dom->host_data;

	unsigned long flags;

	int pos;



	spin_lock_irqsave(&pcie->used_msi_lock, flags);

	pos = find_first_zero_bit(pcie->used_msi, MSI_MAX);

	if (pos >= MSI_MAX) {

		spin_unlock_irqrestore(&pcie->used_msi_lock, flags);

		return -ENOSPC;

	}

	__set_bit(pos, pcie->used_msi);

	spin_unlock_irqrestore(&pcie->used_msi_lock, flags);

	irq_domain_set_info(dom, virq, pos, &tango_chip,

			pcie, handle_edge_irq, NULL, NULL);



	return 0;

}



static void tango_irq_domain_free(struct irq_domain *dom, unsigned int virq,

				  unsigned int nr_irqs)

{

	unsigned long flags;

	struct irq_data *d = irq_domain_get_irq_data(dom, virq);

	struct tango_pcie *pcie = d->chip_data;



	spin_lock_irqsave(&pcie->used_msi_lock, flags);

	__clear_bit(d->hwirq, pcie->used_msi);

	spin_unlock_irqrestore(&pcie->used_msi_lock, flags);

}



static const struct irq_domain_ops dom_ops = {

	.alloc	= tango_irq_domain_alloc,

	.free	= tango_irq_domain_free,

};



static int smp8759_config_read(struct pci_bus *bus, unsigned int devfn,
@@ -76,7 +236,11 @@ static int tango_pcie_probe(struct platform_device *pdev) 
	struct device *dev = &pdev->dev;

	struct tango_pcie *pcie;

	struct resource *res;

	int ret;

	struct fwnode_handle *fwnode = of_node_to_fwnode(dev->of_node);

	struct irq_domain *msi_dom, *irq_dom;

	struct of_pci_range_parser parser;

	struct of_pci_range range;

	int virq, offset;



	dev_warn(dev, "simultaneous PCI config and MMIO accesses may cause data corruption\n");

	add_taint(TAINT_CRAP, LOCKDEP_STILL_OK);
@@ -95,6 +259,41 @@ static int tango_pcie_probe(struct platform_device *pdev) 
	if (!tango_pcie_link_up(pcie))

		return -ENODEV;



	if (of_pci_dma_range_parser_init(&parser, dev->of_node) < 0)

		return -ENOENT;



	if (of_pci_range_parser_one(&parser, &range) == NULL)

		return -ENOENT;



	range.pci_addr += range.size;

	pcie->msi_doorbell = range.pci_addr + res->start + SMP8759_DOORBELL;



	for (offset = 0; offset < MSI_MAX / 8; offset += 4)

		writel_relaxed(0, pcie->base + SMP8759_ENABLE + offset);



	virq = platform_get_irq(pdev, 1);

	if (virq <= 0) {

		dev_err(dev, "Failed to map IRQ\n");

		return -ENXIO;

	}



	irq_dom = irq_domain_create_linear(fwnode, MSI_MAX, &dom_ops, pcie);

	if (!irq_dom) {

		dev_err(dev, "Failed to create IRQ domain\n");

		return -ENOMEM;

	}



	msi_dom = pci_msi_create_irq_domain(fwnode, &msi_dom_info, irq_dom);

	if (!msi_dom) {

		dev_err(dev, "Failed to create MSI domain\n");

		irq_domain_remove(irq_dom);

		return -ENOMEM;

	}



	pcie->dom = irq_dom;

	spin_lock_init(&pcie->used_msi_lock);

	irq_set_chained_handler_and_data(virq, tango_msi_isr, pcie);



	return pci_host_common_probe(pdev, &smp8759_ecam_ops);

}