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Commit 290c1fb3 authored by Phil Edworthy's avatar Phil Edworthy Committed by Bjorn Helgaas
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PCI: rcar: Add MSI support for PCIe



Add MSI support to the R-Car PCIe driver.

Signed-off-by: default avatarPhil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarLucas Stach <l.stach@pengutronix.de>
Acked-by: default avatarSimon Horman <horms+renesas@verge.net.au>
parent c25da477
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+241 −1
Original line number Diff line number Diff line
@@ -15,8 +15,11 @@
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/msi.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/of_pci.h>
@@ -35,6 +38,7 @@
#define PCIECDR			0x000020
#define PCIEMSR			0x000028
#define PCIEINTXR		0x000400
#define PCIEMSITXR		0x000840

/* Transfer control */
#define PCIETCTLR		0x02000
@@ -43,6 +47,11 @@
#define  DATA_LINK_ACTIVE	1
#define PCIEERRFR		0x02020
#define  UNSUPPORTED_REQUEST	(1 << 4)
#define PCIEMSIFR		0x02044
#define PCIEMSIALR		0x02048
#define  MSIFE			1
#define PCIEMSIAUR		0x0204c
#define PCIEMSIIER		0x02050

/* root port address */
#define PCIEPRAR(x)		(0x02080 + ((x) * 0x4))
@@ -85,6 +94,8 @@
#define H1_PCIEPHYDOUTR		0x040014
#define H1_PCIEPHYSR		0x040018

#define INT_PCI_MSI_NR	32

#define RCONF(x)	(PCICONF(0)+(x))
#define RPMCAP(x)	(PMCAP(0)+(x))
#define REXPCAP(x)	(EXPCAP(0)+(x))
@@ -97,6 +108,21 @@
#define PCI_MAX_RESOURCES 4
#define MAX_NR_INBOUND_MAPS 6

struct rcar_msi {
	DECLARE_BITMAP(used, INT_PCI_MSI_NR);
	struct irq_domain *domain;
	struct msi_chip chip;
	unsigned long pages;
	struct mutex lock;
	int irq1;
	int irq2;
};

static inline struct rcar_msi *to_rcar_msi(struct msi_chip *chip)
{
	return container_of(chip, struct rcar_msi, chip);
}

/* Structure representing the PCIe interface */
struct rcar_pcie {
	struct device		*dev;
@@ -106,6 +132,7 @@ struct rcar_pcie {
	int			root_bus_nr;
	struct clk		*clk;
	struct clk		*bus_clk;
	struct			rcar_msi msi;
};

static inline struct rcar_pcie *sys_to_pcie(struct pci_sys_data *sys)
@@ -356,10 +383,20 @@ static int rcar_pcie_setup(int nr, struct pci_sys_data *sys)
	return 1;
}

static void rcar_pcie_add_bus(struct pci_bus *bus)
{
	if (IS_ENABLED(CONFIG_PCI_MSI)) {
		struct rcar_pcie *pcie = sys_to_pcie(bus->sysdata);

		bus->msi = &pcie->msi.chip;
	}
}

struct hw_pci rcar_pci = {
	.setup          = rcar_pcie_setup,
	.map_irq        = of_irq_parse_and_map_pci,
	.ops            = &rcar_pcie_ops,
	.add_bus        = rcar_pcie_add_bus,
};

static void rcar_pcie_enable(struct rcar_pcie *pcie)
@@ -477,6 +514,10 @@ static int rcar_pcie_hw_init(struct rcar_pcie *pcie)
	/* Enable MAC data scrambling. */
	rcar_rmw32(pcie, MACCTLR, SCRAMBLE_DISABLE, 0);

	/* Enable MSI */
	if (IS_ENABLED(CONFIG_PCI_MSI))
		pci_write_reg(pcie, 0x101f0000, PCIEMSITXR);

	/* Finish initialization - establish a PCI Express link */
	pci_write_reg(pcie, CFINIT, PCIETCTLR);

@@ -530,11 +571,184 @@ static int rcar_pcie_hw_init_h1(struct rcar_pcie *pcie)
	return -ETIMEDOUT;
}

static int rcar_msi_alloc(struct rcar_msi *chip)
{
	int msi;

	mutex_lock(&chip->lock);

	msi = find_first_zero_bit(chip->used, INT_PCI_MSI_NR);
	if (msi < INT_PCI_MSI_NR)
		set_bit(msi, chip->used);
	else
		msi = -ENOSPC;

	mutex_unlock(&chip->lock);

	return msi;
}

static void rcar_msi_free(struct rcar_msi *chip, unsigned long irq)
{
	mutex_lock(&chip->lock);
	clear_bit(irq, chip->used);
	mutex_unlock(&chip->lock);
}

static irqreturn_t rcar_pcie_msi_irq(int irq, void *data)
{
	struct rcar_pcie *pcie = data;
	struct rcar_msi *msi = &pcie->msi;
	unsigned long reg;

	reg = pci_read_reg(pcie, PCIEMSIFR);

	/* MSI & INTx share an interrupt - we only handle MSI here */
	if (!reg)
		return IRQ_NONE;

	while (reg) {
		unsigned int index = find_first_bit(&reg, 32);
		unsigned int irq;

		/* clear the interrupt */
		pci_write_reg(pcie, 1 << index, PCIEMSIFR);

		irq = irq_find_mapping(msi->domain, index);
		if (irq) {
			if (test_bit(index, msi->used))
				generic_handle_irq(irq);
			else
				dev_info(pcie->dev, "unhandled MSI\n");
		} else {
			/* Unknown MSI, just clear it */
			dev_dbg(pcie->dev, "unexpected MSI\n");
		}

		/* see if there's any more pending in this vector */
		reg = pci_read_reg(pcie, PCIEMSIFR);
	}

	return IRQ_HANDLED;
}

static int rcar_msi_setup_irq(struct msi_chip *chip, struct pci_dev *pdev,
			      struct msi_desc *desc)
{
	struct rcar_msi *msi = to_rcar_msi(chip);
	struct rcar_pcie *pcie = container_of(chip, struct rcar_pcie, msi.chip);
	struct msi_msg msg;
	unsigned int irq;
	int hwirq;

	hwirq = rcar_msi_alloc(msi);
	if (hwirq < 0)
		return hwirq;

	irq = irq_create_mapping(msi->domain, hwirq);
	if (!irq) {
		rcar_msi_free(msi, hwirq);
		return -EINVAL;
	}

	irq_set_msi_desc(irq, desc);

	msg.address_lo = pci_read_reg(pcie, PCIEMSIALR) & ~MSIFE;
	msg.address_hi = pci_read_reg(pcie, PCIEMSIAUR);
	msg.data = hwirq;

	write_msi_msg(irq, &msg);

	return 0;
}

static void rcar_msi_teardown_irq(struct msi_chip *chip, unsigned int irq)
{
	struct rcar_msi *msi = to_rcar_msi(chip);
	struct irq_data *d = irq_get_irq_data(irq);

	rcar_msi_free(msi, d->hwirq);
}

static struct irq_chip rcar_msi_irq_chip = {
	.name = "R-Car PCIe MSI",
	.irq_enable = unmask_msi_irq,
	.irq_disable = mask_msi_irq,
	.irq_mask = mask_msi_irq,
	.irq_unmask = unmask_msi_irq,
};

static int rcar_msi_map(struct irq_domain *domain, unsigned int irq,
			irq_hw_number_t hwirq)
{
	irq_set_chip_and_handler(irq, &rcar_msi_irq_chip, handle_simple_irq);
	irq_set_chip_data(irq, domain->host_data);
	set_irq_flags(irq, IRQF_VALID);

	return 0;
}

static const struct irq_domain_ops msi_domain_ops = {
	.map = rcar_msi_map,
};

static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
{
	struct platform_device *pdev = to_platform_device(pcie->dev);
	struct rcar_msi *msi = &pcie->msi;
	unsigned long base;
	int err;

	mutex_init(&msi->lock);

	msi->chip.dev = pcie->dev;
	msi->chip.setup_irq = rcar_msi_setup_irq;
	msi->chip.teardown_irq = rcar_msi_teardown_irq;

	msi->domain = irq_domain_add_linear(pcie->dev->of_node, INT_PCI_MSI_NR,
					    &msi_domain_ops, &msi->chip);
	if (!msi->domain) {
		dev_err(&pdev->dev, "failed to create IRQ domain\n");
		return -ENOMEM;
	}

	/* Two irqs are for MSI, but they are also used for non-MSI irqs */
	err = devm_request_irq(&pdev->dev, msi->irq1, rcar_pcie_msi_irq,
			       IRQF_SHARED, rcar_msi_irq_chip.name, pcie);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
		goto err;
	}

	err = devm_request_irq(&pdev->dev, msi->irq2, rcar_pcie_msi_irq,
			       IRQF_SHARED, rcar_msi_irq_chip.name, pcie);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
		goto err;
	}

	/* setup MSI data target */
	msi->pages = __get_free_pages(GFP_KERNEL, 0);
	base = virt_to_phys((void *)msi->pages);

	pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
	pci_write_reg(pcie, 0, PCIEMSIAUR);

	/* enable all MSI interrupts */
	pci_write_reg(pcie, 0xffffffff, PCIEMSIIER);

	return 0;

err:
	irq_domain_remove(msi->domain);
	return err;
}

static int rcar_pcie_get_resources(struct platform_device *pdev,
				   struct rcar_pcie *pcie)
{
	struct resource res;
	int err;
	int err, i;

	err = of_address_to_resource(pdev->dev.of_node, 0, &res);
	if (err)
@@ -559,6 +773,22 @@ static int rcar_pcie_get_resources(struct platform_device *pdev,
	if (err)
		goto err_map_reg;

	i = irq_of_parse_and_map(pdev->dev.of_node, 0);
	if (i < 0) {
		dev_err(pcie->dev, "cannot get platform resources for msi interrupt\n");
		err = -ENOENT;
		goto err_map_reg;
	}
	pcie->msi.irq1 = i;

	i = irq_of_parse_and_map(pdev->dev.of_node, 1);
	if (i < 0) {
		dev_err(pcie->dev, "cannot get platform resources for msi interrupt\n");
		err = -ENOENT;
		goto err_map_reg;
	}
	pcie->msi.irq2 = i;

	pcie->base = devm_ioremap_resource(&pdev->dev, &res);
	if (IS_ERR(pcie->base)) {
		err = PTR_ERR(pcie->base);
@@ -732,6 +962,16 @@ static int rcar_pcie_probe(struct platform_device *pdev)
	 if (err)
		return err;

	if (IS_ENABLED(CONFIG_PCI_MSI)) {
		err = rcar_pcie_enable_msi(pcie);
		if (err < 0) {
			dev_err(&pdev->dev,
				"failed to enable MSI support: %d\n",
				err);
			return err;
		}
	}

	of_id = of_match_device(rcar_pcie_of_match, pcie->dev);
	if (!of_id || !of_id->data)
		return -EINVAL;