[PATCH v3 03/14] PCI: rcar: Convert to MSI domains

From: Marc Zyngier
Date: Tue Mar 30 2021 - 11:13:27 EST

In anticipation of the removal of the msi_controller structure, convert
the Rcar host controller driver to MSI domains.

We end-up with the usual two domain structure, the top one being a
generic PCI/MSI domain, the bottom one being Rcar-specific and handling
the actual HW interrupt allocation.

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Tested-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
drivers/pci/controller/Kconfig | 1 -
drivers/pci/controller/pcie-rcar-host.c | 352 ++++++++++++------------
2 files changed, 170 insertions(+), 183 deletions(-)

diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
index be8f9ff512a0..5cc07d28a3a0 100644
--- a/drivers/pci/controller/Kconfig
+++ b/drivers/pci/controller/Kconfig
@@ -58,7 +58,6 @@ config PCIE_RCAR_HOST
bool "Renesas R-Car PCIe host controller"
depends on ARCH_RENESAS || COMPILE_TEST
depends on PCI_MSI_IRQ_DOMAIN
- select PCI_MSI_ARCH_FALLBACKS
help
Say Y here if you want PCIe controller support on R-Car SoCs in host
mode.
diff --git a/drivers/pci/controller/pcie-rcar-host.c b/drivers/pci/controller/pcie-rcar-host.c
index ce952403e22c..f7331ad0d6dc 100644
--- a/drivers/pci/controller/pcie-rcar-host.c
+++ b/drivers/pci/controller/pcie-rcar-host.c
@@ -35,17 +35,12 @@
struct rcar_msi {
DECLARE_BITMAP(used, INT_PCI_MSI_NR);
struct irq_domain *domain;
- struct msi_controller chip;
- struct mutex lock;
+ struct mutex map_lock;
+ spinlock_t mask_lock;
int irq1;
int irq2;
};

-static inline struct rcar_msi *to_rcar_msi(struct msi_controller *chip)
-{
- return container_of(chip, struct rcar_msi, chip);
-}
-
/* Structure representing the PCIe interface */
struct rcar_pcie_host {
struct rcar_pcie pcie;
@@ -55,6 +50,11 @@ struct rcar_pcie_host {
int (*phy_init_fn)(struct rcar_pcie_host *host);
};

+static struct rcar_pcie_host *msi_to_host(struct rcar_msi *msi)
+{
+ return container_of(msi, struct rcar_pcie_host, msi);
+}
+
static u32 rcar_read_conf(struct rcar_pcie *pcie, int where)
{
unsigned int shift = BITS_PER_BYTE * (where & 3);
@@ -291,8 +291,6 @@ static int rcar_pcie_enable(struct rcar_pcie_host *host)

bridge->sysdata = host;
bridge->ops = &rcar_pcie_ops;
- if (IS_ENABLED(CONFIG_PCI_MSI))
- bridge->msi = &host->msi.chip;

return pci_host_probe(bridge);
}
@@ -472,42 +470,6 @@ static int rcar_pcie_phy_init_gen3(struct rcar_pcie_host *host)
return err;
}

-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 int rcar_msi_alloc_region(struct rcar_msi *chip, int no_irqs)
-{
- int msi;
-
- mutex_lock(&chip->lock);
- msi = bitmap_find_free_region(chip->used, INT_PCI_MSI_NR,
- order_base_2(no_irqs));
- 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_host *host = data;
@@ -526,18 +488,13 @@ static irqreturn_t rcar_pcie_msi_irq(int irq, void *data)
unsigned int index = find_first_bit(&reg, 32);
unsigned int msi_irq;

- /* clear the interrupt */
- rcar_pci_write_reg(pcie, 1 << index, PCIEMSIFR);
-
- msi_irq = irq_find_mapping(msi->domain, index);
+ msi_irq = irq_find_mapping(msi->domain->parent, index);
if (msi_irq) {
- if (test_bit(index, msi->used))
- generic_handle_irq(msi_irq);
- else
- dev_info(dev, "unhandled MSI\n");
+ generic_handle_irq(msi_irq);
} else {
/* Unknown MSI, just clear it */
dev_dbg(dev, "unexpected MSI\n");
+ rcar_pci_write_reg(pcie, BIT(index), PCIEMSIFR);
}

/* see if there's any more pending in this vector */
@@ -547,150 +504,170 @@ static irqreturn_t rcar_pcie_msi_irq(int irq, void *data)
return IRQ_HANDLED;
}

-static int rcar_msi_setup_irq(struct msi_controller *chip, struct pci_dev *pdev,
- struct msi_desc *desc)
+static void rcar_msi_top_irq_ack(struct irq_data *d)
{
- struct rcar_msi *msi = to_rcar_msi(chip);
- struct rcar_pcie_host *host = container_of(chip, struct rcar_pcie_host,
- msi.chip);
- struct rcar_pcie *pcie = &host->pcie;
- struct msi_msg msg;
- unsigned int irq;
- int hwirq;
+ irq_chip_ack_parent(d);
+}

- hwirq = rcar_msi_alloc(msi);
- if (hwirq < 0)
- return hwirq;
+static void rcar_msi_top_irq_mask(struct irq_data *d)
+{
+ pci_msi_mask_irq(d);
+ irq_chip_mask_parent(d);
+}

- irq = irq_find_mapping(msi->domain, hwirq);
- if (!irq) {
- rcar_msi_free(msi, hwirq);
- return -EINVAL;
- }
+static void rcar_msi_top_irq_unmask(struct irq_data *d)
+{
+ pci_msi_unmask_irq(d);
+ irq_chip_unmask_parent(d);
+}

- irq_set_msi_desc(irq, desc);
+static struct irq_chip rcar_msi_top_chip = {
+ .name = "PCIe MSI",
+ .irq_ack = rcar_msi_top_irq_ack,
+ .irq_mask = rcar_msi_top_irq_mask,
+ .irq_unmask = rcar_msi_top_irq_unmask,
+};

- msg.address_lo = rcar_pci_read_reg(pcie, PCIEMSIALR) & ~MSIFE;
- msg.address_hi = rcar_pci_read_reg(pcie, PCIEMSIAUR);
- msg.data = hwirq;
+static void rcar_msi_irq_ack(struct irq_data *d)
+{
+ struct rcar_msi *msi = irq_data_get_irq_chip_data(d);
+ struct rcar_pcie *pcie = &msi_to_host(msi)->pcie;

- pci_write_msi_msg(irq, &msg);
+ /* clear the interrupt */
+ rcar_pci_write_reg(pcie, BIT(d->hwirq), PCIEMSIFR);
+}

- return 0;
+static void rcar_msi_irq_mask(struct irq_data *d)
+{
+ struct rcar_msi *msi = irq_data_get_irq_chip_data(d);
+ struct rcar_pcie *pcie = &msi_to_host(msi)->pcie;
+ unsigned long flags;
+ u32 value;
+
+ spin_lock_irqsave(&msi->mask_lock, flags);
+ value = rcar_pci_read_reg(pcie, PCIEMSIIER);
+ value &= ~BIT(d->hwirq);
+ rcar_pci_write_reg(pcie, value, PCIEMSIIER);
+ spin_unlock_irqrestore(&msi->mask_lock, flags);
}

-static int rcar_msi_setup_irqs(struct msi_controller *chip,
- struct pci_dev *pdev, int nvec, int type)
+static void rcar_msi_irq_unmask(struct irq_data *d)
{
- struct rcar_msi *msi = to_rcar_msi(chip);
- struct rcar_pcie_host *host = container_of(chip, struct rcar_pcie_host,
- msi.chip);
- struct rcar_pcie *pcie = &host->pcie;
- struct msi_desc *desc;
- struct msi_msg msg;
- unsigned int irq;
- int hwirq;
- int i;
+ struct rcar_msi *msi = irq_data_get_irq_chip_data(d);
+ struct rcar_pcie *pcie = &msi_to_host(msi)->pcie;
+ unsigned long flags;
+ u32 value;
+
+ spin_lock_irqsave(&msi->mask_lock, flags);
+ value = rcar_pci_read_reg(pcie, PCIEMSIIER);
+ value |= BIT(d->hwirq);
+ rcar_pci_write_reg(pcie, value, PCIEMSIIER);
+ spin_unlock_irqrestore(&msi->mask_lock, flags);
+}

- /* MSI-X interrupts are not supported */
- if (type == PCI_CAP_ID_MSIX)
- return -EINVAL;
+static int rcar_msi_set_affinity(struct irq_data *d, const struct cpumask *mask, bool force)
+{
+ return -EINVAL;
+}

- WARN_ON(!list_is_singular(&pdev->dev.msi_list));
- desc = list_entry(pdev->dev.msi_list.next, struct msi_desc, list);
+static void rcar_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
+{
+ struct rcar_msi *msi = irq_data_get_irq_chip_data(data);
+ unsigned long pa = virt_to_phys(msi);

- hwirq = rcar_msi_alloc_region(msi, nvec);
- if (hwirq < 0)
- return -ENOSPC;
+ /* Use the msi structure as the PA for the MSI doorbell */
+ msg->address_lo = lower_32_bits(pa);
+ msg->address_hi = upper_32_bits(pa);
+ msg->data = data->hwirq;
+}

- irq = irq_find_mapping(msi->domain, hwirq);
- if (!irq)
- return -ENOSPC;
+static struct irq_chip rcar_msi_bottom_chip = {
+ .name = "Rcar MSI",
+ .irq_ack = rcar_msi_irq_ack,
+ .irq_mask = rcar_msi_irq_mask,
+ .irq_unmask = rcar_msi_irq_unmask,
+ .irq_set_affinity = rcar_msi_set_affinity,
+ .irq_compose_msi_msg = rcar_compose_msi_msg,
+};

- for (i = 0; i < nvec; i++) {
- /*
- * irq_create_mapping() called from rcar_pcie_probe() pre-
- * allocates descs, so there is no need to allocate descs here.
- * We can therefore assume that if irq_find_mapping() above
- * returns non-zero, then the descs are also successfully
- * allocated.
- */
- if (irq_set_msi_desc_off(irq, i, desc)) {
- /* TODO: clear */
- return -EINVAL;
- }
- }
+static int rcar_msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs, void *args)
+{
+ struct rcar_msi *msi = domain->host_data;
+ unsigned int i;
+ int hwirq;
+
+ mutex_lock(&msi->map_lock);

- desc->nvec_used = nvec;
- desc->msi_attrib.multiple = order_base_2(nvec);
+ hwirq = bitmap_find_free_region(msi->used, INT_PCI_MSI_NR, order_base_2(nr_irqs));

- msg.address_lo = rcar_pci_read_reg(pcie, PCIEMSIALR) & ~MSIFE;
- msg.address_hi = rcar_pci_read_reg(pcie, PCIEMSIAUR);
- msg.data = hwirq;
+ mutex_unlock(&msi->map_lock);
+
+ if (hwirq < 0)
+ return -ENOSPC;

- pci_write_msi_msg(irq, &msg);
+ for (i = 0; i < nr_irqs; i++)
+ irq_domain_set_info(domain, virq + i, hwirq + i,
+ &rcar_msi_bottom_chip, domain->host_data,
+ handle_edge_irq, NULL, NULL);

return 0;
}

-static void rcar_msi_teardown_irq(struct msi_controller *chip, unsigned int irq)
+static void rcar_msi_domain_free(struct irq_domain *domain, unsigned int virq,
+ unsigned int nr_irqs)
{
- struct rcar_msi *msi = to_rcar_msi(chip);
- struct irq_data *d = irq_get_irq_data(irq);
+ struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+ struct rcar_msi *msi = domain->host_data;

- rcar_msi_free(msi, d->hwirq);
-}
-
-static struct irq_chip rcar_msi_irq_chip = {
- .name = "R-Car PCIe MSI",
- .irq_enable = pci_msi_unmask_irq,
- .irq_disable = pci_msi_mask_irq,
- .irq_mask = pci_msi_mask_irq,
- .irq_unmask = pci_msi_unmask_irq,
-};
+ mutex_lock(&msi->map_lock);

-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);
+ bitmap_release_region(msi->used, d->hwirq, order_base_2(nr_irqs));

- return 0;
+ mutex_unlock(&msi->map_lock);
}

-static const struct irq_domain_ops msi_domain_ops = {
- .map = rcar_msi_map,
+static const struct irq_domain_ops rcar_msi_domain_ops = {
+ .alloc = rcar_msi_domain_alloc,
+ .free = rcar_msi_domain_free,
+};
+
+static struct msi_domain_info rcar_msi_info = {
+ .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
+ MSI_FLAG_MULTI_PCI_MSI),
+ .chip = &rcar_msi_top_chip,
};

-static void rcar_pcie_unmap_msi(struct rcar_pcie_host *host)
+static int rcar_allocate_domains(struct rcar_msi *msi)
{
- struct rcar_msi *msi = &host->msi;
- int i, irq;
+ struct rcar_pcie *pcie = &msi_to_host(msi)->pcie;
+ struct fwnode_handle *fwnode = dev_fwnode(pcie->dev);
+ struct irq_domain *parent;
+
+ parent = irq_domain_create_linear(fwnode, INT_PCI_MSI_NR,
+ &rcar_msi_domain_ops, msi);
+ if (!parent) {
+ dev_err(pcie->dev, "failed to create IRQ domain\n");
+ return -ENOMEM;
+ }
+ irq_domain_update_bus_token(parent, DOMAIN_BUS_NEXUS);

- for (i = 0; i < INT_PCI_MSI_NR; i++) {
- irq = irq_find_mapping(msi->domain, i);
- if (irq > 0)
- irq_dispose_mapping(irq);
+ msi->domain = pci_msi_create_irq_domain(fwnode, &rcar_msi_info, parent);
+ if (!msi->domain) {
+ dev_err(pcie->dev, "failed to create MSI domain\n");
+ irq_domain_remove(parent);
+ return -ENOMEM;
}

- irq_domain_remove(msi->domain);
+ return 0;
}

-static void rcar_pcie_hw_enable_msi(struct rcar_pcie_host *host)
+static void rcar_free_domains(struct rcar_msi *msi)
{
- struct rcar_pcie *pcie = &host->pcie;
- struct device *dev = pcie->dev;
- struct resource res;
+ struct irq_domain *parent = msi->domain->parent;

- if (WARN_ON(of_address_to_resource(dev->of_node, 0, &res)))
- return;
-
- /* setup MSI data target */
- rcar_pci_write_reg(pcie, lower_32_bits(res.start) | MSIFE, PCIEMSIALR);
- rcar_pci_write_reg(pcie, upper_32_bits(res.start), PCIEMSIAUR);
-
- /* enable all MSI interrupts */
- rcar_pci_write_reg(pcie, 0xffffffff, PCIEMSIIER);
+ irq_domain_remove(msi->domain);
+ irq_domain_remove(parent);
}

static int rcar_pcie_enable_msi(struct rcar_pcie_host *host)
@@ -698,29 +675,24 @@ static int rcar_pcie_enable_msi(struct rcar_pcie_host *host)
struct rcar_pcie *pcie = &host->pcie;
struct device *dev = pcie->dev;
struct rcar_msi *msi = &host->msi;
- int err, i;
-
- mutex_init(&msi->lock);
+ struct resource res;
+ int err;

- msi->chip.dev = dev;
- msi->chip.setup_irq = rcar_msi_setup_irq;
- msi->chip.setup_irqs = rcar_msi_setup_irqs;
- msi->chip.teardown_irq = rcar_msi_teardown_irq;
+ mutex_init(&msi->map_lock);
+ spin_lock_init(&msi->mask_lock);

- msi->domain = irq_domain_add_linear(dev->of_node, INT_PCI_MSI_NR,
- &msi_domain_ops, &msi->chip);
- if (!msi->domain) {
- dev_err(dev, "failed to create IRQ domain\n");
- return -ENOMEM;
- }
+ err = of_address_to_resource(dev->of_node, 0, &res);
+ if (err)
+ return err;

- for (i = 0; i < INT_PCI_MSI_NR; i++)
- irq_create_mapping(msi->domain, i);
+ err = rcar_allocate_domains(msi);
+ if (err)
+ return err;

/* Two irqs are for MSI, but they are also used for non-MSI irqs */
err = devm_request_irq(dev, msi->irq1, rcar_pcie_msi_irq,
IRQF_SHARED | IRQF_NO_THREAD,
- rcar_msi_irq_chip.name, host);
+ rcar_msi_bottom_chip.name, host);
if (err < 0) {
dev_err(dev, "failed to request IRQ: %d\n", err);
goto err;
@@ -728,19 +700,26 @@ static int rcar_pcie_enable_msi(struct rcar_pcie_host *host)

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

- /* setup MSI data target */
- rcar_pcie_hw_enable_msi(host);
+ /* disable all MSIs */
+ rcar_pci_write_reg(pcie, 0, PCIEMSIIER);
+
+ /*
+ * Setup MSI data target using RC base address address, which
+ * is guaranteed to be in the low 32bit range on any RCar HW.
+ */
+ rcar_pci_write_reg(pcie, lower_32_bits(res.start) | MSIFE, PCIEMSIALR);
+ rcar_pci_write_reg(pcie, upper_32_bits(res.start), PCIEMSIAUR);

return 0;

err:
- rcar_pcie_unmap_msi(host);
+ rcar_free_domains(msi);
return err;
}

@@ -754,7 +733,7 @@ static void rcar_pcie_teardown_msi(struct rcar_pcie_host *host)
/* Disable address decoding of the MSI interrupt, MSIFE */
rcar_pci_write_reg(pcie, 0, PCIEMSIALR);

- rcar_pcie_unmap_msi(host);
+ rcar_free_domains(&host->msi);
}

static int rcar_pcie_get_resources(struct rcar_pcie_host *host)
@@ -1007,8 +986,17 @@ static int __maybe_unused rcar_pcie_resume(struct device *dev)
dev_info(dev, "PCIe x%d: link up\n", (data >> 20) & 0x3f);

/* Enable MSI */
- if (IS_ENABLED(CONFIG_PCI_MSI))
- rcar_pcie_hw_enable_msi(host);
+ if (IS_ENABLED(CONFIG_PCI_MSI)) {
+ struct resource res;
+ u32 val;
+
+ of_address_to_resource(dev->of_node, 0, &res);
+ rcar_pci_write_reg(pcie, upper_32_bits(res.start), PCIEMSIAUR);
+ rcar_pci_write_reg(pcie, lower_32_bits(res.start) | MSIFE, PCIEMSIALR);
+
+ bitmap_to_arr32(&val, host->msi.used, INT_PCI_MSI_NR);
+ rcar_pci_write_reg(pcie, val, PCIEMSIIER);
+ }

rcar_pcie_hw_enable(host);

--
2.29.2