[PATCH v2 2/6] irqchip: irq-armada-370-xp: use the generic MSI infrastructure

[thomas.petazzoni@free-electrons.com (Thomas Petazzoni)]

This commit moves the irq-armada-370-xp driver from using the
PCI-specific MSI infrastructure to the generic MSI infrastructure, to
which drivers are progressively converted.

In this hardware, the MSI controller is directly bundled inside the
interrupt controller, so we have a single Device Tree node to which
multiple IRQ domaines are attached: the wired interrupt domain and the
MSI interrupt domain. In order to ensure that they can be
differentiated, we have to force the bus_token of the wired interrupt
domain to be DOMAIN_BUS_WIRED. The MSI domain bus_token is
automatically set to the appropriate value by
pci_msi_create_irq_domain().

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Suggested-by: Marc Zyngier <marc.zyngier@arm.com>
---
 drivers/irqchip/Kconfig             |   1 +
 drivers/irqchip/irq-armada-370-xp.c | 149 +++++++++++++++---------------------
 2 files changed, 62 insertions(+), 88 deletions(-)

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index e2cab87..d233a80 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -64,6 +64,7 @@ config ARMADA_370_XP_IRQ
 	bool
 	default y if ARCH_MVEBU
 	select GENERIC_IRQ_CHIP
+	select PCI_MSI_IRQ_DOMAIN if PCI_MSI
 
 config ATMEL_AIC_IRQ
 	bool
diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
index 3f3a8c3..e5738c5 100644
--- a/drivers/irqchip/irq-armada-370-xp.c
+++ b/drivers/irqchip/irq-armada-370-xp.c
@@ -71,6 +71,7 @@ static u32 doorbell_mask_reg;
 static int parent_irq;
 #ifdef CONFIG_PCI_MSI
 static struct irq_domain *armada_370_xp_msi_domain;
+static struct irq_domain *armada_370_xp_msi_inner_domain;
 static DECLARE_BITMAP(msi_used, PCI_MSI_DOORBELL_NR);
 static DEFINE_MUTEX(msi_used_lock);
 static phys_addr_t msi_doorbell_addr;
@@ -115,127 +116,99 @@ static void armada_370_xp_irq_unmask(struct irq_data *d)
 
 #ifdef CONFIG_PCI_MSI
 
-static int armada_370_xp_alloc_msi(void)
-{
-	int hwirq;
-
-	mutex_lock(&msi_used_lock);
-	hwirq = find_first_zero_bit(&msi_used, PCI_MSI_DOORBELL_NR);
-	if (hwirq >= PCI_MSI_DOORBELL_NR)
-		hwirq = -ENOSPC;
-	else
-		set_bit(hwirq, msi_used);
-	mutex_unlock(&msi_used_lock);
+static struct irq_chip armada_370_xp_msi_irq_chip = {
+	.name = "armada_370_xp_msi_irq",
+	.irq_mask = pci_msi_mask_irq,
+	.irq_unmask = pci_msi_unmask_irq,
+};
 
-	return hwirq;
-}
+static struct msi_domain_info armada_370_xp_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+	.chip	= &armada_370_xp_msi_irq_chip,
+};
 
-static void armada_370_xp_free_msi(int hwirq)
+static void armada_370_xp_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
-	mutex_lock(&msi_used_lock);
-	if (!test_bit(hwirq, msi_used))
-		pr_err("trying to free unused MSI#%d\n", hwirq);
-	else
-		clear_bit(hwirq, msi_used);
-	mutex_unlock(&msi_used_lock);
+	msg->address_lo = lower_32_bits(msi_doorbell_addr);
+	msg->address_hi = upper_32_bits(msi_doorbell_addr);
+	msg->data = 0xf00 | (data->hwirq + PCI_MSI_DOORBELL_START);
 }
 
-static int armada_370_xp_setup_msi_irq(struct msi_controller *chip,
-				       struct pci_dev *pdev,
-				       struct msi_desc *desc)
+static int armada_370_xp_msi_set_affinity(struct irq_data *irq_data,
+					  const struct cpumask *mask, bool force)
 {
-	struct msi_msg msg;
-	int virq, hwirq;
+	 return -EINVAL;
+}
 
-	/* We support MSI, but not MSI-X */
-	if (desc->msi_attrib.is_msix)
-		return -EINVAL;
+static struct irq_chip armada_370_xp_msi_bottom_irq_chip = {
+	.name			= "armada_370_xp_msi_irq",
+	.irq_compose_msi_msg	= armada_370_xp_compose_msi_msg,
+	.irq_set_affinity	= armada_370_xp_msi_set_affinity,
+};
 
-	hwirq = armada_370_xp_alloc_msi();
-	if (hwirq < 0)
-		return hwirq;
+static int armada_370_xp_msi_alloc(struct irq_domain *domain, unsigned int virq,
+				   unsigned int nr_irqs, void *args)
+{
+	int hwirq;
 
-	virq = irq_create_mapping(armada_370_xp_msi_domain, hwirq);
-	if (!virq) {
-		armada_370_xp_free_msi(hwirq);
-		return -EINVAL;
+	mutex_lock(&msi_used_lock);
+	hwirq = find_first_zero_bit(&msi_used, PCI_MSI_DOORBELL_NR);
+	if (hwirq >= PCI_MSI_DOORBELL_NR) {
+		mutex_unlock(&msi_used_lock);
+		return -ENOSPC;
 	}
 
-	irq_set_msi_desc(virq, desc);
+	set_bit(hwirq, msi_used);
+	mutex_unlock(&msi_used_lock);
 
-	msg.address_lo = msi_doorbell_addr;
-	msg.address_hi = 0;
-	msg.data = 0xf00 | (hwirq + 16);
+	irq_domain_set_info(domain, virq, hwirq, &armada_370_xp_msi_bottom_irq_chip,
+			    domain->host_data, handle_simple_irq,
+			    NULL, NULL);
 
-	pci_write_msi_msg(virq, &msg);
-	return 0;
+	return hwirq;
 }
 
-static void armada_370_xp_teardown_msi_irq(struct msi_controller *chip,
-					   unsigned int irq)
+static void armada_370_xp_msi_free(struct irq_domain *domain,
+				   unsigned int virq, unsigned int nr_irqs)
 {
-	struct irq_data *d = irq_get_irq_data(irq);
-	unsigned long hwirq = d->hwirq;
-
-	irq_dispose_mapping(irq);
-	armada_370_xp_free_msi(hwirq);
-}
-
-static struct irq_chip armada_370_xp_msi_irq_chip = {
-	.name = "armada_370_xp_msi_irq",
-	.irq_enable = pci_msi_unmask_irq,
-	.irq_disable = pci_msi_mask_irq,
-	.irq_mask = pci_msi_mask_irq,
-	.irq_unmask = pci_msi_unmask_irq,
-};
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
 
-static int armada_370_xp_msi_map(struct irq_domain *domain, unsigned int virq,
-				 irq_hw_number_t hw)
-{
-	irq_set_chip_and_handler(virq, &armada_370_xp_msi_irq_chip,
-				 handle_simple_irq);
-
-	return 0;
+	mutex_lock(&msi_used_lock);
+	if (!test_bit(d->hwirq, msi_used))
+		pr_err("trying to free unused MSI#%lu\n", d->hwirq);
+	else
+		clear_bit(d->hwirq, msi_used);
+	mutex_unlock(&msi_used_lock);
 }
 
-static const struct irq_domain_ops armada_370_xp_msi_irq_ops = {
-	.map = armada_370_xp_msi_map,
+static const struct irq_domain_ops armada_370_xp_msi_domain_ops = {
+	.alloc	= armada_370_xp_msi_alloc,
+	.free	= armada_370_xp_msi_free,
 };
 
 static int armada_370_xp_msi_init(struct device_node *node,
 				  phys_addr_t main_int_phys_base)
 {
-	struct msi_controller *msi_chip;
 	u32 reg;
-	int ret;
 
 	msi_doorbell_addr = main_int_phys_base +
 		ARMADA_370_XP_SW_TRIG_INT_OFFS;
 
-	msi_chip = kzalloc(sizeof(*msi_chip), GFP_KERNEL);
-	if (!msi_chip)
+	armada_370_xp_msi_inner_domain =
+		irq_domain_add_linear(NULL, PCI_MSI_DOORBELL_NR,
+				      &armada_370_xp_msi_domain_ops, NULL);
+	if (!armada_370_xp_msi_inner_domain)
 		return -ENOMEM;
 
-	msi_chip->setup_irq = armada_370_xp_setup_msi_irq;
-	msi_chip->teardown_irq = armada_370_xp_teardown_msi_irq;
-	msi_chip->of_node = node;
-
 	armada_370_xp_msi_domain =
-		irq_domain_add_linear(NULL, PCI_MSI_DOORBELL_NR,
-				      &armada_370_xp_msi_irq_ops,
-				      NULL);
+		pci_msi_create_irq_domain(of_node_to_fwnode(node),
+					  &armada_370_xp_msi_domain_info,
+					  armada_370_xp_msi_inner_domain);
 	if (!armada_370_xp_msi_domain) {
-		kfree(msi_chip);
+		irq_domain_remove(armada_370_xp_msi_inner_domain);
 		return -ENOMEM;
 	}
 
-	ret = of_pci_msi_chip_add(msi_chip);
-	if (ret < 0) {
-		irq_domain_remove(armada_370_xp_msi_domain);
-		kfree(msi_chip);
-		return ret;
-	}
-
 	reg = readl(per_cpu_int_base + ARMADA_370_XP_IN_DRBEL_MSK_OFFS)
 		| PCI_MSI_DOORBELL_MASK;
 
@@ -427,12 +400,12 @@ static void armada_370_xp_handle_msi_irq(struct pt_regs *regs, bool is_chained)
 			continue;
 
 		if (is_chained) {
-			irq = irq_find_mapping(armada_370_xp_msi_domain,
+			irq = irq_find_mapping(armada_370_xp_msi_inner_domain,
 					       msinr - 16);
 			generic_handle_irq(irq);
 		} else {
 			irq = msinr - 16;
-			handle_domain_irq(armada_370_xp_msi_domain,
+			handle_domain_irq(armada_370_xp_msi_inner_domain,
 					  irq, regs);
 		}
 	}
@@ -604,8 +577,8 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
 	armada_370_xp_mpic_domain =
 		irq_domain_add_linear(node, nr_irqs,
 				&armada_370_xp_mpic_irq_ops, NULL);
-
 	BUG_ON(!armada_370_xp_mpic_domain);
+	armada_370_xp_mpic_domain->bus_token = DOMAIN_BUS_WIRED;
 
 	/* Setup for the boot CPU */
 	armada_xp_mpic_perf_init();
-- 
2.6.4