irqchip/armada-370-xp: Use the generic MSI infrastructure

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>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/1455115621-22846-3-git-send-email-thomas.petazzoni@free-electrons.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>

2 files changed, 62 insertions, 88 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index dfe4ed8d838d..ba6a084f24cd 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 3f3a8c3d2175..e5738c5d7a6c 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();