PCI/xgene-msi: Convert to hotplug state machine

Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-pci@vger.kernel.org
Cc: Duc Dang <dhdang@apm.com>
Cc: rt@linuxtronix.de
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-arm-kernel@lists.infradead.org
Link: http://lkml.kernel.org/r/20161117183541.8588-8-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

2 files changed, 20 insertions, 50 deletions

diff --git a/drivers/pci/host/pci-xgene-msi.c b/drivers/pci/host/pci-xgene-msi.c
index a6456b578269..1f38d0836751 100644
--- a/drivers/pci/host/pci-xgene-msi.c
+++ b/drivers/pci/host/pci-xgene-msi.c
@@ -360,16 +360,16 @@ static void xgene_msi_isr(struct irq_desc *desc)
         chained_irq_exit(chip, desc);
 }
 
+static enum cpuhp_state pci_xgene_online;
+
 static int xgene_msi_remove(struct platform_device *pdev)
 {
-        int virq, i;
         struct xgene_msi *msi = platform_get_drvdata(pdev);
 
-        for (i = 0; i < NR_HW_IRQS; i++) {
-                virq = msi->msi_groups[i].gic_irq;
-                if (virq != 0)
-                        irq_set_chained_handler_and_data(virq, NULL, NULL);
-        }
+        if (pci_xgene_online)
+                cpuhp_remove_state(pci_xgene_online);
+        cpuhp_remove_state(CPUHP_PCI_XGENE_DEAD);
+
         kfree(msi->msi_groups);
 
         kfree(msi->bitmap);
@@ -427,7 +427,7 @@ static int xgene_msi_hwirq_alloc(unsigned int cpu)
         return 0;
 }
 
-static void xgene_msi_hwirq_free(unsigned int cpu)
+static int xgene_msi_hwirq_free(unsigned int cpu)
 {
         struct xgene_msi *msi = &xgene_msi_ctrl;
         struct xgene_msi_group *msi_group;
@@ -441,33 +441,9 @@ static void xgene_msi_hwirq_free(unsigned int cpu)
                 irq_set_chained_handler_and_data(msi_group->gic_irq, NULL,
                                                  NULL);
         }
+        return 0;
 }
 
-static int xgene_msi_cpu_callback(struct notifier_block *nfb,
-                                  unsigned long action, void *hcpu)
-{
-        unsigned cpu = (unsigned long)hcpu;
-
-        switch (action) {
-        case CPU_ONLINE:
-        case CPU_ONLINE_FROZEN:
-                xgene_msi_hwirq_alloc(cpu);
-                break;
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                xgene_msi_hwirq_free(cpu);
-                break;
-        default:
-                break;
-        }
-
-        return NOTIFY_OK;
-}
-
-static struct notifier_block xgene_msi_cpu_notifier = {
-        .notifier_call = xgene_msi_cpu_callback,
-};
-
 static const struct of_device_id xgene_msi_match_table[] = {
         {.compatible = "apm,xgene1-msi"},
         {},
@@ -478,7 +454,6 @@ static int xgene_msi_probe(struct platform_device *pdev)
         struct resource *res;
         int rc, irq_index;
         struct xgene_msi *xgene_msi;
-        unsigned int cpu;
         int virt_msir;
         u32 msi_val, msi_idx;
 
@@ -540,28 +515,22 @@ static int xgene_msi_probe(struct platform_device *pdev)
                 }
         }
 
-        cpu_notifier_register_begin();
-
-        for_each_online_cpu(cpu)
-                if (xgene_msi_hwirq_alloc(cpu)) {
-                        dev_err(&pdev->dev, "failed to register MSI handlers\n");
-                        cpu_notifier_register_done();
-                        goto error;
-                }
-
-        rc = __register_hotcpu_notifier(&xgene_msi_cpu_notifier);
-        if (rc) {
-                dev_err(&pdev->dev, "failed to add CPU MSI notifier\n");
-                cpu_notifier_register_done();
-                goto error;
-        }
-
-        cpu_notifier_register_done();
+        rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "pci/xgene:online",
+                               xgene_msi_hwirq_alloc, NULL);
+        if (rc)
+                goto err_cpuhp;
+        pci_xgene_online = rc;
+        rc = cpuhp_setup_state(CPUHP_PCI_XGENE_DEAD, "pci/xgene:dead", NULL,
+                               xgene_msi_hwirq_free);
+        if (rc)
+                goto err_cpuhp;
 
         dev_info(&pdev->dev, "APM X-Gene PCIe MSI driver loaded\n");
 
         return 0;
 
+err_cpuhp:
+        dev_err(&pdev->dev, "failed to add CPU MSI notifier\n");
 error:
         xgene_msi_remove(pdev);
         return rc;
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 79b96f647d64..94c6a189421f 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -38,6 +38,7 @@ enum cpuhp_state {
         CPUHP_RADIX_DEAD,
         CPUHP_PAGE_ALLOC_DEAD,
         CPUHP_NET_DEV_DEAD,
+        CPUHP_PCI_XGENE_DEAD,
         CPUHP_WORKQUEUE_PREP,
         CPUHP_POWER_NUMA_PREPARE,
         CPUHP_HRTIMERS_PREPARE,