misc/pvpanic: probe multiple instances

Create the mecahism that allows multiple pvpanic instances to call
pvpanic_probe and receive panic events. A global list will retain all the
mapped addresses where to write panic events.

Signed-off-by: Mihai Carabas <mihai.carabas@oracle.com>
Link: https://lore.kernel.org/r/1616597356-20696-3-git-send-email-mihai.carabas@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/misc/pvpanic/pvpanic-mmio.c b/drivers/misc/pvpanic/pvpanic-mmio.c
index d7bf7db6c19c392d38b02ea5072cb21964517893..4c08417760874b0995af3be387c5829f1f3589fc 100644 (file)
--- a/drivers/misc/pvpanic/pvpanic-mmio.c
+++ b/drivers/misc/pvpanic/pvpanic-mmio.c
@@ -14,6 +14,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
+#include <linux/slab.h>
 
 #include <uapi/misc/pvpanic.h>
 
@@ -23,25 +24,26 @@ MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>");
 MODULE_DESCRIPTION("pvpanic-mmio device driver");
 MODULE_LICENSE("GPL");
 
-static void __iomem *base;
-static unsigned int capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
-static unsigned int events;
-
 static ssize_t capability_show(struct device *dev,
                               struct device_attribute *attr, char *buf)
 {
-       return sysfs_emit(buf, "%x\n", capability);
+       struct pvpanic_instance *pi = dev_get_drvdata(dev);
+
+       return sysfs_emit(buf, "%x\n", pi->capability);
 }
 static DEVICE_ATTR_RO(capability);
 
 static ssize_t events_show(struct device *dev,  struct device_attribute *attr, char *buf)
 {
-       return sysfs_emit(buf, "%x\n", events);
+       struct pvpanic_instance *pi = dev_get_drvdata(dev);
+
+       return sysfs_emit(buf, "%x\n", pi->events);
 }
 
 static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
                            const char *buf, size_t count)
 {
+       struct pvpanic_instance *pi = dev_get_drvdata(dev);
        unsigned int tmp;
        int err;
 
@@ -49,15 +51,12 @@ static ssize_t events_store(struct device *dev,  struct device_attribute *attr,
        if (err)
                return err;
 
-       if ((tmp & capability) != tmp)
+       if ((tmp & pi->capability) != tmp)
                return -EINVAL;
 
-       events = tmp;
-
-       pvpanic_set_events(events);
+       pi->events = tmp;
 
        return count;
-
 }
 static DEVICE_ATTR_RW(events);
 
@@ -71,7 +70,9 @@ ATTRIBUTE_GROUPS(pvpanic_mmio_dev);
 static int pvpanic_mmio_probe(struct platform_device *pdev)
 {
        struct device *dev = &pdev->dev;
+       struct pvpanic_instance *pi;
        struct resource *res;
+       void __iomem *base;
 
        res = platform_get_mem_or_io(pdev, 0);
        if (!res)
@@ -92,19 +93,28 @@ static int pvpanic_mmio_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
+       pi = kmalloc(sizeof(*pi), GFP_ATOMIC);
+       if (!pi)
+               return -ENOMEM;
+
+       pi->base = base;
+       pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED;
+
        /* initlize capability by RDPT */
-       capability &= ioread8(base);
-       events = capability;
+       pi->capability &= ioread8(base);
+       pi->events = pi->capability;
 
-       pvpanic_probe(base, capability);
+       dev_set_drvdata(dev, pi);
 
-       return 0;
+       return pvpanic_probe(pi);
 }
 
 static int pvpanic_mmio_remove(struct platform_device *pdev)
 {
+       struct pvpanic_instance *pi = dev_get_drvdata(&pdev->dev);
 
-       pvpanic_remove();
+       pvpanic_remove(pi);
+       kfree(pi);
 
        return 0;
 }

diff --git a/drivers/misc/pvpanic/pvpanic.c b/drivers/misc/pvpanic/pvpanic.c
index a9605f90c5347096db2f30b524d11c17fe90bfdc..804099c2d7fa5c68f581f50eac3ea918784c6dbe 100644 (file)
--- a/drivers/misc/pvpanic/pvpanic.c
+++ b/drivers/misc/pvpanic/pvpanic.c
@@ -14,6 +14,8 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
+#include <linux/cdev.h>
+#include <linux/list.h>
 
 #include <uapi/misc/pvpanic.h>
 
@@ -23,15 +25,20 @@ MODULE_AUTHOR("Mihai Carabas <mihai.carabas@oracle.com>");
 MODULE_DESCRIPTION("pvpanic device driver ");
 MODULE_LICENSE("GPL");
 
-static void __iomem *base;
-static unsigned int capability;
-static unsigned int events;
+struct list_head pvpanic_list;
+spinlock_t pvpanic_lock;
 
 static void
 pvpanic_send_event(unsigned int event)
 {
-       if (event & capability & events)
-               iowrite8(event, base);
+       struct pvpanic_instance *pi_cur;
+
+       spin_lock(&pvpanic_lock);
+       list_for_each_entry(pi_cur, &pvpanic_list, list) {
+               if (event & pi_cur->capability & pi_cur->events)
+                       iowrite8(event, pi_cur->base);
+       }
+       spin_unlock(&pvpanic_lock);
 }
 
 static int
@@ -53,29 +60,54 @@ static struct notifier_block pvpanic_panic_nb = {
        .priority = 1, /* let this called before broken drm_fb_helper */
 };
 
-void pvpanic_probe(void __iomem *pbase, unsigned int dev_cap)
+int pvpanic_probe(struct pvpanic_instance *pi)
 {
-       base = pbase;
-       capability = dev_cap;
-       events = capability;
+       if (!pi || !pi->base)
+               return -EINVAL;
+
+       spin_lock(&pvpanic_lock);
+       list_add(&pi->list, &pvpanic_list);
+       spin_unlock(&pvpanic_lock);
 
-       if (capability)
-               atomic_notifier_chain_register(&panic_notifier_list,
-                                              &pvpanic_panic_nb);
+       return 0;
 }
 EXPORT_SYMBOL_GPL(pvpanic_probe);
 
-void pvpanic_remove(void)
+void pvpanic_remove(struct pvpanic_instance *pi)
 {
-       if (capability)
-               atomic_notifier_chain_unregister(&panic_notifier_list,
-                                                &pvpanic_panic_nb);
-       base = NULL;
+       struct pvpanic_instance *pi_cur, *pi_next;
+
+       if (!pi)
+               return;
+
+       spin_lock(&pvpanic_lock);
+       list_for_each_entry_safe(pi_cur, pi_next, &pvpanic_list, list) {
+               if (pi_cur == pi) {
+                       list_del(&pi_cur->list);
+                       break;
+               }
+       }
+       spin_unlock(&pvpanic_lock);
 }
 EXPORT_SYMBOL_GPL(pvpanic_remove);
 
-void pvpanic_set_events(unsigned int dev_events)
+static int pvpanic_init(void)
 {
-       events = dev_events;
+       INIT_LIST_HEAD(&pvpanic_list);
+       spin_lock_init(&pvpanic_lock);
+
+       atomic_notifier_chain_register(&panic_notifier_list,
+                                      &pvpanic_panic_nb);
+
+       return 0;
 }
-EXPORT_SYMBOL_GPL(pvpanic_set_events);
+
+static void pvpanic_exit(void)
+{
+       atomic_notifier_chain_unregister(&panic_notifier_list,
+                                        &pvpanic_panic_nb);
+
+}
+
+module_init(pvpanic_init);
+module_exit(pvpanic_exit);

diff --git a/drivers/misc/pvpanic/pvpanic.h b/drivers/misc/pvpanic/pvpanic.h
index 3abe15fa24b802ee56156870ee114140b53903c9..1afccc2e9fec781cc940dc081abea05b5d7bc5bf 100644 (file)
--- a/drivers/misc/pvpanic/pvpanic.h
+++ b/drivers/misc/pvpanic/pvpanic.h
@@ -8,8 +8,14 @@
 #ifndef PVPANIC_H_
 #define PVPANIC_H_
 
-void pvpanic_probe(void __iomem *base, unsigned int dev_cap);
-void pvpanic_remove(void);
-void pvpanic_set_events(unsigned int dev_events);
+struct pvpanic_instance {
+       void __iomem *base;
+       unsigned int capability;
+       unsigned int events;
+       struct list_head list;
+};
+
+int pvpanic_probe(struct pvpanic_instance *pi);
+void pvpanic_remove(struct pvpanic_instance *pi);
 
 #endif /* PVPANIC_H_ */