tifm_7xx1: switch from workqueue to kthread

As there's only one work item (media_switcher) to handle and it's effectively
serialized with itself, I found it more convenient to use kthread instead of
workqueue. This also allows for a working implementation of suspend/resume,
which were totally broken in the past version.

Signed-off-by: Alex Dubov <oakad@yahoo.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

2 files changed, 94 insertions, 68 deletions

diff --git a/drivers/misc/tifm_7xx1.c b/drivers/misc/tifm_7xx1.c
index 5ab81dd37857..d3e8ff46c237 100644
--- a/drivers/misc/tifm_7xx1.c
+++ b/drivers/misc/tifm_7xx1.c
@@ -11,6 +11,7 @@
 
 #include <linux/tifm.h>
 #include <linux/dma-mapping.h>
+#include <linux/freezer.h>
 
 #define DRIVER_NAME "tifm_7xx1"
 #define DRIVER_VERSION "0.7"
@@ -20,10 +21,8 @@ static void tifm_7xx1_eject(struct tifm_adapter *fm, struct tifm_dev *sock)
         unsigned long flags;
 
         spin_lock_irqsave(&fm->lock, flags);
-        if (!fm->inhibit_new_cards) {
-                fm->socket_change_set |= 1 << sock->socket_id;
-                queue_work(fm->wq, &fm->media_switcher);
-        }
+        fm->socket_change_set |= 1 << sock->socket_id;
+        wake_up_all(&fm->change_set_notify);
         spin_unlock_irqrestore(&fm->lock, flags);
 }
 
@@ -59,14 +58,10 @@ static irqreturn_t tifm_7xx1_isr(int irq, void *dev_id)
         }
         writel(irq_status, fm->addr + FM_INTERRUPT_STATUS);
 
-        if (!fm->inhibit_new_cards) {
-                if (!fm->socket_change_set) {
-                        writel(TIFM_IRQ_ENABLE,
-                                fm->addr + FM_SET_INTERRUPT_ENABLE);
-                } else {
-                        queue_work(fm->wq, &fm->media_switcher);
-                }
-        }
+        if (!fm->socket_change_set)
+                writel(TIFM_IRQ_ENABLE, fm->addr + FM_SET_INTERRUPT_ENABLE);
+        else
+                wake_up_all(&fm->change_set_notify);
 
         spin_unlock(&fm->lock);
         return IRQ_HANDLED;
@@ -123,21 +118,22 @@ tifm_7xx1_sock_addr(char __iomem *base_addr, unsigned int sock_num)
         return base_addr + ((sock_num + 1) << 10);
 }
 
-static void tifm_7xx1_switch_media(struct work_struct *work)
+static int tifm_7xx1_switch_media(void *data)
 {
-        struct tifm_adapter *fm =
-                container_of(work, struct tifm_adapter, media_switcher);
+        struct tifm_adapter *fm = data;
         unsigned long flags;
         tifm_media_id media_id;
         char *card_name = "xx";
-        int cnt;
+        int cnt, rc;
         struct tifm_dev *sock;
         unsigned int socket_change_set;
 
-        if (!class_device_get(&fm->cdev))
-                return;
-
         while (1) {
+                rc = wait_event_interruptible(fm->change_set_notify,
+                                              fm->socket_change_set);
+                if (rc == -ERESTARTSYS)
+                        try_to_freeze();
+
                 spin_lock_irqsave(&fm->lock, flags);
                 socket_change_set = fm->socket_change_set;
                 fm->socket_change_set = 0;
@@ -145,12 +141,12 @@ static void tifm_7xx1_switch_media(struct work_struct *work)
                 dev_dbg(fm->dev, "checking media set %x\n",
                         socket_change_set);
 
-                if (fm->inhibit_new_cards)
+                if (kthread_should_stop())
                         socket_change_set = (1 << fm->num_sockets) - 1;
                 spin_unlock_irqrestore(&fm->lock, flags);
 
                 if (!socket_change_set)
-                        break;
+                        continue;
 
                 spin_lock_irqsave(&fm->lock, flags);
                 for (cnt = 0; cnt < fm->num_sockets; cnt++) {
@@ -169,7 +165,7 @@ static void tifm_7xx1_switch_media(struct work_struct *work)
                                        tifm_7xx1_sock_addr(fm->addr, cnt)
                                        + SOCK_CONTROL);
                         }
-                        if (fm->inhibit_new_cards)
+                        if (kthread_should_stop())
                                 continue;
 
                         spin_unlock_irqrestore(&fm->lock, flags);
@@ -218,7 +214,7 @@ static void tifm_7xx1_switch_media(struct work_struct *work)
                         }
                 }
 
-                if (!fm->inhibit_new_cards) {
+                if (!kthread_should_stop()) {
                         writel(TIFM_IRQ_FIFOMASK(socket_change_set)
                                | TIFM_IRQ_CARDMASK(socket_change_set),
                                fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
@@ -228,7 +224,6 @@ static void tifm_7xx1_switch_media(struct work_struct *work)
                         writel(TIFM_IRQ_ENABLE,
                                fm->addr + FM_SET_INTERRUPT_ENABLE);
                         spin_unlock_irqrestore(&fm->lock, flags);
-                        break;
                 } else {
                         for (cnt = 0; cnt < fm->num_sockets; cnt++) {
                                 if (fm->sockets[cnt])
@@ -236,56 +231,93 @@ static void tifm_7xx1_switch_media(struct work_struct *work)
                         }
                         if (!fm->socket_change_set) {
                                 spin_unlock_irqrestore(&fm->lock, flags);
-                                break;
+                                return 0;
                         } else {
                                 spin_unlock_irqrestore(&fm->lock, flags);
                         }
                 }
         }
-        class_device_put(&fm->cdev);
+        return 0;
 }
 
+#ifdef CONFIG_PM
+
 static int tifm_7xx1_suspend(struct pci_dev *dev, pm_message_t state)
 {
-        struct tifm_adapter *fm = pci_get_drvdata(dev);
-        unsigned long flags;
+        dev_dbg(&dev->dev, "suspending host\n");
 
-        spin_lock_irqsave(&fm->lock, flags);
-        fm->inhibit_new_cards = 1;
-        fm->socket_change_set = 0xf;
-        writel(TIFM_IRQ_ENABLE, fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
-        spin_unlock_irqrestore(&fm->lock, flags);
-        flush_workqueue(fm->wq);
-
-        tifm_7xx1_switch_media(&fm->media_switcher);
-
-        pci_set_power_state(dev, PCI_D3hot);
-        pci_disable_device(dev);
-        pci_save_state(dev);
+        pci_save_state(dev);
+        pci_enable_wake(dev, pci_choose_state(dev, state), 0);
+        pci_disable_device(dev);
+        pci_set_power_state(dev, pci_choose_state(dev, state));
         return 0;
 }
 
 static int tifm_7xx1_resume(struct pci_dev *dev)
 {
         struct tifm_adapter *fm = pci_get_drvdata(dev);
+        int cnt, rc;
         unsigned long flags;
+        tifm_media_id new_ids[fm->num_sockets];
 
+        pci_set_power_state(dev, PCI_D0);
         pci_restore_state(dev);
-        pci_enable_device(dev);
-        pci_set_power_state(dev, PCI_D0);
-        pci_set_master(dev);
+        rc = pci_enable_device(dev);
+        if (rc)
+                return rc;
+        pci_set_master(dev);
+
+        dev_dbg(&dev->dev, "resuming host\n");
 
+        for (cnt = 0; cnt < fm->num_sockets; cnt++)
+                new_ids[cnt] = tifm_7xx1_toggle_sock_power(
+                                        tifm_7xx1_sock_addr(fm->addr, cnt),
+                                        fm->num_sockets == 2);
         spin_lock_irqsave(&fm->lock, flags);
-        fm->inhibit_new_cards = 0;
-        writel(TIFM_IRQ_SETALL, fm->addr + FM_INTERRUPT_STATUS);
-        writel(TIFM_IRQ_SETALL, fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
+        fm->socket_change_set = 0;
+        for (cnt = 0; cnt < fm->num_sockets; cnt++) {
+                if (fm->sockets[cnt]) {
+                        if (fm->sockets[cnt]->media_id == new_ids[cnt])
+                                fm->socket_change_set |= 1 << cnt;
+
+                        fm->sockets[cnt]->media_id = new_ids[cnt];
+                }
+        }
+
         writel(TIFM_IRQ_ENABLE | TIFM_IRQ_SOCKMASK((1 << fm->num_sockets) - 1),
-                fm->addr + FM_SET_INTERRUPT_ENABLE);
-        fm->socket_change_set = 0xf;
+               fm->addr + FM_SET_INTERRUPT_ENABLE);
+        if (!fm->socket_change_set) {
+                spin_unlock_irqrestore(&fm->lock, flags);
+                return 0;
+        } else {
+                fm->socket_change_set = 0;
+                spin_unlock_irqrestore(&fm->lock, flags);
+        }
+
+        wait_event_timeout(fm->change_set_notify, fm->socket_change_set, HZ);
+
+        spin_lock_irqsave(&fm->lock, flags);
+        writel(TIFM_IRQ_FIFOMASK(fm->socket_change_set)
+               | TIFM_IRQ_CARDMASK(fm->socket_change_set),
+               fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
+        writel(TIFM_IRQ_FIFOMASK(fm->socket_change_set)
+               | TIFM_IRQ_CARDMASK(fm->socket_change_set),
+               fm->addr + FM_SET_INTERRUPT_ENABLE);
+        writel(TIFM_IRQ_ENABLE,
+               fm->addr + FM_SET_INTERRUPT_ENABLE);
+        fm->socket_change_set = 0;
+
         spin_unlock_irqrestore(&fm->lock, flags);
         return 0;
 }
 
+#else
+
+#define tifm_7xx1_suspend NULL
+#define tifm_7xx1_resume NULL
+
+#endif /* CONFIG_PM */
+
 static int tifm_7xx1_probe(struct pci_dev *dev,
                         const struct pci_device_id *dev_id)
 {
@@ -324,7 +356,6 @@ static int tifm_7xx1_probe(struct pci_dev *dev,
         if (!fm->sockets)
                 goto err_out_free;
 
-        INIT_WORK(&fm->media_switcher, tifm_7xx1_switch_media);
         fm->eject = tifm_7xx1_eject;
         pci_set_drvdata(dev, fm);
 
@@ -337,16 +368,15 @@ static int tifm_7xx1_probe(struct pci_dev *dev,
         if (rc)
                 goto err_out_unmap;
 
-        rc = tifm_add_adapter(fm);
+        init_waitqueue_head(&fm->change_set_notify);
+        rc = tifm_add_adapter(fm, tifm_7xx1_switch_media);
         if (rc)
                 goto err_out_irq;
 
         writel(TIFM_IRQ_SETALL, fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
         writel(TIFM_IRQ_ENABLE | TIFM_IRQ_SOCKMASK((1 << fm->num_sockets) - 1),
                 fm->addr + FM_SET_INTERRUPT_ENABLE);
-
-        fm->socket_change_set = 0xf;
-
+        wake_up_process(fm->media_switcher);
         return 0;
 
 err_out_irq:
@@ -370,18 +400,15 @@ static void tifm_7xx1_remove(struct pci_dev *dev)
         struct tifm_adapter *fm = pci_get_drvdata(dev);
         unsigned long flags;
 
+        writel(TIFM_IRQ_SETALL, fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
+        mmiowb();
+        free_irq(dev->irq, fm);
+
         spin_lock_irqsave(&fm->lock, flags);
-        fm->inhibit_new_cards = 1;
-        fm->socket_change_set = 0xf;
-        writel(TIFM_IRQ_ENABLE, fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
+        fm->socket_change_set = (1 << fm->num_sockets) - 1;
         spin_unlock_irqrestore(&fm->lock, flags);
 
-        flush_workqueue(fm->wq);
-
-        tifm_7xx1_switch_media(&fm->media_switcher);
-
-        writel(TIFM_IRQ_SETALL, fm->addr + FM_CLEAR_INTERRUPT_ENABLE);
-        free_irq(dev->irq, fm);
+        kthread_stop(fm->media_switcher);
 
         tifm_remove_adapter(fm);
 
diff --git a/drivers/misc/tifm_core.c b/drivers/misc/tifm_core.c
index 3eaf2c985b7d..4d62dab2ada3 100644
--- a/drivers/misc/tifm_core.c
+++ b/drivers/misc/tifm_core.c
@@ -71,8 +71,6 @@ static void tifm_free(struct class_device *cdev)
         struct tifm_adapter *fm = container_of(cdev, struct tifm_adapter, cdev);
 
         kfree(fm->sockets);
-        if (fm->wq)
-                destroy_workqueue(fm->wq);
         kfree(fm);
 }
 
@@ -101,7 +99,8 @@ void tifm_free_adapter(struct tifm_adapter *fm)
 }
 EXPORT_SYMBOL(tifm_free_adapter);
 
-int tifm_add_adapter(struct tifm_adapter *fm)
+int tifm_add_adapter(struct tifm_adapter *fm,
+                     int (*mediathreadfn)(void *data))
 {
         int rc;
 
@@ -113,10 +112,10 @@ int tifm_add_adapter(struct tifm_adapter *fm)
         spin_unlock(&tifm_adapter_lock);
         if (!rc) {
                 snprintf(fm->cdev.class_id, BUS_ID_SIZE, "tifm%u", fm->id);
-                strncpy(fm->wq_name, fm->cdev.class_id, KOBJ_NAME_LEN);
+                fm->media_switcher = kthread_create(mediathreadfn,
+                                                    fm, "tifm/%u", fm->id);
 
-                fm->wq = create_singlethread_workqueue(fm->wq_name);
-                if (fm->wq)
+                if (!IS_ERR(fm->media_switcher))
                         return class_device_add(&fm->cdev);
 
                 spin_lock(&tifm_adapter_lock);