ARM: 5967/1: at91_udc.c use spinlocks instead of local_irq_xxx

The locking code of this driver is reworked for preempt-rt.

For more info see:
http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20100203/09cdb3b4/attachment.el
http://lists.infradead.org/pipermail/linux-arm-kernel/attachments/20100203/3ad44e30/attachment.el

First applied: "at91_udc HW glitch"
http://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=5966/1

Reviewed-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Harro Haan <hrhaan@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 94 insertions, 46 deletions

diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
index eaa79c8a9b8c..fd6a7577ad25 100644
--- a/drivers/usb/gadget/at91_udc.c
+++ b/drivers/usb/gadget/at91_udc.c
@@ -77,10 +77,10 @@ static const char driver_name [] = "at91_udc";
 static const char ep0name[] = "ep0";
 
 
-#define at91_udp_read(dev, reg) \
-        __raw_readl((dev)->udp_baseaddr + (reg))
-#define at91_udp_write(dev, reg, val) \
-        __raw_writel((val), (dev)->udp_baseaddr + (reg))
+#define at91_udp_read(udc, reg) \
+        __raw_readl((udc)->udp_baseaddr + (reg))
+#define at91_udp_write(udc, reg, val) \
+        __raw_writel((val), (udc)->udp_baseaddr + (reg))
 
 /*-------------------------------------------------------------------------*/
 
@@ -102,8 +102,9 @@ static void proc_ep_show(struct seq_file *s, struct at91_ep *ep)
         u32                     csr;
         struct at91_request     *req;
         unsigned long   flags;
+        struct at91_udc *udc = ep->udc;
 
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
 
         csr = __raw_readl(ep->creg);
 
@@ -147,7 +148,7 @@ static void proc_ep_show(struct seq_file *s, struct at91_ep *ep)
                                 &req->req, length,
                                 req->req.length, req->req.buf);
         }
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
 }
 
 static void proc_irq_show(struct seq_file *s, const char *label, u32 mask)
@@ -272,7 +273,9 @@ static void done(struct at91_ep *ep, struct at91_request *req, int status)
                 VDBG("%s done %p, status %d\n", ep->ep.name, req, status);
 
         ep->stopped = 1;
+        spin_unlock(&udc->lock);
         req->req.complete(&ep->ep, &req->req);
+        spin_lock(&udc->lock);
         ep->stopped = stopped;
 
         /* ep0 is always ready; other endpoints need a non-empty queue */
@@ -472,7 +475,7 @@ static int at91_ep_enable(struct usb_ep *_ep,
                                 const struct usb_endpoint_descriptor *desc)
 {
         struct at91_ep  *ep = container_of(_ep, struct at91_ep, ep);
-        struct at91_udc *dev = ep->udc;
+        struct at91_udc *udc = ep->udc;
         u16             maxpacket;
         u32             tmp;
         unsigned long   flags;
@@ -487,7 +490,7 @@ static int at91_ep_enable(struct usb_ep *_ep,
                 return -EINVAL;
         }
 
-        if (!dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN) {
+        if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
                 DBG("bogus device state\n");
                 return -ESHUTDOWN;
         }
@@ -521,7 +524,7 @@ bogus_max:
         }
 
 ok:
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
 
         /* initialize endpoint to match this descriptor */
         ep->is_in = usb_endpoint_dir_in(desc);
@@ -540,10 +543,10 @@ ok:
          * reset/init endpoint fifo.  NOTE:  leaves fifo_bank alone,
          * since endpoint resets don't reset hw pingpong state.
          */
-        at91_udp_write(dev, AT91_UDP_RST_EP, ep->int_mask);
-        at91_udp_write(dev, AT91_UDP_RST_EP, 0);
+        at91_udp_write(udc, AT91_UDP_RST_EP, ep->int_mask);
+        at91_udp_write(udc, AT91_UDP_RST_EP, 0);
 
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return 0;
 }
 
@@ -556,7 +559,7 @@ static int at91_ep_disable (struct usb_ep * _ep)
         if (ep == &ep->udc->ep[0])
                 return -EINVAL;
 
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
 
         nuke(ep, -ESHUTDOWN);
 
@@ -571,7 +574,7 @@ static int at91_ep_disable (struct usb_ep * _ep)
                 __raw_writel(0, ep->creg);
         }
 
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return 0;
 }
 
@@ -607,7 +610,7 @@ static int at91_ep_queue(struct usb_ep *_ep,
 {
         struct at91_request     *req;
         struct at91_ep          *ep;
-        struct at91_udc         *dev;
+        struct at91_udc         *udc;
         int                     status;
         unsigned long           flags;
 
@@ -625,9 +628,9 @@ static int at91_ep_queue(struct usb_ep *_ep,
                 return -EINVAL;
         }
 
-        dev = ep->udc;
+        udc = ep->udc;
 
-        if (!dev || !dev->driver || dev->gadget.speed == USB_SPEED_UNKNOWN) {
+        if (!udc || !udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN) {
                 DBG("invalid device\n");
                 return -EINVAL;
         }
@@ -635,7 +638,7 @@ static int at91_ep_queue(struct usb_ep *_ep,
         _req->status = -EINPROGRESS;
         _req->actual = 0;
 
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
 
         /* try to kickstart any empty and idle queue */
         if (list_empty(&ep->queue) && !ep->stopped) {
@@ -653,7 +656,7 @@ static int at91_ep_queue(struct usb_ep *_ep,
                 if (is_ep0) {
                         u32     tmp;
 
-                        if (!dev->req_pending) {
+                        if (!udc->req_pending) {
                                 status = -EINVAL;
                                 goto done;
                         }
@@ -662,11 +665,11 @@ static int at91_ep_queue(struct usb_ep *_ep,
                          * defer changing CONFG until after the gadget driver
                          * reconfigures the endpoints.
                          */
-                        if (dev->wait_for_config_ack) {
-                                tmp = at91_udp_read(dev, AT91_UDP_GLB_STAT);
+                        if (udc->wait_for_config_ack) {
+                                tmp = at91_udp_read(udc, AT91_UDP_GLB_STAT);
                                 tmp ^= AT91_UDP_CONFG;
                                 VDBG("toggle config\n");
-                                at91_udp_write(dev, AT91_UDP_GLB_STAT, tmp);
+                                at91_udp_write(udc, AT91_UDP_GLB_STAT, tmp);
                         }
                         if (req->req.length == 0) {
 ep0_in_status:
@@ -676,7 +679,7 @@ ep0_in_status:
                                 tmp &= ~SET_FX;
                                 tmp |= CLR_FX | AT91_UDP_TXPKTRDY;
                                 __raw_writel(tmp, ep->creg);
-                                dev->req_pending = 0;
+                                udc->req_pending = 0;
                                 goto done;
                         }
                 }
@@ -695,31 +698,40 @@ ep0_in_status:
 
         if (req && !status) {
                 list_add_tail (&req->queue, &ep->queue);
-                at91_udp_write(dev, AT91_UDP_IER, ep->int_mask);
+                at91_udp_write(udc, AT91_UDP_IER, ep->int_mask);
         }
 done:
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return (status < 0) ? status : 0;
 }
 
 static int at91_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 {
-        struct at91_ep  *ep;
+        struct at91_ep          *ep;
         struct at91_request     *req;
+        unsigned long           flags;
+        struct at91_udc         *udc;
 
         ep = container_of(_ep, struct at91_ep, ep);
         if (!_ep || ep->ep.name == ep0name)
                 return -EINVAL;
 
+        udc = ep->udc;
+
+        spin_lock_irqsave(&udc->lock, flags);
+
         /* make sure it's actually queued on this endpoint */
         list_for_each_entry (req, &ep->queue, queue) {
                 if (&req->req == _req)
                         break;
         }
-        if (&req->req != _req)
+        if (&req->req != _req) {
+                spin_unlock_irqrestore(&udc->lock, flags);
                 return -EINVAL;
+        }
 
         done(ep, req, -ECONNRESET);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return 0;
 }
 
@@ -736,7 +748,7 @@ static int at91_ep_set_halt(struct usb_ep *_ep, int value)
                 return -EINVAL;
 
         creg = ep->creg;
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
 
         csr = __raw_readl(creg);
 
@@ -761,7 +773,7 @@ static int at91_ep_set_halt(struct usb_ep *_ep, int value)
                 __raw_writel(csr, creg);
         }
 
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return status;
 }
 
@@ -795,7 +807,7 @@ static int at91_wakeup(struct usb_gadget *gadget)
         unsigned long   flags;
 
         DBG("%s\n", __func__ );
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
 
         if (!udc->clocked || !udc->suspended)
                 goto done;
@@ -809,7 +821,7 @@ static int at91_wakeup(struct usb_gadget *gadget)
         at91_udp_write(udc, AT91_UDP_GLB_STAT, glbstate);
 
 done:
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return status;
 }
 
@@ -851,8 +863,11 @@ static void stop_activity(struct at91_udc *udc)
                 ep->stopped = 1;
                 nuke(ep, -ESHUTDOWN);
         }
-        if (driver)
+        if (driver) {
+                spin_unlock(&udc->lock);
                 driver->disconnect(&udc->gadget);
+                spin_lock(&udc->lock);
+        }
 
         udc_reinit(udc);
 }
@@ -935,13 +950,13 @@ static int at91_vbus_session(struct usb_gadget *gadget, int is_active)
         unsigned long   flags;
 
         // VDBG("vbus %s\n", is_active ? "on" : "off");
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
         udc->vbus = (is_active != 0);
         if (udc->driver)
                 pullup(udc, is_active);
         else
                 pullup(udc, 0);
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return 0;
 }
 
@@ -950,10 +965,10 @@ static int at91_pullup(struct usb_gadget *gadget, int is_on)
         struct at91_udc *udc = to_udc(gadget);
         unsigned long   flags;
 
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
         udc->enabled = is_on = !!is_on;
         pullup(udc, is_on);
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return 0;
 }
 
@@ -962,9 +977,9 @@ static int at91_set_selfpowered(struct usb_gadget *gadget, int is_on)
         struct at91_udc *udc = to_udc(gadget);
         unsigned long   flags;
 
-        local_irq_save(flags);
+        spin_lock_irqsave(&udc->lock, flags);
         udc->selfpowered = (is_on != 0);
-        local_irq_restore(flags);
+        spin_unlock_irqrestore(&udc->lock, flags);
         return 0;
 }
 
@@ -1226,8 +1241,11 @@ static void handle_setup(struct at91_udc *udc, struct at91_ep *ep, u32 csr)
 #undef w_length
 
         /* pass request up to the gadget driver */
-        if (udc->driver)
+        if (udc->driver) {
+                spin_unlock(&udc->lock);
                 status = udc->driver->setup(&udc->gadget, &pkt.r);
+                spin_lock(&udc->lock);
+        }
         else
                 status = -ENODEV;
         if (status < 0) {
@@ -1378,6 +1396,9 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc)
         struct at91_udc         *udc = _udc;
         u32                     rescans = 5;
         int                     disable_clock = 0;
+        unsigned long           flags;
+
+        spin_lock_irqsave(&udc->lock, flags);
 
         if (!udc->clocked) {
                 clk_on(udc);
@@ -1433,8 +1454,11 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc)
                          * and then into standby to avoid drawing more than
                          * 500uA power (2500uA for some high-power configs).
                          */
-                        if (udc->driver && udc->driver->suspend)
+                        if (udc->driver && udc->driver->suspend) {
+                                spin_unlock(&udc->lock);
                                 udc->driver->suspend(&udc->gadget);
+                                spin_lock(&udc->lock);
+                        }
 
                 /* host initiated resume */
                 } else if (status & AT91_UDP_RXRSM) {
@@ -1451,8 +1475,11 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc)
                          * would normally want to switch out of slow clock
                          * mode into normal mode.
                          */
-                        if (udc->driver && udc->driver->resume)
+                        if (udc->driver && udc->driver->resume) {
+                                spin_unlock(&udc->lock);
                                 udc->driver->resume(&udc->gadget);
+                                spin_lock(&udc->lock);
+                        }
 
                 /* endpoint IRQs are cleared by handling them */
                 } else {
@@ -1474,6 +1501,8 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc)
         if (disable_clock)
                 clk_off(udc);
 
+        spin_unlock_irqrestore(&udc->lock, flags);
+
         return IRQ_HANDLED;
 }
 
@@ -1574,6 +1603,7 @@ int usb_gadget_register_driver (struct usb_gadget_driver *driver)
 {
         struct at91_udc *udc = &controller;
         int             retval;
+        unsigned long   flags;
 
         if (!driver
                         || driver->speed < USB_SPEED_FULL
@@ -1605,9 +1635,9 @@ int usb_gadget_register_driver (struct usb_gadget_driver *driver)
                 return retval;
         }
 
-        local_irq_disable();
+        spin_lock_irqsave(&udc->lock, flags);
         pullup(udc, 1);
-        local_irq_enable();
+        spin_unlock_irqrestore(&udc->lock, flags);
 
         DBG("bound to %s\n", driver->driver.name);
         return 0;
@@ -1617,15 +1647,16 @@ EXPORT_SYMBOL (usb_gadget_register_driver);
 int usb_gadget_unregister_driver (struct usb_gadget_driver *driver)
 {
         struct at91_udc *udc = &controller;
+        unsigned long   flags;
 
         if (!driver || driver != udc->driver || !driver->unbind)
                 return -EINVAL;
 
-        local_irq_disable();
+        spin_lock_irqsave(&udc->lock, flags);
         udc->enabled = 0;
         at91_udp_write(udc, AT91_UDP_IDR, ~0);
         pullup(udc, 0);
-        local_irq_enable();
+        spin_unlock_irqrestore(&udc->lock, flags);
 
         driver->unbind(&udc->gadget);
         udc->gadget.dev.driver = NULL;
@@ -1641,8 +1672,13 @@ EXPORT_SYMBOL (usb_gadget_unregister_driver);
 
 static void at91udc_shutdown(struct platform_device *dev)
 {
+        struct at91_udc *udc = platform_get_drvdata(dev);
+        unsigned long   flags;
+
         /* force disconnect on reboot */
+        spin_lock_irqsave(&udc->lock, flags);
         pullup(platform_get_drvdata(dev), 0);
+        spin_unlock_irqrestore(&udc->lock, flags);
 }
 
 static int __init at91udc_probe(struct platform_device *pdev)
@@ -1683,6 +1719,7 @@ static int __init at91udc_probe(struct platform_device *pdev)
         udc->board = *(struct at91_udc_data *) dev->platform_data;
         udc->pdev = pdev;
         udc->enabled = 0;
+        spin_lock_init(&udc->lock);
 
         /* rm9200 needs manual D+ pullup; off by default */
         if (cpu_is_at91rm9200()) {
@@ -1804,13 +1841,16 @@ static int __exit at91udc_remove(struct platform_device *pdev)
 {
         struct at91_udc *udc = platform_get_drvdata(pdev);
         struct resource *res;
+        unsigned long   flags;
 
         DBG("remove\n");
 
         if (udc->driver)
                 return -EBUSY;
 
+        spin_lock_irqsave(&udc->lock, flags);
         pullup(udc, 0);
+        spin_unlock_irqrestore(&udc->lock, flags);
 
         device_init_wakeup(&pdev->dev, 0);
         remove_debug_file(udc);
@@ -1840,6 +1880,7 @@ static int at91udc_suspend(struct platform_device *pdev, pm_message_t mesg)
 {
         struct at91_udc *udc = platform_get_drvdata(pdev);
         int             wake = udc->driver && device_may_wakeup(&pdev->dev);
+        unsigned long   flags;
 
         /* Unless we can act normally to the host (letting it wake us up
          * whenever it has work for us) force disconnect.  Wakeup requires
@@ -1849,8 +1890,10 @@ static int at91udc_suspend(struct platform_device *pdev, pm_message_t mesg)
         if ((!udc->suspended && udc->addr)
                         || !wake
                         || at91_suspend_entering_slow_clock()) {
+                spin_lock_irqsave(&udc->lock, flags);
                 pullup(udc, 0);
                 wake = 0;
+                spin_unlock_irqrestore(&udc->lock, flags);
         } else
                 enable_irq_wake(udc->udp_irq);
 
@@ -1863,6 +1906,7 @@ static int at91udc_suspend(struct platform_device *pdev, pm_message_t mesg)
 static int at91udc_resume(struct platform_device *pdev)
 {
         struct at91_udc *udc = platform_get_drvdata(pdev);
+        unsigned long   flags;
 
         if (udc->board.vbus_pin > 0 && udc->active_suspend)
                 disable_irq_wake(udc->board.vbus_pin);
@@ -1870,8 +1914,11 @@ static int at91udc_resume(struct platform_device *pdev)
         /* maybe reconnect to host; if so, clocks on */
         if (udc->active_suspend)
                 disable_irq_wake(udc->udp_irq);
-        else
+        else {
+                spin_lock_irqsave(&udc->lock, flags);
                 pullup(udc, 1);
+                spin_unlock_irqrestore(&udc->lock, flags);
+        }
         return 0;
 }
 #else
diff --git a/drivers/usb/gadget/at91_udc.h b/drivers/usb/gadget/at91_udc.h
index c65d62295890..bc76a39c2bb1 100644
--- a/drivers/usb/gadget/at91_udc.h
+++ b/drivers/usb/gadget/at91_udc.h
@@ -144,6 +144,7 @@ struct at91_udc {
         struct proc_dir_entry           *pde;
         void __iomem                    *udp_baseaddr;
         int                             udp_irq;
+        spinlock_t                      lock;
 };
 
 static inline struct at91_udc *to_udc(struct usb_gadget *g)