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 eaa79c8..fd6a757 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 c65d622..bc76a39 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)