USB: AT91 UDC updates, mostly power management

UDC updates for AT91 series processors:

 - Get ready for at91sam926x processors (ARMv5tej not ARMv4t)

 - Suspend/resume support now behaves properly

 - In "standby" mode, UDC can be a source of system wakeup events
   (host resume, device connect/disconnect, etc)

 - Fix IRQ storming issues, seemingly related to clock disabling
   changes that went in a while back

And minor cleanups, especially whitespace.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Victor  <andrew@sanpeople.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 113 insertions, 64 deletions

diff --git a/drivers/usb/gadget/at91_udc.c b/drivers/usb/gadget/at91_udc.c
index 1c459ff037ce..cfebca05ead5 100644
--- a/drivers/usb/gadget/at91_udc.c
+++ b/drivers/usb/gadget/at91_udc.c
@@ -57,19 +57,23 @@
 
 /*
  * This controller is simple and PIO-only.  It's used in many AT91-series
- * ARMv4T controllers, including the at91rm9200 (arm920T, with MMU),
- * at91sam9261 (arm926ejs, with MMU), and several no-mmu versions.
+ * full speed USB controllers, including the at91rm9200 (arm920T, with MMU),
+ * at91sam926x (arm926ejs, with MMU), and several no-mmu versions.
  *
  * This driver expects the board has been wired with two GPIOs suppporting
  * a VBUS sensing IRQ, and a D+ pullup.  (They may be omitted, but the
- * testing hasn't covered such cases.)  The pullup is most important; it
+ * testing hasn't covered such cases.)
+ *
+ * The pullup is most important (so it's integrated on sam926x parts).  It
  * provides software control over whether the host enumerates the device.
+ *
  * The VBUS sensing helps during enumeration, and allows both USB clocks
  * (and the transceiver) to stay gated off until they're necessary, saving
- * power.  During USB suspend, the 48 MHz clock is gated off.
+ * power.  During USB suspend, the 48 MHz clock is gated off in hardware;
+ * it may also be gated off by software during some Linux sleep states.
  */
 
-#define DRIVER_VERSION  "8 March 2005"
+#define DRIVER_VERSION  "3 May 2006"
 
 static const char driver_name [] = "at91_udc";
 static const char ep0name[] = "ep0";
@@ -316,9 +320,15 @@ static void done(struct at91_ep *ep, struct at91_request *req, int status)
  *
  * There are also state bits like FORCESTALL, EPEDS, DIR, and EPTYPE
  * that shouldn't normally be changed.
+ *
+ * NOTE at91sam9260 docs mention synch between UDPCK and MCK clock domains,
+ * implying a need to wait for one write to complete (test relevant bits)
+ * before starting the next write.  This shouldn't be an issue given how
+ * infrequently we write, except maybe for write-then-read idioms.
  */
 #define SET_FX  (AT91_UDP_TXPKTRDY)
-#define CLR_FX  (RX_DATA_READY | AT91_UDP_RXSETUP | AT91_UDP_STALLSENT | AT91_UDP_TXCOMP)
+#define CLR_FX  (RX_DATA_READY | AT91_UDP_RXSETUP \
+                | AT91_UDP_STALLSENT | AT91_UDP_TXCOMP)
 
 /* pull OUT packet data from the endpoint's fifo */
 static int read_fifo (struct at91_ep *ep, struct at91_request *req)
@@ -472,7 +482,8 @@ static void nuke(struct at91_ep *ep, int status)
 
 /*-------------------------------------------------------------------------*/
 
-static int at91_ep_enable(struct usb_ep *_ep, const struct usb_endpoint_descriptor *desc)
+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;
@@ -582,11 +593,12 @@ static int at91_ep_disable (struct usb_ep * _ep)
  * interesting for request or buffer allocation.
  */
 
-static struct usb_request *at91_ep_alloc_request (struct usb_ep *_ep, unsigned int gfp_flags)
+static struct usb_request *
+at91_ep_alloc_request(struct usb_ep *_ep, unsigned int gfp_flags)
 {
         struct at91_request *req;
 
-        req = kcalloc(1, sizeof (struct at91_request), SLAB_KERNEL);
+        req = kcalloc(1, sizeof (struct at91_request), gfp_flags);
         if (!req)
                 return NULL;
 
@@ -862,6 +874,7 @@ static void stop_activity(struct at91_udc *udc)
         if (udc->gadget.speed == USB_SPEED_UNKNOWN)
                 driver = NULL;
         udc->gadget.speed = USB_SPEED_UNKNOWN;
+        udc->suspended = 0;
 
         for (i = 0; i < NUM_ENDPOINTS; i++) {
                 struct at91_ep *ep = &udc->ep[i];
@@ -889,8 +902,8 @@ static void clk_off(struct at91_udc *udc)
                 return;
         udc->clocked = 0;
         udc->gadget.speed = USB_SPEED_UNKNOWN;
-        clk_disable(udc->iclk);
         clk_disable(udc->fclk);
+        clk_disable(udc->iclk);
 }
 
 /*
@@ -911,9 +924,6 @@ static void pullup(struct at91_udc *udc, int is_on)
                 at91_udp_write(AT91_UDP_TXVC, AT91_UDP_TXVC_TXVDIS);
                 at91_set_gpio_value(udc->board.pullup_pin, 0);
                 clk_off(udc);
-
-                // REVISIT:  with transceiver disabled, will D- float
-                // so that a host would falsely detect a device?
         }
 }
 
@@ -1290,7 +1300,8 @@ static void handle_ep0(struct at91_udc *udc)
                         if (udc->wait_for_addr_ack) {
                                 u32     tmp;
 
-                                at91_udp_write(AT91_UDP_FADDR, AT91_UDP_FEN | udc->addr);
+                                at91_udp_write(AT91_UDP_FADDR,
+                                                AT91_UDP_FEN | udc->addr);
                                 tmp = at91_udp_read(AT91_UDP_GLB_STAT);
                                 tmp &= ~AT91_UDP_FADDEN;
                                 if (udc->addr)
@@ -1361,9 +1372,10 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc, struct pt_regs *r)
         u32                     rescans = 5;
 
         while (rescans--) {
-                u32     status = at91_udp_read(AT91_UDP_ISR);
+                u32 status;
 
-                status &= at91_udp_read(AT91_UDP_IMR);
+                status = at91_udp_read(AT91_UDP_ISR)
+                        & at91_udp_read(AT91_UDP_IMR);
                 if (!status)
                         break;
 
@@ -1379,18 +1391,17 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc, struct pt_regs *r)
                         stop_activity(udc);
 
                         /* enable ep0 */
-                        at91_udp_write(AT91_UDP_CSR(0), AT91_UDP_EPEDS | AT91_UDP_EPTYPE_CTRL);
+                        at91_udp_write(AT91_UDP_CSR(0),
+                                        AT91_UDP_EPEDS | AT91_UDP_EPTYPE_CTRL);
                         udc->gadget.speed = USB_SPEED_FULL;
                         udc->suspended = 0;
                         at91_udp_write(AT91_UDP_IER, AT91_UDP_EP(0));
 
                         /*
                          * NOTE:  this driver keeps clocks off unless the
-                         * USB host is present.  That saves power, and also
-                         * eliminates IRQs (reset, resume, suspend) that can
-                         * otherwise flood from the controller.  If your
-                         * board doesn't support VBUS detection, suspend and
-                         * resume irq logic may need more attention...
+                         * USB host is present.  That saves power, but for
+                         * boards that don't support VBUS detection, both
+                         * clocks need to be active most of the time.
                          */
 
                 /* host initiated suspend (3+ms bus idle) */
@@ -1452,13 +1463,19 @@ static irqreturn_t at91_udc_irq (int irq, void *_udc, struct pt_regs *r)
 
 /*-------------------------------------------------------------------------*/
 
+static void nop_release(struct device *dev)
+{
+        /* nothing to free */
+}
+
 static struct at91_udc controller = {
         .gadget = {
-                .ops = &at91_udc_ops,
-                .ep0 = &controller.ep[0].ep,
-                .name = driver_name,
-                .dev = {
-                        .bus_id = "gadget"
+                .ops    = &at91_udc_ops,
+                .ep0    = &controller.ep[0].ep,
+                .name   = driver_name,
+                .dev    = {
+                        .bus_id = "gadget",
+                        .release = nop_release,
                 }
         },
         .ep[0] = {
@@ -1468,7 +1485,8 @@ static struct at91_udc controller = {
                 },
                 .udc            = &controller,
                 .maxpacket      = 8,
-                .creg           = (void __iomem *)(AT91_VA_BASE_UDP + AT91_UDP_CSR(0)),
+                .creg           = (void __iomem *)(AT91_VA_BASE_UDP
+                                        + AT91_UDP_CSR(0)),
                 .int_mask       = 1 << 0,
         },
         .ep[1] = {
@@ -1479,7 +1497,8 @@ static struct at91_udc controller = {
                 .udc            = &controller,
                 .is_pingpong    = 1,
                 .maxpacket      = 64,
-                .creg           = (void __iomem *)(AT91_VA_BASE_UDP + AT91_UDP_CSR(1)),
+                .creg           = (void __iomem *)(AT91_VA_BASE_UDP
+                                        + AT91_UDP_CSR(1)),
                 .int_mask       = 1 << 1,
         },
         .ep[2] = {
@@ -1490,7 +1509,8 @@ static struct at91_udc controller = {
                 .udc            = &controller,
                 .is_pingpong    = 1,
                 .maxpacket      = 64,
-                .creg           = (void __iomem *)(AT91_VA_BASE_UDP + AT91_UDP_CSR(2)),
+                .creg           = (void __iomem *)(AT91_VA_BASE_UDP
+                                        + AT91_UDP_CSR(2)),
                 .int_mask       = 1 << 2,
         },
         .ep[3] = {
@@ -1501,7 +1521,8 @@ static struct at91_udc controller = {
                 },
                 .udc            = &controller,
                 .maxpacket      = 8,
-                .creg           = (void __iomem *)(AT91_VA_BASE_UDP + AT91_UDP_CSR(3)),
+                .creg           = (void __iomem *)(AT91_VA_BASE_UDP
+                                        + AT91_UDP_CSR(3)),
                 .int_mask       = 1 << 3,
         },
         .ep[4] = {
@@ -1512,7 +1533,8 @@ static struct at91_udc controller = {
                 .udc            = &controller,
                 .is_pingpong    = 1,
                 .maxpacket      = 256,
-                .creg           = (void __iomem *)(AT91_VA_BASE_UDP + AT91_UDP_CSR(4)),
+                .creg           = (void __iomem *)(AT91_VA_BASE_UDP
+                                        + AT91_UDP_CSR(4)),
                 .int_mask       = 1 << 4,
         },
         .ep[5] = {
@@ -1523,10 +1545,11 @@ static struct at91_udc controller = {
                 .udc            = &controller,
                 .is_pingpong    = 1,
                 .maxpacket      = 256,
-                .creg           = (void __iomem *)(AT91_VA_BASE_UDP + AT91_UDP_CSR(5)),
+                .creg           = (void __iomem *)(AT91_VA_BASE_UDP
+                                        + AT91_UDP_CSR(5)),
                 .int_mask       = 1 << 5,
         },
-        /* ep6 and ep7 are also reserved */
+        /* ep6 and ep7 are also reserved (custom silicon might use them) */
 };
 
 static irqreturn_t at91_vbus_irq(int irq, void *_udc, struct pt_regs *r)
@@ -1593,6 +1616,7 @@ int usb_gadget_unregister_driver (struct usb_gadget_driver *driver)
 
         local_irq_disable();
         udc->enabled = 0;
+        at91_udp_write(AT91_UDP_IDR, ~0);
         pullup(udc, 0);
         local_irq_enable();
 
@@ -1624,6 +1648,16 @@ static int __devinit at91udc_probe(struct platform_device *pdev)
                 return -ENODEV;
         }
 
+        if (pdev->num_resources != 2) {
+                DBG("invalid num_resources");
+                return -ENODEV;
+        }
+        if ((pdev->resource[0].flags != IORESOURCE_MEM)
+                        || (pdev->resource[1].flags != IORESOURCE_IRQ)) {
+                DBG("invalid resource type");
+                return -ENODEV;
+        }
+
         if (!request_mem_region(AT91_BASE_UDP, SZ_16K, driver_name)) {
                 DBG("someone's using UDC memory\n");
                 return -EBUSY;
@@ -1649,19 +1683,26 @@ static int __devinit at91udc_probe(struct platform_device *pdev)
         if (retval < 0)
                 goto fail0;
 
-        /* disable everything until there's a gadget driver and vbus */
-        pullup(udc, 0);
+        /* don't do anything until we have both gadget driver and VBUS */
+        clk_enable(udc->iclk);
+        at91_udp_write(AT91_UDP_TXVC, AT91_UDP_TXVC_TXVDIS);
+        at91_udp_write(AT91_UDP_IDR, 0xffffffff);
+        clk_disable(udc->iclk);
 
         /* request UDC and maybe VBUS irqs */
-        if (request_irq(AT91_ID_UDP, at91_udc_irq, IRQF_DISABLED, driver_name, udc)) {
-                DBG("request irq %d failed\n", AT91_ID_UDP);
+        udc->udp_irq = platform_get_irq(pdev, 0);
+        if (request_irq(udc->udp_irq, at91_udc_irq,
+                        IRQF_DISABLED, driver_name, udc)) {
+                DBG("request irq %d failed\n", udc->udp_irq);
                 retval = -EBUSY;
                 goto fail1;
         }
         if (udc->board.vbus_pin > 0) {
-                if (request_irq(udc->board.vbus_pin, at91_vbus_irq, IRQF_DISABLED, driver_name, udc)) {
-                        DBG("request vbus irq %d failed\n", udc->board.vbus_pin);
-                        free_irq(AT91_ID_UDP, udc);
+                if (request_irq(udc->board.vbus_pin, at91_vbus_irq,
+                                IRQF_DISABLED, driver_name, udc)) {
+                        DBG("request vbus irq %d failed\n",
+                                        udc->board.vbus_pin);
+                        free_irq(udc->udp_irq, udc);
                         retval = -EBUSY;
                         goto fail1;
                 }
@@ -1670,6 +1711,7 @@ static int __devinit at91udc_probe(struct platform_device *pdev)
                 udc->vbus = 1;
         }
         dev_set_drvdata(dev, udc);
+        device_init_wakeup(dev, 1);
         create_debug_file(udc);
 
         INFO("%s version %s\n", driver_name, DRIVER_VERSION);
@@ -1678,14 +1720,14 @@ static int __devinit at91udc_probe(struct platform_device *pdev)
 fail1:
         device_unregister(&udc->gadget.dev);
 fail0:
-        release_mem_region(AT91_VA_BASE_UDP, SZ_16K);
+        release_mem_region(AT91_BASE_UDP, SZ_16K);
         DBG("%s probe failed, %d\n", driver_name, retval);
         return retval;
 }
 
-static int __devexit at91udc_remove(struct platform_device *dev)
+static int __devexit at91udc_remove(struct platform_device *pdev)
 {
-        struct at91_udc *udc = platform_get_drvdata(dev);
+        struct at91_udc *udc = platform_get_drvdata(pdev);
 
         DBG("remove\n");
 
@@ -1694,10 +1736,11 @@ static int __devexit at91udc_remove(struct platform_device *dev)
         if (udc->driver != 0)
                 usb_gadget_unregister_driver(udc->driver);
 
+        device_init_wakeup(&pdev->dev, 0);
         remove_debug_file(udc);
         if (udc->board.vbus_pin > 0)
                 free_irq(udc->board.vbus_pin, udc);
-        free_irq(AT91_ID_UDP, udc);
+        free_irq(udc->udp_irq, udc);
         device_unregister(&udc->gadget.dev);
         release_mem_region(AT91_BASE_UDP, SZ_16K);
 
@@ -1708,31 +1751,36 @@ static int __devexit at91udc_remove(struct platform_device *dev)
 }
 
 #ifdef CONFIG_PM
-static int at91udc_suspend(struct platform_device *dev, pm_message_t mesg)
+static int at91udc_suspend(struct platform_device *pdev, pm_message_t mesg)
 {
-        struct at91_udc *udc = platform_get_drvdata(dev);
+        struct at91_udc *udc = platform_get_drvdata(pdev);
+        int             wake = udc->driver && device_may_wakeup(&pdev->dev);
 
-        /*
-         * The "safe" suspend transitions are opportunistic ... e.g. when
-         * the USB link is suspended (48MHz clock autogated off), or when
-         * it's disconnected (programmatically gated off, elsewhere).
-         * Then we can suspend, and the chip can enter slow clock mode.
-         *
-         * The problem case is some component (user mode?) suspending this
-         * device while it's active, with the 48 MHz clock in use.  There
-         * are two basic approaches:  (a) veto suspend levels involving slow
-         * clock mode, (b) disconnect, so 48 MHz will no longer be in use
-         * and we can enter slow clock mode.  This uses (b) for now, since
-         * it's simplest until AT91 PM exists and supports the other option.
+        /* Unless we can act normally to the host (letting it wake us up
+         * whenever it has work for us) force disconnect.  Wakeup requires
+         * PLLB for USB events (signaling for reset, wakeup, or incoming
+         * tokens) and VBUS irqs (on systems which support them).
          */
-        if (udc->vbus && !udc->suspended)
+        if ((!udc->suspended && udc->addr)
+                        || !wake
+                        || at91_suspend_entering_slow_clock()) {
                 pullup(udc, 0);
+                disable_irq_wake(udc->udp_irq);
+        } else
+                enable_irq_wake(udc->udp_irq);
+
+        if (udc->board.vbus_pin > 0) {
+                if (wake)
+                        enable_irq_wake(udc->board.vbus_pin);
+                else
+                        disable_irq_wake(udc->board.vbus_pin);
+        }
         return 0;
 }
 
-static int at91udc_resume(struct platform_device *dev)
+static int at91udc_resume(struct platform_device *pdev)
 {
-        struct at91_udc *udc = platform_get_drvdata(dev);
+        struct at91_udc *udc = platform_get_drvdata(pdev);
 
         /* maybe reconnect to host; if so, clocks on */
         pullup(udc, 1);
@@ -1748,7 +1796,7 @@ static struct platform_driver at91_udc = {
         .remove         = __devexit_p(at91udc_remove),
         .shutdown       = at91udc_shutdown,
         .suspend        = at91udc_suspend,
-        .resume         = at91udc_resume,
+        .resume         = at91udc_resume,
         .driver         = {
                 .name   = (char *) driver_name,
                 .owner  = THIS_MODULE,
@@ -1767,6 +1815,6 @@ static void __devexit udc_exit_module(void)
 }
 module_exit(udc_exit_module);
 
-MODULE_DESCRIPTION("AT91RM9200 udc driver");
+MODULE_DESCRIPTION("AT91 udc driver");
 MODULE_AUTHOR("Thomas Rathbone, David Brownell");
 MODULE_LICENSE("GPL");
diff --git a/drivers/usb/gadget/at91_udc.h b/drivers/usb/gadget/at91_udc.h
index 5a4799cedd19..882af42e86cc 100644
--- a/drivers/usb/gadget/at91_udc.h
+++ b/drivers/usb/gadget/at91_udc.h
@@ -141,6 +141,7 @@ struct at91_udc {
         struct clk                      *iclk, *fclk;
         struct platform_device          *pdev;
         struct proc_dir_entry           *pde;
+        int                             udp_irq;
 };
 
 static inline struct at91_udc *to_udc(struct usb_gadget *g)