[U-Boot-Users] RFC About USB Keyboard Polling

[Jon Loeliger]

Wolfgang,

We need to add USB Keyboard support to the 8641 HPCN board.
We currently have this working in a mode that is polled
rather than configuring any interrupts and handlers.

However, to do so, we needed to extend the usb_kbd_getc()
routine to possibly poll for interrupts as well.  So as
to avoid introducing extra code for platforms that do not
need it, we propose the following two patches.

Does this seem look a good approach to you?

Thanks,
jdl

PS -- The actual USB OHCI driver is a separate patch too,
        but it is board specific.  The patches below represent
        the changes to the common code.



commit 78c25c38ba8786b12b5d08d2555493ad74564825
Author: Zhang Wei <wei.zhang at freescale.com>
Date:   Wed Feb 14 14:43:53 2007 +0800
 
    Add CFG_USB_INTERRUPT_POLL support.
     
    Allow the USB controller to use interrupt polling
    in the input waiting loop in usb_kbd_getc() instead
    of asynchronous interrupts.
     
    Signed-off-by: Zhang Wei <wei.zhang at freescale.com>
    Signed-off-by: Jon Loeliger <jdl at freescale.com>
 
diff --git a/README b/README
index ecfd1f8..93467a0 100644
--- a/README
+++ b/README
@@ -883,6 +883,9 @@ The following options need to be configured:
                                for differential drivers: 0x00001000
                                for single ended drivers: 0x00005000
  
+               CFG_USB_INTERRUPT_POLL
+                       May be defined to allow interrupt polling
+                       instead of using aysnchronous interrupts.
  
 - MMC Support:
                The MMC controller on the Intel PXA is supported. To
diff --git a/common/usb_kbd.c b/common/usb_kbd.c
index 56c2166..3464bd7 100644
--- a/common/usb_kbd.c
+++ b/common/usb_kbd.c
@@ -129,7 +129,11 @@ static int usb_kbd_testc(void)
 static int usb_kbd_getc(void)
 {
        char c;
-       while(usb_in_pointer==usb_out_pointer);
+       while(usb_in_pointer==usb_out_pointer) {
+#ifdef CFG_USB_INTERRUPT_POLL
+               usb_interrupt_query();
+#endif
+       }
        if((usb_out_pointer+1)==USB_KBD_BUFFER_LEN)
                usb_out_pointer=0;
        else
diff --git a/include/configs/MPC8641HPCN.h b/include/configs/MPC8641HPCN.h
index 657162a..f663d72 100644
--- a/include/configs/MPC8641HPCN.h
+++ b/include/configs/MPC8641HPCN.h
@@ -337,6 +337,7 @@
 #define CONFIG_USB_OHCI                1
 #define CONFIG_USB_KEYBOARD    1
 #define CFG_DEVICE_DEREGISTER
+#define CFG_USB_INTERRUPT_POLL 1
  
 #if !defined(CONFIG_PCI_PNP)
     #define PCI_ENET0_IOADDR   0xe0000000


And then the actual poll routine itself:


commit f4a95829c0b9ef555d1ce750a5e501985e7c31b1
Author: Zhang Wei <wei.zhang at freescale.com>
Date:   Mon Feb 12 19:00:37 2007 +0800
 
    Add interrupt query function to USB core.
     
    Without asynchronous interrupt support, it may be
    necessary to poll for USB keyboard interrupts.
     
    Signed-off-by: Zhang Wei <wei.zhang at freescale.com>
    Signed-off-by: Jon Loeliger <jdl at freescale.com>
 
diff --git a/common/usb.c b/common/usb.c
index 0857494..a5062a6 100644
--- a/common/usb.c
+++ b/common/usb.c
@@ -143,6 +143,17 @@ void usb_disable_asynch(int disable)
 }
  
  
+#ifdef CFG_USB_INTERRUPT_POLL
+/*
+ * Poll for USB keyboard interrupts.
+ */
+void usb_interrupt_query(void)
+{
+       interrupt_poll();
+}
+#endif
+
+
 /*-------------------------------------------------------------------
  * Message wrappers.
  *
diff --git a/include/usb.h b/include/usb.h
index bf71554..f6bf1aa 100644
--- a/include/usb.h
+++ b/include/usb.h
@@ -177,6 +177,7 @@ int submit_control_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
                        int transfer_len,struct devrequest *setup);
 int submit_int_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
                        int transfer_len, int interval);
+void interrupt_poll(void);     /* Might need to poll for interrupts */
  
 /* Defines */
 #define USB_UHCI_VEND_ID 0x8086
@@ -218,6 +219,7 @@ int usb_bulk_msg(struct usb_device *dev, unsigned int pipe,
 int usb_submit_int_msg(struct usb_device *dev, unsigned long pipe,
                        void *buffer,int transfer_len, int interval);
 void usb_disable_asynch(int disable);
+void usb_interrupt_query(void);
 int usb_maxpacket(struct usb_device *dev,unsigned long pipe);
 void __inline__ wait_ms(unsigned long ms);
 int usb_get_configuration_no(struct usb_device *dev,unsigned char *buffer,int cfgno);