drivers/char/rtc.c: Handle memory-mapped chips properly

[Martin Michlmayr <tbm@cyrius.com>]

Maciej,

The following change you made to drivers/char/rtc.c ("Handle
memory-mapped chips properly") never made it into mainline.  Can you
please review the change again and submit it to the appropriate
sub-system maintainer.


--- linux-2.6.16-rc4/drivers/char/rtc.c 2006-02-19 20:08:44.000000000 +0000
+++ mips-2.6.16-rc4/drivers/char/rtc.c  2006-02-19 20:15:07.000000000 +0000
@@ -35,23 +35,22 @@
  *     1.09a   Pete Zaitcev: Sun SPARC
  *     1.09b   Jeff Garzik: Modularize, init cleanup
  *     1.09c   Jeff Garzik: SMP cleanup
- *     1.10    Paul Barton-Davis: add support for async I/O
+ *     1.10    Paul Barton-Davis: add support for async I/O
  *     1.10a   Andrea Arcangeli: Alpha updates
  *     1.10b   Andrew Morton: SMP lock fix
  *     1.10c   Cesar Barros: SMP locking fixes and cleanup
  *     1.10d   Paul Gortmaker: delete paranoia check in rtc_exit
  *     1.10e   Maciej W. Rozycki: Handle DECstation's year weirdness.
- *      1.11    Takashi Iwai: Kernel access functions
+ *     1.11    Takashi Iwai: Kernel access functions
  *                           rtc_register/rtc_unregister/rtc_control
  *      1.11a   Daniele Bellucci: Audit create_proc_read_entry in rtc_init
- *     1.12    Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
+ *     1.12    Venkatesh Pallipadi: Hooks for emulating rtc on HPET base-timer
  *             CONFIG_HPET_EMULATE_RTC
+ *     1.12a   Maciej W. Rozycki: Handle memory-mapped chips properly.
  *     1.12ac  Alan Cox: Allow read access to the day of week register
  */
 
-#define RTC_VERSION            "1.12ac"
-
-#define RTC_IO_EXTENT  0x8
+#define RTC_VERSION            "1.12a"
 
 /*
  *     Note that *all* calls to CMOS_READ and CMOS_WRITE are done with
@@ -338,7 +337,15 @@
        if (rtc_has_irq == 0)
                return -EIO;
 
-       if (count < sizeof(unsigned))
+       /*
+        * Historically this function used to assume that sizeof(unsigned long)
+        * is the same in userspace and kernelspace.  This lead to problems
+        * for configurations with multiple ABIs such a the MIPS o32 and 64
+        * ABIs supported on the same kernel.  So now we support read of both
+        * 4 and 8 bytes and assume that's the sizeof(unsigned long) in the
+        * userspace ABI.
+        */
+       if (count != sizeof(unsigned int) && count !=  sizeof(unsigned long))
                return -EINVAL;
 
        add_wait_queue(&rtc_wait, &wait);
@@ -369,10 +376,12 @@
                schedule();
        } while (1);
 
-       if (count < sizeof(unsigned long))
-               retval = put_user(data, (unsigned int __user *)buf) ?: 
sizeof(int); 
+       if (count == sizeof(unsigned int))
+               retval = put_user(data, (unsigned int __user *)buf) ?: 
sizeof(int);
        else
                retval = put_user(data, (unsigned long __user *)buf) ?: 
sizeof(long);
+       if (!retval)
+               retval = count;
  out:
        current->state = TASK_RUNNING;
        remove_wait_queue(&rtc_wait, &wait);
@@ -924,6 +933,9 @@
        struct sparc_isa_device *isa_dev;
 #endif
 #endif
+#ifndef __sparc__
+       void *r;
+#endif
 
 #ifdef __sparc__
        for_each_ebus(ebus) {
@@ -969,8 +981,13 @@
        }
 no_irq:
 #else
-       if (!request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc")) {
-               printk(KERN_ERR "rtc: I/O port %d is not free.\n", RTC_PORT 
(0));
+       if (RTC_IOMAPPED)
+               r = request_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
+       else
+               r = request_mem_region(RTC_PORT(0), RTC_IO_EXTENT, "rtc");
+       if (!r) {
+               printk(KERN_ERR "rtc: I/O resource %lx is not free.\n",
+                      (long)(RTC_PORT(0)));
                return -EIO;
        }
 
@@ -984,7 +1001,10 @@
        if(request_irq(RTC_IRQ, rtc_int_handler_ptr, SA_INTERRUPT, "rtc", 
NULL)) {
                /* Yeah right, seeing as irq 8 doesn't even hit the bus. */
                printk(KERN_ERR "rtc: IRQ %d is not free.\n", RTC_IRQ);
-               release_region(RTC_PORT(0), RTC_IO_EXTENT);
+               if (RTC_IOMAPPED)
+                       release_region(RTC_PORT(0), RTC_IO_EXTENT);
+               else
+                       release_mem_region(RTC_PORT(0), RTC_IO_EXTENT);
                return -EIO;
        }
        hpet_rtc_timer_init();
@@ -1084,7 +1104,10 @@
        if (rtc_has_irq)
                free_irq (rtc_irq, &rtc_port);
 #else
-       release_region (RTC_PORT (0), RTC_IO_EXTENT);
+       if (RTC_IOMAPPED)
+               release_region(RTC_PORT(0), RTC_IO_EXTENT);
+       else
+               release_mem_region(RTC_PORT(0), RTC_IO_EXTENT);
 #ifdef RTC_IRQ
        if (rtc_has_irq)
                free_irq (RTC_IRQ, NULL);


-- 
Martin Michlmayr
http://www.cyrius.com/