Firmware like PNPBIOS or ACPI can report the address space consumed by the
RTC. The actual space consumed may be less than the size (RTC_IO_EXTENT)
assumed by the RTC driver.
The PNP core doesn't request resources yet, but I'd like to make it do so.
If/when it does, the RTC_IO_EXTENT request may fail, which prevents the RTC
driver from loading.
Since we only use the RTC index and data registers at RTC_PORT(0) and
RTC_PORT(1), we can fall back to requesting just enough space for those.
If the PNP core requests resources, this results in typical I/O port usage
like this:
0070-0073 : 00:06 <-- PNP device 00:06 responds to 70-73
0070-0071 : rtc <-- RTC driver uses only 70-71
instead of the current:
0070-0077 : rtc <-- RTC_IO_EXTENT == 8
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+static resource_size_t rtc_size;
+
+static struct resource * __init rtc_request_region(resource_size_t size)
+{
+ struct resource *r;
+
+ if (RTC_IOMAPPED)
+ r = request_region(RTC_PORT(0), size, "rtc");
+ else
+ r = request_mem_region(RTC_PORT(0), size, "rtc");
+
+ if (r)
+ rtc_size = size;
+
+ return r;
+}
+
static void rtc_release_region(void)
{
if (RTC_IOMAPPED)
static void rtc_release_region(void)
{
if (RTC_IOMAPPED)
- release_region(RTC_PORT(0), RTC_IO_EXTENT);
+ release_region(RTC_PORT(0), rtc_size);
- release_mem_region(RTC_PORT(0), RTC_IO_EXTENT);
+ release_mem_region(RTC_PORT(0), rtc_size);
}
static int __init rtc_init(void)
}
static int __init rtc_init(void)
- 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");
+ r = rtc_request_region(RTC_IO_EXTENT);
+
+ /*
+ * If we've already requested a smaller range (for example, because
+ * PNPBIOS or ACPI told us how the device is configured), the request
+ * above might fail because it's too big.
+ *
+ * If so, request just the range we actually use.
+ */
+ if (!r)
+ r = rtc_request_region(RTC_IO_EXTENT_USED);
if (!r) {
#ifdef RTC_IRQ
rtc_has_irq = 0;
if (!r) {
#ifdef RTC_IRQ
rtc_has_irq = 0;
#ifndef ARCH_RTC_LOCATION /* Override by <asm/mc146818rtc.h>? */
#define RTC_IO_EXTENT 0x8
#ifndef ARCH_RTC_LOCATION /* Override by <asm/mc146818rtc.h>? */
#define RTC_IO_EXTENT 0x8
+#define RTC_IO_EXTENT_USED 0x2
#define RTC_IOMAPPED 1 /* Default to I/O mapping. */
#define RTC_IOMAPPED 1 /* Default to I/O mapping. */
+#else
+#define RTC_IO_EXTENT_USED RTC_IO_EXTENT
#endif /* ARCH_RTC_LOCATION */
#endif /* _MC146818RTC_H */
#endif /* ARCH_RTC_LOCATION */
#endif /* _MC146818RTC_H */