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path: root/drivers/rtc/rtc-cmos.c
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Diffstat (limited to 'drivers/rtc/rtc-cmos.c')
-rw-r--r--drivers/rtc/rtc-cmos.c70
1 files changed, 63 insertions, 7 deletions
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
index 963ad0b..f1695d7 100644
--- a/drivers/rtc/rtc-cmos.c
+++ b/drivers/rtc/rtc-cmos.c
@@ -143,6 +143,43 @@ static inline int hpet_unregister_irq_handler(irq_handler_t handler)
/*----------------------------------------------------------------*/
+#ifdef RTC_PORT
+
+/* Most newer x86 systems have two register banks, the first used
+ * for RTC and NVRAM and the second only for NVRAM. Caller must
+ * own rtc_lock ... and we won't worry about access during NMI.
+ */
+#define can_bank2 true
+
+static inline unsigned char cmos_read_bank2(unsigned char addr)
+{
+ outb(addr, RTC_PORT(2));
+ return inb(RTC_PORT(3));
+}
+
+static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
+{
+ outb(addr, RTC_PORT(2));
+ outb(val, RTC_PORT(2));
+}
+
+#else
+
+#define can_bank2 false
+
+static inline unsigned char cmos_read_bank2(unsigned char addr)
+{
+ return 0;
+}
+
+static inline void cmos_write_bank2(unsigned char val, unsigned char addr)
+{
+}
+
+#endif
+
+/*----------------------------------------------------------------*/
+
static int cmos_read_time(struct device *dev, struct rtc_time *t)
{
/* REVISIT: if the clock has a "century" register, use
@@ -491,12 +528,21 @@ cmos_nvram_read(struct kobject *kobj, struct bin_attribute *attr,
if (unlikely(off >= attr->size))
return 0;
+ if (unlikely(off < 0))
+ return -EINVAL;
if ((off + count) > attr->size)
count = attr->size - off;
+ off += NVRAM_OFFSET;
spin_lock_irq(&rtc_lock);
- for (retval = 0, off += NVRAM_OFFSET; count--; retval++, off++)
- *buf++ = CMOS_READ(off);
+ for (retval = 0; count; count--, off++, retval++) {
+ if (off < 128)
+ *buf++ = CMOS_READ(off);
+ else if (can_bank2)
+ *buf++ = cmos_read_bank2(off);
+ else
+ break;
+ }
spin_unlock_irq(&rtc_lock);
return retval;
@@ -512,6 +558,8 @@ cmos_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
cmos = dev_get_drvdata(container_of(kobj, struct device, kobj));
if (unlikely(off >= attr->size))
return -EFBIG;
+ if (unlikely(off < 0))
+ return -EINVAL;
if ((off + count) > attr->size)
count = attr->size - off;
@@ -520,15 +568,20 @@ cmos_nvram_write(struct kobject *kobj, struct bin_attribute *attr,
* here. If userspace is smart enough to know what fields of
* NVRAM to update, updating checksums is also part of its job.
*/
+ off += NVRAM_OFFSET;
spin_lock_irq(&rtc_lock);
- for (retval = 0, off += NVRAM_OFFSET; count--; retval++, off++) {
+ for (retval = 0; count; count--, off++, retval++) {
/* don't trash RTC registers */
if (off == cmos->day_alrm
|| off == cmos->mon_alrm
|| off == cmos->century)
buf++;
- else
+ else if (off < 128)
CMOS_WRITE(*buf++, off);
+ else if (can_bank2)
+ cmos_write_bank2(*buf++, off);
+ else
+ break;
}
spin_unlock_irq(&rtc_lock);
@@ -631,8 +684,8 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
/* Heuristic to deduce NVRAM size ... do what the legacy NVRAM
* driver did, but don't reject unknown configs. Old hardware
- * won't address 128 bytes, and for now we ignore the way newer
- * chips can address 256 bytes (using two more i/o ports).
+ * won't address 128 bytes. Newer chips have multiple banks,
+ * though they may not be listed in one I/O resource.
*/
#if defined(CONFIG_ATARI)
address_space = 64;
@@ -642,6 +695,8 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
#warning Assuming 128 bytes of RTC+NVRAM address space, not 64 bytes.
address_space = 128;
#endif
+ if (can_bank2 && ports->end > (ports->start + 1))
+ address_space = 256;
/* For ACPI systems extension info comes from the FADT. On others,
* board specific setup provides it as appropriate. Systems where
@@ -740,7 +795,7 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
goto cleanup2;
}
- pr_info("%s: alarms up to one %s%s%s\n",
+ pr_info("%s: alarms up to one %s%s, %zd bytes nvram, %s irqs\n",
cmos_rtc.rtc->dev.bus_id,
is_valid_irq(rtc_irq)
? (cmos_rtc.mon_alrm
@@ -749,6 +804,7 @@ cmos_do_probe(struct device *dev, struct resource *ports, int rtc_irq)
? "month" : "day"))
: "no",
cmos_rtc.century ? ", y3k" : "",
+ nvram.size,
is_hpet_enabled() ? ", hpet irqs" : "");
return 0;
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