macintosh: Use common code to access RTC

Now that the 68k Mac port has adopted the via-pmu driver, the same RTC
code can be shared between m68k and powerpc. Replace duplicated code in
arch/powerpc and arch/m68k with common RTC accessors for Cuda and PMU.

Drop the problematic WARN_ON which was introduced in commit 22db552b50fa
("powerpc/powermac: Fix rtc read/write functions").

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 33 insertions, 0 deletions

diff --git a/drivers/macintosh/via-pmu.c b/drivers/macintosh/via-pmu.c
index d72c450aebe5..60f57e2abf21 100644
--- a/drivers/macintosh/via-pmu.c
+++ b/drivers/macintosh/via-pmu.c
@@ -1737,6 +1737,39 @@ pmu_enable_irled(int on)
 	pmu_wait_complete(&req);
 }
 
+/* Offset between Unix time (1970-based) and Mac time (1904-based) */
+#define RTC_OFFSET	2082844800
+
+time64_t pmu_get_time(void)
+{
+	struct adb_request req;
+	u32 now;
+
+	if (pmu_request(&req, NULL, 1, PMU_READ_RTC) < 0)
+		return 0;
+	pmu_wait_complete(&req);
+	if (req.reply_len != 4)
+		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
+	now = (req.reply[0] << 24) + (req.reply[1] << 16) +
+	      (req.reply[2] << 8) + req.reply[3];
+	return (time64_t)now - RTC_OFFSET;
+}
+
+int pmu_set_rtc_time(struct rtc_time *tm)
+{
+	u32 now;
+	struct adb_request req;
+
+	now = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
+	if (pmu_request(&req, NULL, 5, PMU_SET_RTC,
+	                now >> 24, now >> 16, now >> 8, now) < 0)
+		return -ENXIO;
+	pmu_wait_complete(&req);
+	if (req.reply_len != 0)
+		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
+	return 0;
+}
+
 void
 pmu_restart(void)
 {