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, 35 insertions, 0 deletions

diff --git a/drivers/macintosh/via-cuda.c b/drivers/macintosh/via-cuda.c
index 98dd702eb867..bbec6ac0a966 100644
--- a/drivers/macintosh/via-cuda.c
+++ b/drivers/macintosh/via-cuda.c
@@ -766,3 +766,38 @@ cuda_input(unsigned char *buf, int nb)
 	               buf, nb, false);
     }
 }
+
+/* Offset between Unix time (1970-based) and Mac time (1904-based) */
+#define RTC_OFFSET	2082844800
+
+time64_t cuda_get_time(void)
+{
+	struct adb_request req;
+	u32 now;
+
+	if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
+		return 0;
+	while (!req.complete)
+		cuda_poll();
+	if (req.reply_len != 7)
+		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
+	now = (req.reply[3] << 24) + (req.reply[4] << 16) +
+	      (req.reply[5] << 8) + req.reply[6];
+	return (time64_t)now - RTC_OFFSET;
+}
+
+int cuda_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 (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
+	                 now >> 24, now >> 16, now >> 8, now) < 0)
+		return -ENXIO;
+	while (!req.complete)
+		cuda_poll();
+	if ((req.reply_len != 3) && (req.reply_len != 7))
+		pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
+	return 0;
+}