drivers/pc80/mc146818rtc: Assume we always have ALTCENTURY

This patch has a rather twisted history. It was originally split off
from a chromium patch, which moved ALTCENTURY to Kconfig. However,
since we have no user without ALTCENTURY, we've agreed that the best
way to proceed is to eliminate the non-ALTCENTURY case entirely.

The old commit message and identifiers are kept below for reference:

The availability of "ALTCENTURY" is now set through a kconfig
variable so it can be available to the RTC driver without having to have a
specialized interface.

BUG=None
TEST=Built and booted on Link with the event log code modified to use the RTC
interface. Verified that the event times were accurate.
BRANCH=nyan

Original-Change-Id: Ifa807898e583254e57167fd44932ea86627a02ee
Original-Signed-off-by: Gabe Black <gabeblack@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/197795
Original-Reviewed-by: David Hendricks <dhendrix@chromium.org>
Original-Tested-by: Gabe Black <gabeblack@chromium.org>
Original-Commit-Queue: Gabe Black <gabeblack@chromium.org>

This is the second half the following patch.
(cherry picked from commit 9e0fd75142d29afe34f6c6b9ce0099f478ca5a93)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I8e871f31c3d4be7676abf9454ca90808d1ddca03
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Reviewed-on: http://review.coreboot.org/7987
Reviewed-by: Marc Jones <marc.jones@se-eng.com>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins)

src/drivers/pc80/mc146818rtc.c

@@ -32,7 +32,7 @@
 #endif
 
 
-static void cmos_reset_date(u8 has_century)
+static void cmos_reset_date(void)
 {
 	/* Now setup a default date equals to the build date */
 	struct rtc_time time = {
@@ -45,7 +45,7 @@ static void cmos_reset_date(u8 has_century)
 			bcd2bin(coreboot_build_date.year),
 		.wday = bcd2bin(coreboot_build_date.weekday)
 	};
-	rtc_set(&time, has_century);
+	rtc_set(&time);
 }
 
 #if CONFIG_USE_OPTION_TABLE
@@ -123,7 +123,7 @@ void cmos_init(int invalid)
 			cmos_write(0, i);
 #endif
 		if (cmos_invalid)
-			cmos_reset_date(RTC_HAS_NO_ALTCENTURY);
+			cmos_reset_date();
 
 		printk(BIOS_WARNING, "RTC:%s%s%s%s\n",
 			invalid?" Clear requested":"",
@@ -325,12 +325,12 @@ enum cb_err set_option(const char *name, void *value)
  * hurts some OSes. Even if we don't set USE_OPTION_TABLE, we need
  * to make sure the date is valid.
  */
-void cmos_check_update_date(u8 has_century)
+void cmos_check_update_date()
 {
 	u8 year, century;
 
-	/* Note: Need to check if the hardware supports RTC_CLK_ALTCENTURY. */
+	/* Assume hardware always supports RTC_CLK_ALTCENTURY. */
-	century = has_century ? cmos_read(RTC_CLK_ALTCENTURY) : 0;
+	century = cmos_read(RTC_CLK_ALTCENTURY);
 	year = cmos_read(RTC_CLK_YEAR);
 
 	/*
@@ -339,25 +339,23 @@ void cmos_check_update_date(u8 has_century)
 	 * if the date is valid.
 	 */
 	if (century > 0x99 || year > 0x99) /* Invalid date */
-		cmos_reset_date(has_century);
+		cmos_reset_date();
 }
 
-int rtc_set(const struct rtc_time *time, u8 has_century)
+int rtc_set(const struct rtc_time *time){
-{
 	cmos_write(bin2bcd(time->sec), RTC_CLK_SECOND);
 	cmos_write(bin2bcd(time->min), RTC_CLK_MINUTE);
 	cmos_write(bin2bcd(time->hour), RTC_CLK_HOUR);
 	cmos_write(bin2bcd(time->mday), RTC_CLK_DAYOFMONTH);
 	cmos_write(bin2bcd(time->mon), RTC_CLK_MONTH);
 	cmos_write(bin2bcd(time->year % 100), RTC_CLK_YEAR);
-	if (has_century)
+	/* Same assumption as above: We always have RTC_CLK_ALTCENTURY */
-		cmos_write(bin2bcd(time->year / 100),
+	cmos_write(bin2bcd(time->year / 100), RTC_CLK_ALTCENTURY);
-			   RTC_CLK_ALTCENTURY);
 	cmos_write(bin2bcd(time->wday + 1), RTC_CLK_DAYOFWEEK);
 	return 0;
 }
 
-int rtc_get(struct rtc_time *time, u8 has_century)
+int rtc_get(struct rtc_time *time)
 {
 	time->sec = bcd2bin(cmos_read(RTC_CLK_SECOND));
 	time->min = bcd2bin(cmos_read(RTC_CLK_MINUTE));
@@ -365,10 +363,8 @@ int rtc_get(struct rtc_time *time, u8 has_century)
 	time->mday = bcd2bin(cmos_read(RTC_CLK_DAYOFMONTH));
 	time->mon = bcd2bin(cmos_read(RTC_CLK_MONTH));
 	time->year = bcd2bin(cmos_read(RTC_CLK_YEAR));
-	if (has_century)
+	/* Same assumption as above: We always have RTC_CLK_ALTCENTURY */
 	time->year += bcd2bin(cmos_read(RTC_CLK_ALTCENTURY)) * 100;
-	else
-		time->year += 2000;
 	time->wday = bcd2bin(cmos_read(RTC_CLK_DAYOFWEEK)) - 1;
 	return 0;
 }

src/include/pc80/mc146818rtc.h

@@ -94,9 +94,6 @@
 #define RTC_CLK_YEAR		9
 #define RTC_CLK_ALTCENTURY	0x32
 
-#define RTC_HAS_ALTCENTURY	1
-#define RTC_HAS_NO_ALTCENTURY	0
-
 /* On PCs, the checksum is built only over bytes 16..45 */
 #define PC_CKS_RANGE_START	16
 #define PC_CKS_RANGE_END	45
@@ -173,7 +170,7 @@ static inline void cmos_write32(u8 offset, u32 value)
 
 #if !defined(__ROMCC__)
 void cmos_init(int invalid);
-void cmos_check_update_date(u8 has_century);
+void cmos_check_update_date(void);
 #if CONFIG_USE_OPTION_TABLE
 enum cb_err set_option(const char *name, void *val);
 enum cb_err get_option(void *dest, const char *name);

src/include/rtc.h

@@ -31,7 +31,7 @@ struct rtc_time
 	int wday;
 };
 
-int rtc_set(const struct rtc_time *time, u8 has_century);
+int rtc_set(const struct rtc_time *time);
-int rtc_get(struct rtc_time *time, u8 has_century);
+int rtc_get(struct rtc_time *time);
 
 #endif /* _RTC_H_ */

src/southbridge/amd/agesa/hudson/lpc.c

@@ -71,7 +71,7 @@ static void lpc_init(device_t dev)
 	byte |= 1 << 0 | 1 << 3;
 	pci_write_config8(dev, 0xBB, byte);
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 
 	/* Initialize the real time clock.
 	 * The 0 argument tells cmos_init not to

src/southbridge/amd/cimx/sb700/late.c

@@ -81,7 +81,7 @@ static void lpc_init(device_t dev)
 {
 	printk(BIOS_DEBUG, "SB700 - Late.c - lpc_init - Start.\n");
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 
 	/* Initialize the real time clock.
 	 * The 0 argument tells cmos_init not to

src/southbridge/amd/cimx/sb800/late.c

@@ -132,7 +132,7 @@ static void lpc_init(device_t dev)
 {
 	printk(BIOS_DEBUG, "SB800 - Late.c - lpc_init - Start.\n");
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 
 	/* Initialize the real time clock.
 	 * The 0 argument tells cmos_init not to

src/southbridge/amd/cimx/sb900/late.c

@@ -103,7 +103,7 @@ static void lpc_init(device_t dev)
 	printk(BIOS_DEBUG, "SB900 - Late.c - lpc_init - Start.\n");
 	/* SB Configure HPET base and enable bit */
 //-	hpetInit(sb_config, &(sb_config->BuildParameters));
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 
 	/* Initialize the real time clock.
 	 * The 0 argument tells cmos_init not to

src/southbridge/amd/pi/avalon/lpc.c

@@ -70,7 +70,7 @@ static void lpc_init(device_t dev)
 	byte |= 1 << 0 | 1 << 3;
 	pci_write_config8(dev, 0xBB, byte);
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 
 	/* Initialize the real time clock.
 	 * The 0 argument tells cmos_init not to

src/southbridge/amd/sb600/lpc.c

@@ -63,7 +63,7 @@ static void lpc_init(device_t dev)
 	byte &= ~(1 << 1);
 	pci_write_config8(dev, 0x78, byte);
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 }
 
 static void sb600_lpc_read_resources(device_t dev)

src/southbridge/amd/sb700/lpc.c

@@ -90,7 +90,7 @@ static void lpc_init(device_t dev)
 	}
 #endif
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 }
 
 void backup_top_of_ram(uint64_t ramtop)

src/southbridge/amd/sb800/lpc.c

@@ -74,7 +74,7 @@ static void lpc_init(device_t dev)
 	byte |= 1 << 0 | 1 << 3;
 	pci_write_config8(dev, 0xBB, byte);
 
-	cmos_check_update_date(RTC_HAS_ALTCENTURY);
+	cmos_check_update_date();
 }
 
 static void sb800_lpc_read_resources(device_t dev)