Support epoch of 1980 in RTC emulation for MIPS Magnum

On the MIPS Magnum, the time that is held in the RTC's NVRAM should be
relative to midnight on 1980-01-01.  This patch adds an extra parameter
to rtc_init(), allowing different epochs to be used.  For the Magnum,
1980 is specified, and for all other machines, 2000 is specified.

I've not modified the handling of the century byte, as with an epoch of
1980 and a year of 2009, one could argue that it should hold either
0, 1, 19 or 20.  NT 3.50 on MIPS does not read the century byte.

Signed-off-by: Stuart Brady <stuart.brady@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6429 c046a42c-6fe2-441c-8c8c-71466251a162

7 files changed, 20 insertions, 11 deletions

diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index cd57bf376..74d9e1f20 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -60,6 +60,7 @@ struct RTCState {
     uint8_t cmos_data[128];
     uint8_t cmos_index;
     struct tm current_tm;
+    int base_year;
     qemu_irq irq;
     int it_shift;
     /* periodic timer */
@@ -235,12 +236,13 @@ static void rtc_set_time(RTCState *s)
     tm->tm_wday = from_bcd(s, s->cmos_data[RTC_DAY_OF_WEEK]) - 1;
     tm->tm_mday = from_bcd(s, s->cmos_data[RTC_DAY_OF_MONTH]);
     tm->tm_mon = from_bcd(s, s->cmos_data[RTC_MONTH]) - 1;
-    tm->tm_year = from_bcd(s, s->cmos_data[RTC_YEAR]) + 100;
+    tm->tm_year = from_bcd(s, s->cmos_data[RTC_YEAR]) + s->base_year - 1900;
 }
 
 static void rtc_copy_date(RTCState *s)
 {
     const struct tm *tm = &s->current_tm;
+    int year;
 
     s->cmos_data[RTC_SECONDS] = to_bcd(s, tm->tm_sec);
     s->cmos_data[RTC_MINUTES] = to_bcd(s, tm->tm_min);
@@ -256,7 +258,10 @@ static void rtc_copy_date(RTCState *s)
     s->cmos_data[RTC_DAY_OF_WEEK] = to_bcd(s, tm->tm_wday + 1);
     s->cmos_data[RTC_DAY_OF_MONTH] = to_bcd(s, tm->tm_mday);
     s->cmos_data[RTC_MONTH] = to_bcd(s, tm->tm_mon + 1);
-    s->cmos_data[RTC_YEAR] = to_bcd(s, tm->tm_year % 100);
+    year = (tm->tm_year - s->base_year) % 100;
+    if (year < 0)
+        year += 100;
+    s->cmos_data[RTC_YEAR] = to_bcd(s, year);
 }
 
 /* month is between 0 and 11. */
@@ -522,7 +527,7 @@ static int rtc_load_td(QEMUFile *f, void *opaque, int version_id)
 }
 #endif
 
-RTCState *rtc_init(int base, qemu_irq irq)
+RTCState *rtc_init(int base, qemu_irq irq, int base_year)
 {
     RTCState *s;
 
@@ -536,6 +541,7 @@ RTCState *rtc_init(int base, qemu_irq irq)
     s->cmos_data[RTC_REG_C] = 0x00;
     s->cmos_data[RTC_REG_D] = 0x80;
 
+    s->base_year = base_year;
     rtc_set_date_from_host(s);
 
     s->periodic_timer = qemu_new_timer(vm_clock,
@@ -631,7 +637,8 @@ static CPUWriteMemoryFunc *rtc_mm_write[] = {
     &cmos_mm_writel,
 };
 
-RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq)
+RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq,
+                      int base_year)
 {
     RTCState *s;
     int io_memory;
@@ -646,6 +653,7 @@ RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq)
     s->cmos_data[RTC_REG_C] = 0x00;
     s->cmos_data[RTC_REG_D] = 0x80;
 
+    s->base_year = base_year;
     rtc_set_date_from_host(s);
 
     s->periodic_timer = qemu_new_timer(vm_clock,
diff --git a/hw/mips_jazz.c b/hw/mips_jazz.c
index eb4d15bcc..9bdb903ee 100644
--- a/hw/mips_jazz.c
+++ b/hw/mips_jazz.c
@@ -241,7 +241,7 @@ void mips_jazz_init (ram_addr_t ram_size, int vga_ram_size,
     fdctrl_init(rc4030[1], 0, 1, 0x80003000, fds);
 
     /* Real time clock */
-    rtc_init(0x70, i8259[8]);
+    rtc_init(0x70, i8259[8], 1980);
     s_rtc = cpu_register_io_memory(0, rtc_read, rtc_write, env);
     cpu_register_physical_memory(0x80004000, 0x00001000, s_rtc);
 
diff --git a/hw/mips_malta.c b/hw/mips_malta.c
index ba6794770..b7afb2d9a 100644
--- a/hw/mips_malta.c
+++ b/hw/mips_malta.c
@@ -918,7 +918,7 @@ void mips_malta_init (ram_addr_t ram_size, int vga_ram_size,
 
     /* Super I/O */
     i8042_init(i8259[1], i8259[12], 0x60);
-    rtc_state = rtc_init(0x70, i8259[8]);
+    rtc_state = rtc_init(0x70, i8259[8], 2000);
     serial_init(0x3f8, i8259[4], 115200, serial_hds[0]);
     serial_init(0x2f8, i8259[3], 115200, serial_hds[1]);
     if (parallel_hds[0])
diff --git a/hw/mips_r4k.c b/hw/mips_r4k.c
index 1ed123e4e..ab0c110f0 100644
--- a/hw/mips_r4k.c
+++ b/hw/mips_r4k.c
@@ -235,7 +235,7 @@ void mips_r4k_init (ram_addr_t ram_size, int vga_ram_size,
     /* The PIC is attached to the MIPS CPU INT0 pin */
     i8259 = i8259_init(env->irq[2]);
 
-    rtc_state = rtc_init(0x70, i8259[8]);
+    rtc_state = rtc_init(0x70, i8259[8], 2000);
 
     /* Register 64 KB of ISA IO space at 0x14000000 */
     isa_mmio_init(0x14000000, 0x00010000);
diff --git a/hw/pc.c b/hw/pc.c
index dd5fb8f9b..176730e06 100644
--- a/hw/pc.c
+++ b/hw/pc.c
@@ -968,7 +968,7 @@ vga_bios_error:
         }
     }
 
-    rtc_state = rtc_init(0x70, i8259[8]);
+    rtc_state = rtc_init(0x70, i8259[8], 2000);
 
     qemu_register_boot_set(pc_boot_set, rtc_state);
 
diff --git a/hw/pc.h b/hw/pc.h
index 1ba3d9eb9..c67294d0f 100644
--- a/hw/pc.h
+++ b/hw/pc.h
@@ -83,8 +83,9 @@ void i8042_mm_init(qemu_irq kbd_irq, qemu_irq mouse_irq,
 
 typedef struct RTCState RTCState;
 
-RTCState *rtc_init(int base, qemu_irq irq);
-RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq);
+RTCState *rtc_init(int base, qemu_irq irq, int base_year);
+RTCState *rtc_mm_init(target_phys_addr_t base, int it_shift, qemu_irq irq,
+                      int base_year);
 void rtc_set_memory(RTCState *s, int addr, int val);
 void rtc_set_date(RTCState *s, const struct tm *tm);
 void cmos_set_s3_resume(void);
diff --git a/hw/ppc_prep.c b/hw/ppc_prep.c
index 934d520d3..f9d0acc8b 100644
--- a/hw/ppc_prep.c
+++ b/hw/ppc_prep.c
@@ -659,7 +659,7 @@ static void ppc_prep_init (ram_addr_t ram_size, int vga_ram_size,
                  vga_ram_size, 0, 0);
     //    openpic = openpic_init(0x00000000, 0xF0000000, 1);
     //    pit = pit_init(0x40, i8259[0]);
-    rtc_init(0x70, i8259[8]);
+    rtc_init(0x70, i8259[8], 2000);
 
     serial_init(0x3f8, i8259[4], 115200, serial_hds[0]);
     nb_nics1 = nb_nics;