iPod Classic: update timer API using 32-bit timers.

Change-Id: I49dab8ae955a339ad0a27402fa21caa411c4ecf6
Reviewed-on: http://gerrit.rockbox.org/1032
Reviewed-by: Marcin Bukat <marcin.bukat@gmail.com>

3 files changed, 69 insertions, 47 deletions

diff --git a/firmware/export/s5l8702.h b/firmware/export/s5l8702.h
index 8e1d827f54..a83fe371e0 100644
--- a/firmware/export/s5l8702.h
+++ b/firmware/export/s5l8702.h
@@ -28,8 +28,6 @@
 #define REG16_PTR_T volatile uint16_t *
 #define REG32_PTR_T volatile uint32_t *
 
-#define TIMER_FREQ  54000000
-
 #define CACHEALIGN_BITS (5) /* 2^5 = 32 bytes */
 
 #define DRAM_ORIG 0x08000000
@@ -65,6 +63,34 @@
 
 
 /////TIMER/////
+/* 16/32-bit timers:
+ *
+ * - Timers A..D: 16-bit counter, very similar to 16-bit timers described
+ *   in S5L8700 DS, it seems that the timers C and D are disabled or not
+ *   implemented.
+ *
+ * - Timers E..H: 32-bit counter, they are like 16-bit timers, but the
+ *   interrupt status for all 32-bit timers is located in TSTAT register.
+ *
+ * - Clock source configuration:
+ *
+ *   TCON[10:8] (Tx_CS)     TCON[6]=0           TCON[6]=1
+ *   ------------------     ---------           ---------
+ *   000                    PCLK / 2            ECLK / 2
+ *   001                    PCLK / 4            ECLK / 4
+ *   010                    PCLK / 16           ECLK / 16
+ *   011                    PCLK / 64           ECLK / 64
+ *   10x (timers E..H)      PCLK                ECLK
+ *   10x (timers A..D)      Ext. Clock 0        Ext. Clock 0
+ *   11x                    Ext. Clock 1        Ext. Clock 1
+ *
+ *   On Classic:
+ *   - Ext. Clock 0: not connected or disabled
+ *   - Ext. Clock 1: 32768 Hz, external OSC1?, PMU?
+ *   - ECLK: 12 MHz, external OSC0?
+ */
+#define TIMER_FREQ  12000000    /* ECLK */
+
 #define TACON        (*((uint32_t volatile*)(0x3C700000)))
 #define TACMD        (*((uint32_t volatile*)(0x3C700004)))
 #define TADATA0      (*((uint32_t volatile*)(0x3C700008)))
@@ -113,6 +139,7 @@
 #define THDATA1      (*((uint32_t volatile*)(0x3C70010C)))
 #define THPRE        (*((uint32_t volatile*)(0x3C700110)))
 #define THCNT        (*((uint32_t volatile*)(0x3C700114)))
+#define TSTAT        (*((uint32_t volatile*)(0x3C700118)))
 #define USEC_TIMER   TECNT
 
 
@@ -816,6 +843,7 @@ struct dma_lli
 
 
 /////INTERRUPTS/////
+#define IRQ_TIMER32 7
 #define IRQ_TIMER 8
 #define IRQ_USB_FUNC 19
 #define IRQ_DMAC(d) 16 + d
diff --git a/firmware/target/arm/s5l8702/system-s5l8702.c b/firmware/target/arm/s5l8702/system-s5l8702.c
index c3f20c506b..09aff3d84e 100644
--- a/firmware/target/arm/s5l8702/system-s5l8702.c
+++ b/firmware/target/arm/s5l8702/system-s5l8702.c
@@ -39,15 +39,14 @@ default_interrupt(INT_IRQ3);
 default_interrupt(INT_IRQ4);
 default_interrupt(INT_IRQ5);
 default_interrupt(INT_IRQ6);
-default_interrupt(INT_IRQ7);
-default_interrupt(INT_TIMERA);
-default_interrupt(INT_TIMERB);
-default_interrupt(INT_TIMERC);
-default_interrupt(INT_TIMERD);
-default_interrupt(INT_TIMERE);
+default_interrupt(INT_TIMERE);  /* IRQ7: 32-bit timers */
 default_interrupt(INT_TIMERF);
 default_interrupt(INT_TIMERG);
 default_interrupt(INT_TIMERH);
+default_interrupt(INT_TIMERA);  /* IRQ8: 16-bit timers */
+default_interrupt(INT_TIMERB);
+default_interrupt(INT_TIMERC);
+default_interrupt(INT_TIMERD);
 default_interrupt(INT_IRQ9);
 default_interrupt(INT_IRQ10);
 default_interrupt(INT_IRQ11);
@@ -129,9 +128,16 @@ void INT_TIMER()
     if (TBCON & (TBCON >> 4) & 0x7000) INT_TIMERB();
     if (TCCON & (TCCON >> 4) & 0x7000) INT_TIMERC();
     if (TDCON & (TDCON >> 4) & 0x7000) INT_TIMERD();
-    if (TFCON & (TFCON >> 4) & 0x7000) INT_TIMERF();
-    if (TGCON & (TGCON >> 4) & 0x7000) INT_TIMERG();
-    if (THCON & (THCON >> 4) & 0x7000) INT_TIMERH();
+}
+
+void INT_TIMER32(void) ICODE_ATTR;
+void INT_TIMER32()
+{
+    uint32_t tstat = TSTAT;
+    /*if ((TECON >> 12) & 0x7 & (tstat >> 24)) INT_TIMERE();*/
+    if ((TFCON >> 12) & 0x7 & (tstat >> 16)) INT_TIMERF();
+    if ((TGCON >> 12) & 0x7 & (tstat >> 8)) INT_TIMERG();
+    if ((THCON >> 12) & 0x7 & tstat) INT_TIMERH();
 }
 
 void INT_DMAC0(void) ICODE_ATTR;
@@ -164,7 +170,7 @@ void INT_DMAC1()
 
 static void (* const irqvector[])(void) =
 {
-    INT_IRQ0,INT_IRQ1,INT_IRQ2,INT_IRQ3,INT_IRQ4,INT_IRQ5,INT_IRQ6,INT_IRQ7,
+    INT_IRQ0,INT_IRQ1,INT_IRQ2,INT_IRQ3,INT_IRQ4,INT_IRQ5,INT_IRQ6,INT_TIMER32,
     INT_TIMER,INT_IRQ9,INT_IRQ10,INT_IRQ11,INT_IRQ12,INT_IRQ13,INT_IRQ14,INT_IRQ15,
     INT_DMAC0,INT_DMAC1,INT_IRQ18,INT_USB_FUNC,INT_IRQ20,INT_IRQ21,INT_IRQ22,INT_WHEEL,
     INT_IRQ24,INT_IRQ25,INT_IRQ26,INT_IRQ27,INT_IRQ28,INT_ATA,INT_IRQ30,INT_IRQ31,
@@ -220,6 +226,7 @@ void system_init(void)
     VIC0INTENABLE = 1 << IRQ_WHEEL;
     VIC0INTENABLE = 1 << IRQ_ATA;
     VIC1INTENABLE = 1 << (IRQ_MMC - 32);
+    VIC0INTENABLE = 1 << IRQ_TIMER32;
 }
 
 void system_reboot(void)
diff --git a/firmware/target/arm/s5l8702/timer-s5l8702.c b/firmware/target/arm/s5l8702/timer-s5l8702.c
index 61d4d590e4..7c69ab123a 100644
--- a/firmware/target/arm/s5l8702/timer-s5l8702.c
+++ b/firmware/target/arm/s5l8702/timer-s5l8702.c
@@ -26,13 +26,11 @@
 #include "system.h"
 #include "timer.h"
 
-//TODO: This needs calibration once we figure out the clocking
-
-void INT_TIMERC(void)
+void INT_TIMERF(void)
 {
     /* clear interrupt */
-    TCCON = TCCON;
-    
+    TSTAT = (0x07 << 16);
+
     if (pfn_timer != NULL) {
         pfn_timer();
     }
@@ -40,12 +38,8 @@ void INT_TIMERC(void)
 
 bool timer_set(long cycles, bool start)
 {
-    static const int cs_table[] = {1, 2, 4, 6};
-    int prescale, cs;
-    long count;
-
-    /* stop and clear timer */
-    TCCMD = (1 << 1);   /* TD_CLR */
+    /* stop timer */
+    TFCMD = (0 << 0);       /* TF_ENABLE */
 
     /* optionally unregister any previously registered timer user */
     if (start) {
@@ -55,40 +49,33 @@ bool timer_set(long cycles, bool start)
         }
     }
 
-    /* scale the count down with the clock select */
-    for (cs = 0; cs < 4; cs++) {
-        count = cycles >> cs_table[cs];
-        if ((count < 65536) || (cs == 3)) {
-            break;
-        }
-    }
-    
-    /* scale the count down with the prescaler */
-    prescale = 1;
-    while (count >= 65536) {
-        count >>= 1;
-        prescale <<= 1;
-    }
+    /* There is an odd behaviour when the 32-bit timers are launched
+       for the first time, the interrupt status bits are set and an
+       unexpected interrupt is generated if they are enabled. A way to
+       workaround this is to write the data registers before clearing
+       the counter. */
+    TFDATA0 = cycles;
+    TFCMD = (1 << 1);       /* TF_CLR */
 
     /* configure timer */
-    TCCON = (1 << 12) |     /* TD_INT0_EN */
-            (cs << 8) |     /* TS_CS */
-            (0 << 4);       /* TD_MODE_SEL, 0 = interval mode */
-    TCPRE = prescale - 1;
-    TCDATA0 = count;
-    TCCMD = (1 << 0);       /* TD_ENABLE */
-    
+    TFCON = (1 << 12) |     /* TF_INT0_EN */
+            (4 << 8) |      /* TF_CS, 4 = ECLK / 1 */
+            (1 << 6) |      /* use ECLK (12MHz) */
+            (0 << 4);       /* TF_MODE_SEL, 0 = interval mode */
+    TFPRE = 0;              /* no prescaler */
+
+    TFCMD = (1 << 0);       /* TF_ENABLE */
+
     return true;
 }
 
 bool timer_start(void)
 {
-    TCCMD = (1 << 0);       /* TD_ENABLE */
+    TFCMD = (1 << 0);       /* TF_ENABLE */
     return true;
 }
 
 void timer_stop(void)
 {
-    TCCMD = (0 << 0);       /* TD_ENABLE */
+    TFCMD = (0 << 0);       /* TF_ENABLE */
 }
-