Changeset 4a238002 in rtems for c/src/lib/libcpu/sh/sh7032/clock

Timestamp:

11/18/99 21:22:58 (23 years ago)

Author:

Joel Sherrill <joel.sherrill@…>

Branches:

4.10, 4.11, 4.8, 4.9, 5, master

Children:

97c465c

Parents:

5503d75

Message:

Patch from "John M. Mills" <jmills@…> with subsequent cleanup from
Ralf Corsepius <corsepiu@…> that adds initial Hitachi SH-2
support to RTEMS. Ralf's comments are:

Changes:
------

1. SH-Port:

• Many files renamed.
• CONSOLE_DEVNAME and MHZ defines removed from libcpu.
• console.c moved to libbsp/sh/shared, build in libbsp/sh/<BSP>/console applying VPATH.
• CONSOLE_DEVNAME made BSP-specific, replacement is defined in bsp.h
• MHZ define replaced with HZ (extendent resolution) in custom/*.cfg
• -DHZ=HZ used in bspstart.c, only
• Makefile variable HZ used in bsp-dependent directories only.

2. SH1-Port

• clock-driver rewritten to provide better resolution for odd CPU frequencies. This driver is only partially tested on hardware, ie. sightly experimental, but I don't expect severe problems with it.
• Polling SCI-driver added. This driver is experimental and completly untested yet. Therefore it is not yet used for the console (/dev/console is still pointing to /dev/null, cf. gensh1/bsp.h).
• minor changes to the timer driver
• SH1 specific delay()/CPU_delay() now is implemented as a function

3. SH2-Port

• Merged
• IMO, the code is still in its infancy. Therefore I have interspersed comments (FIXME) it for items which I think John should look after.
• sci and console drivers partially rewritten and extended (John, I hope you don't mind).
• Copyright notices are not yet adapted

Location:

c/src/lib/libcpu/sh/sh7032/clock

Files:

• Makefile.in (modified) (1 diff)
• ckinit.c (modified) (7 diffs)

c/src/lib/libcpu/sh/sh7032/clock/Makefile.in

@@ -41 +41 @@
 
 DEFINES +=
-CPPFLAGS += -DMHZ=$(MHZ)
+CPPFLAGS +=
 CFLAGS += $(CFLAGS_OS_V)
 

c/src/lib/libcpu/sh/sh7032/clock/ckinit.c

@@ -30 +30 @@
 #include <rtems/score/sh_io.h>
 #include <rtems/score/sh.h>
-#include <rtems/score/cpu_isps.h>
-#include <rtems/score/iosh7030.h>
-
-#define _ITU_COUNTER0_MICROSECOND (MHZ/4)
+#include <rtems/score/ispsh7032.h>
+#include <rtems/score/iosh7032.h>
 
 #ifndef CLOCKPRIO
@@ -39 +37 @@
 #endif
 
+#define I_CLK_PHI_1     0
+#define I_CLK_PHI_2     1
+#define I_CLK_PHI_4     2
+#define I_CLK_PHI_8     3
+
+/* 
+ * Set I_CLK_PHI to one of the I_CLK_PHI_X values from above to choose
+ * a PHI/X clock rate.
+ */
+ 
+#define I_CLK_PHI       I_CLK_PHI_4
+#define CLOCK_SCALE     (1<<I_CLK_PHI)
+
 #define ITU0_STARTMASK  0xfe
 #define ITU0_SYNCMASK   0xfe
 #define ITU0_MODEMASK   0xfe
-#define ITU0_TCRMASK    0x22
+#define ITU0_TCRMASK    (0x20 | I_CLK_PHI)
 #define ITU_STAT_MASK   0xf8
 #define ITU0_IRQMASK    0xfe
@@ -50 +61 @@
 
 /*
+ * clicks_per_tick := clicks_per_sec * usec_per_tick
+ *
+ * This is a very expensive function ;-)
+ * 
+ * Below are two variants:
+ * 1. A variant applying integer arithmetics, only.
+ * 2. A variant applying floating point arithmetics
+ *
+ * The floating point variant pulls in the fmath routines when linking, 
+ * resulting in slightly larger executables for applications that do not
+ * apply fmath otherwise. However, the imath variant is significantly slower
+ * than the fmath variant and more complex.
+ *
+ * Assuming that most applications will not use fmath, but are critical
+ * in memory size constraints, we apply the integer variant.
+ *
+ * To the sake of simplicity, we might abandon one of both variants in
+ * future.
+ */
+static unsigned int sh_clicks_per_tick( 
+  unsigned int clicks_per_sec,
+  unsigned int usec_per_tick )
+{
+#if 1
+  unsigned int clicks_per_tick = 0 ;
+  
+  unsigned int b = clicks_per_sec ;
+  unsigned int c = 1000000 ;
+  unsigned int d = 1 ;
+  unsigned int a = ( ( b / c ) * usec_per_tick ) / d;
+
+  clicks_per_tick += a ;
+
+  while ( ( b %= c ) > 0 )
+  {
+    c /= 10 ;
+    d *= 10 ;
+    a = ( ( b / c ) * usec_per_tick ) / d ;
+    clicks_per_tick += a ;
+  } 
+  return clicks_per_tick ;
+#else
+  double fclicks_per_tick = 
+    ((double) clicks_per_sec * (double) usec_per_tick) / 1000000.0 ;
+  return (unsigned32) fclicks_per_tick ;
+#endif
+}
+
+/*
  *  The interrupt vector number associated with the clock tick device
  *  driver.
@@ -101 +161 @@
    * bump the number of clock driver ticks since initialization
    *
-
    * determine if it is time to announce the passing of tick as configured
    * to RTEMS through the rtems_clock_tick directive
@@ -138 +197 @@
 {
   unsigned8 temp8 = 0;
+  unsigned32 microseconds_per_tick ;
+  unsigned32 cclicks_per_tick ;
+  unsigned16 Clock_limit ;
   
   /*
@@ -144 +206 @@
 
   Clock_driver_ticks = 0;
-  Clock_isrs_const = rtems_configuration_get_microseconds_per_tick() / 10000;
+    
+  if ( rtems_configuration_get_microseconds_per_tick() != 0 )
+    microseconds_per_tick = rtems_configuration_get_microseconds_per_tick() ;
+  else
+    microseconds_per_tick = 10000 ; /* 10000 us */
+
+  /* clock clicks per tick */
+  cclicks_per_tick = 
+    sh_clicks_per_tick(
+      rtems_cpu_configuration_get_clicks_per_second() / CLOCK_SCALE,
+      microseconds_per_tick );
+
+  Clock_isrs_const = cclicks_per_tick >> 16 ;
+  if ( ( cclicks_per_tick | 0xffff ) > 0 ) 
+    Clock_isrs_const++ ;
+  Clock_limit = cclicks_per_tick / Clock_isrs_const ;
   Clock_isrs = Clock_isrs_const;
 
@@ -192 +269 @@
 
     /* set counter limits */
-    write16( _ITU_COUNTER0_MICROSECOND * rtems_configuration_get_microseconds_per_tick(),
-             ITU_GRA0);
+    write16( Clock_limit, ITU_GRA0);
    
     /* start counter */