Subject: [PATCH v2] ARM: Davinci: Fix DM644x timer overflow handling and cleanup

Fix ARM based DaVinci DM644x timer overflow handling and cleanup timer code.

Acked-by: Pieter Voorthuijsen pieter.voorthuijsen@Prodrive.nl

Please apply, tested on DaVinci DVEVM and other board, working OK!

Changes:

• Remove *_masked() functions as noted by Wolfgang

• Adapt register naming to recent TI spec (sprue26, March 2007)

• Fix reset_timer() handling

• As reported by Pieter [1] the overflow fix introduced a

delay of factor 16 (e.g 2 seconds became 32). While the overflow fix is basically okay, it missed to divide udelay by 16, too. Fix this.

[1] http://article.gmane.org/gmane.comp.boot-loaders.u-boot/38179

• Remove software division of timer count value (DIV(x)

macro) and do it in hardware (TIM_CLK_DIV).

Many thanks to Troy Kisky troy.kisky@boundarydevices.com and Pieter Voorthuijsen pieter.voorthuijsen@Prodrive.nl for the hints & testing!

Patch is compile tested with davinci_dvevm & sonata & schmoogie configuration and tested by Pieter on DaVinci EVM hardware.

Signed-off-by: Dirk Behme dirk.behme@gmail.com

---

This patch completely replaces first version of this patch

http://article.gmane.org/gmane.comp.boot-loaders.u-boot/38312/

Changes:

• Incorporate findings from testing on real HW: Don't change

CFG_HZ_CLOCK in config files, instead divide in udelay() and get_timer() correctly.

Thanks to Pieter!

Index: uboot_davinci/cpu/arm926ejs/davinci/timer.c

--- uboot_davinci.orig/cpu/arm926ejs/davinci/timer.c +++ uboot_davinci/cpu/arm926ejs/davinci/timer.c @@ -42,9 +42,9 @@

typedef volatile struct { u_int32_t pid12;

• u_int32_t emumgt_clksped;
• u_int32_t gpint_en;
• u_int32_t gpdir_dat;

• u_int32_t emumgt;
• u_int32_t na1;
• u_int32_t na2; u_int32_t tim12; u_int32_t tim34; u_int32_t prd12;

@@ -52,21 +52,12 @@ typedef volatile struct { u_int32_t tcr; u_int32_t tgcr; u_int32_t wdtcr;

• u_int32_t tlgc;
• u_int32_t tlmr;

} davinci_timer;

davinci_timer *timer = (davinci_timer *)CFG_TIMERBASE;

#define TIMER_LOAD_VAL (CFG_HZ_CLOCK / CFG_HZ) -#define READ_TIMER timer->tim34

-/*

• • Timer runs with CFG_HZ_CLOCK, currently 27MHz. To avoid wrap
• • around of timestamp already after min ~159s, divide it,

e.g. by 16.

• • timestamp will then wrap around all min ~42min
• */

-#define DIV(x) ((x) >> 4) +#define TIM_CLK_DIV 16

static ulong timestamp; static ulong lastinc; @@ -76,63 +67,51 @@ int timer_init(void) /* We are using timer34 in unchained 32-bit mode, full speed */ timer->tcr = 0x0; timer->tgcr = 0x0;

• timer->tgcr = 0x06;

• timer->tgcr = 0x06 | ((TIM_CLK_DIV - 1) << 8); timer->tim34 = 0x0; timer->prd34 = TIMER_LOAD_VAL; lastinc = 0;

• timer->tcr = 0x80 << 16; timestamp = 0;

• timer->tcr = 2 << 22;

  return(0);

}

void reset_timer(void) {

• reset_timer_masked();

-}

-ulong get_timer(ulong base) -{

• return(get_timer_masked() - base);

-}

-void set_timer(ulong t) -{

• timestamp = t;

-}

-void udelay(unsigned long usec) -{

• udelay_masked(usec);

-}

-void reset_timer_masked(void) -{

• lastinc = DIV(READ_TIMER);

• timer->tcr = 0x0;
• timer->tim34 = 0;
• lastinc = 0; timestamp = 0;
• timer->tcr = 2 << 22;

}

-ulong get_timer_raw(void) +static ulong get_timer_raw(void) {

• ulong now = DIV(READ_TIMER);

• ulong now = timer->tim34;

  if (now >= lastinc) { /* normal mode */ timestamp += now - lastinc; } else { /* overflow ... */

• timestamp += now + DIV(TIMER_LOAD_VAL) - lastinc;
  

• timestamp += now + TIMER_LOAD_VAL - lastinc;
  

  } lastinc = now; return timestamp;

}

-ulong get_timer_masked(void) +ulong get_timer(ulong base) +{

• return((get_timer_raw() / (TIMER_LOAD_VAL /

TIM_CLK_DIV)) - base); }

+void set_timer(ulong t) {

• return(get_timer_raw() / DIV(TIMER_LOAD_VAL));

• timestamp = t;

}

-void udelay_masked(unsigned long usec) +void udelay(unsigned long usec) { ulong tmo; ulong endtime; @@ -140,7 +119,7 @@ void udelay_masked(unsigned long usec)

tmo = CFG_HZ_CLOCK / 1000; tmo *= usec;

• tmo /= 1000;

• tmo /= (1000 * TIM_CLK_DIV);

  endtime = get_timer_raw() + tmo;

@@ -165,8 +144,5 @@ unsigned long long get_ticks(void) */ ulong get_tbclk(void) {

• ulong tbclk;
• tbclk = CFG_HZ;
• return(tbclk);

• return CFG_HZ;

}