[U-Boot] [PATCH] ARM: S3C64XX: fix timer broken by relocation
Albert ARIBAUD
albert.aribaud at free.fr
Fri Nov 12 20:25:09 CET 2010
Le 12/11/2010 19:18, Darius Augulis a écrit :
> Dear Minkyu Kang,
>
> On 11/12/2010 05:10 AM, Minkyu Kang wrote:
>> Dear Darius Augulis,
>>
>> On 2 November 2010 05:49, Darius Augulis<augulis.darius at gmail.com> wrote:
>>> S3C64XX timer uses static variables which
>>> are initialized before relocation and used after it.
>>> Move them to global data structure.
>>>
>>> Signed-off-by: Darius Augulis<augulis.darius at gmail.com>
>>> ---
>>> arch/arm/cpu/arm1176/s3c64xx/timer.c | 36 ++++++++++++++--------------------
>>> arch/arm/include/asm/global_data.h | 6 ++++++
>>> 2 files changed, 21 insertions(+), 21 deletions(-)
>>>
>>> diff --git a/arch/arm/cpu/arm1176/s3c64xx/timer.c b/arch/arm/cpu/arm1176/s3c64xx/timer.c
>>> index 9768319..4e420cb 100644
>>> --- a/arch/arm/cpu/arm1176/s3c64xx/timer.c
>>> +++ b/arch/arm/cpu/arm1176/s3c64xx/timer.c
>>> @@ -43,7 +43,7 @@
>>> #include<asm/arch/s3c6400.h>
>>> #include<div64.h>
>>>
>>> -static ulong timer_load_val;
>>> +DECLARE_GLOBAL_DATA_PTR;
>>>
>>> #define PRESCALER 167
>>>
>>> @@ -60,12 +60,6 @@ static inline ulong read_timer(void)
>>> return timers->TCNTO4;
>>> }
>>>
>>> -/* Internal tick units */
>>> -/* Last decremneter snapshot */
>>> -static unsigned long lastdec;
>>> -/* Monotonic incrementing timer */
>>> -static unsigned long long timestamp;
>>> -
>>> int timer_init(void)
>>> {
>>> s3c64xx_timers *const timers = s3c64xx_get_base_timers();
>>> @@ -83,20 +77,20 @@ int timer_init(void)
>>> * the prescaler automatically for other PCLK frequencies.
>>> */
>>> timers->TCFG0 = PRESCALER<< 8;
>>> - if (timer_load_val == 0) {
>>> - timer_load_val = get_PCLK() / PRESCALER * (100 / 4); /* 100s */
>>> + if (gd->timer_load_val == 0) {
>>> + gd->timer_load_val = get_PCLK() / PRESCALER * (100 / 4); /* 100s */
>>> timers->TCFG1 = (timers->TCFG1& ~0xf0000) | 0x20000;
>>> }
>>>
>>> /* load value for 10 ms timeout */
>>> - lastdec = timers->TCNTB4 = timer_load_val;
>>> + gd->lastdec = timers->TCNTB4 = gd->timer_load_val;
>>> /* auto load, manual update of Timer 4 */
>>> timers->TCON = (timers->TCON& ~0x00700000) | TCON_4_AUTO |
>>> TCON_4_UPDATE;
>>>
>>> /* auto load, start Timer 4 */
>>> timers->TCON = (timers->TCON& ~0x00700000) | TCON_4_AUTO | COUNT_4_ON;
>>> - timestamp = 0;
>>> + gd->timestamp = 0;
>>>
>>> return 0;
>>> }
>>> @@ -113,16 +107,16 @@ unsigned long long get_ticks(void)
>>> {
>>> ulong now = read_timer();
>>>
>>> - if (lastdec>= now) {
>>> + if (gd->lastdec>= now) {
>>> /* normal mode */
>>> - timestamp += lastdec - now;
>>> + gd->timestamp += gd->lastdec - now;
>>> } else {
>>> /* we have an overflow ... */
>>> - timestamp += lastdec + timer_load_val - now;
>>> + gd->timestamp += gd->lastdec + gd->timer_load_val - now;
>>> }
>>> - lastdec = now;
>>> + gd->lastdec = now;
>>>
>>> - return timestamp;
>>> + return gd->timestamp;
>>> }
>>>
>>> /*
>>> @@ -132,14 +126,14 @@ unsigned long long get_ticks(void)
>>> ulong get_tbclk(void)
>>> {
>>> /* We overrun in 100s */
>>> - return (ulong)(timer_load_val / 100);
>>> + return (ulong)(gd->timer_load_val / 100);
>>> }
>>>
>>> void reset_timer_masked(void)
>>> {
>>> /* reset time */
>>> - lastdec = read_timer();
>>> - timestamp = 0;
>>> + gd->lastdec = read_timer();
>>> + gd->timestamp = 0;
>>> }
>>>
>>> void reset_timer(void)
>>> @@ -150,7 +144,7 @@ void reset_timer(void)
>>> ulong get_timer_masked(void)
>>> {
>>> unsigned long long res = get_ticks();
>>> - do_div (res, (timer_load_val / (100 * CONFIG_SYS_HZ)));
>>> + do_div (res, (gd->timer_load_val / (100 * CONFIG_SYS_HZ)));
>>> return res;
>>> }
>>>
>>> @@ -161,7 +155,7 @@ ulong get_timer(ulong base)
>>>
>>> void set_timer(ulong t)
>>> {
>>> - timestamp = t * (timer_load_val / (100 * CONFIG_SYS_HZ));
>>> + gd->timestamp = t * (gd->timer_load_val / (100 * CONFIG_SYS_HZ));
>>> }
>>>
>>> void __udelay(unsigned long usec)
>>> diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
>>> index ada3fbb..69fb7b6 100644
>>> --- a/arch/arm/include/asm/global_data.h
>>> +++ b/arch/arm/include/asm/global_data.h
>>> @@ -61,6 +61,12 @@ typedef struct global_data {
>>> unsigned long tbu;
>>> unsigned long long timer_reset_value;
>>> #endif
>>> +#ifdef CONFIG_S3C64XX
>>> + /* "static data" needed by s3c64xx's timer.c */
>>> + unsigned long timer_load_val;
>>> + unsigned long lastdec;
>>> + unsigned long long timestamp;
>>> +#endif
>>> unsigned long relocaddr; /* Start address of U-Boot in RAM */
>>> phys_size_t ram_size; /* RAM size */
>>> unsigned long mon_len; /* monitor len */
>>>
>>
>> I think it's not good way.
>> We just need to fix the timer_init function.
>> Because we can use the static variables after relocation.
>
> at least it's working one and not new - at91 does it the same way. But
> please send your patch, if it's better solution then I will be happy to
> have it instead of mine.
> Please remember, that these static variables are used in almost all
> timer functions and timer is initialised before relocation. So you
> should not change them during relocation to have correct ones after it.
> Looking forward for your solution.
>
> regards,
> Darius.
FWIW, there already is a solution based on statics and post-relocation
initialization for orion5x. The principle there is that the timer is not
used before calling board_init_r, so we don't need initializing
timestamp before relocation.
I'm not saying that's how it should be done, mind; it's just how I did
it then.
Amicalement,
--
Albert.
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