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Thu, 28 Mar 2013 23:12:39 +0900 (KST) X-AuditID: cbfee68d-b7f786d000005188-19-51544fd71c74 Received: from epmmp2 ( [203.254.227.17]) by epcpsbgm2.samsung.com (EPCPMTA) with SMTP id 7F.A8.13494.7DF44515; Thu, 28 Mar 2013 23:12:39 +0900 (KST) Received: from chrome-ubuntu.sisodomain.com ([107.108.73.106]) by mmp2.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MKD00MY2JGUVB00@mmp2.samsung.com>; Thu, 28 Mar 2013 23:12:39 +0900 (KST) From: Akshay Saraswat To: u-boot@lists.denx.de, mk7.kang@samsung.com Date: Thu, 28 Mar 2013 10:32:16 -0400 Message-id: <1364481144-17495-3-git-send-email-akshay.s@samsung.com> X-Mailer: git-send-email 1.8.0 In-reply-to: <1364481144-17495-1-git-send-email-akshay.s@samsung.com> References: <1364481144-17495-1-git-send-email-akshay.s@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFnrGLMWRmVeSWpSXmKPExsWyRsSkRve6f0igwaTtohYdR1oYLVYd3sBu MfXBOUaLb1u2MVq83dvJ7sDqMbvhIovHzll32T3O3tnB6NG3ZRVjAEsUl01Kak5mWWqRvl0C V8aaGZ2MBfs1KlqeNLA0MM5U6GLk5JAQMJE4eeIOM4QtJnHh3nq2LkYuDiGBpYwS+6bOZYEp Wn6zgxEiMZ1R4s2iRnYIp5dJ4uri50wgVWwCOhLbl3xnB7FFBPQk5k16xwZiMws4SnTd+QPU zcEhLOAm8f+GDUiYRUBVovfnGrBWXgEXiQdPT7JDLJOT+LDnETtIOaeAq8TfNaIgYSGgksX7 W6AO7WaXePjSEGKMgMS3yYdYQMolBGQlNh2AKpGUOLjiBssERuEFjAyrGEVTC5ILipPSiwz1 ihNzi0vz0vWS83M3MQLD+PS/Z707GG8fsD7EmAw0biKzlGhyPjAO8kriDY3NjCxMTUyNjcwt zUgTVhLnVWuxDhQSSE8sSc1OTS1ILYovKs1JLT7EyMTBKdXA2HwpzNjui0H0k+eTqgxCYu5b KfR7X7jMtmdKBs+OxzXuhVESpVwnmEJ2vH/je/lQq8UpWWuv5cte885cOvPJ5Vn+Up6mH/OC xQL5197d/2xZ6LL7zp0Rdn2CNWHs5zPOuj+78rBlrfSayVvMLRu22jF9TjGUFa2OkFNkKrjt L15/KX8jw9IPSizFGYmGWsxFxYkA2YDeTXkCAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrCIsWRmVeSWpSXmKPExsVy+t9jQd3r/iGBBnefcll0HGlhtFh1eAO7 xdQH5xgtvm3Zxmjxdm8nuwOrx+yGiyweO2fdZfc4e2cHo0ffllWMASxRDYw2GamJKalFCql5 yfkpmXnptkrewfHO8aZmBoa6hpYW5koKeYm5qbZKLj4Bum6ZOUCblRTKEnNKgUIBicXFSvp2 mCaEhrjpWsA0Ruj6hgTB9RgZoIGENYwZa2Z0Mhbs16hoedLA0sA4U6GLkZNDQsBEYvnNDkYI W0ziwr31bF2MXBxCAtMZJd4samSHcHqZJK4ufs4EUsUmoCOxfcl3dhBbREBPYt6kd2wgNrOA o0TXnT9Akzg4hAXcJP7fsAEJswioSvT+XAPWyivgIvHg6Ul2iGVyEh/2PGIHKecUcJX4u0YU JCwEVLJ4fwvzBEbeBYwMqxhFUwuSC4qT0nON9IoTc4tL89L1kvNzNzGC4+SZ9A7GVQ0WhxgF OBiVeHgrBIIDhVgTy4orcw8xSnAwK4nwTpYJCRTiTUmsrEotyo8vKs1JLT7EmAx01ERmKdHk fGAM55XEGxqbmJsam1qaWJiYWZImrCTOe7DVOlBIID2xJDU7NbUgtQhmCxMHp1QDo8UKr9kX +bp8ooIDtzreLVk7o6RNJrdL+9DipY/33hOxuvT3Widz4f+L0RVZHFesTbNW1GtEb/Vu7D25 cyXzc2PP73P4ezftqr1784yBzAqmA+H/z6w4bJB99pTccsaemkML7hSqHbVy+HV2kZ7myqeT uy8+ffzz4RWNs38fd4pr/97Uf0yjrFyJpTgj0VCLuag4EQBAzrTc1wIAAA== DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Cc: prashanth.g@samsung.com Subject: [U-Boot] [PATCH 02/11 v3] Exynos: Change get_timer() to work correctly X-BeenThere: u-boot@lists.denx.de X-Mailman-Version: 2.1.11 Precedence: list List-Id: U-Boot discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: u-boot-bounces@lists.denx.de Errors-To: u-boot-bounces@lists.denx.de From: Simon Glass At present get_timer() does not return sane values. It should count up smoothly in milliscond intervals. We can change the PWM to count down at 1MHz, providing a resolution of 1us and a range of about an hour between required get_timer() calls. Test with command "sf probe 1:0; time sf read 40008000 0 1000". Try with different numbers of bytes and see that sane values are obtained Signed-off-by: Simon Glass Signed-off-by: Akshay Saraswat Acked-by: Simon Glass --- Changes since v2: - None. Changes since v1: - Added "Acked-by: Simon Glass". arch/arm/cpu/armv7/s5p-common/pwm.c | 6 ++ arch/arm/cpu/armv7/s5p-common/timer.c | 100 +++++++++++++--------------------- 2 files changed, 44 insertions(+), 62 deletions(-) diff --git a/arch/arm/cpu/armv7/s5p-common/pwm.c b/arch/arm/cpu/armv7/s5p-common/pwm.c index 44d7bc3..3147f59 100644 --- a/arch/arm/cpu/armv7/s5p-common/pwm.c +++ b/arch/arm/cpu/armv7/s5p-common/pwm.c @@ -174,6 +174,12 @@ int pwm_init(int pwm_id, int div, int invert) /* set count value */ offset = pwm_id * 3; + + /* + * TODO(sjg): Use this as a countdown timer for now. We count down + * from the maximum value to 0, then reset. + */ + timer_rate_hz = -1; writel(timer_rate_hz, &pwm->tcntb0 + offset); val = readl(&pwm->tcon) & ~(0xf << TCON_OFFSET(pwm_id)); diff --git a/arch/arm/cpu/armv7/s5p-common/timer.c b/arch/arm/cpu/armv7/s5p-common/timer.c index e78c716..c48a297 100644 --- a/arch/arm/cpu/armv7/s5p-common/timer.c +++ b/arch/arm/cpu/armv7/s5p-common/timer.c @@ -39,13 +39,33 @@ static inline struct s5p_timer *s5p_get_base_timer(void) return (struct s5p_timer *)samsung_get_base_timer(); } +/** + * Read the countdown timer. + * + * This operates at 1MHz and counts downwards. It will wrap about every + * hour (2^32 microseconds). + * + * @return current value of timer + */ +static unsigned long timer_get_us_down(void) +{ + struct s5p_timer *const timer = s5p_get_base_timer(); + + return readl(&timer->tcnto4); +} + int timer_init(void) { /* PWM Timer 4 */ - pwm_init(4, MUX_DIV_2, 0); + pwm_init(4, MUX_DIV_4, 0); pwm_config(4, 0, 0); pwm_enable(4); + /* Use this as the current monotonic time in us */ + gd->arch.timer_reset_value = 0; + + /* Use this as the last timer value we saw */ + gd->arch.lastinc = timer_get_us_down(); reset_timer_masked(); return 0; @@ -56,48 +76,28 @@ int timer_init(void) */ unsigned long get_timer(unsigned long base) { - return get_timer_masked() - base; + ulong now = timer_get_us_down(); + + /* + * Increment the time by the amount elapsed since the last read. + * The timer may have wrapped around, but it makes no difference to + * our arithmetic here. + */ + gd->arch.timer_reset_value += gd->arch.lastinc - now; + gd->arch.lastinc = now; + + /* Divide by 1000 to convert from us to ms */ + return gd->arch.timer_reset_value / 1000 - base; } /* delay x useconds */ void __udelay(unsigned long usec) { - struct s5p_timer *const timer = s5p_get_base_timer(); - unsigned long tmo, tmp, count_value; - - count_value = readl(&timer->tcntb4); - - if (usec >= 1000) { - /* - * if "big" number, spread normalization - * to seconds - * 1. start to normalize for usec to ticks per sec - * 2. find number of "ticks" to wait to achieve target - * 3. finish normalize. - */ - tmo = usec / 1000; - tmo *= (CONFIG_SYS_HZ * count_value); - tmo /= 1000; - } else { - /* else small number, don't kill it prior to HZ multiply */ - tmo = usec * CONFIG_SYS_HZ * count_value; - tmo /= (1000 * 1000); - } - - /* get current timestamp */ - tmp = get_current_tick(); - - /* if setting this fordward will roll time stamp */ - /* reset "advancing" timestamp to 0, set lastinc value */ - /* else, set advancing stamp wake up time */ - if ((tmo + tmp + 1) < tmp) - reset_timer_masked(); - else - tmo += tmp; - - /* loop till event */ - while (get_current_tick() < tmo) - ; /* nop */ + unsigned long count_value; + + count_value = timer_get_us_down(); + while ((int)(count_value - timer_get_us_down()) < (int)usec) + ; } void reset_timer_masked(void) @@ -109,30 +109,6 @@ void reset_timer_masked(void) gd->arch.tbl = 0; } -unsigned long get_timer_masked(void) -{ - struct s5p_timer *const timer = s5p_get_base_timer(); - unsigned long count_value = readl(&timer->tcntb4); - - return get_current_tick() / count_value; -} - -unsigned long get_current_tick(void) -{ - struct s5p_timer *const timer = s5p_get_base_timer(); - unsigned long now = readl(&timer->tcnto4); - unsigned long count_value = readl(&timer->tcntb4); - - if (gd->arch.lastinc >= now) - gd->arch.tbl += gd->arch.lastinc - now; - else - gd->arch.tbl += gd->arch.lastinc + count_value - now; - - gd->arch.lastinc = now; - - return gd->arch.tbl; -} - /* * This function is derived from PowerPC code (read timebase as long long). * On ARM it just returns the timer value.