From patchwork Thu Feb 28 10:59:16 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Akshay Saraswat X-Patchwork-Id: 223866 X-Patchwork-Delegate: promsoft@gmail.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from theia.denx.de (theia.denx.de [85.214.87.163]) by ozlabs.org (Postfix) with ESMTP id 5D9B12C0297 for ; Thu, 28 Feb 2013 21:39:16 +1100 (EST) Received: from localhost (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 7D1EC4A04F; Thu, 28 Feb 2013 11:39:12 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at theia.denx.de Received: from theia.denx.de ([127.0.0.1]) by localhost (theia.denx.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id l0kHwpjepo-z; Thu, 28 Feb 2013 11:39:12 +0100 (CET) Received: from theia.denx.de (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 1B4644A020; Thu, 28 Feb 2013 11:39:06 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by theia.denx.de (Postfix) with ESMTP id 6F6D44A01E for ; 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Thu, 28 Feb 2013 19:38:55 +0900 (KST) X-AuditID: cbfee68f-b7f6a6d000004969-9d-512f33bff23a Received: from epmmp1.local.host ( [203.254.227.16]) by epcpsbgm1.samsung.com (EPCPMTA) with SMTP id FC.A8.03918.FB33F215; Thu, 28 Feb 2013 19:38:55 +0900 (KST) Received: from chrome-ubuntu.sisodomain.com ([107.108.73.106]) by mmp1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTPA id <0MIX001ILEWPCT50@mmp1.samsung.com> for u-boot@lists.denx.de; Thu, 28 Feb 2013 19:38:55 +0900 (KST) From: Akshay Saraswat To: u-boot@lists.denx.de Date: Thu, 28 Feb 2013 05:59:16 -0500 Message-id: <1362049164-10297-2-git-send-email-akshay.s@samsung.com> X-Mailer: git-send-email 1.8.0 In-reply-to: <1362049164-10297-1-git-send-email-akshay.s@samsung.com> References: <1362049164-10297-1-git-send-email-akshay.s@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrCLMWRmVeSWpSXmKPExsWyRsSkWne/sX6gwZXnZhZv93ayOzB6nL2z gzGAMYrLJiU1J7MstUjfLoEr4/ikxywFH9Ur9n3/xNbA+Fi+i5GTQ0LAROLWiwlMELaYxIV7 69m6GLk4hASWMko8/t/AClN04O9eVojEIkaJ9m2XmCGcZUwSe3ofMoNUsQnoSGxf8p0dxBYR kJD41X+VEcRmFnCU2HfkG9gKYQEXifauu2D1LAKqEv2rV4PZvEDxhv37WSC2yUl82PMIaA4H B6eAq8TDbiOQsBBQyaWfX6AOuswmcWtlFMQYAYlvkw+xgJRLCMhKbDrADFEiKXFwxQ2WCYzC CxgZVjGKphYkFxQnpRcZ6xUn5haX5qXrJefnbmIEhuDpf8/6dzDePWB9iDEZaNxEZinR5Hxg COeVxBsam5ibGpuaGVlaWpqSJqwkzit/SSZQSCA9sSQ1OzW1ILUovqg0J7X4ECMTB6dUA2PJ k9gYR/eCaSuO3NHa9mvZt7VPdzUnnHofmuk8v8XZ2kp0pp3qSlV/TZeDS/8197xZ473Dt9+4 3zDt6Z8pB5d0vUj+792k3+tSyWzs83INx0bbSTccMq/d62JY+bPHNVjMyVg+YekKUyOPA3Nj 1nb//fJZLKTtjOTOvHoLX9m9+9fumn7i0CclluKMREMt5qLiRACIcrWQVwIAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrEIsWRmVeSWpSXmKPExsVy+t9jAd39xvqBBlO3aVi83dvJ7sDocfbO DsYAxqgGRpuM1MSU1CKF1Lzk/JTMvHRbJe/geOd4UzMDQ11DSwtzJYW8xNxUWyUXnwBdt8wc oLFKCmWJOaVAoYDE4mIlfTtME0JD3HQtYBojdH1DguB6jAzQQMIaxozjkx6zFHxUr9j3/RNb A+Nj+S5GTg4JAROJA3/3skLYYhIX7q1n62Lk4hASWMQo0b7tEjOEs4xJYk/vQ2aQKjYBHYnt S76zg9giAhISv/qvMoLYzAKOEvuOfGMCsYUFXCTau+6C1bMIqEr0r14NZvMCxRv272eB2CYn 8WHPI6A5HBycAq4SD7uNQMJCQCWXfn5hncDIu4CRYRWjaGpBckFxUnquoV5xYm5xaV66XnJ+ 7iZGcIg/k9rBuLLB4hCjAAejEg9vh4leoBBrYllxZe4hRgkOZiURXhd+/UAh3pTEyqrUovz4 otKc1OJDjMlAR01klhJNzgfGX15JvKGxibmpsamliYWJmSVpwkrivIynngQICaQnlqRmp6YW pBbBbGHi4JRqYGR2d1PxVT1jqm6dM/vXl0lBS4UZI0/PvPZtwcN0gUpZk6rlHd8jk8W5v739 cvNs+LrGvoTpHt9+dzAcNL1r8yCr4/i0tDWbg4PPPOeXXtQdy1sUylKuMTV9Y4C2id27itY/ +3ZnTG423mHol96+PWh5eq76BsXHQau+b9vrpSkW1H6Nl82XT4mlOCPRUIu5qDgRAL7Wtse1 AgAA DLP-Filter: Pass X-MTR: 20000000000000000@CPGS X-CFilter-Loop: Reflected Cc: prashanth.g@samsung.com Subject: [U-Boot] [PATCH 1/9 v2] 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 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 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.