diff options
Diffstat (limited to 'arch/arm/mach-omap2/timer.c')
| -rw-r--r-- | arch/arm/mach-omap2/timer.c | 46 |
1 files changed, 40 insertions, 6 deletions
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c index 4f61148ec16..cef67af9e9b 100644 --- a/arch/arm/mach-omap2/timer.c +++ b/arch/arm/mach-omap2/timer.c @@ -54,6 +54,7 @@ #include "soc.h" #include "common.h" +#include "control.h" #include "powerdomain.h" #include "omap-secure.h" @@ -146,6 +147,8 @@ static const struct of_device_id omap_timer_match[] __initconst = { { .compatible = "ti,omap3430-timer", }, { .compatible = "ti,omap4430-timer", }, { .compatible = "ti,omap5430-timer", }, + { .compatible = "ti,dm814-timer", }, + { .compatible = "ti,dm816-timer", }, { .compatible = "ti,am335x-timer", }, { .compatible = "ti,am335x-timer-1ms", }, { } @@ -496,7 +499,8 @@ static void __init realtime_counter_init(void) void __iomem *base; static struct clk *sys_clk; unsigned long rate; - unsigned int reg, num, den; + unsigned int reg; + unsigned long long num, den; base = ioremap(REALTIME_COUNTER_BASE, SZ_32); if (!base) { @@ -511,13 +515,42 @@ static void __init realtime_counter_init(void) } rate = clk_get_rate(sys_clk); + + if (soc_is_dra7xx()) { + /* + * Errata i856 says the 32.768KHz crystal does not start at + * power on, so the CPU falls back to an emulated 32KHz clock + * based on sysclk / 610 instead. This causes the master counter + * frequency to not be 6.144MHz but at sysclk / 610 * 375 / 2 + * (OR sysclk * 75 / 244) + * + * This affects at least the DRA7/AM572x 1.0, 1.1 revisions. + * Of course any board built without a populated 32.768KHz + * crystal would also need this fix even if the CPU is fixed + * later. + * + * Either case can be detected by using the two speedselect bits + * If they are not 0, then the 32.768KHz clock driving the + * coarse counter that corrects the fine counter every time it + * ticks is actually rate/610 rather than 32.768KHz and we + * should compensate to avoid the 570ppm (at 20MHz, much worse + * at other rates) too fast system time. + */ + reg = omap_ctrl_readl(DRA7_CTRL_CORE_BOOTSTRAP); + if (reg & DRA7_SPEEDSELECT_MASK) { + num = 75; + den = 244; + goto sysclk1_based; + } + } + /* Numerator/denumerator values refer TRM Realtime Counter section */ switch (rate) { - case 1200000: + case 12000000: num = 64; den = 125; break; - case 1300000: + case 13000000: num = 768; den = 1625; break; @@ -529,11 +562,11 @@ static void __init realtime_counter_init(void) num = 192; den = 625; break; - case 2600000: + case 26000000: num = 384; den = 1625; break; - case 2700000: + case 27000000: num = 256; den = 1125; break; @@ -545,6 +578,7 @@ static void __init realtime_counter_init(void) break; } +sysclk1_based: /* Program numerator and denumerator registers */ reg = readl_relaxed(base + INCREMENTER_NUMERATOR_OFFSET) & NUMERATOR_DENUMERATOR_MASK; @@ -556,7 +590,7 @@ static void __init realtime_counter_init(void) reg |= den; writel_relaxed(reg, base + INCREMENTER_DENUMERATOR_RELOAD_OFFSET); - arch_timer_freq = (rate / den) * num; + arch_timer_freq = DIV_ROUND_UP_ULL(rate * num, den); set_cntfreq(); iounmap(base); |