diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/tcb_clksrc.c | 90 |
1 files changed, 62 insertions, 28 deletions
diff --git a/drivers/clocksource/tcb_clksrc.c b/drivers/clocksource/tcb_clksrc.c index 55d0f95f82f9..32cb929b8eb6 100644 --- a/drivers/clocksource/tcb_clksrc.c +++ b/drivers/clocksource/tcb_clksrc.c @@ -19,6 +19,8 @@ * - Two channels combine to create a free-running 32 bit counter * with a base rate of 5+ MHz, packaged as a clocksource (with * resolution better than 200 nsec). + * - Some chips support 32 bit counter. A single channel is used for + * this 32 bit free-running counter. the second channel is not used. * * - The third channel may be used to provide a 16-bit clockevent * source, used in either periodic or oneshot mode. This runs @@ -54,6 +56,11 @@ static cycle_t tc_get_cycles(struct clocksource *cs) return (upper << 16) | lower; } +static cycle_t tc_get_cycles32(struct clocksource *cs) +{ + return __raw_readl(tcaddr + ATMEL_TC_REG(0, CV)); +} + static struct clocksource clksrc = { .name = "tcb_clksrc", .rating = 200, @@ -209,6 +216,48 @@ static void __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx) #endif +static void __init tcb_setup_dual_chan(struct atmel_tc *tc, int mck_divisor_idx) +{ + /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */ + __raw_writel(mck_divisor_idx /* likely divide-by-8 */ + | ATMEL_TC_WAVE + | ATMEL_TC_WAVESEL_UP /* free-run */ + | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */ + | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */ + tcaddr + ATMEL_TC_REG(0, CMR)); + __raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA)); + __raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC)); + __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */ + __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR)); + + /* channel 1: waveform mode, input TIOA0 */ + __raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */ + | ATMEL_TC_WAVE + | ATMEL_TC_WAVESEL_UP, /* free-run */ + tcaddr + ATMEL_TC_REG(1, CMR)); + __raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */ + __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR)); + + /* chain channel 0 to channel 1*/ + __raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR); + /* then reset all the timers */ + __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR); +} + +static void __init tcb_setup_single_chan(struct atmel_tc *tc, int mck_divisor_idx) +{ + /* channel 0: waveform mode, input mclk/8 */ + __raw_writel(mck_divisor_idx /* likely divide-by-8 */ + | ATMEL_TC_WAVE + | ATMEL_TC_WAVESEL_UP, /* free-run */ + tcaddr + ATMEL_TC_REG(0, CMR)); + __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */ + __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR)); + + /* then reset all the timers */ + __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR); +} + static int __init tcb_clksrc_init(void) { static char bootinfo[] __initdata @@ -260,34 +309,19 @@ static int __init tcb_clksrc_init(void) divided_rate / 1000000, ((divided_rate + 500000) % 1000000) / 1000); - /* tclib will give us three clocks no matter what the - * underlying platform supports. - */ - clk_enable(tc->clk[1]); - - /* channel 0: waveform mode, input mclk/8, clock TIOA0 on overflow */ - __raw_writel(best_divisor_idx /* likely divide-by-8 */ - | ATMEL_TC_WAVE - | ATMEL_TC_WAVESEL_UP /* free-run */ - | ATMEL_TC_ACPA_SET /* TIOA0 rises at 0 */ - | ATMEL_TC_ACPC_CLEAR, /* (duty cycle 50%) */ - tcaddr + ATMEL_TC_REG(0, CMR)); - __raw_writel(0x0000, tcaddr + ATMEL_TC_REG(0, RA)); - __raw_writel(0x8000, tcaddr + ATMEL_TC_REG(0, RC)); - __raw_writel(0xff, tcaddr + ATMEL_TC_REG(0, IDR)); /* no irqs */ - __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(0, CCR)); - - /* channel 1: waveform mode, input TIOA0 */ - __raw_writel(ATMEL_TC_XC1 /* input: TIOA0 */ - | ATMEL_TC_WAVE - | ATMEL_TC_WAVESEL_UP, /* free-run */ - tcaddr + ATMEL_TC_REG(1, CMR)); - __raw_writel(0xff, tcaddr + ATMEL_TC_REG(1, IDR)); /* no irqs */ - __raw_writel(ATMEL_TC_CLKEN, tcaddr + ATMEL_TC_REG(1, CCR)); - - /* chain channel 0 to channel 1, then reset all the timers */ - __raw_writel(ATMEL_TC_TC1XC1S_TIOA0, tcaddr + ATMEL_TC_BMR); - __raw_writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR); + if (tc->tcb_config && tc->tcb_config->counter_width == 32) { + /* use apropriate function to read 32 bit counter */ + clksrc.read = tc_get_cycles32; + /* setup ony channel 0 */ + tcb_setup_single_chan(tc, best_divisor_idx); + } else { + /* tclib will give us three clocks no matter what the + * underlying platform supports. + */ + clk_enable(tc->clk[1]); + /* setup both channel 0 & 1 */ + tcb_setup_dual_chan(tc, best_divisor_idx); + } /* and away we go! */ clocksource_register_hz(&clksrc, divided_rate); |