diff options
Diffstat (limited to 'arch/c6x/platforms/timer64.c')
| -rw-r--r-- | arch/c6x/platforms/timer64.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/arch/c6x/platforms/timer64.c b/arch/c6x/platforms/timer64.c new file mode 100644 index 000000000..241a9a607 --- /dev/null +++ b/arch/c6x/platforms/timer64.c @@ -0,0 +1,249 @@ +/* + * Copyright (C) 2010, 2011 Texas Instruments Incorporated + * Contributed by: Mark Salter (msalter@redhat.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/clockchips.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> +#include <asm/soc.h> +#include <asm/dscr.h> +#include <asm/special_insns.h> +#include <asm/timer64.h> + +struct timer_regs { + u32 reserved0; + u32 emumgt; + u32 reserved1; + u32 reserved2; + u32 cntlo; + u32 cnthi; + u32 prdlo; + u32 prdhi; + u32 tcr; + u32 tgcr; + u32 wdtcr; +}; + +static struct timer_regs __iomem *timer; + +#define TCR_TSTATLO 0x001 +#define TCR_INVOUTPLO 0x002 +#define TCR_INVINPLO 0x004 +#define TCR_CPLO 0x008 +#define TCR_ENAMODELO_ONCE 0x040 +#define TCR_ENAMODELO_CONT 0x080 +#define TCR_ENAMODELO_MASK 0x0c0 +#define TCR_PWIDLO_MASK 0x030 +#define TCR_CLKSRCLO 0x100 +#define TCR_TIENLO 0x200 +#define TCR_TSTATHI (0x001 << 16) +#define TCR_INVOUTPHI (0x002 << 16) +#define TCR_CPHI (0x008 << 16) +#define TCR_PWIDHI_MASK (0x030 << 16) +#define TCR_ENAMODEHI_ONCE (0x040 << 16) +#define TCR_ENAMODEHI_CONT (0x080 << 16) +#define TCR_ENAMODEHI_MASK (0x0c0 << 16) + +#define TGCR_TIMLORS 0x001 +#define TGCR_TIMHIRS 0x002 +#define TGCR_TIMMODE_UD32 0x004 +#define TGCR_TIMMODE_WDT64 0x008 +#define TGCR_TIMMODE_CD32 0x00c +#define TGCR_TIMMODE_MASK 0x00c +#define TGCR_PSCHI_MASK (0x00f << 8) +#define TGCR_TDDRHI_MASK (0x00f << 12) + +/* + * Timer clocks are divided down from the CPU clock + * The divisor is in the EMUMGTCLKSPD register + */ +#define TIMER_DIVISOR \ + ((soc_readl(&timer->emumgt) & (0xf << 16)) >> 16) + +#define TIMER64_RATE (c6x_core_freq / TIMER_DIVISOR) + +#define TIMER64_MODE_DISABLED 0 +#define TIMER64_MODE_ONE_SHOT TCR_ENAMODELO_ONCE +#define TIMER64_MODE_PERIODIC TCR_ENAMODELO_CONT + +static int timer64_mode; +static int timer64_devstate_id = -1; + +static void timer64_config(unsigned long period) +{ + u32 tcr = soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK; + + soc_writel(tcr, &timer->tcr); + soc_writel(period - 1, &timer->prdlo); + soc_writel(0, &timer->cntlo); + tcr |= timer64_mode; + soc_writel(tcr, &timer->tcr); +} + +static void timer64_enable(void) +{ + u32 val; + + if (timer64_devstate_id >= 0) + dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED); + + /* disable timer, reset count */ + soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr); + soc_writel(0, &timer->prdlo); + + /* use internal clock and 1 cycle pulse width */ + val = soc_readl(&timer->tcr); + soc_writel(val & ~(TCR_CLKSRCLO | TCR_PWIDLO_MASK), &timer->tcr); + + /* dual 32-bit unchained mode */ + val = soc_readl(&timer->tgcr) & ~TGCR_TIMMODE_MASK; + soc_writel(val, &timer->tgcr); + soc_writel(val | (TGCR_TIMLORS | TGCR_TIMMODE_UD32), &timer->tgcr); +} + +static void timer64_disable(void) +{ + /* disable timer, reset count */ + soc_writel(soc_readl(&timer->tcr) & ~TCR_ENAMODELO_MASK, &timer->tcr); + soc_writel(0, &timer->prdlo); + + if (timer64_devstate_id >= 0) + dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_DISABLED); +} + +static int next_event(unsigned long delta, + struct clock_event_device *evt) +{ + timer64_config(delta); + return 0; +} + +static int set_periodic(struct clock_event_device *evt) +{ + timer64_enable(); + timer64_mode = TIMER64_MODE_PERIODIC; + timer64_config(TIMER64_RATE / HZ); + return 0; +} + +static int set_oneshot(struct clock_event_device *evt) +{ + timer64_enable(); + timer64_mode = TIMER64_MODE_ONE_SHOT; + return 0; +} + +static int shutdown(struct clock_event_device *evt) +{ + timer64_mode = TIMER64_MODE_DISABLED; + timer64_disable(); + return 0; +} + +static struct clock_event_device t64_clockevent_device = { + .name = "TIMER64_EVT32_TIMER", + .features = CLOCK_EVT_FEAT_ONESHOT | + CLOCK_EVT_FEAT_PERIODIC, + .rating = 200, + .set_state_shutdown = shutdown, + .set_state_periodic = set_periodic, + .set_state_oneshot = set_oneshot, + .set_next_event = next_event, +}; + +static irqreturn_t timer_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *cd = &t64_clockevent_device; + + cd->event_handler(cd); + + return IRQ_HANDLED; +} + +static struct irqaction timer_iact = { + .name = "timer", + .flags = IRQF_TIMER, + .handler = timer_interrupt, + .dev_id = &t64_clockevent_device, +}; + +void __init timer64_init(void) +{ + struct clock_event_device *cd = &t64_clockevent_device; + struct device_node *np, *first = NULL; + u32 val; + int err, found = 0; + + for_each_compatible_node(np, NULL, "ti,c64x+timer64") { + err = of_property_read_u32(np, "ti,core-mask", &val); + if (!err) { + if (val & (1 << get_coreid())) { + found = 1; + break; + } + } else if (!first) + first = np; + } + if (!found) { + /* try first one with no core-mask */ + if (first) + np = of_node_get(first); + else { + pr_debug("Cannot find ti,c64x+timer64 timer.\n"); + return; + } + } + + timer = of_iomap(np, 0); + if (!timer) { + pr_debug("%pOF: Cannot map timer registers.\n", np); + goto out; + } + pr_debug("%pOF: Timer registers=%p.\n", np, timer); + + cd->irq = irq_of_parse_and_map(np, 0); + if (cd->irq == NO_IRQ) { + pr_debug("%pOF: Cannot find interrupt.\n", np); + iounmap(timer); + goto out; + } + + /* If there is a device state control, save the ID. */ + err = of_property_read_u32(np, "ti,dscr-dev-enable", &val); + if (!err) { + timer64_devstate_id = val; + + /* + * It is necessary to enable the timer block here because + * the TIMER_DIVISOR macro needs to read a timer register + * to get the divisor. + */ + dscr_set_devstate(timer64_devstate_id, DSCR_DEVSTATE_ENABLED); + } + + pr_debug("%pOF: Timer irq=%d.\n", np, cd->irq); + + clockevents_calc_mult_shift(cd, c6x_core_freq / TIMER_DIVISOR, 5); + + cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd); + cd->max_delta_ticks = 0x7fffffff; + cd->min_delta_ns = clockevent_delta2ns(250, cd); + cd->min_delta_ticks = 250; + + cd->cpumask = cpumask_of(smp_processor_id()); + + clockevents_register_device(cd); + setup_irq(cd->irq, &timer_iact); + +out: + of_node_put(np); + return; +} |