diff options
Diffstat (limited to 'drivers/clocksource/dw_apb_timer_of.c')
| -rw-r--r-- | drivers/clocksource/dw_apb_timer_of.c | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c new file mode 100644 index 000000000..a19a3f619 --- /dev/null +++ b/drivers/clocksource/dw_apb_timer_of.c @@ -0,0 +1,155 @@ +/* + * Copyright (C) 2012 Altera Corporation + * Copyright (c) 2011 Picochip Ltd., Jamie Iles + * + * Modified from mach-picoxcell/time.c + * + * 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. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <linux/dw_apb_timer.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/clk.h> +#include <linux/sched_clock.h> + +static void __init timer_get_base_and_rate(struct device_node *np, + void __iomem **base, u32 *rate) +{ + struct clk *timer_clk; + struct clk *pclk; + + *base = of_iomap(np, 0); + + if (!*base) + panic("Unable to map regs for %s", np->name); + + /* + * Not all implementations use a periphal clock, so don't panic + * if it's not present + */ + pclk = of_clk_get_by_name(np, "pclk"); + if (!IS_ERR(pclk)) + if (clk_prepare_enable(pclk)) + pr_warn("pclk for %s is present, but could not be activated\n", + np->name); + + timer_clk = of_clk_get_by_name(np, "timer"); + if (IS_ERR(timer_clk)) + goto try_clock_freq; + + if (!clk_prepare_enable(timer_clk)) { + *rate = clk_get_rate(timer_clk); + return; + } + +try_clock_freq: + if (of_property_read_u32(np, "clock-freq", rate) && + of_property_read_u32(np, "clock-frequency", rate)) + panic("No clock nor clock-frequency property for %s", np->name); +} + +static void __init add_clockevent(struct device_node *event_timer) +{ + void __iomem *iobase; + struct dw_apb_clock_event_device *ced; + u32 irq, rate; + + irq = irq_of_parse_and_map(event_timer, 0); + if (irq == 0) + panic("No IRQ for clock event timer"); + + timer_get_base_and_rate(event_timer, &iobase, &rate); + + ced = dw_apb_clockevent_init(0, event_timer->name, 300, iobase, irq, + rate); + if (!ced) + panic("Unable to initialise clockevent device"); + + dw_apb_clockevent_register(ced); +} + +static void __iomem *sched_io_base; +static u32 sched_rate; + +static void __init add_clocksource(struct device_node *source_timer) +{ + void __iomem *iobase; + struct dw_apb_clocksource *cs; + u32 rate; + + timer_get_base_and_rate(source_timer, &iobase, &rate); + + cs = dw_apb_clocksource_init(300, source_timer->name, iobase, rate); + if (!cs) + panic("Unable to initialise clocksource device"); + + dw_apb_clocksource_start(cs); + dw_apb_clocksource_register(cs); + + /* + * Fallback to use the clocksource as sched_clock if no separate + * timer is found. sched_io_base then points to the current_value + * register of the clocksource timer. + */ + sched_io_base = iobase + 0x04; + sched_rate = rate; +} + +static u64 notrace read_sched_clock(void) +{ + return ~readl_relaxed(sched_io_base); +} + +static const struct of_device_id sptimer_ids[] __initconst = { + { .compatible = "picochip,pc3x2-rtc" }, + { /* Sentinel */ }, +}; + +static void __init init_sched_clock(void) +{ + struct device_node *sched_timer; + + sched_timer = of_find_matching_node(NULL, sptimer_ids); + if (sched_timer) { + timer_get_base_and_rate(sched_timer, &sched_io_base, + &sched_rate); + of_node_put(sched_timer); + } + + sched_clock_register(read_sched_clock, 32, sched_rate); +} + +static int num_called; +static void __init dw_apb_timer_init(struct device_node *timer) +{ + switch (num_called) { + case 0: + pr_debug("%s: found clockevent timer\n", __func__); + add_clockevent(timer); + break; + case 1: + pr_debug("%s: found clocksource timer\n", __func__); + add_clocksource(timer); + init_sched_clock(); + break; + default: + break; + } + + num_called++; +} +CLOCKSOURCE_OF_DECLARE(pc3x2_timer, "picochip,pc3x2-timer", dw_apb_timer_init); +CLOCKSOURCE_OF_DECLARE(apb_timer_osc, "snps,dw-apb-timer-osc", dw_apb_timer_init); +CLOCKSOURCE_OF_DECLARE(apb_timer_sp, "snps,dw-apb-timer-sp", dw_apb_timer_init); +CLOCKSOURCE_OF_DECLARE(apb_timer, "snps,dw-apb-timer", dw_apb_timer_init); |