diff options
Diffstat (limited to 'arch/mips/ralink/cevt-rt3352.c')
| -rw-r--r-- | arch/mips/ralink/cevt-rt3352.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/arch/mips/ralink/cevt-rt3352.c b/arch/mips/ralink/cevt-rt3352.c new file mode 100644 index 000000000..269d4877d --- /dev/null +++ b/arch/mips/ralink/cevt-rt3352.c @@ -0,0 +1,153 @@ +/* + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2013 by John Crispin <john@phrozen.org> + */ + +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/interrupt.h> +#include <linux/reset.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/of.h> +#include <linux/of_irq.h> +#include <linux/of_address.h> + +#include <asm/mach-ralink/ralink_regs.h> + +#define SYSTICK_FREQ (50 * 1000) + +#define SYSTICK_CONFIG 0x00 +#define SYSTICK_COMPARE 0x04 +#define SYSTICK_COUNT 0x08 + +/* route systick irq to mips irq 7 instead of the r4k-timer */ +#define CFG_EXT_STK_EN 0x2 +/* enable the counter */ +#define CFG_CNT_EN 0x1 + +struct systick_device { + void __iomem *membase; + struct clock_event_device dev; + int irq_requested; + int freq_scale; +}; + +static int systick_set_oneshot(struct clock_event_device *evt); +static int systick_shutdown(struct clock_event_device *evt); + +static int systick_next_event(unsigned long delta, + struct clock_event_device *evt) +{ + struct systick_device *sdev; + u32 count; + + sdev = container_of(evt, struct systick_device, dev); + count = ioread32(sdev->membase + SYSTICK_COUNT); + count = (count + delta) % SYSTICK_FREQ; + iowrite32(count, sdev->membase + SYSTICK_COMPARE); + + return 0; +} + +static void systick_event_handler(struct clock_event_device *dev) +{ + /* noting to do here */ +} + +static irqreturn_t systick_interrupt(int irq, void *dev_id) +{ + struct clock_event_device *dev = (struct clock_event_device *) dev_id; + + dev->event_handler(dev); + + return IRQ_HANDLED; +} + +static struct systick_device systick = { + .dev = { + /* + * cevt-r4k uses 300, make sure systick + * gets used if available + */ + .rating = 310, + .features = CLOCK_EVT_FEAT_ONESHOT, + .set_next_event = systick_next_event, + .set_state_shutdown = systick_shutdown, + .set_state_oneshot = systick_set_oneshot, + .event_handler = systick_event_handler, + }, +}; + +static int systick_shutdown(struct clock_event_device *evt) +{ + struct systick_device *sdev; + + sdev = container_of(evt, struct systick_device, dev); + + if (sdev->irq_requested) + free_irq(systick.dev.irq, &systick.dev); + sdev->irq_requested = 0; + iowrite32(0, systick.membase + SYSTICK_CONFIG); + + return 0; +} + +static int systick_set_oneshot(struct clock_event_device *evt) +{ + const char *name = systick.dev.name; + struct systick_device *sdev; + int irq = systick.dev.irq; + + sdev = container_of(evt, struct systick_device, dev); + + if (!sdev->irq_requested) { + if (request_irq(irq, systick_interrupt, + IRQF_PERCPU | IRQF_TIMER, name, &systick.dev)) + pr_err("Failed to request irq %d (%s)\n", irq, name); + } + sdev->irq_requested = 1; + iowrite32(CFG_EXT_STK_EN | CFG_CNT_EN, + systick.membase + SYSTICK_CONFIG); + + return 0; +} + +static int __init ralink_systick_init(struct device_node *np) +{ + int ret; + + systick.membase = of_iomap(np, 0); + if (!systick.membase) + return -ENXIO; + + systick.dev.name = np->name; + clockevents_calc_mult_shift(&systick.dev, SYSTICK_FREQ, 60); + systick.dev.max_delta_ns = clockevent_delta2ns(0x7fff, &systick.dev); + systick.dev.max_delta_ticks = 0x7fff; + systick.dev.min_delta_ns = clockevent_delta2ns(0x3, &systick.dev); + systick.dev.min_delta_ticks = 0x3; + systick.dev.irq = irq_of_parse_and_map(np, 0); + if (!systick.dev.irq) { + pr_err("%pOFn: request_irq failed", np); + return -EINVAL; + } + + ret = clocksource_mmio_init(systick.membase + SYSTICK_COUNT, np->name, + SYSTICK_FREQ, 301, 16, + clocksource_mmio_readl_up); + if (ret) + return ret; + + clockevents_register_device(&systick.dev); + + pr_info("%pOFn: running - mult: %d, shift: %d\n", + np, systick.dev.mult, systick.dev.shift); + + return 0; +} + +TIMER_OF_DECLARE(systick, "ralink,cevt-systick", ralink_systick_init); |