diff options
| -rw-r--r-- | drivers/Kconfig | 1 | ||||
| -rw-r--r-- | drivers/Makefile | 1 | ||||
| -rw-r--r-- | drivers/clocksource/Kconfig | 3 | ||||
| -rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
| -rw-r--r-- | drivers/clocksource/arm_smp_twd.c | 101 |
5 files changed, 107 insertions, 0 deletions
diff --git a/drivers/Kconfig b/drivers/Kconfig index d0b5e3abdb..6f7864455e 100644 --- a/drivers/Kconfig +++ b/drivers/Kconfig @@ -11,6 +11,7 @@ source "drivers/usb/Kconfig" source "drivers/video/Kconfig" source "drivers/mci/Kconfig" source "drivers/clk/Kconfig" +source "drivers/clocksource/Kconfig" source "drivers/mfd/Kconfig" source "drivers/misc/Kconfig" source "drivers/led/Kconfig" diff --git a/drivers/Makefile b/drivers/Makefile index 2a1f8b0f23..742a5bd0b2 100644 --- a/drivers/Makefile +++ b/drivers/Makefile @@ -11,6 +11,7 @@ obj-$(CONFIG_I2C) += i2c/ obj-$(CONFIG_MCI) += mci/ obj-$(CONFIG_VIDEO) += video/ obj-y += clk/ +obj-y += clocksource/ obj-y += mfd/ obj-$(CONFIG_LED) += led/ obj-y += eeprom/ diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig new file mode 100644 index 0000000000..05c1f0a88e --- /dev/null +++ b/drivers/clocksource/Kconfig @@ -0,0 +1,3 @@ +config ARM_SMP_TWD + bool + depends on ARM && CPU_V7 diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile new file mode 100644 index 0000000000..9186a5cf59 --- /dev/null +++ b/drivers/clocksource/Makefile @@ -0,0 +1 @@ +obj-$(CONFIG_ARM_SMP_TWD) += arm_smp_twd.o diff --git a/drivers/clocksource/arm_smp_twd.c b/drivers/clocksource/arm_smp_twd.c new file mode 100644 index 0000000000..746d566441 --- /dev/null +++ b/drivers/clocksource/arm_smp_twd.c @@ -0,0 +1,101 @@ +/* + * Copyright (C) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnio@jcrosoft.com> + * + * Under GPL v2 + */ +#include <common.h> +#include <init.h> +#include <clock.h> +#include <io.h> +#include <driver.h> +#include <errno.h> +#include <linux/clk.h> +#include <linux/err.h> + +#define TWD_TIMER_LOAD 0x00 +#define TWD_TIMER_COUNTER 0x04 +#define TWD_TIMER_CONTROL 0x08 +#define TWD_TIMER_INTSTAT 0x0C + +#define TWD_TIMER_CONTROL_ENABLE (1 << 0) +#define TWD_TIMER_CONTROL_ONESHOT (0 << 1) +#define TWD_TIMER_CONTROL_PERIODIC (1 << 1) +#define TWD_TIMER_CONTROL_IT_ENABLE (1 << 2) + +#define TWD_TIMER_CONTROL_PRESC(x) (((x) & 0xff) << 8) + +static __iomem void *twd_base; +static struct clk *twd_clk; + +static uint64_t smp_twd_read(void) +{ + return ~readl(twd_base + TWD_TIMER_COUNTER); +} + +static struct clocksource smp_twd_clksrc = { + .read = smp_twd_read, + .shift = 20, + .mask = CLOCKSOURCE_MASK(32), +}; + +#define SMP_TWD_MAX_FREQ (25 *1000 * 1000) + +static int smp_twd_probe(struct device_d *dev) +{ + u32 tick_rate; + u32 val; + int ret; + u32 presc = 0; + + twd_clk = clk_get(dev, NULL); + if (IS_ERR(twd_clk)) { + ret = PTR_ERR(twd_clk); + dev_err(dev, "clock not found: %d\n", ret); + return ret; + } + + ret = clk_enable(twd_clk); + if (ret < 0) { + dev_err(dev, "clock failed to enable: %d\n", ret); + clk_put(twd_clk); + return ret; + } + + twd_base = dev_request_mem_region(dev, 0); + + tick_rate = clk_get_rate(twd_clk); + if (tick_rate > SMP_TWD_MAX_FREQ) { + presc = tick_rate / SMP_TWD_MAX_FREQ; + if (presc) + presc--; + presc = min((u32)0xff, presc); + tick_rate /= presc + 1; + } + + val = TWD_TIMER_CONTROL_PRESC(presc) | + TWD_TIMER_CONTROL_PERIODIC; + writel(val, twd_base + TWD_TIMER_CONTROL); + + writel(0xffffffff, twd_base + TWD_TIMER_LOAD); + + val = readl(twd_base + TWD_TIMER_CONTROL); + val |= TWD_TIMER_CONTROL_ENABLE; + writel(val, twd_base + TWD_TIMER_CONTROL); + + smp_twd_clksrc.mult = clocksource_hz2mult(tick_rate, smp_twd_clksrc.shift); + + init_clock(&smp_twd_clksrc); + + return 0; +} + +static struct driver_d smp_twd_driver = { + .name = "smp_twd", + .probe = smp_twd_probe, +}; + +static int smp_twd_init(void) +{ + return platform_driver_register(&smp_twd_driver); +} +coredevice_initcall(smp_twd_init); |