diff options
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/Makefile | 1 | ||||
| -rw-r--r-- | drivers/clocksource/sh_mtu2.c | 357 |
2 files changed, 358 insertions, 0 deletions
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile index 1efb287..9785586 100644 --- a/drivers/clocksource/Makefile +++ b/drivers/clocksource/Makefile @@ -3,3 +3,4 @@ obj-$(CONFIG_X86_CYCLONE_TIMER) += cyclone.o obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o obj-$(CONFIG_SCx200HR_TIMER) += scx200_hrt.o obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o +obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o diff --git a/drivers/clocksource/sh_mtu2.c b/drivers/clocksource/sh_mtu2.c new file mode 100644 index 0000000..420566f --- /dev/null +++ b/drivers/clocksource/sh_mtu2.c @@ -0,0 +1,357 @@ +/* + * SuperH Timer Support - MTU2 + * + * Copyright (C) 2009 Magnus Damm + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License + * + * 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/init.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> +#include <linux/interrupt.h> +#include <linux/ioport.h> +#include <linux/delay.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/irq.h> +#include <linux/err.h> +#include <linux/clockchips.h> +#include <linux/sh_mtu2.h> + +struct sh_mtu2_priv { + void __iomem *mapbase; + struct clk *clk; + struct irqaction irqaction; + struct platform_device *pdev; + unsigned long rate; + unsigned long periodic; + struct clock_event_device ced; +}; + +static DEFINE_SPINLOCK(sh_mtu2_lock); + +#define TSTR -1 /* shared register */ +#define TCR 0 /* channel register */ +#define TMDR 1 /* channel register */ +#define TIOR 2 /* channel register */ +#define TIER 3 /* channel register */ +#define TSR 4 /* channel register */ +#define TCNT 5 /* channel register */ +#define TGR 6 /* channel register */ + +static unsigned long mtu2_reg_offs[] = { + [TCR] = 0, + [TMDR] = 1, + [TIOR] = 2, + [TIER] = 4, + [TSR] = 5, + [TCNT] = 6, + [TGR] = 8, +}; + +static inline unsigned long sh_mtu2_read(struct sh_mtu2_priv *p, int reg_nr) +{ + struct sh_mtu2_config *cfg = p->pdev->dev.platform_data; + void __iomem *base = p->mapbase; + unsigned long offs; + + if (reg_nr == TSTR) + return ioread8(base + cfg->channel_offset); + + offs = mtu2_reg_offs[reg_nr]; + + if ((reg_nr == TCNT) || (reg_nr == TGR)) + return ioread16(base + offs); + else + return ioread8(base + offs); +} + +static inline void sh_mtu2_write(struct sh_mtu2_priv *p, int reg_nr, + unsigned long value) +{ + struct sh_mtu2_config *cfg = p->pdev->dev.platform_data; + void __iomem *base = p->mapbase; + unsigned long offs; + + if (reg_nr == TSTR) { + iowrite8(value, base + cfg->channel_offset); + return; + } + + offs = mtu2_reg_offs[reg_nr]; + + if ((reg_nr == TCNT) || (reg_nr == TGR)) + iowrite16(value, base + offs); + else + iowrite8(value, base + offs); +} + +static void sh_mtu2_start_stop_ch(struct sh_mtu2_priv *p, int start) +{ + struct sh_mtu2_config *cfg = p->pdev->dev.platform_data; + unsigned long flags, value; + + /* start stop register shared by multiple timer channels */ + spin_lock_irqsave(&sh_mtu2_lock, flags); + value = sh_mtu2_read(p, TSTR); + + if (start) + value |= 1 << cfg->timer_bit; + else + value &= ~(1 << cfg->timer_bit); + + sh_mtu2_write(p, TSTR, value); + spin_unlock_irqrestore(&sh_mtu2_lock, flags); +} + +static int sh_mtu2_enable(struct sh_mtu2_priv *p) +{ + struct sh_mtu2_config *cfg = p->pdev->dev.platform_data; + int ret; + + /* enable clock */ + ret = clk_enable(p->clk); + if (ret) { + pr_err("sh_mtu2: cannot enable clock \"%s\"\n", cfg->clk); + return ret; + } + + /* make sure channel is disabled */ + sh_mtu2_start_stop_ch(p, 0); + + p->rate = clk_get_rate(p->clk) / 64; + p->periodic = (p->rate + HZ/2) / HZ; + + /* "Periodic Counter Operation" */ + sh_mtu2_write(p, TCR, 0x23); /* TGRA clear, divide clock by 64 */ + sh_mtu2_write(p, TIOR, 0); + sh_mtu2_write(p, TGR, p->periodic); + sh_mtu2_write(p, TCNT, 0); + sh_mtu2_write(p, TMDR, 0); + sh_mtu2_write(p, TIER, 0x01); + + /* enable channel */ + sh_mtu2_start_stop_ch(p, 1); + + return 0; +} + +static void sh_mtu2_disable(struct sh_mtu2_priv *p) +{ + /* disable channel */ + sh_mtu2_start_stop_ch(p, 0); + + /* stop clock */ + clk_disable(p->clk); +} + +static irqreturn_t sh_mtu2_interrupt(int irq, void *dev_id) +{ + struct sh_mtu2_priv *p = dev_id; + + /* acknowledge interrupt */ + sh_mtu2_read(p, TSR); + sh_mtu2_write(p, TSR, 0xfe); + + /* notify clockevent layer */ + p->ced.event_handler(&p->ced); + return IRQ_HANDLED; +} + +static struct sh_mtu2_priv *ced_to_sh_mtu2(struct clock_event_device *ced) +{ + return container_of(ced, struct sh_mtu2_priv, ced); +} + +static void sh_mtu2_clock_event_mode(enum clock_event_mode mode, + struct clock_event_device *ced) +{ + struct sh_mtu2_priv *p = ced_to_sh_mtu2(ced); + int disabled = 0; + + /* deal with old setting first */ + switch (ced->mode) { + case CLOCK_EVT_MODE_PERIODIC: + sh_mtu2_disable(p); + disabled = 1; + break; + default: + break; + } + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + pr_info("sh_mtu2: %s used for periodic clock events\n", + ced->name); + sh_mtu2_enable(p); + break; + case CLOCK_EVT_MODE_UNUSED: + if (!disabled) + sh_mtu2_disable(p); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + default: + break; + } +} + +static void sh_mtu2_register_clockevent(struct sh_mtu2_priv *p, + char *name, unsigned long rating) +{ + struct clock_event_device *ced = &p->ced; + int ret; + + memset(ced, 0, sizeof(*ced)); + + ced->name = name; + ced->features = CLOCK_EVT_FEAT_PERIODIC; + ced->rating = rating; + ced->cpumask = cpumask_of(0); + ced->set_mode = sh_mtu2_clock_event_mode; + + ret = setup_irq(p->irqaction.irq, &p->irqaction); + if (ret) { + pr_err("sh_mtu2: failed to request irq %d\n", + p->irqaction.irq); + return; + } + + pr_info("sh_mtu2: %s used for clock events\n", ced->name); + clockevents_register_device(ced); +} + +int sh_mtu2_register(struct sh_mtu2_priv *p, char *name, + unsigned long clockevent_rating) +{ + if (clockevent_rating) + sh_mtu2_register_clockevent(p, name, clockevent_rating); + + return 0; +} + +static int sh_mtu2_setup(struct sh_mtu2_priv *p, struct platform_device *pdev) +{ + struct sh_mtu2_config *cfg = pdev->dev.platform_data; + struct resource *res; + int irq, ret; + ret = -ENXIO; + + memset(p, 0, sizeof(*p)); + p->pdev = pdev; + + if (!cfg) { + dev_err(&p->pdev->dev, "missing platform data\n"); + goto err0; + } + + platform_set_drvdata(pdev, p); + + res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0); + if (!res) { + dev_err(&p->pdev->dev, "failed to get I/O memory\n"); + goto err0; + } + + irq = platform_get_irq(p->pdev, 0); + if (irq < 0) { + dev_err(&p->pdev->dev, "failed to get irq\n"); + goto err0; + } + + /* map memory, let mapbase point to our channel */ + p->mapbase = ioremap_nocache(res->start, resource_size(res)); + if (p->mapbase == NULL) { + pr_err("sh_mtu2: failed to remap I/O memory\n"); + goto err0; + } + + /* setup data for setup_irq() (too early for request_irq()) */ + p->irqaction.name = cfg->name; + p->irqaction.handler = sh_mtu2_interrupt; + p->irqaction.dev_id = p; + p->irqaction.irq = irq; + p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL; + p->irqaction.mask = CPU_MASK_NONE; + + /* get hold of clock */ + p->clk = clk_get(&p->pdev->dev, cfg->clk); + if (IS_ERR(p->clk)) { + pr_err("sh_mtu2: cannot get clock \"%s\"\n", cfg->clk); + ret = PTR_ERR(p->clk); + goto err1; + } + + return sh_mtu2_register(p, cfg->name, cfg->clockevent_rating); + err1: + iounmap(p->mapbase); + err0: + return ret; +} + +static int __devinit sh_mtu2_probe(struct platform_device *pdev) +{ + struct sh_mtu2_priv *p = platform_get_drvdata(pdev); + struct sh_mtu2_config *cfg = pdev->dev.platform_data; + int ret; + + if (p) { + pr_info("sh_mtu2: %s kept as earlytimer\n", cfg->name); + return 0; + } + + p = kmalloc(sizeof(*p), GFP_KERNEL); + if (p == NULL) { + dev_err(&pdev->dev, "failed to allocate driver data\n"); + return -ENOMEM; + } + + ret = sh_mtu2_setup(p, pdev); + if (ret) { + kfree(p); + platform_set_drvdata(pdev, NULL); + } + return ret; +} + +static int __devexit sh_mtu2_remove(struct platform_device *pdev) +{ + return -EBUSY; /* cannot unregister clockevent */ +} + +static struct platform_driver sh_mtu2_device_driver = { + .probe = sh_mtu2_probe, + .remove = __devexit_p(sh_mtu2_remove), + .driver = { + .name = "sh_mtu2", + } +}; + +static int __init sh_mtu2_init(void) +{ + return platform_driver_register(&sh_mtu2_device_driver); +} + +static void __exit sh_mtu2_exit(void) +{ + platform_driver_unregister(&sh_mtu2_device_driver); +} + +early_platform_init("earlytimer", &sh_mtu2_device_driver); +module_init(sh_mtu2_init); +module_exit(sh_mtu2_exit); + +MODULE_AUTHOR("Magnus Damm"); +MODULE_DESCRIPTION("SuperH MTU2 Timer Driver"); +MODULE_LICENSE("GPL v2"); |