diff options
Diffstat (limited to 'kernel/drivers/clocksource/sh_cmt.c')
| -rw-r--r-- | kernel/drivers/clocksource/sh_cmt.c | 1110 |
1 files changed, 1110 insertions, 0 deletions
diff --git a/kernel/drivers/clocksource/sh_cmt.c b/kernel/drivers/clocksource/sh_cmt.c new file mode 100644 index 000000000..b8ff3c64c --- /dev/null +++ b/kernel/drivers/clocksource/sh_cmt.c @@ -0,0 +1,1110 @@ +/* + * SuperH Timer Support - CMT + * + * Copyright (C) 2008 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. + */ + +#include <linux/clk.h> +#include <linux/clockchips.h> +#include <linux/clocksource.h> +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/io.h> +#include <linux/ioport.h> +#include <linux/irq.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/pm_domain.h> +#include <linux/pm_runtime.h> +#include <linux/sh_timer.h> +#include <linux/slab.h> +#include <linux/spinlock.h> + +struct sh_cmt_device; + +/* + * The CMT comes in 5 different identified flavours, depending not only on the + * SoC but also on the particular instance. The following table lists the main + * characteristics of those flavours. + * + * 16B 32B 32B-F 48B 48B-2 + * ----------------------------------------------------------------------------- + * Channels 2 1/4 1 6 2/8 + * Control Width 16 16 16 16 32 + * Counter Width 16 32 32 32/48 32/48 + * Shared Start/Stop Y Y Y Y N + * + * The 48-bit gen2 version has a per-channel start/stop register located in the + * channel registers block. All other versions have a shared start/stop register + * located in the global space. + * + * Channels are indexed from 0 to N-1 in the documentation. The channel index + * infers the start/stop bit position in the control register and the channel + * registers block address. Some CMT instances have a subset of channels + * available, in which case the index in the documentation doesn't match the + * "real" index as implemented in hardware. This is for instance the case with + * CMT0 on r8a7740, which is a 32-bit variant with a single channel numbered 0 + * in the documentation but using start/stop bit 5 and having its registers + * block at 0x60. + * + * Similarly CMT0 on r8a73a4, r8a7790 and r8a7791, while implementing 32-bit + * channels only, is a 48-bit gen2 CMT with the 48-bit channels unavailable. + */ + +enum sh_cmt_model { + SH_CMT_16BIT, + SH_CMT_32BIT, + SH_CMT_32BIT_FAST, + SH_CMT_48BIT, + SH_CMT_48BIT_GEN2, +}; + +struct sh_cmt_info { + enum sh_cmt_model model; + + unsigned long width; /* 16 or 32 bit version of hardware block */ + unsigned long overflow_bit; + unsigned long clear_bits; + + /* callbacks for CMSTR and CMCSR access */ + unsigned long (*read_control)(void __iomem *base, unsigned long offs); + void (*write_control)(void __iomem *base, unsigned long offs, + unsigned long value); + + /* callbacks for CMCNT and CMCOR access */ + unsigned long (*read_count)(void __iomem *base, unsigned long offs); + void (*write_count)(void __iomem *base, unsigned long offs, + unsigned long value); +}; + +struct sh_cmt_channel { + struct sh_cmt_device *cmt; + + unsigned int index; /* Index in the documentation */ + unsigned int hwidx; /* Real hardware index */ + + void __iomem *iostart; + void __iomem *ioctrl; + + unsigned int timer_bit; + unsigned long flags; + unsigned long match_value; + unsigned long next_match_value; + unsigned long max_match_value; + unsigned long rate; + raw_spinlock_t lock; + struct clock_event_device ced; + struct clocksource cs; + unsigned long total_cycles; + bool cs_enabled; +}; + +struct sh_cmt_device { + struct platform_device *pdev; + + const struct sh_cmt_info *info; + + void __iomem *mapbase; + struct clk *clk; + + raw_spinlock_t lock; /* Protect the shared start/stop register */ + + struct sh_cmt_channel *channels; + unsigned int num_channels; + unsigned int hw_channels; + + bool has_clockevent; + bool has_clocksource; +}; + +#define SH_CMT16_CMCSR_CMF (1 << 7) +#define SH_CMT16_CMCSR_CMIE (1 << 6) +#define SH_CMT16_CMCSR_CKS8 (0 << 0) +#define SH_CMT16_CMCSR_CKS32 (1 << 0) +#define SH_CMT16_CMCSR_CKS128 (2 << 0) +#define SH_CMT16_CMCSR_CKS512 (3 << 0) +#define SH_CMT16_CMCSR_CKS_MASK (3 << 0) + +#define SH_CMT32_CMCSR_CMF (1 << 15) +#define SH_CMT32_CMCSR_OVF (1 << 14) +#define SH_CMT32_CMCSR_WRFLG (1 << 13) +#define SH_CMT32_CMCSR_STTF (1 << 12) +#define SH_CMT32_CMCSR_STPF (1 << 11) +#define SH_CMT32_CMCSR_SSIE (1 << 10) +#define SH_CMT32_CMCSR_CMS (1 << 9) +#define SH_CMT32_CMCSR_CMM (1 << 8) +#define SH_CMT32_CMCSR_CMTOUT_IE (1 << 7) +#define SH_CMT32_CMCSR_CMR_NONE (0 << 4) +#define SH_CMT32_CMCSR_CMR_DMA (1 << 4) +#define SH_CMT32_CMCSR_CMR_IRQ (2 << 4) +#define SH_CMT32_CMCSR_CMR_MASK (3 << 4) +#define SH_CMT32_CMCSR_DBGIVD (1 << 3) +#define SH_CMT32_CMCSR_CKS_RCLK8 (4 << 0) +#define SH_CMT32_CMCSR_CKS_RCLK32 (5 << 0) +#define SH_CMT32_CMCSR_CKS_RCLK128 (6 << 0) +#define SH_CMT32_CMCSR_CKS_RCLK1 (7 << 0) +#define SH_CMT32_CMCSR_CKS_MASK (7 << 0) + +static unsigned long sh_cmt_read16(void __iomem *base, unsigned long offs) +{ + return ioread16(base + (offs << 1)); +} + +static unsigned long sh_cmt_read32(void __iomem *base, unsigned long offs) +{ + return ioread32(base + (offs << 2)); +} + +static void sh_cmt_write16(void __iomem *base, unsigned long offs, + unsigned long value) +{ + iowrite16(value, base + (offs << 1)); +} + +static void sh_cmt_write32(void __iomem *base, unsigned long offs, + unsigned long value) +{ + iowrite32(value, base + (offs << 2)); +} + +static const struct sh_cmt_info sh_cmt_info[] = { + [SH_CMT_16BIT] = { + .model = SH_CMT_16BIT, + .width = 16, + .overflow_bit = SH_CMT16_CMCSR_CMF, + .clear_bits = ~SH_CMT16_CMCSR_CMF, + .read_control = sh_cmt_read16, + .write_control = sh_cmt_write16, + .read_count = sh_cmt_read16, + .write_count = sh_cmt_write16, + }, + [SH_CMT_32BIT] = { + .model = SH_CMT_32BIT, + .width = 32, + .overflow_bit = SH_CMT32_CMCSR_CMF, + .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF), + .read_control = sh_cmt_read16, + .write_control = sh_cmt_write16, + .read_count = sh_cmt_read32, + .write_count = sh_cmt_write32, + }, + [SH_CMT_32BIT_FAST] = { + .model = SH_CMT_32BIT_FAST, + .width = 32, + .overflow_bit = SH_CMT32_CMCSR_CMF, + .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF), + .read_control = sh_cmt_read16, + .write_control = sh_cmt_write16, + .read_count = sh_cmt_read32, + .write_count = sh_cmt_write32, + }, + [SH_CMT_48BIT] = { + .model = SH_CMT_48BIT, + .width = 32, + .overflow_bit = SH_CMT32_CMCSR_CMF, + .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF), + .read_control = sh_cmt_read32, + .write_control = sh_cmt_write32, + .read_count = sh_cmt_read32, + .write_count = sh_cmt_write32, + }, + [SH_CMT_48BIT_GEN2] = { + .model = SH_CMT_48BIT_GEN2, + .width = 32, + .overflow_bit = SH_CMT32_CMCSR_CMF, + .clear_bits = ~(SH_CMT32_CMCSR_CMF | SH_CMT32_CMCSR_OVF), + .read_control = sh_cmt_read32, + .write_control = sh_cmt_write32, + .read_count = sh_cmt_read32, + .write_count = sh_cmt_write32, + }, +}; + +#define CMCSR 0 /* channel register */ +#define CMCNT 1 /* channel register */ +#define CMCOR 2 /* channel register */ + +static inline unsigned long sh_cmt_read_cmstr(struct sh_cmt_channel *ch) +{ + if (ch->iostart) + return ch->cmt->info->read_control(ch->iostart, 0); + else + return ch->cmt->info->read_control(ch->cmt->mapbase, 0); +} + +static inline void sh_cmt_write_cmstr(struct sh_cmt_channel *ch, + unsigned long value) +{ + if (ch->iostart) + ch->cmt->info->write_control(ch->iostart, 0, value); + else + ch->cmt->info->write_control(ch->cmt->mapbase, 0, value); +} + +static inline unsigned long sh_cmt_read_cmcsr(struct sh_cmt_channel *ch) +{ + return ch->cmt->info->read_control(ch->ioctrl, CMCSR); +} + +static inline void sh_cmt_write_cmcsr(struct sh_cmt_channel *ch, + unsigned long value) +{ + ch->cmt->info->write_control(ch->ioctrl, CMCSR, value); +} + +static inline unsigned long sh_cmt_read_cmcnt(struct sh_cmt_channel *ch) +{ + return ch->cmt->info->read_count(ch->ioctrl, CMCNT); +} + +static inline void sh_cmt_write_cmcnt(struct sh_cmt_channel *ch, + unsigned long value) +{ + ch->cmt->info->write_count(ch->ioctrl, CMCNT, value); +} + +static inline void sh_cmt_write_cmcor(struct sh_cmt_channel *ch, + unsigned long value) +{ + ch->cmt->info->write_count(ch->ioctrl, CMCOR, value); +} + +static unsigned long sh_cmt_get_counter(struct sh_cmt_channel *ch, + int *has_wrapped) +{ + unsigned long v1, v2, v3; + int o1, o2; + + o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit; + + /* Make sure the timer value is stable. Stolen from acpi_pm.c */ + do { + o2 = o1; + v1 = sh_cmt_read_cmcnt(ch); + v2 = sh_cmt_read_cmcnt(ch); + v3 = sh_cmt_read_cmcnt(ch); + o1 = sh_cmt_read_cmcsr(ch) & ch->cmt->info->overflow_bit; + } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3) + || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2))); + + *has_wrapped = o1; + return v2; +} + +static void sh_cmt_start_stop_ch(struct sh_cmt_channel *ch, int start) +{ + unsigned long flags, value; + + /* start stop register shared by multiple timer channels */ + raw_spin_lock_irqsave(&ch->cmt->lock, flags); + value = sh_cmt_read_cmstr(ch); + + if (start) + value |= 1 << ch->timer_bit; + else + value &= ~(1 << ch->timer_bit); + + sh_cmt_write_cmstr(ch, value); + raw_spin_unlock_irqrestore(&ch->cmt->lock, flags); +} + +static int sh_cmt_enable(struct sh_cmt_channel *ch, unsigned long *rate) +{ + int k, ret; + + pm_runtime_get_sync(&ch->cmt->pdev->dev); + dev_pm_syscore_device(&ch->cmt->pdev->dev, true); + + /* enable clock */ + ret = clk_enable(ch->cmt->clk); + if (ret) { + dev_err(&ch->cmt->pdev->dev, "ch%u: cannot enable clock\n", + ch->index); + goto err0; + } + + /* make sure channel is disabled */ + sh_cmt_start_stop_ch(ch, 0); + + /* configure channel, periodic mode and maximum timeout */ + if (ch->cmt->info->width == 16) { + *rate = clk_get_rate(ch->cmt->clk) / 512; + sh_cmt_write_cmcsr(ch, SH_CMT16_CMCSR_CMIE | + SH_CMT16_CMCSR_CKS512); + } else { + *rate = clk_get_rate(ch->cmt->clk) / 8; + sh_cmt_write_cmcsr(ch, SH_CMT32_CMCSR_CMM | + SH_CMT32_CMCSR_CMTOUT_IE | + SH_CMT32_CMCSR_CMR_IRQ | + SH_CMT32_CMCSR_CKS_RCLK8); + } + + sh_cmt_write_cmcor(ch, 0xffffffff); + sh_cmt_write_cmcnt(ch, 0); + + /* + * According to the sh73a0 user's manual, as CMCNT can be operated + * only by the RCLK (Pseudo 32 KHz), there's one restriction on + * modifying CMCNT register; two RCLK cycles are necessary before + * this register is either read or any modification of the value + * it holds is reflected in the LSI's actual operation. + * + * While at it, we're supposed to clear out the CMCNT as of this + * moment, so make sure it's processed properly here. This will + * take RCLKx2 at maximum. + */ + for (k = 0; k < 100; k++) { + if (!sh_cmt_read_cmcnt(ch)) + break; + udelay(1); + } + + if (sh_cmt_read_cmcnt(ch)) { + dev_err(&ch->cmt->pdev->dev, "ch%u: cannot clear CMCNT\n", + ch->index); + ret = -ETIMEDOUT; + goto err1; + } + + /* enable channel */ + sh_cmt_start_stop_ch(ch, 1); + return 0; + err1: + /* stop clock */ + clk_disable(ch->cmt->clk); + + err0: + return ret; +} + +static void sh_cmt_disable(struct sh_cmt_channel *ch) +{ + /* disable channel */ + sh_cmt_start_stop_ch(ch, 0); + + /* disable interrupts in CMT block */ + sh_cmt_write_cmcsr(ch, 0); + + /* stop clock */ + clk_disable(ch->cmt->clk); + + dev_pm_syscore_device(&ch->cmt->pdev->dev, false); + pm_runtime_put(&ch->cmt->pdev->dev); +} + +/* private flags */ +#define FLAG_CLOCKEVENT (1 << 0) +#define FLAG_CLOCKSOURCE (1 << 1) +#define FLAG_REPROGRAM (1 << 2) +#define FLAG_SKIPEVENT (1 << 3) +#define FLAG_IRQCONTEXT (1 << 4) + +static void sh_cmt_clock_event_program_verify(struct sh_cmt_channel *ch, + int absolute) +{ + unsigned long new_match; + unsigned long value = ch->next_match_value; + unsigned long delay = 0; + unsigned long now = 0; + int has_wrapped; + + now = sh_cmt_get_counter(ch, &has_wrapped); + ch->flags |= FLAG_REPROGRAM; /* force reprogram */ + + if (has_wrapped) { + /* we're competing with the interrupt handler. + * -> let the interrupt handler reprogram the timer. + * -> interrupt number two handles the event. + */ + ch->flags |= FLAG_SKIPEVENT; + return; + } + + if (absolute) + now = 0; + + do { + /* reprogram the timer hardware, + * but don't save the new match value yet. + */ + new_match = now + value + delay; + if (new_match > ch->max_match_value) + new_match = ch->max_match_value; + + sh_cmt_write_cmcor(ch, new_match); + + now = sh_cmt_get_counter(ch, &has_wrapped); + if (has_wrapped && (new_match > ch->match_value)) { + /* we are changing to a greater match value, + * so this wrap must be caused by the counter + * matching the old value. + * -> first interrupt reprograms the timer. + * -> interrupt number two handles the event. + */ + ch->flags |= FLAG_SKIPEVENT; + break; + } + + if (has_wrapped) { + /* we are changing to a smaller match value, + * so the wrap must be caused by the counter + * matching the new value. + * -> save programmed match value. + * -> let isr handle the event. + */ + ch->match_value = new_match; + break; + } + + /* be safe: verify hardware settings */ + if (now < new_match) { + /* timer value is below match value, all good. + * this makes sure we won't miss any match events. + * -> save programmed match value. + * -> let isr handle the event. + */ + ch->match_value = new_match; + break; + } + + /* the counter has reached a value greater + * than our new match value. and since the + * has_wrapped flag isn't set we must have + * programmed a too close event. + * -> increase delay and retry. + */ + if (delay) + delay <<= 1; + else + delay = 1; + + if (!delay) + dev_warn(&ch->cmt->pdev->dev, "ch%u: too long delay\n", + ch->index); + + } while (delay); +} + +static void __sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta) +{ + if (delta > ch->max_match_value) + dev_warn(&ch->cmt->pdev->dev, "ch%u: delta out of range\n", + ch->index); + + ch->next_match_value = delta; + sh_cmt_clock_event_program_verify(ch, 0); +} + +static void sh_cmt_set_next(struct sh_cmt_channel *ch, unsigned long delta) +{ + unsigned long flags; + + raw_spin_lock_irqsave(&ch->lock, flags); + __sh_cmt_set_next(ch, delta); + raw_spin_unlock_irqrestore(&ch->lock, flags); +} + +static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id) +{ + struct sh_cmt_channel *ch = dev_id; + + /* clear flags */ + sh_cmt_write_cmcsr(ch, sh_cmt_read_cmcsr(ch) & + ch->cmt->info->clear_bits); + + /* update clock source counter to begin with if enabled + * the wrap flag should be cleared by the timer specific + * isr before we end up here. + */ + if (ch->flags & FLAG_CLOCKSOURCE) + ch->total_cycles += ch->match_value + 1; + + if (!(ch->flags & FLAG_REPROGRAM)) + ch->next_match_value = ch->max_match_value; + + ch->flags |= FLAG_IRQCONTEXT; + + if (ch->flags & FLAG_CLOCKEVENT) { + if (!(ch->flags & FLAG_SKIPEVENT)) { + if (ch->ced.mode == CLOCK_EVT_MODE_ONESHOT) { + ch->next_match_value = ch->max_match_value; + ch->flags |= FLAG_REPROGRAM; + } + + ch->ced.event_handler(&ch->ced); + } + } + + ch->flags &= ~FLAG_SKIPEVENT; + + if (ch->flags & FLAG_REPROGRAM) { + ch->flags &= ~FLAG_REPROGRAM; + sh_cmt_clock_event_program_verify(ch, 1); + + if (ch->flags & FLAG_CLOCKEVENT) + if ((ch->ced.mode == CLOCK_EVT_MODE_SHUTDOWN) + || (ch->match_value == ch->next_match_value)) + ch->flags &= ~FLAG_REPROGRAM; + } + + ch->flags &= ~FLAG_IRQCONTEXT; + + return IRQ_HANDLED; +} + +static int sh_cmt_start(struct sh_cmt_channel *ch, unsigned long flag) +{ + int ret = 0; + unsigned long flags; + + raw_spin_lock_irqsave(&ch->lock, flags); + + if (!(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE))) + ret = sh_cmt_enable(ch, &ch->rate); + + if (ret) + goto out; + ch->flags |= flag; + + /* setup timeout if no clockevent */ + if ((flag == FLAG_CLOCKSOURCE) && (!(ch->flags & FLAG_CLOCKEVENT))) + __sh_cmt_set_next(ch, ch->max_match_value); + out: + raw_spin_unlock_irqrestore(&ch->lock, flags); + + return ret; +} + +static void sh_cmt_stop(struct sh_cmt_channel *ch, unsigned long flag) +{ + unsigned long flags; + unsigned long f; + + raw_spin_lock_irqsave(&ch->lock, flags); + + f = ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE); + ch->flags &= ~flag; + + if (f && !(ch->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE))) + sh_cmt_disable(ch); + + /* adjust the timeout to maximum if only clocksource left */ + if ((flag == FLAG_CLOCKEVENT) && (ch->flags & FLAG_CLOCKSOURCE)) + __sh_cmt_set_next(ch, ch->max_match_value); + + raw_spin_unlock_irqrestore(&ch->lock, flags); +} + +static struct sh_cmt_channel *cs_to_sh_cmt(struct clocksource *cs) +{ + return container_of(cs, struct sh_cmt_channel, cs); +} + +static cycle_t sh_cmt_clocksource_read(struct clocksource *cs) +{ + struct sh_cmt_channel *ch = cs_to_sh_cmt(cs); + unsigned long flags, raw; + unsigned long value; + int has_wrapped; + + raw_spin_lock_irqsave(&ch->lock, flags); + value = ch->total_cycles; + raw = sh_cmt_get_counter(ch, &has_wrapped); + + if (unlikely(has_wrapped)) + raw += ch->match_value + 1; + raw_spin_unlock_irqrestore(&ch->lock, flags); + + return value + raw; +} + +static int sh_cmt_clocksource_enable(struct clocksource *cs) +{ + int ret; + struct sh_cmt_channel *ch = cs_to_sh_cmt(cs); + + WARN_ON(ch->cs_enabled); + + ch->total_cycles = 0; + + ret = sh_cmt_start(ch, FLAG_CLOCKSOURCE); + if (!ret) { + __clocksource_update_freq_hz(cs, ch->rate); + ch->cs_enabled = true; + } + return ret; +} + +static void sh_cmt_clocksource_disable(struct clocksource *cs) +{ + struct sh_cmt_channel *ch = cs_to_sh_cmt(cs); + + WARN_ON(!ch->cs_enabled); + + sh_cmt_stop(ch, FLAG_CLOCKSOURCE); + ch->cs_enabled = false; +} + +static void sh_cmt_clocksource_suspend(struct clocksource *cs) +{ + struct sh_cmt_channel *ch = cs_to_sh_cmt(cs); + + sh_cmt_stop(ch, FLAG_CLOCKSOURCE); + pm_genpd_syscore_poweroff(&ch->cmt->pdev->dev); +} + +static void sh_cmt_clocksource_resume(struct clocksource *cs) +{ + struct sh_cmt_channel *ch = cs_to_sh_cmt(cs); + + pm_genpd_syscore_poweron(&ch->cmt->pdev->dev); + sh_cmt_start(ch, FLAG_CLOCKSOURCE); +} + +static int sh_cmt_register_clocksource(struct sh_cmt_channel *ch, + const char *name) +{ + struct clocksource *cs = &ch->cs; + + cs->name = name; + cs->rating = 125; + cs->read = sh_cmt_clocksource_read; + cs->enable = sh_cmt_clocksource_enable; + cs->disable = sh_cmt_clocksource_disable; + cs->suspend = sh_cmt_clocksource_suspend; + cs->resume = sh_cmt_clocksource_resume; + cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8); + cs->flags = CLOCK_SOURCE_IS_CONTINUOUS; + + dev_info(&ch->cmt->pdev->dev, "ch%u: used as clock source\n", + ch->index); + + /* Register with dummy 1 Hz value, gets updated in ->enable() */ + clocksource_register_hz(cs, 1); + return 0; +} + +static struct sh_cmt_channel *ced_to_sh_cmt(struct clock_event_device *ced) +{ + return container_of(ced, struct sh_cmt_channel, ced); +} + +static void sh_cmt_clock_event_start(struct sh_cmt_channel *ch, int periodic) +{ + struct clock_event_device *ced = &ch->ced; + + sh_cmt_start(ch, FLAG_CLOCKEVENT); + + /* TODO: calculate good shift from rate and counter bit width */ + + ced->shift = 32; + ced->mult = div_sc(ch->rate, NSEC_PER_SEC, ced->shift); + ced->max_delta_ns = clockevent_delta2ns(ch->max_match_value, ced); + ced->min_delta_ns = clockevent_delta2ns(0x1f, ced); + + if (periodic) + sh_cmt_set_next(ch, ((ch->rate + HZ/2) / HZ) - 1); + else + sh_cmt_set_next(ch, ch->max_match_value); +} + +static void sh_cmt_clock_event_mode(enum clock_event_mode mode, + struct clock_event_device *ced) +{ + struct sh_cmt_channel *ch = ced_to_sh_cmt(ced); + + /* deal with old setting first */ + switch (ced->mode) { + case CLOCK_EVT_MODE_PERIODIC: + case CLOCK_EVT_MODE_ONESHOT: + sh_cmt_stop(ch, FLAG_CLOCKEVENT); + break; + default: + break; + } + + switch (mode) { + case CLOCK_EVT_MODE_PERIODIC: + dev_info(&ch->cmt->pdev->dev, + "ch%u: used for periodic clock events\n", ch->index); + sh_cmt_clock_event_start(ch, 1); + break; + case CLOCK_EVT_MODE_ONESHOT: + dev_info(&ch->cmt->pdev->dev, + "ch%u: used for oneshot clock events\n", ch->index); + sh_cmt_clock_event_start(ch, 0); + break; + case CLOCK_EVT_MODE_SHUTDOWN: + case CLOCK_EVT_MODE_UNUSED: + sh_cmt_stop(ch, FLAG_CLOCKEVENT); + break; + default: + break; + } +} + +static int sh_cmt_clock_event_next(unsigned long delta, + struct clock_event_device *ced) +{ + struct sh_cmt_channel *ch = ced_to_sh_cmt(ced); + + BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT); + if (likely(ch->flags & FLAG_IRQCONTEXT)) + ch->next_match_value = delta - 1; + else + sh_cmt_set_next(ch, delta - 1); + + return 0; +} + +static void sh_cmt_clock_event_suspend(struct clock_event_device *ced) +{ + struct sh_cmt_channel *ch = ced_to_sh_cmt(ced); + + pm_genpd_syscore_poweroff(&ch->cmt->pdev->dev); + clk_unprepare(ch->cmt->clk); +} + +static void sh_cmt_clock_event_resume(struct clock_event_device *ced) +{ + struct sh_cmt_channel *ch = ced_to_sh_cmt(ced); + + clk_prepare(ch->cmt->clk); + pm_genpd_syscore_poweron(&ch->cmt->pdev->dev); +} + +static int sh_cmt_register_clockevent(struct sh_cmt_channel *ch, + const char *name) +{ + struct clock_event_device *ced = &ch->ced; + int irq; + int ret; + + irq = platform_get_irq(ch->cmt->pdev, ch->index); + if (irq < 0) { + dev_err(&ch->cmt->pdev->dev, "ch%u: failed to get irq\n", + ch->index); + return irq; + } + + ret = request_irq(irq, sh_cmt_interrupt, + IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, + dev_name(&ch->cmt->pdev->dev), ch); + if (ret) { + dev_err(&ch->cmt->pdev->dev, "ch%u: failed to request irq %d\n", + ch->index, irq); + return ret; + } + + ced->name = name; + ced->features = CLOCK_EVT_FEAT_PERIODIC; + ced->features |= CLOCK_EVT_FEAT_ONESHOT; + ced->rating = 125; + ced->cpumask = cpu_possible_mask; + ced->set_next_event = sh_cmt_clock_event_next; + ced->set_mode = sh_cmt_clock_event_mode; + ced->suspend = sh_cmt_clock_event_suspend; + ced->resume = sh_cmt_clock_event_resume; + + dev_info(&ch->cmt->pdev->dev, "ch%u: used for clock events\n", + ch->index); + clockevents_register_device(ced); + + return 0; +} + +static int sh_cmt_register(struct sh_cmt_channel *ch, const char *name, + bool clockevent, bool clocksource) +{ + int ret; + + if (clockevent) { + ch->cmt->has_clockevent = true; + ret = sh_cmt_register_clockevent(ch, name); + if (ret < 0) + return ret; + } + + if (clocksource) { + ch->cmt->has_clocksource = true; + sh_cmt_register_clocksource(ch, name); + } + + return 0; +} + +static int sh_cmt_setup_channel(struct sh_cmt_channel *ch, unsigned int index, + unsigned int hwidx, bool clockevent, + bool clocksource, struct sh_cmt_device *cmt) +{ + int ret; + + /* Skip unused channels. */ + if (!clockevent && !clocksource) + return 0; + + ch->cmt = cmt; + ch->index = index; + ch->hwidx = hwidx; + + /* + * Compute the address of the channel control register block. For the + * timers with a per-channel start/stop register, compute its address + * as well. + */ + switch (cmt->info->model) { + case SH_CMT_16BIT: + ch->ioctrl = cmt->mapbase + 2 + ch->hwidx * 6; + break; + case SH_CMT_32BIT: + case SH_CMT_48BIT: + ch->ioctrl = cmt->mapbase + 0x10 + ch->hwidx * 0x10; + break; + case SH_CMT_32BIT_FAST: + /* + * The 32-bit "fast" timer has a single channel at hwidx 5 but + * is located at offset 0x40 instead of 0x60 for some reason. + */ + ch->ioctrl = cmt->mapbase + 0x40; + break; + case SH_CMT_48BIT_GEN2: + ch->iostart = cmt->mapbase + ch->hwidx * 0x100; + ch->ioctrl = ch->iostart + 0x10; + break; + } + + if (cmt->info->width == (sizeof(ch->max_match_value) * 8)) + ch->max_match_value = ~0; + else + ch->max_match_value = (1 << cmt->info->width) - 1; + + ch->match_value = ch->max_match_value; + raw_spin_lock_init(&ch->lock); + + ch->timer_bit = cmt->info->model == SH_CMT_48BIT_GEN2 ? 0 : ch->hwidx; + + ret = sh_cmt_register(ch, dev_name(&cmt->pdev->dev), + clockevent, clocksource); + if (ret) { + dev_err(&cmt->pdev->dev, "ch%u: registration failed\n", + ch->index); + return ret; + } + ch->cs_enabled = false; + + return 0; +} + +static int sh_cmt_map_memory(struct sh_cmt_device *cmt) +{ + struct resource *mem; + + mem = platform_get_resource(cmt->pdev, IORESOURCE_MEM, 0); + if (!mem) { + dev_err(&cmt->pdev->dev, "failed to get I/O memory\n"); + return -ENXIO; + } + + cmt->mapbase = ioremap_nocache(mem->start, resource_size(mem)); + if (cmt->mapbase == NULL) { + dev_err(&cmt->pdev->dev, "failed to remap I/O memory\n"); + return -ENXIO; + } + + return 0; +} + +static const struct platform_device_id sh_cmt_id_table[] = { + { "sh-cmt-16", (kernel_ulong_t)&sh_cmt_info[SH_CMT_16BIT] }, + { "sh-cmt-32", (kernel_ulong_t)&sh_cmt_info[SH_CMT_32BIT] }, + { "sh-cmt-32-fast", (kernel_ulong_t)&sh_cmt_info[SH_CMT_32BIT_FAST] }, + { "sh-cmt-48", (kernel_ulong_t)&sh_cmt_info[SH_CMT_48BIT] }, + { "sh-cmt-48-gen2", (kernel_ulong_t)&sh_cmt_info[SH_CMT_48BIT_GEN2] }, + { } +}; +MODULE_DEVICE_TABLE(platform, sh_cmt_id_table); + +static const struct of_device_id sh_cmt_of_table[] __maybe_unused = { + { .compatible = "renesas,cmt-32", .data = &sh_cmt_info[SH_CMT_32BIT] }, + { .compatible = "renesas,cmt-32-fast", .data = &sh_cmt_info[SH_CMT_32BIT_FAST] }, + { .compatible = "renesas,cmt-48", .data = &sh_cmt_info[SH_CMT_48BIT] }, + { .compatible = "renesas,cmt-48-gen2", .data = &sh_cmt_info[SH_CMT_48BIT_GEN2] }, + { } +}; +MODULE_DEVICE_TABLE(of, sh_cmt_of_table); + +static int sh_cmt_parse_dt(struct sh_cmt_device *cmt) +{ + struct device_node *np = cmt->pdev->dev.of_node; + + return of_property_read_u32(np, "renesas,channels-mask", + &cmt->hw_channels); +} + +static int sh_cmt_setup(struct sh_cmt_device *cmt, struct platform_device *pdev) +{ + unsigned int mask; + unsigned int i; + int ret; + + memset(cmt, 0, sizeof(*cmt)); + cmt->pdev = pdev; + raw_spin_lock_init(&cmt->lock); + + if (IS_ENABLED(CONFIG_OF) && pdev->dev.of_node) { + const struct of_device_id *id; + + id = of_match_node(sh_cmt_of_table, pdev->dev.of_node); + cmt->info = id->data; + + ret = sh_cmt_parse_dt(cmt); + if (ret < 0) + return ret; + } else if (pdev->dev.platform_data) { + struct sh_timer_config *cfg = pdev->dev.platform_data; + const struct platform_device_id *id = pdev->id_entry; + + cmt->info = (const struct sh_cmt_info *)id->driver_data; + cmt->hw_channels = cfg->channels_mask; + } else { + dev_err(&cmt->pdev->dev, "missing platform data\n"); + return -ENXIO; + } + + /* Get hold of clock. */ + cmt->clk = clk_get(&cmt->pdev->dev, "fck"); + if (IS_ERR(cmt->clk)) { + dev_err(&cmt->pdev->dev, "cannot get clock\n"); + return PTR_ERR(cmt->clk); + } + + ret = clk_prepare(cmt->clk); + if (ret < 0) + goto err_clk_put; + + /* Map the memory resource(s). */ + ret = sh_cmt_map_memory(cmt); + if (ret < 0) + goto err_clk_unprepare; + + /* Allocate and setup the channels. */ + cmt->num_channels = hweight8(cmt->hw_channels); + cmt->channels = kzalloc(cmt->num_channels * sizeof(*cmt->channels), + GFP_KERNEL); + if (cmt->channels == NULL) { + ret = -ENOMEM; + goto err_unmap; + } + + /* + * Use the first channel as a clock event device and the second channel + * as a clock source. If only one channel is available use it for both. + */ + for (i = 0, mask = cmt->hw_channels; i < cmt->num_channels; ++i) { + unsigned int hwidx = ffs(mask) - 1; + bool clocksource = i == 1 || cmt->num_channels == 1; + bool clockevent = i == 0; + + ret = sh_cmt_setup_channel(&cmt->channels[i], i, hwidx, + clockevent, clocksource, cmt); + if (ret < 0) + goto err_unmap; + + mask &= ~(1 << hwidx); + } + + platform_set_drvdata(pdev, cmt); + + return 0; + +err_unmap: + kfree(cmt->channels); + iounmap(cmt->mapbase); +err_clk_unprepare: + clk_unprepare(cmt->clk); +err_clk_put: + clk_put(cmt->clk); + return ret; +} + +static int sh_cmt_probe(struct platform_device *pdev) +{ + struct sh_cmt_device *cmt = platform_get_drvdata(pdev); + int ret; + + if (!is_early_platform_device(pdev)) { + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); + } + + if (cmt) { + dev_info(&pdev->dev, "kept as earlytimer\n"); + goto out; + } + + cmt = kzalloc(sizeof(*cmt), GFP_KERNEL); + if (cmt == NULL) + return -ENOMEM; + + ret = sh_cmt_setup(cmt, pdev); + if (ret) { + kfree(cmt); + pm_runtime_idle(&pdev->dev); + return ret; + } + if (is_early_platform_device(pdev)) + return 0; + + out: + if (cmt->has_clockevent || cmt->has_clocksource) + pm_runtime_irq_safe(&pdev->dev); + else + pm_runtime_idle(&pdev->dev); + + return 0; +} + +static int sh_cmt_remove(struct platform_device *pdev) +{ + return -EBUSY; /* cannot unregister clockevent and clocksource */ +} + +static struct platform_driver sh_cmt_device_driver = { + .probe = sh_cmt_probe, + .remove = sh_cmt_remove, + .driver = { + .name = "sh_cmt", + .of_match_table = of_match_ptr(sh_cmt_of_table), + }, + .id_table = sh_cmt_id_table, +}; + +static int __init sh_cmt_init(void) +{ + return platform_driver_register(&sh_cmt_device_driver); +} + +static void __exit sh_cmt_exit(void) +{ + platform_driver_unregister(&sh_cmt_device_driver); +} + +early_platform_init("earlytimer", &sh_cmt_device_driver); +subsys_initcall(sh_cmt_init); +module_exit(sh_cmt_exit); + +MODULE_AUTHOR("Magnus Damm"); +MODULE_DESCRIPTION("SuperH CMT Timer Driver"); +MODULE_LICENSE("GPL v2"); |