diff options
Diffstat (limited to 'arch/powerpc/sysdev/fsl_gtm.c')
| -rw-r--r-- | arch/powerpc/sysdev/fsl_gtm.c | 434 |
1 files changed, 434 insertions, 0 deletions
diff --git a/arch/powerpc/sysdev/fsl_gtm.c b/arch/powerpc/sysdev/fsl_gtm.c new file mode 100644 index 000000000..39186ad6b --- /dev/null +++ b/arch/powerpc/sysdev/fsl_gtm.c @@ -0,0 +1,434 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Freescale General-purpose Timers Module + * + * Copyright (c) Freescale Semiconductor, Inc. 2006. + * Shlomi Gridish <gridish@freescale.com> + * Jerry Huang <Chang-Ming.Huang@freescale.com> + * Copyright (c) MontaVista Software, Inc. 2008. + * Anton Vorontsov <avorontsov@ru.mvista.com> + */ + +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/list.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/spinlock.h> +#include <linux/bitops.h> +#include <linux/slab.h> +#include <linux/export.h> +#include <asm/fsl_gtm.h> + +#define GTCFR_STP(x) ((x) & 1 ? 1 << 5 : 1 << 1) +#define GTCFR_RST(x) ((x) & 1 ? 1 << 4 : 1 << 0) + +#define GTMDR_ICLK_MASK (3 << 1) +#define GTMDR_ICLK_ICAS (0 << 1) +#define GTMDR_ICLK_ICLK (1 << 1) +#define GTMDR_ICLK_SLGO (2 << 1) +#define GTMDR_FRR (1 << 3) +#define GTMDR_ORI (1 << 4) +#define GTMDR_SPS(x) ((x) << 8) + +struct gtm_timers_regs { + u8 gtcfr1; /* Timer 1, Timer 2 global config register */ + u8 res0[0x3]; + u8 gtcfr2; /* Timer 3, timer 4 global config register */ + u8 res1[0xB]; + __be16 gtmdr1; /* Timer 1 mode register */ + __be16 gtmdr2; /* Timer 2 mode register */ + __be16 gtrfr1; /* Timer 1 reference register */ + __be16 gtrfr2; /* Timer 2 reference register */ + __be16 gtcpr1; /* Timer 1 capture register */ + __be16 gtcpr2; /* Timer 2 capture register */ + __be16 gtcnr1; /* Timer 1 counter */ + __be16 gtcnr2; /* Timer 2 counter */ + __be16 gtmdr3; /* Timer 3 mode register */ + __be16 gtmdr4; /* Timer 4 mode register */ + __be16 gtrfr3; /* Timer 3 reference register */ + __be16 gtrfr4; /* Timer 4 reference register */ + __be16 gtcpr3; /* Timer 3 capture register */ + __be16 gtcpr4; /* Timer 4 capture register */ + __be16 gtcnr3; /* Timer 3 counter */ + __be16 gtcnr4; /* Timer 4 counter */ + __be16 gtevr1; /* Timer 1 event register */ + __be16 gtevr2; /* Timer 2 event register */ + __be16 gtevr3; /* Timer 3 event register */ + __be16 gtevr4; /* Timer 4 event register */ + __be16 gtpsr1; /* Timer 1 prescale register */ + __be16 gtpsr2; /* Timer 2 prescale register */ + __be16 gtpsr3; /* Timer 3 prescale register */ + __be16 gtpsr4; /* Timer 4 prescale register */ + u8 res2[0x40]; +} __attribute__ ((packed)); + +struct gtm { + unsigned int clock; + struct gtm_timers_regs __iomem *regs; + struct gtm_timer timers[4]; + spinlock_t lock; + struct list_head list_node; +}; + +static LIST_HEAD(gtms); + +/** + * gtm_get_timer - request GTM timer to use it with the rest of GTM API + * Context: non-IRQ + * + * This function reserves GTM timer for later use. It returns gtm_timer + * structure to use with the rest of GTM API, you should use timer->irq + * to manage timer interrupt. + */ +struct gtm_timer *gtm_get_timer16(void) +{ + struct gtm *gtm; + int i; + + list_for_each_entry(gtm, >ms, list_node) { + spin_lock_irq(>m->lock); + + for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) { + if (!gtm->timers[i].requested) { + gtm->timers[i].requested = true; + spin_unlock_irq(>m->lock); + return >m->timers[i]; + } + } + + spin_unlock_irq(>m->lock); + } + + if (!list_empty(>ms)) + return ERR_PTR(-EBUSY); + return ERR_PTR(-ENODEV); +} +EXPORT_SYMBOL(gtm_get_timer16); + +/** + * gtm_get_specific_timer - request specific GTM timer + * @gtm: specific GTM, pass here GTM's device_node->data + * @timer: specific timer number, Timer1 is 0. + * Context: non-IRQ + * + * This function reserves GTM timer for later use. It returns gtm_timer + * structure to use with the rest of GTM API, you should use timer->irq + * to manage timer interrupt. + */ +struct gtm_timer *gtm_get_specific_timer16(struct gtm *gtm, + unsigned int timer) +{ + struct gtm_timer *ret = ERR_PTR(-EBUSY); + + if (timer > 3) + return ERR_PTR(-EINVAL); + + spin_lock_irq(>m->lock); + + if (gtm->timers[timer].requested) + goto out; + + ret = >m->timers[timer]; + ret->requested = true; + +out: + spin_unlock_irq(>m->lock); + return ret; +} +EXPORT_SYMBOL(gtm_get_specific_timer16); + +/** + * gtm_put_timer16 - release 16 bits GTM timer + * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer + * Context: any + * + * This function releases GTM timer so others may request it. + */ +void gtm_put_timer16(struct gtm_timer *tmr) +{ + gtm_stop_timer16(tmr); + + spin_lock_irq(&tmr->gtm->lock); + tmr->requested = false; + spin_unlock_irq(&tmr->gtm->lock); +} +EXPORT_SYMBOL(gtm_put_timer16); + +/* + * This is back-end for the exported functions, it's used to reset single + * timer in reference mode. + */ +static int gtm_set_ref_timer16(struct gtm_timer *tmr, int frequency, + int reference_value, bool free_run) +{ + struct gtm *gtm = tmr->gtm; + int num = tmr - >m->timers[0]; + unsigned int prescaler; + u8 iclk = GTMDR_ICLK_ICLK; + u8 psr; + u8 sps; + unsigned long flags; + int max_prescaler = 256 * 256 * 16; + + /* CPM2 doesn't have primary prescaler */ + if (!tmr->gtpsr) + max_prescaler /= 256; + + prescaler = gtm->clock / frequency; + /* + * We have two 8 bit prescalers -- primary and secondary (psr, sps), + * plus "slow go" mode (clk / 16). So, total prescale value is + * 16 * (psr + 1) * (sps + 1). Though, for CPM2 GTMs we losing psr. + */ + if (prescaler > max_prescaler) + return -EINVAL; + + if (prescaler > max_prescaler / 16) { + iclk = GTMDR_ICLK_SLGO; + prescaler /= 16; + } + + if (prescaler <= 256) { + psr = 0; + sps = prescaler - 1; + } else { + psr = 256 - 1; + sps = prescaler / 256 - 1; + } + + spin_lock_irqsave(>m->lock, flags); + + /* + * Properly reset timers: stop, reset, set up prescalers, reference + * value and clear event register. + */ + clrsetbits_8(tmr->gtcfr, ~(GTCFR_STP(num) | GTCFR_RST(num)), + GTCFR_STP(num) | GTCFR_RST(num)); + + setbits8(tmr->gtcfr, GTCFR_STP(num)); + + if (tmr->gtpsr) + out_be16(tmr->gtpsr, psr); + clrsetbits_be16(tmr->gtmdr, 0xFFFF, iclk | GTMDR_SPS(sps) | + GTMDR_ORI | (free_run ? GTMDR_FRR : 0)); + out_be16(tmr->gtcnr, 0); + out_be16(tmr->gtrfr, reference_value); + out_be16(tmr->gtevr, 0xFFFF); + + /* Let it be. */ + clrbits8(tmr->gtcfr, GTCFR_STP(num)); + + spin_unlock_irqrestore(>m->lock, flags); + + return 0; +} + +/** + * gtm_set_timer16 - (re)set 16 bit timer with arbitrary precision + * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer + * @usec: timer interval in microseconds + * @reload: if set, the timer will reset upon expiry rather than + * continue running free. + * Context: any + * + * This function (re)sets the GTM timer so that it counts up to the requested + * interval value, and fires the interrupt when the value is reached. This + * function will reduce the precision of the timer as needed in order for the + * requested timeout to fit in a 16-bit register. + */ +int gtm_set_timer16(struct gtm_timer *tmr, unsigned long usec, bool reload) +{ + /* quite obvious, frequency which is enough for µSec precision */ + int freq = 1000000; + unsigned int bit; + + bit = fls_long(usec); + if (bit > 15) { + freq >>= bit - 15; + usec >>= bit - 15; + } + + if (!freq) + return -EINVAL; + + return gtm_set_ref_timer16(tmr, freq, usec, reload); +} +EXPORT_SYMBOL(gtm_set_timer16); + +/** + * gtm_set_exact_utimer16 - (re)set 16 bits timer + * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer + * @usec: timer interval in microseconds + * @reload: if set, the timer will reset upon expiry rather than + * continue running free. + * Context: any + * + * This function (re)sets GTM timer so that it counts up to the requested + * interval value, and fires the interrupt when the value is reached. If reload + * flag was set, timer will also reset itself upon reference value, otherwise + * it continues to increment. + * + * The _exact_ bit in the function name states that this function will not + * crop precision of the "usec" argument, thus usec is limited to 16 bits + * (single timer width). + */ +int gtm_set_exact_timer16(struct gtm_timer *tmr, u16 usec, bool reload) +{ + /* quite obvious, frequency which is enough for µSec precision */ + const int freq = 1000000; + + /* + * We can lower the frequency (and probably power consumption) by + * dividing both frequency and usec by 2 until there is no remainder. + * But we won't bother with this unless savings are measured, so just + * run the timer as is. + */ + + return gtm_set_ref_timer16(tmr, freq, usec, reload); +} +EXPORT_SYMBOL(gtm_set_exact_timer16); + +/** + * gtm_stop_timer16 - stop single timer + * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer + * Context: any + * + * This function simply stops the GTM timer. + */ +void gtm_stop_timer16(struct gtm_timer *tmr) +{ + struct gtm *gtm = tmr->gtm; + int num = tmr - >m->timers[0]; + unsigned long flags; + + spin_lock_irqsave(>m->lock, flags); + + setbits8(tmr->gtcfr, GTCFR_STP(num)); + out_be16(tmr->gtevr, 0xFFFF); + + spin_unlock_irqrestore(>m->lock, flags); +} +EXPORT_SYMBOL(gtm_stop_timer16); + +/** + * gtm_ack_timer16 - acknowledge timer event (free-run timers only) + * @tmr: pointer to the gtm_timer structure obtained from gtm_get_timer + * @events: events mask to ack + * Context: any + * + * Thus function used to acknowledge timer interrupt event, use it inside the + * interrupt handler. + */ +void gtm_ack_timer16(struct gtm_timer *tmr, u16 events) +{ + out_be16(tmr->gtevr, events); +} +EXPORT_SYMBOL(gtm_ack_timer16); + +static void __init gtm_set_shortcuts(struct device_node *np, + struct gtm_timer *timers, + struct gtm_timers_regs __iomem *regs) +{ + /* + * Yeah, I don't like this either, but timers' registers a bit messed, + * so we have to provide shortcuts to write timer independent code. + * Alternative option is to create gt*() accessors, but that will be + * even uglier and cryptic. + */ + timers[0].gtcfr = ®s->gtcfr1; + timers[0].gtmdr = ®s->gtmdr1; + timers[0].gtcnr = ®s->gtcnr1; + timers[0].gtrfr = ®s->gtrfr1; + timers[0].gtevr = ®s->gtevr1; + + timers[1].gtcfr = ®s->gtcfr1; + timers[1].gtmdr = ®s->gtmdr2; + timers[1].gtcnr = ®s->gtcnr2; + timers[1].gtrfr = ®s->gtrfr2; + timers[1].gtevr = ®s->gtevr2; + + timers[2].gtcfr = ®s->gtcfr2; + timers[2].gtmdr = ®s->gtmdr3; + timers[2].gtcnr = ®s->gtcnr3; + timers[2].gtrfr = ®s->gtrfr3; + timers[2].gtevr = ®s->gtevr3; + + timers[3].gtcfr = ®s->gtcfr2; + timers[3].gtmdr = ®s->gtmdr4; + timers[3].gtcnr = ®s->gtcnr4; + timers[3].gtrfr = ®s->gtrfr4; + timers[3].gtevr = ®s->gtevr4; + + /* CPM2 doesn't have primary prescaler */ + if (!of_device_is_compatible(np, "fsl,cpm2-gtm")) { + timers[0].gtpsr = ®s->gtpsr1; + timers[1].gtpsr = ®s->gtpsr2; + timers[2].gtpsr = ®s->gtpsr3; + timers[3].gtpsr = ®s->gtpsr4; + } +} + +static int __init fsl_gtm_init(void) +{ + struct device_node *np; + + for_each_compatible_node(np, NULL, "fsl,gtm") { + int i; + struct gtm *gtm; + const u32 *clock; + int size; + + gtm = kzalloc(sizeof(*gtm), GFP_KERNEL); + if (!gtm) { + pr_err("%pOF: unable to allocate memory\n", + np); + continue; + } + + spin_lock_init(>m->lock); + + clock = of_get_property(np, "clock-frequency", &size); + if (!clock || size != sizeof(*clock)) { + pr_err("%pOF: no clock-frequency\n", np); + goto err; + } + gtm->clock = *clock; + + for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) { + unsigned int irq; + + irq = irq_of_parse_and_map(np, i); + if (!irq) { + pr_err("%pOF: not enough interrupts specified\n", + np); + goto err; + } + gtm->timers[i].irq = irq; + gtm->timers[i].gtm = gtm; + } + + gtm->regs = of_iomap(np, 0); + if (!gtm->regs) { + pr_err("%pOF: unable to iomap registers\n", + np); + goto err; + } + + gtm_set_shortcuts(np, gtm->timers, gtm->regs); + list_add(>m->list_node, >ms); + + /* We don't want to lose the node and its ->data */ + np->data = gtm; + of_node_get(np); + + continue; +err: + kfree(gtm); + } + return 0; +} +arch_initcall(fsl_gtm_init); |