On May 19, 2008, at 12:46 PM, Anton Vorontsov wrote:
GTM stands for General-purpose Timers Module and able to generate
timer{1,2,3,4} interrupts. These timers are used by the drivers that
need time precise interrupts (like for USB transactions scheduling for
the Freescale USB Host controller as found in some QE and CPM chips),
or these timers could be used as wakeup events from the CPU deep-sleep
mode.
Things unimplemented:
1. Cascaded (32 bit) timers (1-2, 3-4).
This is straightforward to implement when needed, two timers should
be marked as "requested" and configured as appropriate.
2. Super-cascaded (64 bit) timers (1-2-3-4).
This is also straightforward to implement when needed, all timers
should be marked as "requested" and configured as appropriate.
Signed-off-by: Anton Vorontsov <[EMAIL PROTECTED]>
---
Documentation/powerpc/booting-without-of.txt | 37 +++-
arch/powerpc/Kconfig | 5 +
arch/powerpc/sysdev/Makefile | 1 +
arch/powerpc/sysdev/fsl_gtm.c | 424 +++++++++++++++++
+++++++++
include/asm-powerpc/fsl_gtm.h | 47 +++
5 files changed, 513 insertions(+), 1 deletions(-)
create mode 100644 arch/powerpc/sysdev/fsl_gtm.c
create mode 100644 include/asm-powerpc/fsl_gtm.h
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 3934e26..e5d3366 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -538,6 +538,11 @@ config FSL_LBC
help
Freescale Localbus support
+config FSL_GTM
+ bool
I'd prefer something like:
depends on PPC_83xx || QUICC_ENGINE || CPM2
+ help
+ Freescale General-purpose Timers support
+
# Yes MCA RS/6000s exist but Linux-PPC does not currently support any
config MCA
bool
diff --git a/arch/powerpc/sysdev/fsl_gtm.c b/arch/powerpc/sysdev/
fsl_gtm.c
new file mode 100644
index 0000000..8b35cc4
--- /dev/null
+++ b/arch/powerpc/sysdev/fsl_gtm.c
@@ -0,0 +1,424 @@
+/*
+ * Freescale General-purpose Timers Module
+ *
+ * Copyright (c) Freescale Semicondutor, Inc. 2006.
+ * Shlomi Gridish <[EMAIL PROTECTED]>
+ * Jerry Huang <[EMAIL PROTECTED]>
+ * Copyright (c) MontaVista Software, Inc. 2008.
+ * Anton Vorontsov <[EMAIL PROTECTED]>
+ *
+ * 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, or
(at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/list.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/spinlock.h>
+#include <linux/bitops.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
+ * @width: timer width (only 16 bits wide timers implemented so far)
+ *
+ * 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_timer(int width)
+{
+ struct gtm *gtm = NULL;
+ int i;
+
+ if (width != 16)
+ return ERR_PTR(-ENOSYS);
+
+ 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 (gtm)
+ return ERR_PTR(-EBUSY);
+ return ERR_PTR(-ENODEV);
+}
+EXPORT_SYMBOL(gtm_get_timer);
+
+/**
+ * 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.
+ * @width: timer width (only 16 bits wide timers implemented so far)
+ *
+ * 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_timer(struct gtm *gtm, int
timer, int width)
+{
+ struct gtm_timer *ret = ERR_PTR(-EBUSY);
+
+ if (width != 16)
+ return ERR_PTR(-ENOSYS);
should we not range check timer (since it can only be 0..3)?
+
+ 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_timer);
+
+/**
+ * gtm_put_timer - release GTM timer
+ * @width: timer width (only 16 bits wide timers implemented so far)
+ *
+ * This function releases GTM timer so others may request it.
+ */
+void gtm_put_timer(struct gtm_timer *tmr)
+{
+ spin_lock_irq(&tmr->gtm->lock);
+
+ tmr->requested = false;
should we not stop the timer as well?
+
+ spin_unlock_irq(&tmr->gtm->lock);
+}
+EXPORT_SYMBOL(gtm_put_timer);
+
+/*
+ * This is back-end for the exported functions, it's used to reset
single
+ * timer in reference mode.
+ */
+static int gtm_reset_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_reset_timer16 - reset 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.
+ *
+ * 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.
is this save to call in interrupt context?
+ */
+int gtm_reset_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_reset_ref_timer16(tmr, freq, usec, reload);
+}
+EXPORT_SYMBOL(gtm_reset_timer16);
+
+/**
+ * gtm_reset_utimer16 - reset 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.
+ *
+ * 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.
is this save to call in interrupt context?
+ */
+int gtm_reset_utimer16(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_reset_ref_timer16(tmr, freq, usec, reload);
+}
+EXPORT_SYMBOL(gtm_reset_utimer16);
+
+/**
+ * gtm_stop_timer16 - stop single timer
+ * @tmr: pointer to the gtm_timer structure obtained from
gtm_get_timer
+ *
+ * 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
+ *
+ * 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;
+ }
+}
+
+void __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("%s: unable to allocate memory\n",
+ np->full_name);
+ continue;
+ }
why bother with making this a dynamic alloc?
+
+ spin_lock_init(>m->lock);
+
+ clock = of_get_property(np, "clock-frequency", &size);
+ if (!clock || size != sizeof(*clock)) {
+ pr_err("%s: no clock-frequency\n", np->full_name);
+ goto err;
+ }
+ gtm->clock = *clock;
+
+ for (i = 0; i < ARRAY_SIZE(gtm->timers); i++) {
+ int ret;
+ struct resource irq;
+
+ ret = of_irq_to_resource(np, i, &irq);
+ if (ret == NO_IRQ) {
+ pr_err("%s: not enough interrupts specified\n",
+ np->full_name);
+ goto err;
+ }
+ gtm->timers[i].irq = irq.start;
+ gtm->timers[i].gtm = gtm;
+ }
+
+ gtm->regs = of_iomap(np, 0);
+ if (!gtm->regs) {
+ pr_err("%s: unable to iomap registers\n",
+ np->full_name);
+ 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);
+ }
+}
Shouldn't we have an arch_initcall(fsl_gtm_init);
diff --git a/include/asm-powerpc/fsl_gtm.h b/include/asm-powerpc/
fsl_gtm.h
new file mode 100644
index 0000000..49f1240
--- /dev/null
+++ b/include/asm-powerpc/fsl_gtm.h
@@ -0,0 +1,47 @@
+/*
+ * Freescale General-purpose Timers Module
+ *
+ * Copyright (c) Freescale Semicondutor, Inc. 2006.
+ * Shlomi Gridish <[EMAIL PROTECTED]>
+ * Jerry Huang <[EMAIL PROTECTED]>
+ * Copyright (c) MontaVista Software, Inc. 2008.
+ * Anton Vorontsov <[EMAIL PROTECTED]>
+ *
+ * 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, or
(at your
+ * option) any later version.
+ */
+
+#ifndef __ASM_FSL_GTM_H
+#define __ASM_FSL_GTM_H
+
+#include <linux/types.h>
+
+struct gtm;
+
+struct gtm_timer {
+ unsigned int irq;
+
+ struct gtm *gtm;
+ bool requested;
+ u8 __iomem *gtcfr;
+ __be16 __iomem *gtmdr;
+ __be16 __iomem *gtpsr;
+ __be16 __iomem *gtcnr;
+ __be16 __iomem *gtrfr;
+ __be16 __iomem *gtevr;
+};
+
+extern void __init fsl_gtm_init(void);
+extern struct gtm_timer *gtm_get_timer(int width);
+extern struct gtm_timer *gtm_get_specific_timer(struct gtm *gtm,
int timer,
+ int width);
+extern void gtm_put_timer(struct gtm_timer *tmr);
+extern int gtm_reset_timer16(struct gtm_timer *tmr, unsigned long
usec,
+ bool reload);
+extern int gtm_reset_utimer16(struct gtm_timer *tmr, u16 usec, bool
reload);
can you explain the difference between these two. I'm not sure I
understand the difference.
+extern void gtm_stop_timer16(struct gtm_timer *tmr);
+extern void gtm_ack_timer16(struct gtm_timer *tmr, u16 events);
+
+#endif /* __ASM_FSL_GTM_H */
--
1.5.5.1
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