[PATCH v2 2/2] powerpc/mpic: add global timer support
Dongsheng.wang at freescale.com
Dongsheng.wang at freescale.com
Fri Aug 10 15:54:41 EST 2012
From: Wang Dongsheng <Dongsheng.Wang at freescale.com>
The MPIC global timer is a hardware timer inside the Freescale PIC comply
to Open-PIC standard. When the timer is timeout of the specified interval,
the hardware timer generates an interrupt. The driver currently is only
tested on fsl chip, but it can potentially support other global timers
complying to Open-PIC standard.
The two independent groups of global timer on fsl chip, group A and group B,
are identical in their functionality, except that they appear at different
locations within the PIC register map. The hardware timer can be cascaded to
create timers larger than the default 31-bit global timers. Timer cascade
fields allow configuration of up to two 63-bit timers. But These two groups
of timers cannot be cascaded together.
It can be used as a wakeup source for low power modes. It also could be used
as periodical timer for protocols, drivers and etc.
Signed-off-by: Wang Dongsheng <Dongsheng.Wang at freescale.com>
Signed-off-by: Li Yang <leoli at freescale.com>
---
arch/powerpc/include/asm/mpic_timer.h | 15 +
arch/powerpc/platforms/Kconfig | 5 +
arch/powerpc/sysdev/Makefile | 1 +
arch/powerpc/sysdev/mpic_timer.c | 525 +++++++++++++++++++++++++++++++++
4 files changed, 546 insertions(+), 0 deletions(-)
create mode 100644 arch/powerpc/include/asm/mpic_timer.h
create mode 100644 arch/powerpc/sysdev/mpic_timer.c
diff --git a/arch/powerpc/include/asm/mpic_timer.h b/arch/powerpc/include/asm/mpic_timer.h
new file mode 100644
index 0000000..01d58a2
--- /dev/null
+++ b/arch/powerpc/include/asm/mpic_timer.h
@@ -0,0 +1,15 @@
+#ifndef __MPIC_TIMER__
+#define __MPIC_TIMER__
+
+#include <linux/interrupt.h>
+#include <linux/time.h>
+
+struct mpic_timer *mpic_request_timer(irq_handler_t fn, void *dev,
+ const struct timeval *time);
+
+void mpic_start_timer(struct mpic_timer *handle);
+
+void mpic_stop_timer(struct mpic_timer *handle);
+
+void mpic_free_timer(struct mpic_timer *handle);
+#endif
diff --git a/arch/powerpc/platforms/Kconfig b/arch/powerpc/platforms/Kconfig
index e7a896a..d82a822 100644
--- a/arch/powerpc/platforms/Kconfig
+++ b/arch/powerpc/platforms/Kconfig
@@ -87,6 +87,11 @@ config MPIC
bool
default n
+config MPIC_TIMER
+ bool "MPIC Global Timer"
+ depends on MPIC && FSL_SOC
+ default n
+
config PPC_EPAPR_HV_PIC
bool
default n
diff --git a/arch/powerpc/sysdev/Makefile b/arch/powerpc/sysdev/Makefile
index 1bd7ecb..b1a9e4d 100644
--- a/arch/powerpc/sysdev/Makefile
+++ b/arch/powerpc/sysdev/Makefile
@@ -6,6 +6,7 @@ mpic-msi-obj-$(CONFIG_PCI_MSI) += mpic_msi.o mpic_u3msi.o mpic_pasemi_msi.o
obj-$(CONFIG_MPIC) += mpic.o $(mpic-msi-obj-y)
mpic-msgr-obj-$(CONFIG_MPIC_MSGR) += mpic_msgr.o
obj-$(CONFIG_MPIC) += mpic.o $(mpic-msi-obj-y) $(mpic-msgr-obj-y)
+obj-$(CONFIG_MPIC_TIMER) += mpic_timer.o
obj-$(CONFIG_PPC_EPAPR_HV_PIC) += ehv_pic.o
fsl-msi-obj-$(CONFIG_PCI_MSI) += fsl_msi.o
obj-$(CONFIG_PPC_MSI_BITMAP) += msi_bitmap.o
diff --git a/arch/powerpc/sysdev/mpic_timer.c b/arch/powerpc/sysdev/mpic_timer.c
new file mode 100644
index 0000000..1b3ee59
--- /dev/null
+++ b/arch/powerpc/sysdev/mpic_timer.c
@@ -0,0 +1,525 @@
+/*
+ * Copyright (c) 2012 Freescale Semiconductor, Inc. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <asm/io.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include <sysdev/fsl_soc.h>
+#include <asm/mpic_timer.h>
+
+#define FSL_GLOBAL_TIMER 0x1
+
+#define MPIC_TIMER_TCR_CLKDIV_64 0x00000300
+#define MPIC_TIMER_TCR_ROVR_OFFSET 24
+
+#define TIMER_STOP 0x80000000
+#define ALL_TIMER 4
+#define MAX_TICKS (~0U>>1)
+#define MAX_TICKS_CASCADE (~0U)
+#define TIMER_OFFSET(num) (1 << (ALL_TIMER - 1 - num))
+#define ONE_SECOND 1000000
+
+struct timer_regs {
+ u32 gtccr;
+ u32 res0[3];
+ u32 gtbcr;
+ u32 res1[3];
+ u32 gtvpr;
+ u32 res2[3];
+ u32 gtdr;
+ u32 res3[3];
+};
+
+struct cascade_priv {
+ u32 tcr_value; /* TCR register: CASC & ROVR value */
+ unsigned int cascade_map; /* cascade map */
+ unsigned int timer_num; /* cascade control timer */
+};
+
+struct mpic_timer {
+ void *dev;
+ struct cascade_priv *cascade_handle;
+ unsigned int num;
+ int irq;
+};
+
+struct group_priv {
+ struct timer_regs __iomem *regs;
+ struct mpic_timer timer[ALL_TIMER];
+ struct list_head node;
+ unsigned int timerfreq;
+ unsigned int idle;
+ unsigned int flags;
+ spinlock_t lock;
+ void __iomem *group_tcr;
+ void __iomem *group_tfrr;
+};
+
+static struct cascade_priv cascade_timer[] = {
+ /* cascade timer 0 and 1 */
+ {0x1, 0xc, 0x1},
+ /* cascade timer 1 and 2 */
+ {0x2, 0x6, 0x2},
+ /* cascade timer 2 and 3 */
+ {0x4, 0x3, 0x3}
+};
+
+static u32 ccbfreq;
+static LIST_HEAD(group_list);
+
+/* the time set by the user is converted to "ticks" */
+static int transform_time(struct group_priv *priv, const struct timeval *time,
+ u64 *ticks)
+{
+ u64 max_value; /* prevent u64 overflow */
+ u64 tmp = 0;
+
+ u64 tmp_sec = 0;
+ u64 tmp_ms = 0;
+ u64 tmp_us = 0;
+ u32 div = 0;
+
+ if (priv->flags & FSL_GLOBAL_TIMER)
+ max_value = div_u64(ULLONG_MAX, ccbfreq);
+ else
+ max_value = div_u64(ULLONG_MAX, priv->timerfreq);
+
+ if (time->tv_sec > max_value ||
+ (time->tv_sec == max_value && time->tv_usec > 0))
+ return -EINVAL;
+
+ if (!(priv->flags & FSL_GLOBAL_TIMER)) {
+ tmp = time->tv_sec * priv->timerfreq;
+ *ticks = tmp;
+
+ return 0;
+ }
+
+ div = (1 << (MPIC_TIMER_TCR_CLKDIV_64 >> 8)) * 8;
+
+ tmp_sec = div_u64((u64)time->tv_sec * (u64)ccbfreq, div);
+ tmp += tmp_sec;
+
+ tmp_ms = time->tv_usec / 1000;
+ tmp_ms = div_u64((u64)tmp_ms * (u64)ccbfreq, div * 1000);
+ tmp += tmp_ms;
+
+ tmp_us = time->tv_usec % 1000;
+ tmp_us = div_u64((u64)tmp_us * (u64)ccbfreq, div * 1000000);
+ tmp += tmp_us;
+
+ *ticks = tmp;
+
+ return 0;
+}
+
+/* detect whether there is a cascade timer available */
+static struct mpic_timer *detect_idle_cascade_timer(struct group_priv *priv)
+{
+ struct cascade_priv *casc_priv;
+ unsigned int tmp;
+ unsigned int array_size = ARRAY_SIZE(cascade_timer);
+ unsigned int num;
+ unsigned int i;
+ unsigned long flags;
+
+ casc_priv = cascade_timer;
+ for (i = 0; i < array_size; i++) {
+ spin_lock_irqsave(&priv->lock, flags);
+ tmp = casc_priv->cascade_map & priv->idle;
+ if (tmp == casc_priv->cascade_map) {
+ num = casc_priv->timer_num;
+ priv->timer[num].cascade_handle = casc_priv;
+
+ /* set timer busy */
+ priv->idle &= ~casc_priv->cascade_map;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return &priv->timer[num];
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+ casc_priv++;
+ }
+
+ return NULL;
+}
+
+static int set_cascade_timer(struct group_priv *priv, u64 ticks,
+ unsigned int num)
+{
+ struct cascade_priv *casc_priv;
+ u32 tmp;
+ u32 tmp_ticks;
+ u32 rem_ticks;
+
+ /* set group tcr reg for cascade */
+ casc_priv = priv->timer[num].cascade_handle;
+ if (!casc_priv)
+ return -EINVAL;
+
+ tmp = casc_priv->tcr_value |
+ (casc_priv->tcr_value << MPIC_TIMER_TCR_ROVR_OFFSET);
+ setbits32(priv->group_tcr, tmp);
+
+ tmp_ticks = div_u64_rem(ticks, MAX_TICKS_CASCADE, &rem_ticks);
+
+ out_be32(&priv->regs[num].gtccr, 0);
+ out_be32(&priv->regs[num].gtbcr, tmp_ticks | TIMER_STOP);
+
+ out_be32(&priv->regs[num - 1].gtccr, 0);
+ out_be32(&priv->regs[num - 1].gtbcr, rem_ticks);
+
+ return 0;
+}
+
+static struct mpic_timer *get_cascade_timer(struct group_priv *priv, u64 ticks)
+{
+ struct mpic_timer *allocated_timer = NULL;
+
+ /* Two cascade timers: Support the maximum time */
+ const u64 max_ticks = (u64)MAX_TICKS * (u64)MAX_TICKS_CASCADE;
+ int ret;
+
+ if (ticks > max_ticks)
+ return NULL;
+
+ /* detect idle timer */
+ allocated_timer = detect_idle_cascade_timer(priv);
+ if (!allocated_timer)
+ return NULL;
+
+ /* set ticks to timer */
+ ret = set_cascade_timer(priv, ticks, allocated_timer->num);
+ if (ret < 0)
+ return NULL;
+
+ return allocated_timer;
+}
+
+static struct mpic_timer *get_timer(const struct timeval *time)
+{
+ struct group_priv *priv;
+ struct mpic_timer *timer = NULL;
+
+ u64 ticks = 0;
+ unsigned int num;
+ unsigned int i;
+ unsigned long flags;
+ int ret = 0;
+
+ list_for_each_entry(priv, &group_list, node) {
+ ret = transform_time(priv, time, &ticks);
+ if (ret < 0)
+ return NULL;
+
+ if (ticks > MAX_TICKS) {
+ if (!(priv->flags & FSL_GLOBAL_TIMER))
+ return NULL;
+
+ timer = get_cascade_timer(priv, ticks);
+ if (!timer)
+ continue;
+ else
+ return timer;
+ }
+
+ for (i = 0; i < ALL_TIMER; i++) {
+ /* one timer: Reverse allocation */
+ num = ALL_TIMER - 1 - i;
+ spin_lock_irqsave(&priv->lock, flags);
+ if (priv->idle & (1 << i)) {
+ /* set timer busy */
+ priv->idle &= ~(1 << i);
+ /* set ticks & stop timer */
+ out_be32(&priv->regs[num].gtbcr,
+ ticks | TIMER_STOP);
+ out_be32(&priv->regs[num].gtccr, 0);
+ priv->timer[num].cascade_handle = NULL;
+ spin_unlock_irqrestore(&priv->lock, flags);
+ return &priv->timer[num];
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+ }
+ }
+
+ return NULL;
+}
+
+/**
+ * mpic_request_timer - get a hardware timer
+ * @fn: interrupt handler function
+ * @dev: callback function of the data
+ * @time: time for timer
+ *
+ * This executes the "request_irq", returning NULL
+ * else "handle" on success.
+ */
+struct mpic_timer *mpic_request_timer(irq_handler_t fn, void *dev,
+ const struct timeval *time)
+{
+ struct mpic_timer *allocated_timer = NULL;
+
+ int ret = 0;
+
+ if (list_empty(&group_list))
+ return NULL;
+
+ if ((time->tv_sec + time->tv_usec) == 0 ||
+ time->tv_sec < 0 || time->tv_usec < 0)
+ return NULL;
+
+ if (time->tv_usec > ONE_SECOND)
+ return NULL;
+
+ allocated_timer = get_timer(time);
+ if (!allocated_timer)
+ return NULL;
+
+ ret = request_irq(allocated_timer->irq, fn, IRQF_TRIGGER_LOW,
+ "global-timer", dev);
+ if (ret)
+ return NULL;
+
+ allocated_timer->dev = dev;
+
+ return allocated_timer;
+}
+EXPORT_SYMBOL_GPL(mpic_request_timer);
+
+/**
+ * mpic_start_timer - start hardware timer
+ * @handle: the timer to be started.
+ *
+ * It will do ->fn(->dev) callback from the hardware interrupt at
+ * the ->timeval point in the future.
+ */
+void mpic_start_timer(struct mpic_timer *handle)
+{
+ struct group_priv *priv = container_of(handle, struct group_priv,
+ timer[handle->num]);
+
+ clrbits32(&priv->regs[handle->num].gtbcr, TIMER_STOP);
+}
+EXPORT_SYMBOL_GPL(mpic_start_timer);
+
+/**
+ * mpic_stop_timer - stop hardware timer
+ * @handle: the timer to be stoped
+ *
+ * The timer periodically generates an interrupt. Unless user stops the timer.
+ */
+void mpic_stop_timer(struct mpic_timer *handle)
+{
+ struct group_priv *priv = container_of(handle, struct group_priv,
+ timer[handle->num]);
+
+ setbits32(&priv->regs[handle->num].gtbcr, TIMER_STOP);
+}
+EXPORT_SYMBOL_GPL(mpic_stop_timer);
+
+/**
+ * mpic_free_timer - free hardware timer
+ * @handle: the timer to be removed.
+ *
+ * Free the timer.
+ *
+ * Note: can not be used in interrupt context.
+ */
+void mpic_free_timer(struct mpic_timer *handle)
+{
+ struct group_priv *priv = container_of(handle, struct group_priv,
+ timer[handle->num]);
+
+ struct cascade_priv *casc_priv = NULL;
+ unsigned long flags;
+
+ mpic_stop_timer(handle);
+
+ casc_priv = priv->timer[handle->num].cascade_handle;
+
+ free_irq(priv->timer[handle->num].irq, priv->timer[handle->num].dev);
+
+ spin_lock_irqsave(&priv->lock, flags);
+ if (casc_priv) {
+ u32 tmp;
+ tmp = casc_priv->tcr_value | (casc_priv->tcr_value <<
+ MPIC_TIMER_TCR_ROVR_OFFSET);
+ clrbits32(priv->group_tcr, tmp);
+ priv->idle |= casc_priv->cascade_map;
+ priv->timer[handle->num].cascade_handle = NULL;
+ } else {
+ priv->idle |= TIMER_OFFSET(handle->num);
+ }
+ spin_unlock_irqrestore(&priv->lock, flags);
+}
+EXPORT_SYMBOL_GPL(mpic_free_timer);
+
+static int group_get_freq(struct group_priv *priv)
+{
+ if (priv->flags & FSL_GLOBAL_TIMER) {
+ ccbfreq = fsl_get_sys_freq();
+ priv->timerfreq = ccbfreq;
+ } else {
+ priv->timerfreq = in_be32(priv->group_tfrr);
+ }
+
+ if (priv->timerfreq <= 0)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int group_init_regmap(struct device_node *np, struct group_priv *priv)
+{
+ priv->group_tfrr = of_iomap(np, 0);
+ if (!priv->group_tfrr) {
+ pr_err("%s: cannot ioremap tfrr address.\n",
+ np->full_name);
+ return -EINVAL;
+ }
+
+ priv->regs = of_iomap(np, 1);
+ if (!priv->regs) {
+ pr_err("%s: cannot ioremap timer register address.\n",
+ np->full_name);
+ return -EINVAL;
+ }
+
+ if (!(priv->flags & FSL_GLOBAL_TIMER))
+ return 0;
+
+ priv->group_tcr = of_iomap(np, 2);
+ if (!priv->group_tcr) {
+ pr_err("%s: cannot ioremap tcr address.\n", np->full_name);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int group_get_irq(struct device_node *np, struct group_priv *priv)
+{
+ const u32 all_timer[] = { 0, ALL_TIMER };
+ const u32 *p = NULL;
+ u32 offset;
+ u32 count;
+
+ unsigned int i = 0;
+ unsigned int j = 0;
+ unsigned int irq_index = 0;
+ int irq = 0;
+ int len = 0;
+
+ p = of_get_property(np, "available-ranges", &len);
+ if (p && len % (2 * sizeof(u32)) != 0) {
+ pr_err("%s: malformed fsl,available-ranges property.\n",
+ np->full_name);
+ return -EINVAL;
+ }
+
+ if (!p) {
+ p = all_timer;
+ len = sizeof(all_timer);
+ }
+
+ len /= 2 * sizeof(u32);
+
+ for (i = 0; i < len; i++) {
+ offset = p[i * 2];
+ count = p[i * 2 + 1];
+ for (j = 0; j < count; j++) {
+ irq = irq_of_parse_and_map(np, irq_index);
+ if (!irq)
+ break;
+ /* Set timer idle */
+ priv->idle |= TIMER_OFFSET((offset + j));
+ priv->timer[offset + j].irq = irq;
+ priv->timer[offset + j].num = offset + j;
+ irq_index++;
+ }
+ }
+
+ return 0;
+}
+
+static void group_init(struct device_node *np)
+{
+ struct group_priv *priv = NULL;
+ int ret = 0;
+
+ priv = kzalloc(sizeof(struct group_priv), GFP_KERNEL);
+ if (!priv) {
+ pr_err("%s: cannot allocate memory for group.\n",
+ np->full_name);
+ return;
+ }
+
+ if (of_device_is_compatible(np, "fsl,global-timer"))
+ priv->flags |= FSL_GLOBAL_TIMER;
+
+ ret = group_init_regmap(np, priv);
+ if (ret < 0)
+ goto out;
+
+ ret = group_get_freq(priv);
+ if (ret < 0)
+ goto out;
+
+ ret = group_get_irq(np, priv);
+ if (ret < 0)
+ goto out;
+
+ spin_lock_init(&priv->lock);
+
+ /* Init FSL timer hardware */
+ if (priv->flags & FSL_GLOBAL_TIMER)
+ setbits32(priv->group_tcr, MPIC_TIMER_TCR_CLKDIV_64);
+
+ list_add_tail(&priv->node, &group_list);
+
+ return;
+out:
+ if (priv->group_tcr)
+ iounmap(priv->group_tcr);
+
+ if (priv->regs)
+ iounmap(priv->regs);
+
+ if (priv->group_tfrr)
+ iounmap(priv->group_tfrr);
+
+ kfree(priv);
+}
+
+static const struct of_device_id mpic_timer_ids[] = {
+ { .compatible = "open-pic,global-timer", },
+ { .compatible = "fsl,global-timer", },
+ {},
+};
+
+static int __init mpic_timer_init(void)
+{
+ struct device_node *np = NULL;
+
+ for_each_node_by_type(np, "open-pic")
+ if (of_match_node(mpic_timer_ids, np))
+ group_init(np);
+
+ if (list_empty(&group_list))
+ return -ENODEV;
+
+ return 0;
+}
+arch_initcall(mpic_timer_init);
--
1.7.5.1
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