This patch adds a OSTM driver for the Renesas architecture.
Signed-off-by: Chris Brandt <chris.brandt@xxxxxxxxxxx>
---
v2:
* changed implementation to be independent channel nodes
---
arch/arm/mach-shmobile/Kconfig | 1 +
drivers/clocksource/Kconfig | 12 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/renesas-ostm.c | 349 +++++++++++++++++++++++++++++++++++++
4 files changed, 363 insertions(+)
create mode 100644 drivers/clocksource/renesas-ostm.c
diff --git a/arch/arm/mach-shmobile/Kconfig b/arch/arm/mach-shmobile/Kconfig
index 2bb4b09..b928634 100644
--- a/arch/arm/mach-shmobile/Kconfig
+++ b/arch/arm/mach-shmobile/Kconfig
@@ -57,6 +57,7 @@ config ARCH_R7S72100
select PM
select PM_GENERIC_DOMAINS
select SYS_SUPPORTS_SH_MTU2
+ select SYS_SUPPORTS_RENESAS_OSTM
config ARCH_R8A73A4
bool "R-Mobile APE6 (R8A73A40)"
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 4866f7a..95c8d56 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -431,6 +431,9 @@ config MTK_TIMER
config SYS_SUPPORTS_SH_MTU2
bool
+config SYS_SUPPORTS_RENESAS_OSTM
+ bool
+
config SYS_SUPPORTS_SH_TMU
bool
@@ -467,6 +470,15 @@ config SH_TIMER_MTU2
Timer Pulse Unit 2 (MTU2) hardware available on SoCs from Renesas.
This hardware comes with 16 bit-timer registers.
+config RENESAS_OSTM
+ bool "Renesas OSTM timer driver" if COMPILE_TEST
+ depends on GENERIC_CLOCKEVENTS
+ select CLKSRC_MMIO
+ default SYS_SUPPORTS_RENESAS_OSTM
+ help
+ This enables the build of the OSTM timer driver.
+ It creates a clock source and clock event device.
+
config SH_TIMER_TMU
bool "Renesas TMU timer driver" if COMPILE_TEST
depends on GENERIC_CLOCKEVENTS
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index a14111e..bbd163b 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_CS5535_CLOCK_EVENT_SRC) += cs5535-clockevt.o
obj-$(CONFIG_CLKSRC_JCORE_PIT) += jcore-pit.o
obj-$(CONFIG_SH_TIMER_CMT) += sh_cmt.o
obj-$(CONFIG_SH_TIMER_MTU2) += sh_mtu2.o
+obj-$(CONFIG_RENESAS_OSTM) += renesas-ostm.o
obj-$(CONFIG_SH_TIMER_TMU) += sh_tmu.o
obj-$(CONFIG_EM_TIMER_STI) += em_sti.o
obj-$(CONFIG_CLKBLD_I8253) += i8253.o
diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c
new file mode 100644
index 0000000..37f2461
--- /dev/null
+++ b/drivers/clocksource/renesas-ostm.c
@@ -0,0 +1,349 @@
+/*
+ * Renesas Timer Support - OSTM
+ *
+ * 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/platform_device.h>
+#include <linux/clk.h>
+#include <linux/clockchips.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/sched_clock.h>
+
+/*
+ * The OSTM contains independent channels.
+ * The first OSTM channel probed will be set up as a free running
+ * clocksource. Additionally we will use this clocksource for the system
+ * schedule timer sched_clock().
+ *
+ * The second (or more) channel probed will be set up as an interrupt
+ * driven clock event.
+ */
+
+struct ostm_device {
+ struct platform_device *pdev;
+
+ int irq;
+ struct clk *clk;
+ unsigned long rate;
+ void __iomem *base;
+ unsigned long ticks_per_jiffy;
+ struct clock_event_device ced;
+};
+
+static void __iomem *system_clock; /* For sched_clock() */
+
+/* OSTM REGISTERS */
+#define OSTM_CMP 0x000 /* RW,32 */
+#define OSTM_CNT 0x004 /* R,32 */
+#define OSTM_TE 0x010 /* R,8 */
+#define OSTM_TS 0x014 /* W,8 */
+#define OSTM_TT 0x018 /* W,8 */
+#define OSTM_CTL 0x020 /* RW,8 */
+
+#define TE 0x01
+#define TS 0x01
+#define TT 0x01
+#define CTL_PERIODIC 0x00
+#define CTL_ONESHOT 0x02
+#define CTL_FREERUN 0x02
+
+static struct ostm_device *ced_to_ostm(struct clock_event_device *ced)
+{
+ return container_of(ced, struct ostm_device, ced);
+}
+
+static int __init ostm_init_clksrc(struct ostm_device *ostm)
+{
+ int ret;
+
+ /* irq not used (clock sources don't use interrupts) */
+
+ /* stop counter */
+ iowrite8(TT, ostm->base + OSTM_TT);
+ while (ioread8(ostm->base + OSTM_TE) & TE)
+ ;
+
+ /* setup as freerun */
+ iowrite32(0, ostm->base + OSTM_CMP);
+ iowrite8(CTL_FREERUN, ostm->base + OSTM_CTL);
+ iowrite8(TS, ostm->base + OSTM_TS);
+
+ /* register */
+ ret = clocksource_mmio_init(ostm->base + OSTM_CNT,
+ "ostm", ostm->rate,
+ 300, 32, clocksource_mmio_readl_up);
+
+ return ret;
+}
+
+static u64 notrace ostm_read_sched_clock(void)
+{
+ return ioread32(system_clock);
+}
+
+static int __init ostm_init_sched_clock(struct ostm_device *ostm)
+{
+ unsigned long flags;
+
+ system_clock = ostm->base + OSTM_CNT;
+ local_irq_save(flags);
+ local_irq_disable();
+ sched_clock_register(ostm_read_sched_clock, 32, ostm->rate);
+ local_irq_restore(flags);
+
+ return 0;
+}
+
+static void ostm_clkevt_timer_stop(struct ostm_device *ostm)
+{
+ if (ioread8(ostm->base + OSTM_TE) & TE) {
+ iowrite8(TT, ostm->base + OSTM_TT);
+ while (ioread8(ostm->base + OSTM_TE) & TE)
+ ;
+ }
+}
+
+static int ostm_clock_event_next(unsigned long delta,
+ struct clock_event_device *ced)
+{
+ struct ostm_device *ostm = ced_to_ostm(ced);
+
+ WARN_ON(!clockevent_state_oneshot(ced));
+
+ ostm_clkevt_timer_stop(ostm);
+
+ iowrite32(delta, ostm->base + OSTM_CMP);
+ iowrite8(CTL_ONESHOT, ostm->base + OSTM_CTL);
+ iowrite8(TS, ostm->base + OSTM_TS);
+
+ return 0;
+}
+
+static int ostm_shutdown(struct clock_event_device *ced)
+{
+ struct ostm_device *ostm = ced_to_ostm(ced);
+
+ ostm_clkevt_timer_stop(ostm);
+
+ return 0;
+}
+static int ostm_set_periodic(struct clock_event_device *ced)
+{
+ struct ostm_device *ostm = ced_to_ostm(ced);
+
+ if (clockevent_state_oneshot(ced) || clockevent_state_periodic(ced))
+ ostm_clkevt_timer_stop(ostm);
+
+ iowrite32(ostm->ticks_per_jiffy - 1, ostm->base + OSTM_CMP);
+ iowrite8(CTL_PERIODIC, ostm->base + OSTM_CTL);
+ iowrite8(TS, ostm->base + OSTM_TS);
+
+ return 0;
+}
+
+static int ostm_set_oneshot(struct clock_event_device *ced)
+{
+ struct ostm_device *ostm = ced_to_ostm(ced);
+
+ ostm_clkevt_timer_stop(ostm);
+
+ return 0;
+}
+
+static irqreturn_t ostm_timer_interrupt(int irq, void *dev_id)
+{
+ struct ostm_device *ostm = dev_id;
+
+ if (clockevent_state_oneshot(&ostm->ced))
+ ostm_clkevt_timer_stop(ostm);
+
+ /* notify clockevent layer */
+ if (ostm->ced.event_handler)
+ ostm->ced.event_handler(&ostm->ced);
+
+ return IRQ_HANDLED;
+}
+
+static int __init ostm_init_clkevt(struct ostm_device *ostm)
+{
+ struct clock_event_device *ced = &ostm->ced;
+ int ret = -ENXIO;
+
+ ret = request_irq(ostm->irq, ostm_timer_interrupt,
+ IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING,
+ dev_name(&ostm->pdev->dev), ostm);
+ if (ret) {
+ dev_err(&ostm->pdev->dev, "failed to request irq\n");
+ return ret;
+ }
+
+ ced->name = "ostm";
+ ced->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_PERIODIC;
+ ced->set_state_shutdown = ostm_shutdown;
+ ced->set_state_periodic = ostm_set_periodic;
+ ced->set_state_oneshot = ostm_set_oneshot;
+ ced->set_next_event = ostm_clock_event_next;
+ ced->shift = 32;
+ ced->rating = 300;
+ ced->cpumask = cpumask_of(0);
+ clockevents_config_and_register(ced, ostm->rate, 0xf, 0xffffffff);
+
+ return 0;
+}
+
+static int __init ostm_probe(struct platform_device *pdev)
+{
+ struct ostm_device *ostm;
+ struct resource *res;
+ int ret = -EFAULT;
+
+ if (!is_early_platform_device(pdev)) {
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+ }
+
+ ostm = platform_get_drvdata(pdev);
+ if (ostm) {
+ dev_info(&pdev->dev, "kept as earlytimer\n");
+ ret = 0;
+ goto out;
+ }
+
+ ostm = kzalloc(sizeof(*ostm), GFP_KERNEL);
+ if (!ostm) {
+ dev_err(&pdev->dev, "failed to allocate memory\n");
+ return -ENOMEM;
+ }
+
+ ostm->pdev = pdev;
+ platform_set_drvdata(ostm->pdev, ostm);
+
+ res = platform_get_resource(ostm->pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&ostm->pdev->dev, "failed to get I/O memory\n");
+ goto err;
+ }
+
+ ostm->base = ioremap_nocache(res->start, resource_size(res));
+ if (!ostm->base) {
+ dev_err(&ostm->pdev->dev, "failed to remap I/O memory\n");
+ goto err;
+ }
+
+ ostm->irq = platform_get_irq(ostm->pdev, 0);
+ if (ostm->irq < 0) {
+ dev_err(&ostm->pdev->dev, "failed to get irq\n");
+ goto err;
+ }
+
+ ostm->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(ostm->clk)) {
+ dev_err(&ostm->pdev->dev, "failed to get clock\n");
+ ostm->clk = NULL;
+ goto err;
+ }
+
+ ret = clk_prepare_enable(ostm->clk);
+ if (ret) {
+ dev_err(&ostm->pdev->dev, "failed to enable clock\n");
+ goto err;
+ }
+
+ ostm->rate = clk_get_rate(ostm->clk);
+ ostm->ticks_per_jiffy = (ostm->rate + HZ / 2) / HZ;
+
+ /* First probed device will be used as system clocksource */
+ if (!system_clock) {
+ /* use as clocksource */
+ ret = ostm_init_clksrc(ostm);
+
+ /* use as system scheduling clock */
+ if (!ret)
+ ret = ostm_init_sched_clock(ostm);
+
+ if (ret) {
+ dev_err(&pdev->dev, "failed to use as sched_clock\n");
+ system_clock = (void *)-1; /* prevent future attempts */
+ ret = 0; /* still works as clocksource */
+ }
+
+ if (!ret)
+ dev_info(&pdev->dev, "used for clocksource\n");
+ } else {
+ /* use as clock event */
+ ret = ostm_init_clkevt(ostm);
+
+ if (!ret)
+ dev_info(&pdev->dev, "used for clock events\n");
+ }
+
+err:
+ if (ret) {
+ if (ostm->clk)
+ clk_disable_unprepare(ostm->clk);
+ if (ostm->base)
+ iounmap(ostm->base);
+ kfree(ostm);
+ platform_set_drvdata(pdev, NULL);
+ pm_runtime_idle(&pdev->dev);
+ return ret;
+ }
+
+ if (is_early_platform_device(pdev))
+ return ret;
+
+out:
+ pm_runtime_irq_safe(&pdev->dev);
+
+ return ret;
+}
+
+static int ostm_remove(struct platform_device *pdev)
+{
+ return -EBUSY; /* cannot unregister clockevent */
+}
+
+static const struct of_device_id ostm_of_table[] __maybe_unused = {
+ { .compatible = "renesas,ostm" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ostm_of_table);
+
+static struct platform_driver ostm_timer = {
+ .probe = ostm_probe,
+ .remove = ostm_remove,
+ .driver = {
+ .name = "ostm",
+ .of_match_table = of_match_ptr(ostm_of_table),
+ },
+};
+
+static int __init ostm_init(void)
+{
+ return platform_driver_register(&ostm_timer);
+}
+
+static void __exit ostm_exit(void)
+{
+ platform_driver_unregister(&ostm_timer);
+}
+
+early_platform_init("earlytimer", &ostm_timer);
+subsys_initcall(ostm_init);
+module_exit(ostm_exit);
+
+MODULE_AUTHOR("Chris Brandt");
+MODULE_DESCRIPTION("Renesas OSTM Timer Driver");
+MODULE_LICENSE("GPL v2");
--
2.10.1
