@@ -3447,6 +3447,7 @@ F: drivers/tty/serial/vt8500_serial.c
F: drivers/video/fbdev/vt8500lcdfb.*
F: drivers/video/fbdev/wm8505fb*
F: drivers/video/fbdev/wmt_ge_rops.*
+F: include/linux/vt8500-timer.h
ARM/ZYNQ ARCHITECTURE
M: Michal Simek <michal.simek@amd.com>
@@ -178,6 +178,7 @@ config TEGRA186_TIMER
config VT8500_TIMER
bool "VT8500 timer driver" if COMPILE_TEST
depends on HAS_IOMEM
+ select AUXILIARY_BUS
help
Enables support for the VT8500 driver.
@@ -11,6 +11,7 @@
* Alexey Charkov. Minor changes have been made for Device Tree Support.
*/
+#include <linux/auxiliary_bus.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
@@ -22,9 +23,6 @@
#include <linux/of_address.h>
#include <linux/of_irq.h>
-#define VT8500_TIMER_OFFSET 0x0100
-#define VT8500_TIMER_HZ 3000000
-
#define TIMER_MATCH_REG(x) (4 * (x))
#define TIMER_COUNT_REG 0x0010 /* clocksource counter */
@@ -53,8 +51,14 @@
#define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t)
#define MIN_OSCR_DELTA 16
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/vt8500-timer.h>
static void __iomem *regbase;
+static unsigned int sys_timer_ch; /* which match register to use
+ * for the system timer
+ */
static u64 vt8500_timer_read(struct clocksource *cs)
{
@@ -75,21 +79,26 @@ static struct clocksource clocksource = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
+static u64 vt8500_timer_next(u64 cycles)
+{
+ return clocksource.read(&clocksource) + cycles;
+}
+
static int vt8500_timer_set_next_event(unsigned long cycles,
struct clock_event_device *evt)
{
int loops = msecs_to_loops(10);
- u64 alarm = clocksource.read(&clocksource) + cycles;
+ u64 alarm = vt8500_timer_next(cycles);
- while (readl(regbase + TIMER_ACC_STS_REG) & TIMER_ACC_WR_MATCH(0)
+ while (readl(regbase + TIMER_ACC_STS_REG) & TIMER_ACC_WR_MATCH(sys_timer_ch)
&& --loops)
cpu_relax();
- writel((unsigned long)alarm, regbase + TIMER_MATCH_REG(0));
+ writel((unsigned long)alarm, regbase + TIMER_MATCH_REG(sys_timer_ch));
if ((signed)(alarm - clocksource.read(&clocksource)) <= MIN_OSCR_DELTA)
return -ETIME;
- writel(TIMER_INT_EN_MATCH(0), regbase + TIMER_INT_EN_REG);
+ writel(TIMER_INT_EN_MATCH(sys_timer_ch), regbase + TIMER_INT_EN_REG);
return 0;
}
@@ -131,7 +140,9 @@ static int __init vt8500_timer_init(struct device_node *np)
return -ENXIO;
}
- timer_irq = irq_of_parse_and_map(np, 0);
+ sys_timer_ch = of_irq_count(np) > 1 ? 1 : 0;
+
+ timer_irq = irq_of_parse_and_map(np, sys_timer_ch);
if (!timer_irq) {
pr_err("%s: Missing irq description in Device Tree\n",
__func__);
@@ -140,7 +151,7 @@ static int __init vt8500_timer_init(struct device_node *np)
writel(TIMER_CTRL_ENABLE, regbase + TIMER_CTRL_REG);
writel(TIMER_STATUS_CLEARALL, regbase + TIMER_STATUS_REG);
- writel(~0, regbase + TIMER_MATCH_REG(0));
+ writel(~0, regbase + TIMER_MATCH_REG(sys_timer_ch));
ret = clocksource_register_hz(&clocksource, VT8500_TIMER_HZ);
if (ret) {
@@ -166,4 +177,86 @@ static int __init vt8500_timer_init(struct device_node *np)
return 0;
}
+static void vt8500_timer_aux_uninit(void *data)
+{
+ auxiliary_device_uninit(data);
+}
+
+static void vt8500_timer_aux_delete(void *data)
+{
+ auxiliary_device_delete(data);
+}
+
+static void vt8500_timer_aux_release(struct device *dev)
+{
+ struct auxiliary_device *aux;
+
+ aux = container_of(dev, struct auxiliary_device, dev);
+ kfree(aux);
+}
+
+/*
+ * This probe gets called after the timer is already up and running. This will
+ * create the watchdog device as a child since the registers are shared.
+ */
+static int vt8500_timer_probe(struct platform_device *pdev)
+{
+ struct vt8500_wdt_info *wdt_info;
+ struct device *dev = &pdev->dev;
+ int ret;
+
+ if (!sys_timer_ch) {
+ dev_info(dev, "Not enabling watchdog: only one irq was given");
+ return 0;
+ }
+
+ if (!regbase)
+ return dev_err_probe(dev, -ENOMEM,
+ "Timer not initialized, cannot create watchdog");
+
+ wdt_info = kzalloc(sizeof(*wdt_info), GFP_KERNEL);
+ if (!wdt_info)
+ return dev_err_probe(dev, -ENOMEM,
+ "Failed to allocate vt8500-wdt info");
+
+ wdt_info->timer_next = &vt8500_timer_next;
+ wdt_info->wdt_en = regbase + TIMER_WATCHDOG_EN_REG;
+ wdt_info->wdt_match = regbase + TIMER_MATCH_REG(0);
+ wdt_info->auxdev.name = "vt8500-wdt";
+ wdt_info->auxdev.dev.parent = dev;
+ wdt_info->auxdev.dev.release = &vt8500_timer_aux_release;
+
+ ret = auxiliary_device_init(&wdt_info->auxdev);
+ if (ret) {
+ kfree(wdt_info);
+ return ret;
+ }
+ ret = devm_add_action_or_reset(dev, vt8500_timer_aux_uninit,
+ &wdt_info->auxdev);
+ if (ret)
+ return ret;
+
+ ret = auxiliary_device_add(&wdt_info->auxdev);
+ if (ret)
+ return ret;
+ return devm_add_action_or_reset(dev, vt8500_timer_aux_delete,
+ &wdt_info->auxdev);
+}
+
+static const struct of_device_id vt8500_timer_of_match[] = {
+ { .compatible = "via,vt8500-timer", },
+ {},
+};
+
+static struct platform_driver vt8500_timer_driver = {
+ .probe = vt8500_timer_probe,
+ .driver = {
+ .name = "vt8500-timer",
+ .of_match_table = vt8500_timer_of_match,
+ .suppress_bind_attrs = true,
+ },
+};
+
+builtin_platform_driver(vt8500_timer_driver);
+
TIMER_OF_DECLARE(vt8500, "via,vt8500-timer", vt8500_timer_init);
new file mode 100644
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef LINUX_VT8500_TIMER_H_
+#define LINUX_VT8500_TIMER_H_
+
+#include <linux/auxiliary_bus.h>
+#include <linux/io.h>
+#include <linux/types.h>
+
+#define VT8500_TIMER_HZ 3000000
+
+struct vt8500_wdt_info {
+ struct auxiliary_device auxdev;
+ u64 (*timer_next)(u64 cycles);
+ void __iomem *wdt_en;
+ void __iomem *wdt_match;
+};
+
+#endif /* LINUX_VT8500_TIMER_H_ */
VIA/WonderMedia system timer can generate a watchdog reset when its clocksource counter matches the value in the match register 0 and watchdog function is enabled. For this to work, obvously the clock event device must use a different match register (1~3) and respective interrupt. Check if at least two interrupts are provided by the device tree, then use match register 1 for system clock events and reserve match register 0 for the watchdog. Instantiate an auxiliary device for the watchdog Signed-off-by: Alexey Charkov <alchark@gmail.com> --- MAINTAINERS | 1 + drivers/clocksource/Kconfig | 1 + drivers/clocksource/timer-vt8500.c | 111 ++++++++++++++++++++++++++++++++++--- include/linux/vt8500-timer.h | 18 ++++++ 4 files changed, 122 insertions(+), 9 deletions(-)