[U-Boot] [PATCH v4 1/2] dm: implement a Timer uclass

Thomas Chou
2015-10-04T13:56:52Z

Implement a Timer uclass to work with lib/time.c.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Simon Glass <sjg@chromium.org>
---
v2
fix coding style.
v3
add description to Kconfig as Simon suggested.
move timer.c code to lib/time.c.
add dm_timer dev to global data.
remove timer_init().
change API name get_clock.
v4
add comment about timer hardware.

common/board_r.c | 3 +++
drivers/Kconfig | 2 ++
drivers/Makefile | 1 +
drivers/timer/Kconfig | 12 +++++++++
drivers/timer/Makefile | 7 +++++
drivers/timer/timer-uclass.c | 44 +++++++++++++++++++++++++++++++
include/asm-generic/global_data.h | 3 +++
include/dm/uclass-id.h | 1 +
include/timer.h | 52 +++++++++++++++++++++++++++++++++++++
lib/time.c | 54 +++++++++++++++++++++++++++++++++++++++
10 files changed, 179 insertions(+)
create mode 100644 drivers/timer/Kconfig
create mode 100644 drivers/timer/Makefile
create mode 100644 drivers/timer/timer-uclass.c
create mode 100644 include/timer.h

diff --git a/common/board_r.c b/common/board_r.c
index f8c1baa..aaf390e 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -290,6 +290,9 @@ static int initr_dm(void)
/* Save the pre-reloc driver model and start a new one */
gd->dm_root_f = gd->dm_root;
gd->dm_root = NULL;
+#ifdef CONFIG_DM_TIMER
+ gd->dm_timer = NULL;
+#endif
return dm_init_and_scan(false);
}
#endif
diff --git a/drivers/Kconfig b/drivers/Kconfig
index 63c92c5..f9496f7 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -56,6 +56,8 @@ source "drivers/spi/Kconfig"

source "drivers/thermal/Kconfig"

+source "drivers/timer/Kconfig"
+
source "drivers/tpm/Kconfig"

source "drivers/usb/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 9d0a595..692da78 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -48,6 +48,7 @@ obj-y += pcmcia/
obj-y += dfu/
obj-y += rtc/
obj-y += sound/
+obj-y += timer/
obj-y += tpm/
obj-y += twserial/
obj-y += video/
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
new file mode 100644
index 0000000..54a4c40
--- /dev/null
+++ b/drivers/timer/Kconfig
@@ -0,0 +1,12 @@
+menu "Timer Support"
+
+config DM_TIMER
+ bool "Enable Driver Model for Timer drivers"
+ depends on DM
+ help
+ Enable driver model for Timer access. It uses the same API as
+ lib/time.c. But now implemented by the uclass. The first timer
+ will be used. The timer is usually a 32 bits free-running up
+ counter. There may be no real tick, and no timer interrupt.
+
+endmenu
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
new file mode 100644
index 0000000..a24179a
--- /dev/null
+++ b/drivers/timer/Makefile
@@ -0,0 +1,7 @@
+#
+# Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-$(CONFIG_DM_TIMER) += timer-uclass.o
diff --git a/drivers/timer/timer-uclass.c b/drivers/timer/timer-uclass.c
new file mode 100644
index 0000000..bcf1dde
--- /dev/null
+++ b/drivers/timer/timer-uclass.c
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
+
+/*
+ * Implement a Timer uclass to work with lib/time.c. The timer is usually
+ * a 32 bits free-running up counter. The get_clock() method is used to get
+ * the input clock frequency of the timer. The get_count() method is used
+ * get the current 32 bits count value. If the hardware is counting down,
+ * the value should be inversed inside the method. There may be no real
+ * tick, and no timer interrupt.
+ */
+
+int timer_get_count(struct udevice *dev, unsigned long *count)
+{
+ const struct dm_timer_ops *ops = device_get_ops(dev);
+
+ if (!ops->get_count)
+ return -ENOSYS;
+
+ return ops->get_count(dev, count);
+}
+
+int timer_get_clock(struct udevice *dev, unsigned long *freq)
+{
+ const struct dm_timer_ops *ops = device_get_ops(dev);
+
+ if (!ops->get_clock)
+ return -ENOSYS;
+
+ return ops->get_clock(dev, freq);
+}
+
+UCLASS_DRIVER(timer) = {
+ .id = UCLASS_TIMER,
+ .name = "timer",
+};
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index 2155265..ebecb5f 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -69,6 +69,9 @@ typedef struct global_data {
struct udevice *dm_root_f; /* Pre-relocation root instance */
struct list_head uclass_root; /* Head of core tree */
#endif
+#ifdef CONFIG_DM_TIMER
+ struct udevice *dm_timer; /* Timer instance for Driver Model */
+#endif

const void *fdt_blob; /* Our device tree, NULL if none */
void *new_fdt; /* Relocated FDT */
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 1eeec74..aff34a4 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -56,6 +56,7 @@ enum uclass_id {
UCLASS_SPI_GENERIC, /* Generic SPI flash target */
UCLASS_SYSCON, /* System configuration device */
UCLASS_THERMAL, /* Thermal sensor */
+ UCLASS_TIMER, /* Timer device */
UCLASS_TPM, /* Trusted Platform Module TIS interface */
UCLASS_USB, /* USB bus */
UCLASS_USB_DEV_GENERIC, /* USB generic device */
diff --git a/include/timer.h b/include/timer.h
new file mode 100644
index 0000000..c18a195
--- /dev/null
+++ b/include/timer.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2015 Thomas Chou <thomas@wytron.com.tw>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef _DM_TIMER_H_
+#define _DM_TIMER_H_
+
+/*
+ * Get the current timer count
+ *
+ * @dev: The Timer device
+ * @count: pointer that returns the current timer count
+ * @return: 0 if OK, -ve on error
+ */
+int timer_get_count(struct udevice *dev, unsigned long *count);
+/*
+ * Get the timer input clock frequency
+ *
+ * @dev: The Timer device
+ * @freq: pointer that returns the timer clock frequency
+ * @return: 0 if OK, -ve on error
+ */
+int timer_get_clock(struct udevice *dev, unsigned long *freq);
+
+/*
+ * struct dm_timer_ops - Driver model Timer operations
+ *
+ * The uclass interface is implemented by all Timer devices which use
+ * driver model.
+ */
+struct dm_timer_ops {
+ /*
+ * Get the current timer count
+ *
+ * @dev: The Timer device
+ * @count: pointer that returns the current timer count
+ * @return: 0 if OK, -ve on error
+ */
+ int (*get_count)(struct udevice *dev, unsigned long *count);
+ /*
+ * Get the timer input clock frequency
+ *
+ * @dev: The Timer device
+ * @freq: pointer that returns the timer clock frequency
+ * @return: 0 if OK, -ve on error
+ */
+ int (*get_clock)(struct udevice *dev, unsigned long *freq);
+};
+
+#endif /* _DM_TIMER_H_ */
diff --git a/lib/time.c b/lib/time.c
index 477440d..ba063cf 100644
--- a/lib/time.c
+++ b/lib/time.c
@@ -6,6 +6,9 @@
*/

#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
#include <watchdog.h>
#include <div64.h>
#include <asm/io.h>
@@ -37,6 +40,57 @@ unsigned long notrace timer_read_counter(void)
extern unsigned long __weak timer_read_counter(void);
#endif

+#ifdef CONFIG_DM_TIMER
+static int notrace dm_timer_init(void)
+{
+ struct udevice *dev;
+ int ret;
+
+ if (!gd->dm_timer) {
+ ret = uclass_first_device(UCLASS_TIMER, &dev);
+ if (ret)
+ return ret;
+ if (!dev)
+ return -ENODEV;
+ gd->dm_timer = dev;
+ }
+
+ return 0;
+}
+
+ulong notrace get_tbclk(void)
+{
+ unsigned long freq;
+ int ret;
+
+ ret = dm_timer_init();
+ if (ret)
+ return ret;
+
+ ret = timer_get_clock(gd->dm_timer, &freq);
+ if (ret)
+ return ret;
+
+ return freq;
+}
+
+unsigned long notrace timer_read_counter(void)
+{
+ unsigned long count;
+ int ret;
+
+ ret = dm_timer_init();
+ if (ret)
+ return ret;
+
+ ret = timer_get_count(gd->dm_timer, &count);
+ if (ret)
+ return ret;
+
+ return count;
+}
+#endif /* CONFIG_DM_TIMER */
+
uint64_t __weak notrace get_ticks(void)
{
unsigned long now = timer_read_counter();
--
2.1.4