[U-Boot] [PATCH 03/12] aspeed: Add Timer Support

Maxim Sloyko
2017-01-04T19:46:47Z

Add support for timer for Aspeed ast2400/ast2500 devices.
The driver actually controls several devices, but because all devices
share the same Control Register, it is somewhat difficult to completely
decouple them. Since only one timer is needed at the moment, this should
be OK.

The timer uses fixed clock, so does not rely on a clock driver.

Signed-off-by: Maxim Sloyko <maxims@google.com>
---

arch/arm/include/asm/arch-aspeed/timer.h | 54 ++++++++++++++++++
drivers/timer/Kconfig | 7 +++
drivers/timer/Makefile | 1 +
drivers/timer/ast_timer.c | 96 ++++++++++++++++++++++++++++++++
4 files changed, 158 insertions(+)
create mode 100644 arch/arm/include/asm/arch-aspeed/timer.h
create mode 100644 drivers/timer/ast_timer.c

diff --git a/arch/arm/include/asm/arch-aspeed/timer.h b/arch/arm/include/asm/arch-aspeed/timer.h
new file mode 100644
index 0000000000..87c5b354ec
--- /dev/null
+++ b/arch/arm/include/asm/arch-aspeed/timer.h
@@ -0,0 +1,54 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#ifndef _ASM_ARCH_TIMER_H
+#define _ASM_ARCH_TIMER_H
+
+/* Each timer has 4 control bits in ctrl1 register.
+ * Timer1 uses bits 0:3, Timer2 uses bits 4:7 and so on,
+ * such that timer X uses bits (4 * X - 4):(4 * X - 1)
+ * If the timer does not support PWM, bit 4 is reserved.
+ */
+#define AST_TMC_EN (1 << 0)
+#define AST_TMC_1MHZ (1 << 1)
+#define AST_TMC_OVFINTR (1 << 2)
+#define AST_TMC_PWM (1 << 3)
+
+/* Timers are counted from 1 in the datasheet. */
+#define AST_TMC_CTRL1_SHIFT(n) (4 * ((n) - 1))
+
+#define AST_TMC_RATE (1000*1000)
+
+#ifndef __ASSEMBLY__
+
+/*
+ * All timers share control registers, which makes it harder to make them
+ * separate devices. Since only one timer is needed@the moment, making
+ * it this just one device.
+ */
+
+struct ast_timer_counter {
+ u32 status;
+ u32 reload_val;
+ u32 match1;
+ u32 match2;
+};
+
+struct ast_timer {
+ struct ast_timer_counter timers1[3];
+ u32 ctrl1;
+ u32 ctrl2;
+#ifdef CONFIG_ASPEED_AST2500
+ u32 ctrl3;
+ u32 ctrl1_clr;
+#else
+ u32 reserved[2];
+#endif
+ struct ast_timer_counter timers2[5];
+};
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_ARCH_TIMER_H */
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index cb18f12fc9..9c5f98bb88 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -46,4 +46,11 @@ config OMAP_TIMER
help
Select this to enable an timer for Omap devices.

+config AST_TIMER
+ bool "Aspeed ast2400/ast2500 timer support"
+ depends on TIMER
+ default y if ARCH_ASPEED
+ help
+ Select this to enable timer for Aspeed ast2400/ast2500 devices.
+
endmenu
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index f351fbb4e0..a4b1a486b0 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -9,3 +9,4 @@ obj-$(CONFIG_ALTERA_TIMER) += altera_timer.o
obj-$(CONFIG_SANDBOX_TIMER) += sandbox_timer.o
obj-$(CONFIG_X86_TSC_TIMER) += tsc_timer.o
obj-$(CONFIG_OMAP_TIMER) += omap-timer.o
+obj-$(CONFIG_AST_TIMER) += ast_timer.o
diff --git a/drivers/timer/ast_timer.c b/drivers/timer/ast_timer.c
new file mode 100644
index 0000000000..f644882f40
--- /dev/null
+++ b/drivers/timer/ast_timer.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <timer.h>
+#include <asm/io.h>
+#include <asm/arch/timer.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define AST_TICK_TIMER 1
+#define AST_TMC_RELOAD_VAL 0xffffffff
+
+struct ast_timer_priv {
+ struct ast_timer *regs;
+};
+
+static struct ast_timer_counter *ast_get_timer_counter(struct ast_timer *timer,
+ int n)
+{
+ if (n > 3)
+ return &timer->timers2[n - 4];
+ else
+ return &timer->timers1[n - 1];
+}
+
+static int ast_timer_probe(struct udevice *dev)
+{
+ struct ast_timer_priv *priv = dev_get_priv(dev);
+ struct ast_timer_counter *tmc = ast_get_timer_counter(priv->regs,
+ AST_TICK_TIMER);
+ struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+
+ writel(AST_TMC_RELOAD_VAL, &tmc->reload_val);
+
+ /*
+ * Stop the timer. This will also load reload_val into
+ * the status register.
+ */
+ clrbits_le32(&priv->regs->ctrl1,
+ AST_TMC_EN << AST_TMC_CTRL1_SHIFT(AST_TICK_TIMER));
+ /* Start the timer from the fixed 1MHz clock. */
+ setbits_le32(&priv->regs->ctrl1,
+ (AST_TMC_EN | AST_TMC_1MHZ) <<
+ AST_TMC_CTRL1_SHIFT(AST_TICK_TIMER));
+
+ uc_priv->clock_rate = AST_TMC_RATE;
+
+ return 0;
+}
+
+static int ast_timer_get_count(struct udevice *dev, u64 *count)
+{
+ struct ast_timer_priv *priv = dev_get_priv(dev);
+ struct ast_timer_counter *tmc = ast_get_timer_counter(priv->regs,
+ AST_TICK_TIMER);
+
+ *count = AST_TMC_RELOAD_VAL - readl(&tmc->status);
+
+ return 0;
+}
+
+static int ast_timer_ofdata_to_platdata(struct udevice *dev)
+{
+ struct ast_timer_priv *priv = dev_get_priv(dev);
+
+ priv->regs = (struct ast_timer *)dev_get_addr(dev);
+
+ return 0;
+}
+
+static const struct timer_ops ast_timer_ops = {
+ .get_count = ast_timer_get_count,
+};
+
+static const struct udevice_id ast_timer_ids[] = {
+ { .compatible = "aspeed,ast2500-timer" },
+ { .compatible = "aspeed,ast2400-timer" },
+ { }
+};
+
+U_BOOT_DRIVER(sandbox_timer) = {
+ .name = "ast_timer",
+ .id = UCLASS_TIMER,
+ .of_match = ast_timer_ids,
+ .probe = ast_timer_probe,
+ .priv_auto_alloc_size = sizeof(struct ast_timer_priv),
+ .ofdata_to_platdata = ast_timer_ofdata_to_platdata,
+ .ops = &ast_timer_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};
--
2.11.0.390.gc69c2f50cf-goog