[U-Boot] [PATCH v2 06/10] timer: Add MPC83xx timer driver

Mario Six mario.six at gdsys.cc
Fri Apr 27 12:52:23 UTC 2018


Add a timer driver for the MPC83xx architecture.

Signed-off-by: Mario Six <mario.six at gdsys.cc>

---

v1 -> v2:
* Removed now-superfluous comments
* Removed usage of uclass_{first,next}_device_compat
* Switched to usage of new board uclass (instead of devinfo)

---
 arch/powerpc/cpu/mpc83xx/cpu.c |   4 +-
 arch/powerpc/lib/Makefile      |   4 ++
 arch/powerpc/lib/interrupts.c  |   5 +-
 drivers/timer/Kconfig          |   7 ++
 drivers/timer/Makefile         |   1 +
 drivers/timer/mpc83xx_timer.c  | 160 +++++++++++++++++++++++++++++++++++++++++
 6 files changed, 178 insertions(+), 3 deletions(-)
 create mode 100644 drivers/timer/mpc83xx_timer.c

diff --git a/arch/powerpc/cpu/mpc83xx/cpu.c b/arch/powerpc/cpu/mpc83xx/cpu.c
index 9a5c1b7d55..376483eda7 100644
--- a/arch/powerpc/cpu/mpc83xx/cpu.c
+++ b/arch/powerpc/cpu/mpc83xx/cpu.c
@@ -176,12 +176,12 @@ do_reset (cmd_tbl_t * cmdtp, int flag, int argc, char * const argv[])
 /*
  * Get timebase clock frequency (like cpu_clk in Hz)
  */
-
+#ifndef CONFIG_TIMER
 unsigned long get_tbclk(void)
 {
 	return (gd->bus_clk + 3L) / 4L;
 }
-
+#endif

 #if defined(CONFIG_WATCHDOG)
 void watchdog_reset (void)
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 9a3043abf8..537693e3bc 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -19,13 +19,17 @@ endif

 ifdef MINIMAL
 obj-y += cache.o time.o
+ifndef CONFIG_TIMER
 obj-y += ticks.o
+endif
 else

 obj-y	+= ppcstring.o

 obj-y	+= ppccache.o
+ifndef CONFIG_TIMER
 obj-y	+= ticks.o
+endif
 obj-y	+= reloc.o

 obj-$(CONFIG_BAT_RW) += bat_rw.o
diff --git a/arch/powerpc/lib/interrupts.c b/arch/powerpc/lib/interrupts.c
index e8784aa16e..56a697d28c 100644
--- a/arch/powerpc/lib/interrupts.c
+++ b/arch/powerpc/lib/interrupts.c
@@ -15,6 +15,7 @@
 #include <status_led.h>
 #endif

+#ifndef CONFIG_MPC83XX_TIMER
 #ifdef CONFIG_SHOW_ACTIVITY
 void board_show_activity (ulong) __attribute__((weak, alias("__board_show_activity")));

@@ -45,7 +46,7 @@ static __inline__ void set_dec (unsigned long val)
 	if (val)
 		asm volatile ("mtdec %0"::"r" (val));
 }
-
+#endif /* !CONFIG_MPC83XX_TIMER */

 void enable_interrupts (void)
 {
@@ -61,6 +62,7 @@ int disable_interrupts (void)
 	return ((msr & MSR_EE) != 0);
 }

+#ifndef CONFIG_MPC83XX_TIMER
 int interrupt_init (void)
 {
 	/* call cpu specific function from $(CPU)/interrupts.c */
@@ -103,3 +105,4 @@ ulong get_timer (ulong base)
 {
 	return (timestamp - base);
 }
+#endif /* !CONFIG_MPC83XX_TIMER */
diff --git a/drivers/timer/Kconfig b/drivers/timer/Kconfig
index 2c96896726..1b78ce784a 100644
--- a/drivers/timer/Kconfig
+++ b/drivers/timer/Kconfig
@@ -126,4 +126,11 @@ config STM32_TIMER
 	  Select this to enable support for the timer found on
 	  STM32 devices.

+config MPC83XX_TIMER
+        bool "MPC83xx timer support"
+	depends on TIMER
+	help
+	  Select this to enable support for the timer found on
+	  devices based on the MPC83xx family of SoCs.
+
 endmenu
diff --git a/drivers/timer/Makefile b/drivers/timer/Makefile
index a6e7832154..d35d235195 100644
--- a/drivers/timer/Makefile
+++ b/drivers/timer/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_ATCPIT100_TIMER) += atcpit100_timer.o
 obj-$(CONFIG_ROCKCHIP_TIMER) += rockchip_timer.o
 obj-$(CONFIG_ATMEL_PIT_TIMER) += atmel_pit_timer.o
 obj-$(CONFIG_STM32_TIMER)	+= stm32_timer.o
+obj-$(CONFIG_MPC83XX_TIMER) += mpc83xx_timer.o
diff --git a/drivers/timer/mpc83xx_timer.c b/drivers/timer/mpc83xx_timer.c
new file mode 100644
index 0000000000..c3dd306c5b
--- /dev/null
+++ b/drivers/timer/mpc83xx_timer.c
@@ -0,0 +1,160 @@
+/*
+ * (C) Copyright 2018
+ * Mario Six, Guntermann & Drunck GmbH, mario.six at gdsys.cc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <clk.h>
+#include <timer.h>
+#include <watchdog.h>
+#include <board.h>
+
+struct mpc83xx_timer_priv {
+};
+
+static uint decrementer_count; /* count value for 1e6/HZ microseconds */
+
+static inline unsigned long get_dec(void)
+{
+	unsigned long val;
+
+	asm volatile ("mfdec %0":"=r" (val):);
+
+	return val;
+}
+
+static inline void set_dec(unsigned long val)
+{
+	if (val)
+		asm volatile ("mtdec %0"::"r" (val));
+}
+
+/* TODO(mario.six at gdsys.cc): This should really be done by timer_init, and the
+ * interrupt init should go into a interrupt driver.
+ */
+int interrupt_init(void)
+{
+	immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
+	struct udevice *csb;
+	struct udevice *board;
+	struct clk clock;
+
+	if (get_board(&board))
+		return -ENOENT;
+
+	uclass_get_device_by_phandle(UCLASS_SIMPLE_BUS, board, "csb", &csb);
+	clk_get_by_index(csb, 0, &clock);
+
+	decrementer_count = (clk_get_rate(&clock) / 4) / CONFIG_SYS_HZ;
+
+	/* Enable e300 time base */
+
+	setbits_be32(&immr->sysconf.spcr, 0x00400000);
+
+	set_dec(decrementer_count);
+
+	set_msr(get_msr() | MSR_EE);
+
+	return 0;
+}
+
+static volatile ulong timestamp = 0;
+
+void timer_interrupt(struct pt_regs *regs)
+{
+	/* Restore Decrementer Count */
+	set_dec(decrementer_count);
+
+	timestamp++;
+
+#if defined(CONFIG_WATCHDOG) || defined(CONFIG_HW_WATCHDOG)
+	if ((timestamp % (CONFIG_SYS_WATCHDOG_FREQ)) == 0)
+		WATCHDOG_RESET();
+#endif    /* CONFIG_WATCHDOG || CONFIG_HW_WATCHDOG */
+
+#ifdef CONFIG_LED_STATUS
+	status_led_tick(timestamp);
+#endif /* CONFIG_LED_STATUS */
+
+#ifdef CONFIG_SHOW_ACTIVITY
+	board_show_activity(timestamp);
+#endif /* CONFIG_SHOW_ACTIVITY */
+}
+
+ulong get_timer(ulong base)
+{
+	return (timestamp - base);
+}
+
+static inline u32 mftbu(void)
+{
+	u32 rval;
+
+	asm volatile("mftbu %0" : "=r" (rval));
+	return rval;
+}
+
+static inline u32 mftb(void)
+{
+	u32 rval;
+
+	asm volatile("mftb %0" : "=r" (rval));
+	return rval;
+}
+
+void wait_ticks(ulong ticks)
+{
+	ulong end = get_ticks() + ticks;
+
+	while (end > get_ticks())
+		WATCHDOG_RESET();
+}
+
+static int mpc83xx_timer_get_count(struct udevice *dev, u64 *count)
+{
+	u32 tbu, tbl;
+
+	do {
+		tbu = mftbu();
+		tbl = mftb();
+	} while (tbu != mftbu());
+
+	*count = (tbu * 0x10000ULL) + tbl;
+
+	return 0;
+}
+
+static int mpc83xx_timer_probe(struct udevice *dev)
+{
+	struct timer_dev_priv *uc_priv = dev->uclass_priv;
+	struct clk clock;
+
+	interrupt_init();
+
+	clk_get_by_index(dev, 0, &clock);
+
+	uc_priv->clock_rate = (clk_get_rate(&clock) + 3L) / 4L;
+
+	return 0;
+}
+
+static const struct timer_ops mpc83xx_timer_ops = {
+	.get_count = mpc83xx_timer_get_count,
+};
+
+static const struct udevice_id mpc83xx_timer_ids[] = {
+	{ .compatible = "fsl,mpc83xx-timer" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(mpc83xx_timer) = {
+	.name	= "mpc83xx_timer",
+	.id	= UCLASS_TIMER,
+	.of_match = mpc83xx_timer_ids,
+	.probe = mpc83xx_timer_probe,
+	.ops	= &mpc83xx_timer_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+};
--
2.16.1



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