timer: Add driver for Nomadik Multi Timer Unit (MTU)

The Nomadik Multi Timer Unit (MTU) provides 4 decrementing free-running timers. It is used in ST-Ericsson Ux500 SoCs. The driver uses the first timer to implement UCLASS_TIMER. Signed-off-by: Stephan Gerhold <stephan@gerhold.net> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

timer: Add driver for Nomadik Multi Timer Unit (MTU)
The Nomadik Multi Timer Unit (MTU) provides 4 decrementing free-running timers. It is used in ST-Ericsson Ux500 SoCs. The driver uses the first timer to implement UCLASS_TIMER. Signed-off-by: Stephan Gerhold <stephan@gerhold.net> Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Stephan Gerhold · Tom Rini
1 parent c82216803d
Showing 3 changed files with 124 additions and 0 deletions Side-by-side Diff
drivers/timer/Kconfig
drivers/timer/Makefile
drivers/timer/nomadik-mtu-timer.c
@@ -127,6 +127,15 @@
 	  hardware ways, nor got from device tree at the time when device
 	  tree is not available yet.
  
+config NOMADIK_MTU_TIMER
+	bool "Nomadik MTU Timer"
+	depends on TIMER
+	help
+	  Enables support for the Nomadik Multi Timer Unit (MTU),
+	  used in ST-Ericsson Ux500 SoCs.
+	  The MTU provides 4 decrementing free-running timers.
+	  At the moment, only the first timer is used by the driver.
+
 config OMAP_TIMER
 	bool "Omap timer support"
 	depends on TIMER
@@ -12,6 +12,7 @@
 obj-$(CONFIG_CADENCE_TTC_TIMER)	+= cadence-ttc.o
 obj-$(CONFIG_DESIGNWARE_APB_TIMER)	+= dw-apb-timer.o
 obj-$(CONFIG_MPC83XX_TIMER) += mpc83xx_timer.o
+obj-$(CONFIG_NOMADIK_MTU_TIMER)	+= nomadik-mtu-timer.o
 obj-$(CONFIG_OMAP_TIMER)	+= omap-timer.o
 obj-$(CONFIG_RENESAS_OSTM_TIMER) += ostm_timer.o
 obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2019 Stephan Gerhold <stephan@gerhold.net>
+ *
+ * Based on arch/arm/cpu/armv7/u8500/timer.c:
+ * Copyright (C) 2010 Linaro Limited
+ * John Rigby <john.rigby@linaro.org>
+ *
+ * Based on Linux kernel source and internal ST-Ericsson U-Boot source:
+ * Copyright (C) 2009 Alessandro Rubini
+ * Copyright (C) 2010 ST-Ericsson
+ * Copyright (C) 2010 Linus Walleij for ST-Ericsson
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <timer.h>
+#include <asm/io.h>
+
+#define MTU_NUM_TIMERS		4
+
+/* The timers */
+struct nomadik_mtu_timer_regs {
+	u32 lr;		/* Load register */
+	u32 cv;		/* Current value */
+	u32 cr;		/* Control register */
+	u32 bglr;	/* Background load register */
+};
+
+/* The MTU that contains the timers */
+struct nomadik_mtu_regs {
+	u32 imsc;	/* Interrupt mask set/clear */
+	u32 ris;	/* Raw interrupt status */
+	u32 mis;	/* Masked interrupt status */
+	u32 icr;	/* Interrupt clear register */
+
+	struct nomadik_mtu_timer_regs timers[MTU_NUM_TIMERS];
+};
+
+/* Bits for the control register */
+#define MTU_CR_ONESHOT		BIT(0)	/* if 0 = wraps reloading from BGLR */
+#define MTU_CR_32BITS		BIT(1)	/* if 0 = 16-bit counter */
+
+#define MTU_CR_PRESCALE_SHIFT	2
+#define MTU_CR_PRESCALE_1	(0 << MTU_CR_PRESCALE_SHIFT)
+#define MTU_CR_PRESCALE_16	(1 << MTU_CR_PRESCALE_SHIFT)
+#define MTU_CR_PRESCALE_256	(2 << MTU_CR_PRESCALE_SHIFT)
+
+#define MTU_CR_PERIODIC		BIT(6)	/* if 0 = free-running */
+#define MTU_CR_ENABLE		BIT(7)
+
+struct nomadik_mtu_priv {
+	struct nomadik_mtu_timer_regs *timer;
+};
+
+static int nomadik_mtu_get_count(struct udevice *dev, u64 *count)
+{
+	struct nomadik_mtu_priv *priv = dev_get_priv(dev);
+
+	/* Decrementing counter: invert the value */
+	*count = timer_conv_64(~readl(&priv->timer->cv));
+
+	return 0;
+}
+
+static int nomadik_mtu_probe(struct udevice *dev)
+{
+	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
+	struct nomadik_mtu_priv *priv = dev_get_priv(dev);
+	struct nomadik_mtu_regs *mtu;
+	fdt_addr_t addr;
+	u32 prescale;
+
+	addr = dev_read_addr(dev);
+	if (addr == FDT_ADDR_T_NONE)
+		return -EINVAL;
+
+	mtu = (struct nomadik_mtu_regs *)addr;
+	priv->timer = mtu->timers; /* Use first timer */
+
+	if (!uc_priv->clock_rate)
+		return -EINVAL;
+
+	/* Use divide-by-16 counter if tick rate is more than 32 MHz */
+	if (uc_priv->clock_rate > 32000000) {
+		uc_priv->clock_rate /= 16;
+		prescale = MTU_CR_PRESCALE_16;
+	} else {
+		prescale = MTU_CR_PRESCALE_1;
+	}
+
+	/* Configure a free-running, auto-wrap counter with selected prescale */
+	writel(MTU_CR_ENABLE | prescale | MTU_CR_32BITS, &priv->timer->cr);
+
+	return 0;
+}
+
+static const struct timer_ops nomadik_mtu_ops = {
+	.get_count = nomadik_mtu_get_count,
+};
+
+static const struct udevice_id nomadik_mtu_ids[] = {
+	{ .compatible = "st,nomadik-mtu" },
+	{}
+};
+
+U_BOOT_DRIVER(nomadik_mtu) = {
+	.name = "nomadik_mtu",
+	.id = UCLASS_TIMER,
+	.of_match = nomadik_mtu_ids,
+	.priv_auto_alloc_size = sizeof(struct nomadik_mtu_priv),
+	.probe = nomadik_mtu_probe,
+	.ops = &nomadik_mtu_ops,
+};
...	...	@@ -127,6 +127,15 @@
127	127	hardware ways, nor got from device tree at the time when device
128	128	tree is not available yet.
129	129
	130	+config NOMADIK_MTU_TIMER
	131	+ bool "Nomadik MTU Timer"
	132	+ depends on TIMER
	133	+ help
	134	+ Enables support for the Nomadik Multi Timer Unit (MTU),
	135	+ used in ST-Ericsson Ux500 SoCs.
	136	+ The MTU provides 4 decrementing free-running timers.
	137	+ At the moment, only the first timer is used by the driver.
	138	+
130	139	config OMAP_TIMER
131	140	bool "Omap timer support"
132	141	depends on TIMER
...	...	@@ -12,6 +12,7 @@
12	12	obj-$(CONFIG_CADENCE_TTC_TIMER) += cadence-ttc.o
13	13	obj-$(CONFIG_DESIGNWARE_APB_TIMER) += dw-apb-timer.o
14	14	obj-$(CONFIG_MPC83XX_TIMER) += mpc83xx_timer.o
	15	+obj-$(CONFIG_NOMADIK_MTU_TIMER) += nomadik-mtu-timer.o
15	16	obj-$(CONFIG_OMAP_TIMER) += omap-timer.o
16	17	obj-$(CONFIG_RENESAS_OSTM_TIMER) += ostm_timer.o
17	18	obj-$(CONFIG_RISCV_TIMER) += riscv_timer.o
	1	+// SPDX-License-Identifier: GPL-2.0-or-later
	2	+/*
	3	+ * Copyright (C) 2019 Stephan Gerhold <stephan@gerhold.net>
	4	+ *
	5	+ * Based on arch/arm/cpu/armv7/u8500/timer.c:
	6	+ * Copyright (C) 2010 Linaro Limited
	7	+ * John Rigby <john.rigby@linaro.org>
	8	+ *
	9	+ * Based on Linux kernel source and internal ST-Ericsson U-Boot source:
	10	+ * Copyright (C) 2009 Alessandro Rubini
	11	+ * Copyright (C) 2010 ST-Ericsson
	12	+ * Copyright (C) 2010 Linus Walleij for ST-Ericsson
	13	+ */
	14	+
	15	+#include <common.h>
	16	+#include <dm.h>
	17	+#include <timer.h>
	18	+#include <asm/io.h>
	19	+
	20	+#define MTU_NUM_TIMERS 4
	21	+
	22	+/* The timers */
	23	+struct nomadik_mtu_timer_regs {
	24	+ u32 lr; /* Load register */
	25	+ u32 cv; /* Current value */
	26	+ u32 cr; /* Control register */
	27	+ u32 bglr; /* Background load register */
	28	+};
	29	+
	30	+/* The MTU that contains the timers */
	31	+struct nomadik_mtu_regs {
	32	+ u32 imsc; /* Interrupt mask set/clear */
	33	+ u32 ris; /* Raw interrupt status */
	34	+ u32 mis; /* Masked interrupt status */
	35	+ u32 icr; /* Interrupt clear register */
	36	+
	37	+ struct nomadik_mtu_timer_regs timers[MTU_NUM_TIMERS];
	38	+};
	39	+
	40	+/* Bits for the control register */
	41	+#define MTU_CR_ONESHOT BIT(0) /* if 0 = wraps reloading from BGLR */
	42	+#define MTU_CR_32BITS BIT(1) /* if 0 = 16-bit counter */
	43	+
	44	+#define MTU_CR_PRESCALE_SHIFT 2
	45	+#define MTU_CR_PRESCALE_1 (0 << MTU_CR_PRESCALE_SHIFT)
	46	+#define MTU_CR_PRESCALE_16 (1 << MTU_CR_PRESCALE_SHIFT)
	47	+#define MTU_CR_PRESCALE_256 (2 << MTU_CR_PRESCALE_SHIFT)
	48	+
	49	+#define MTU_CR_PERIODIC BIT(6) /* if 0 = free-running */
	50	+#define MTU_CR_ENABLE BIT(7)
	51	+
	52	+struct nomadik_mtu_priv {
	53	+ struct nomadik_mtu_timer_regs *timer;
	54	+};
	55	+
	56	+static int nomadik_mtu_get_count(struct udevice dev, u64 count)
	57	+{
	58	+ struct nomadik_mtu_priv *priv = dev_get_priv(dev);
	59	+
	60	+ /* Decrementing counter: invert the value */
	61	+ *count = timer_conv_64(~readl(&priv->timer->cv));
	62	+
	63	+ return 0;
	64	+}
	65	+
	66	+static int nomadik_mtu_probe(struct udevice *dev)
	67	+{
	68	+ struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);
	69	+ struct nomadik_mtu_priv *priv = dev_get_priv(dev);
	70	+ struct nomadik_mtu_regs *mtu;
	71	+ fdt_addr_t addr;
	72	+ u32 prescale;
	73	+
	74	+ addr = dev_read_addr(dev);
	75	+ if (addr == FDT_ADDR_T_NONE)
	76	+ return -EINVAL;
	77	+
	78	+ mtu = (struct nomadik_mtu_regs *)addr;
	79	+ priv->timer = mtu->timers; /* Use first timer */
	80	+
	81	+ if (!uc_priv->clock_rate)
	82	+ return -EINVAL;
	83	+
	84	+ /* Use divide-by-16 counter if tick rate is more than 32 MHz */
	85	+ if (uc_priv->clock_rate > 32000000) {
	86	+ uc_priv->clock_rate /= 16;
	87	+ prescale = MTU_CR_PRESCALE_16;
	88	+ } else {
	89	+ prescale = MTU_CR_PRESCALE_1;
	90	+ }
	91	+
	92	+ /* Configure a free-running, auto-wrap counter with selected prescale */
	93	+ writel(MTU_CR_ENABLE \| prescale \| MTU_CR_32BITS, &priv->timer->cr);
	94	+
	95	+ return 0;
	96	+}
	97	+
	98	+static const struct timer_ops nomadik_mtu_ops = {
	99	+ .get_count = nomadik_mtu_get_count,
	100	+};
	101	+
	102	+static const struct udevice_id nomadik_mtu_ids[] = {
	103	+ { .compatible = "st,nomadik-mtu" },
	104	+ {}
	105	+};
	106	+
	107	+U_BOOT_DRIVER(nomadik_mtu) = {
	108	+ .name = "nomadik_mtu",
	109	+ .id = UCLASS_TIMER,
	110	+ .of_match = nomadik_mtu_ids,
	111	+ .priv_auto_alloc_size = sizeof(struct nomadik_mtu_priv),
	112	+ .probe = nomadik_mtu_probe,
	113	+ .ops = &nomadik_mtu_ops,
	114	+};