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Message-Id: <1420708042-22906-2-git-send-email-linux@rempel-privat.de>
Date: Thu, 8 Jan 2015 10:07:22 +0100
From: Oleksij Rempel <linux@...pel-privat.de>
To: daniel.lezcano@...aro.org, tglx@...utronix.de,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc: Oleksij Rempel <linux@...pel-privat.de>
Subject: [PATCH] ARM: clocksource: add asm9260_timer driver
In some cases asm9260 looks similar to iMX2x. One of exceptions is
timer controller. So this patch introduces new driver for this special case.
Signed-off-by: Oleksij Rempel <linux@...pel-privat.de>
Acked-by: Daniel Lezcano <daniel.lezcano@...aro.org>
---
drivers/clocksource/Kconfig | 9 ++
drivers/clocksource/Makefile | 1 +
drivers/clocksource/asm9260_timer.c | 220 ++++++++++++++++++++++++++++++++++++
3 files changed, 230 insertions(+)
create mode 100644 drivers/clocksource/asm9260_timer.c
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index f657a48..2d38bf6 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -224,4 +224,13 @@ config CLKSRC_VERSATILE
ARM Versatile, RealView and Versatile Express reference
platforms.
+config ASM9260_TIMER
+ bool "Alphascale ASM9260 timer driver"
+ select CLKSRC_MMIO
+ select CLKSRC_OF
+ default y if MACH_ASM9260
+ help
+ This enables build of a clocksource and clockevent driver for
+ the 32-bit System Timer hardware available on a Alphascale ASM9260.
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index fae0435..3da4665 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -47,3 +47,4 @@ obj-$(CONFIG_ARCH_HAS_TICK_BROADCAST) += dummy_timer.o
obj-$(CONFIG_ARCH_KEYSTONE) += timer-keystone.o
obj-$(CONFIG_ARCH_INTEGRATOR_AP) += timer-integrator-ap.o
obj-$(CONFIG_CLKSRC_VERSATILE) += versatile.o
+obj-$(CONFIG_ASM9260_TIMER) += asm9260_timer.o
diff --git a/drivers/clocksource/asm9260_timer.c b/drivers/clocksource/asm9260_timer.c
new file mode 100644
index 0000000..2c9c993
--- /dev/null
+++ b/drivers/clocksource/asm9260_timer.c
@@ -0,0 +1,220 @@
+/*
+ * Copyright (C) 2014 Oleksij Rempel <linux@...pel-privat.de>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/clk.h>
+#include <linux/clocksource.h>
+#include <linux/clockchips.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/bitops.h>
+
+#define DRIVER_NAME "asm9260-timer"
+
+/*
+ * this device provide 4 offsets for each register:
+ * 0x0 - plain read write mode
+ * 0x4 - set mode, OR logic.
+ * 0x8 - clr mode, XOR logic.
+ * 0xc - togle mode.
+ */
+#define SET_REG 4
+#define CLR_REG 8
+
+#define HW_IR 0x0000 /* RW. Interrupt */
+#define BM_IR_CR0 BIT(4)
+#define BM_IR_MR3 BIT(3)
+#define BM_IR_MR2 BIT(2)
+#define BM_IR_MR1 BIT(1)
+#define BM_IR_MR0 BIT(0)
+
+#define HW_TCR 0x0010 /* RW. Timer controller */
+/* BM_C*_RST
+ * Timer Counter and the Prescale Counter are synchronously reset on the
+ * next positive edge of PCLK. The counters remain reset until TCR[1] is
+ * returned to zero. */
+#define BM_C3_RST BIT(7)
+#define BM_C2_RST BIT(6)
+#define BM_C1_RST BIT(5)
+#define BM_C0_RST BIT(4)
+/* BM_C*_EN
+ * 1 - Timer Counter and Prescale Counter are enabled for counting
+ * 0 - counters are disabled */
+#define BM_C3_EN BIT(3)
+#define BM_C2_EN BIT(2)
+#define BM_C1_EN BIT(1)
+#define BM_C0_EN BIT(0)
+
+#define HW_DIR 0x0020 /* RW. Direction? */
+/* 00 - count up
+ * 01 - count down
+ * 10 - ?? 2^n/2 */
+#define BM_DIR_COUNT_UP 0
+#define BM_DIR_COUNT_DOWN 1
+#define BM_DIR0_SHIFT 0
+#define BM_DIR1_SHIFT 4
+#define BM_DIR2_SHIFT 8
+#define BM_DIR3_SHIFT 12
+#define BM_DIR_DEFAULT (BM_DIR_COUNT_UP << BM_DIR0_SHIFT | \
+ BM_DIR_COUNT_UP << BM_DIR1_SHIFT | \
+ BM_DIR_COUNT_UP << BM_DIR2_SHIFT | \
+ BM_DIR_COUNT_UP << BM_DIR3_SHIFT)
+
+#define HW_TC0 0x0030 /* RO. Timer counter 0 */
+/* HW_TC*. Timer counter owerflow (0xffff.ffff to 0x0000.0000) do not generate
+ * interrupt. This registers can be used to detect overflow */
+#define HW_TC1 0x0040
+#define HW_TC2 0x0050
+#define HW_TC3 0x0060
+
+#define HW_PR 0x0070 /* RW. prescaler */
+#define BM_PR_DISABLE 0
+#define HW_PC 0x0080 /* RO. Prescaler counter */
+#define HW_MCR 0x0090 /* RW. Match control */
+/* enable interrupt on match */
+#define BM_MCR_INT_EN(n) (1 << (n * 3 + 0))
+/* enable TC reset on match */
+#define BM_MCR_RES_EN(n) (1 << (n * 3 + 1))
+/* enable stop TC on match */
+#define BM_MCR_STOP_EN(n) (1 << (n * 3 + 2))
+
+#define HW_MR0 0x00a0 /* RW. Match reg */
+#define HW_MR1 0x00b0
+#define HW_MR2 0x00C0
+#define HW_MR3 0x00D0
+
+#define HW_CTCR 0x0180 /* Counter control */
+#define BM_CTCR0_SHIFT 0
+#define BM_CTCR1_SHIFT 2
+#define BM_CTCR2_SHIFT 4
+#define BM_CTCR3_SHIFT 6
+#define BM_CTCR_TM 0 /* Timer mode. Every rising PCLK edge. */
+#define BM_CTCR_DEFAULT (BM_CTCR_TM << BM_CTCR0_SHIFT | \
+ BM_CTCR_TM << BM_CTCR1_SHIFT | \
+ BM_CTCR_TM << BM_CTCR2_SHIFT | \
+ BM_CTCR_TM << BM_CTCR3_SHIFT)
+
+static struct asm9260_timer_priv {
+ void __iomem *base;
+ unsigned long ticks_per_jiffy;
+} priv;
+
+static int asm9260_timer_set_next_event(unsigned long delta,
+ struct clock_event_device *evt)
+{
+ /* configure match count for TC0 */
+ writel_relaxed(delta, priv.base + HW_MR0);
+ /* enable TC0 */
+ writel_relaxed(BM_C0_EN, priv.base + HW_TCR + SET_REG);
+ return 0;
+}
+
+static void asm9260_timer_set_mode(enum clock_event_mode mode,
+ struct clock_event_device *evt)
+{
+ /* stop timer0 */
+ writel_relaxed(BM_C0_EN, priv.base + HW_TCR + CLR_REG);
+
+ switch (mode) {
+ case CLOCK_EVT_MODE_PERIODIC:
+ /* disable reset and stop on match */
+ writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0),
+ priv.base + HW_MCR + CLR_REG);
+ /* configure match count for TC0 */
+ writel_relaxed(priv.ticks_per_jiffy, priv.base + HW_MR0);
+ /* enable TC0 */
+ writel_relaxed(BM_C0_EN, priv.base + HW_TCR + SET_REG);
+ break;
+ case CLOCK_EVT_MODE_ONESHOT:
+ /* enable reset and stop on match */
+ writel_relaxed(BM_MCR_RES_EN(0) | BM_MCR_STOP_EN(0),
+ priv.base + HW_MCR + SET_REG);
+ break;
+ default:
+ break;
+ }
+}
+
+static struct clock_event_device event_dev = {
+ .name = DRIVER_NAME,
+ .rating = 200,
+ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
+ .set_next_event = asm9260_timer_set_next_event,
+ .set_mode = asm9260_timer_set_mode,
+};
+
+static irqreturn_t asm9260_timer_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = dev_id;
+
+ evt->event_handler(evt);
+
+ writel_relaxed(BM_IR_MR0, priv.base + HW_IR);
+
+ return IRQ_HANDLED;
+}
+
+/*
+ * ---------------------------------------------------------------------------
+ * Timer initialization
+ * ---------------------------------------------------------------------------
+ */
+static void __init asm9260_timer_init(struct device_node *np)
+{
+ int irq;
+ struct clk *clk;
+ int ret;
+ unsigned long rate;
+
+ priv.base = of_io_request_and_map(np, 0, np->name);
+ if (!priv.base)
+ panic("%s: unable to map resource", np->name);
+
+ clk = of_clk_get(np, 0);
+
+ ret = clk_prepare_enable(clk);
+ if (ret)
+ panic("Failed to enable clk!\n");
+
+ irq = irq_of_parse_and_map(np, 0);
+ ret = request_irq(irq, asm9260_timer_interrupt, IRQF_TIMER,
+ DRIVER_NAME, &event_dev);
+ if (ret)
+ panic("Failed to setup irq!\n");
+
+ /* set all timers for count-up */
+ writel_relaxed(BM_DIR_DEFAULT, priv.base + HW_DIR);
+ /* disable divider */
+ writel_relaxed(BM_PR_DISABLE, priv.base + HW_PR);
+ /* make sure all timers use every rising PCLK edge. */
+ writel_relaxed(BM_CTCR_DEFAULT, priv.base + HW_CTCR);
+ /* enable interrupt for TC0 and clean setting for all other lines */
+ writel_relaxed(BM_MCR_INT_EN(0) , priv.base + HW_MCR);
+
+ rate = clk_get_rate(clk);
+ clocksource_mmio_init(priv.base + HW_TC1, DRIVER_NAME, rate,
+ 200, 32, clocksource_mmio_readl_up);
+
+ /* Seems like we can't use counter without match register even if
+ * actions for MR are disabled. So, set MR to max value. */
+ writel_relaxed(0xffffffff, priv.base + HW_MR1);
+ /* enable TC1 */
+ writel_relaxed(BM_C1_EN, priv.base + HW_TCR + SET_REG);
+
+ priv.ticks_per_jiffy = DIV_ROUND_CLOSEST(rate, HZ);
+ event_dev.cpumask = cpumask_of(0);
+ clockevents_config_and_register(&event_dev, rate, 0x2c00, 0xfffffffe);
+}
+CLOCKSOURCE_OF_DECLARE(asm9260_timer, "alphascale,asm9260-timer",
+ asm9260_timer_init);
--
1.9.1
--
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