MIPS: lantiq: adds support for gptu timers

Lantiq socs have a General Purpose Timer Unit (GPTU). This driver allows us to
initialize the timers. The voice firmware needs these timers as a reference.

Signed-off-by: John Crispin <[e-mail]>
Patchwork: http://patchwork.linux-mips.org/patch/4236/

arch/mips/lantiq/xway/Makefile

···
-obj-y := prom.o sysctrl.o clk.o reset.o gpio.o dma.o
+obj-y := prom.o sysctrl.o clk.o reset.o gpio.o dma.o gptu.o

arch/mips/lantiq/xway/gptu.c

···
+/*
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License version 2 as published
+ *  by the Free Software Foundation.
+ *
+ *  Copyright (C) 2012 John Crispin <[e-mail]>
+ *  Copyright (C) 2012 Lantiq GmbH
+ */
+
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/of_irq.h>
+
+#include <lantiq_soc.h>
+#include "../clk.h"
+
+/* the magic ID byte of the core */
+#define GPTU_MAGIC	0x59
+/* clock control register */
+#define GPTU_CLC	0x00
+/* id register */
+#define GPTU_ID		0x08
+/* interrupt node enable */
+#define GPTU_IRNEN	0xf4
+/* interrupt control register */
+#define GPTU_IRCR	0xf8
+/* interrupt capture register */
+#define GPTU_IRNCR	0xfc
+/* there are 3 identical blocks of 2 timers. calculate register offsets */
+#define GPTU_SHIFT(x)	(x % 2 ? 4 : 0)
+#define GPTU_BASE(x)	(((x >> 1) * 0x20) + 0x10)
+/* timer control register */
+#define GPTU_CON(x)	(GPTU_BASE(x) + GPTU_SHIFT(x) + 0x00)
+/* timer auto reload register */
+#define GPTU_RUN(x)	(GPTU_BASE(x) + GPTU_SHIFT(x) + 0x08)
+/* timer manual reload register */
+#define GPTU_RLD(x)	(GPTU_BASE(x) + GPTU_SHIFT(x) + 0x10)
+/* timer count register */
+#define GPTU_CNT(x)	(GPTU_BASE(x) + GPTU_SHIFT(x) + 0x18)
+
+/* GPTU_CON(x) */
+#define CON_CNT		BIT(2)
+#define CON_EDGE_ANY	(BIT(7) | BIT(6))
+#define CON_SYNC	BIT(8)
+#define CON_CLK_INT	BIT(10)
+
+/* GPTU_RUN(x) */
+#define RUN_SEN		BIT(0)
+#define RUN_RL		BIT(2)
+
+/* set clock to runmode */
+#define CLC_RMC		BIT(8)
+/* bring core out of suspend */
+#define CLC_SUSPEND	BIT(4)
+/* the disable bit */
+#define CLC_DISABLE	BIT(0)
+
+#define gptu_w32(x, y)	ltq_w32((x), gptu_membase + (y))
+#define gptu_r32(x)	ltq_r32(gptu_membase + (x))
+
+enum gptu_timer {
+	TIMER1A = 0,
+	TIMER1B,
+	TIMER2A,
+	TIMER2B,
+	TIMER3A,
+	TIMER3B
+};
+
+static void __iomem *gptu_membase;
+static struct resource irqres[6];
+
+static irqreturn_t timer_irq_handler(int irq, void *priv)
+{
+	int timer = irq - irqres[0].start;
+	gptu_w32(1 << timer, GPTU_IRNCR);
+	return IRQ_HANDLED;
+}
+
+static void gptu_hwinit(void)
+{
+	gptu_w32(0x00, GPTU_IRNEN);
+	gptu_w32(0xff, GPTU_IRNCR);
+	gptu_w32(CLC_RMC | CLC_SUSPEND, GPTU_CLC);
+}
+
+static void gptu_hwexit(void)
+{
+	gptu_w32(0x00, GPTU_IRNEN);
+	gptu_w32(0xff, GPTU_IRNCR);
+	gptu_w32(CLC_DISABLE, GPTU_CLC);
+}
+
+static int gptu_enable(struct clk *clk)
+{
+	int ret = request_irq(irqres[clk->bits].start, timer_irq_handler,
+		IRQF_TIMER, "gtpu", NULL);
+	if (ret) {
+		pr_err("gptu: failed to request irq\n");
+		return ret;
+	}
+
+	gptu_w32(CON_CNT | CON_EDGE_ANY | CON_SYNC | CON_CLK_INT,
+		GPTU_CON(clk->bits));
+	gptu_w32(1, GPTU_RLD(clk->bits));
+	gptu_w32(gptu_r32(GPTU_IRNEN) | BIT(clk->bits), GPTU_IRNEN);
+	gptu_w32(RUN_SEN | RUN_RL, GPTU_RUN(clk->bits));
+	return 0;
+}
+
+static void gptu_disable(struct clk *clk)
+{
+	gptu_w32(0, GPTU_RUN(clk->bits));
+	gptu_w32(0, GPTU_CON(clk->bits));
+	gptu_w32(0, GPTU_RLD(clk->bits));
+	gptu_w32(gptu_r32(GPTU_IRNEN) & ~BIT(clk->bits), GPTU_IRNEN);
+	free_irq(irqres[clk->bits].start, NULL);
+}
+
+static inline void clkdev_add_gptu(struct device *dev, const char *con,
+							unsigned int timer)
+{
+	struct clk *clk = kzalloc(sizeof(struct clk), GFP_KERNEL);
+
+	clk->cl.dev_id = dev_name(dev);
+	clk->cl.con_id = con;
+	clk->cl.clk = clk;
+	clk->enable = gptu_enable;
+	clk->disable = gptu_disable;
+	clk->bits = timer;
+	clkdev_add(&clk->cl);
+}
+
+static int __devinit gptu_probe(struct platform_device *pdev)
+{
+	struct clk *clk;
+	struct resource *res;
+
+	if (of_irq_to_resource_table(pdev->dev.of_node, irqres, 6) != 6) {
+		dev_err(&pdev->dev, "Failed to get IRQ list\n");
+		return -EINVAL;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Failed to get resource\n");
+		return -ENOMEM;
+	}
+
+	/* remap gptu register range */
+	gptu_membase = devm_request_and_ioremap(&pdev->dev, res);
+	if (!gptu_membase) {
+		dev_err(&pdev->dev, "Failed to remap resource\n");
+		return -ENOMEM;
+	}
+
+	/* enable our clock */
+	clk = clk_get(&pdev->dev, NULL);
+	if (IS_ERR(clk)) {
+		dev_err(&pdev->dev, "Failed to get clock\n");
+		return -ENOENT;
+	}
+	clk_enable(clk);
+
+	/* power up the core */
+	gptu_hwinit();
+
+	/* the gptu has a ID register */
+	if (((gptu_r32(GPTU_ID) >> 8) & 0xff) != GPTU_MAGIC) {
+		dev_err(&pdev->dev, "Failed to find magic\n");
+		gptu_hwexit();
+		return -ENAVAIL;
+	}
+
+	/* register the clocks */
+	clkdev_add_gptu(&pdev->dev, "timer1a", TIMER1A);
+	clkdev_add_gptu(&pdev->dev, "timer1b", TIMER1B);
+	clkdev_add_gptu(&pdev->dev, "timer2a", TIMER2A);
+	clkdev_add_gptu(&pdev->dev, "timer2b", TIMER2B);
+	clkdev_add_gptu(&pdev->dev, "timer3a", TIMER3A);
+	clkdev_add_gptu(&pdev->dev, "timer3b", TIMER3B);
+
+	dev_info(&pdev->dev, "gptu: 6 timers loaded\n");
+
+	return 0;
+}
+
+static const struct of_device_id gptu_match[] = {
+	{ .compatible = "lantiq,gptu-xway" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dma_match);
+
+static struct platform_driver dma_driver = {
+	.probe = gptu_probe,
+	.driver = {
+		.name = "gptu-xway",
+		.owner = THIS_MODULE,
+		.of_match_table = gptu_match,
+	},
+};
+
+int __init gptu_init(void)
+{
+	int ret = platform_driver_register(&dma_driver);
+
+	if (ret)
+		pr_info("gptu: Error registering platform driver\n");
+	return ret;
+}
+
+arch_initcall(gptu_init);