On 05/21/2014 06:26 PM, Matthias Brugger wrote:

This patch adds a clock source and clock event for the timer found
on the Mediatek SoCs.

The Mediatek General Porpose Timer block provides five 32 bit timers and

s/Porpose/Purpose

one 64 bit timer.

Two 32 bit timers are used:
TIMER1: clock events supporting periodic and oneshot events
TIMER2: clock source configured as a free running counter

The General Porpose Timer block can be run with two clocks. A 13 MHz system

s/Porpose/Purpose

clock and the RTC clock running at 32 KHz. This implementation uses the system
clock.

As it is a new driver, could you elaborate a bit the description of this 
driver please ? Behavior, some oddities, etc ...

Please remove unused macros.

+
+#define GPT_CLK_EVT	1
+#define GPT_CLK_SRC	2
+
+
+

extra lines.

+struct mtk_clock_event_device {
+	void __iomem *gpt_base;
+	u32 ticks_per_jiffy;
+	struct clock_event_device dev;
+};
+
+static inline struct mtk_clock_event_device *to_mtk_clk(
+				struct clock_event_device *c)
+{
+	return container_of(c, struct mtk_clock_event_device, dev);
+}
+
+static void mtk_clkevt_time_stop(struct mtk_clock_event_device *evt, u8 timer)
+{
+	u32 val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
+	writel(val & ~TIMER_CTRL_ENABLE, evt->gpt_base +
+			TIMER_CTRL_REG(timer));
+}
+
+static void mtk_clkevt_time_setup(struct mtk_clock_event_device *evt,
+				unsigned long delay, u8 timer)
+{
+	writel(delay, evt->gpt_base + TIMER_CMP_REG(timer));
+}
+
+static void mtk_clkevt_time_start(struct mtk_clock_event_device *evt,
+		bool periodic, u8 timer)
+{
+	u32 val;
+
+	/* Acknowledge interrupt */
+	writel(GPT_IRQ_ACK(timer), evt->gpt_base + GPT_IRQ_ACK_REG);
+
+	val = readl(evt->gpt_base + TIMER_CTRL_REG(timer));
+
+	/* Clear 2 bit timer operation mode field */
+	val &= ~TIMER_CTRL_OP(0x3);
+
+	if (periodic)
+		val |= TIMER_CTRL_OP(TIMER_CTRL_OP_REPEAT);
+	else
+		val |= TIMER_CTRL_OP(TIMER_CTRL_OP_ONESHOT);
+
+	writel(val | TIMER_CTRL_ENABLE | TIMER_CTRL_CLEAR,
+	       evt->gpt_base + TIMER_CTRL_REG(timer));
+}
+
+static void mtk_clkevt_mode(enum clock_event_mode mode,
+				struct clock_event_device *clk)
+{
+	struct mtk_clock_event_device *evt = to_mtk_clk(clk);
+
+	mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
+
+	switch (mode) {
+	case CLOCK_EVT_MODE_PERIODIC:
+		mtk_clkevt_time_setup(evt, evt->ticks_per_jiffy, GPT_CLK_EVT);
+		mtk_clkevt_time_start(evt, true, GPT_CLK_EVT);
+		break;
+	case CLOCK_EVT_MODE_ONESHOT:
+		mtk_clkevt_time_start(evt, false, GPT_CLK_EVT);
+		break;
+	case CLOCK_EVT_MODE_UNUSED:
+	case CLOCK_EVT_MODE_SHUTDOWN:
+	default:
+		/* No more interrupts will occur as source is disabled */
+		break;
+	}
+}
+
+static int mtk_clkevt_next_event(unsigned long event,
+				   struct clock_event_device *clk)
+{
+	struct mtk_clock_event_device *evt = to_mtk_clk(clk);
+
+	mtk_clkevt_time_stop(evt, GPT_CLK_EVT);
+	mtk_clkevt_time_setup(evt, event, GPT_CLK_EVT);
+	mtk_clkevt_time_start(evt, false, GPT_CLK_EVT);
+
+	return 0;
+}
+
+static irqreturn_t mtk_timer_interrupt(int irq, void *dev_id)
+{
+	struct mtk_clock_event_device *evt = dev_id;
+
+	/* Acknowledge timer0 irq */
+	writel(GPT_IRQ_ACK(GPT_CLK_EVT), evt->gpt_base + GPT_IRQ_ACK_REG);
+	evt->dev.event_handler(&evt->dev);
+
+	return IRQ_HANDLED;
+}
+
+static void mtk_timer_global_reset(struct mtk_clock_event_device *evt)
+{
+	/* Disable all interrupts */
+	writel(0x0, evt->gpt_base + GPT_IRQ_EN_REG);
+	/* Acknowledge all interrupts */
+	writel(0x3f, evt->gpt_base + GPT_IRQ_ACK_REG);
+}
+
+static void mtk_timer_reset(struct mtk_clock_event_device *evt, u8 timer)
+{
+	writel(TIMER_CTRL_CLEAR | TIMER_CTRL_DISABLE,
+		evt->gpt_base + TIMER_CTRL_REG(timer));
+	writel(0x0, evt->gpt_base + TIMER_CMP_REG(timer));
+}
+
+static void __init mtk_timer_init(struct device_node *node)
+{
+	struct mtk_clock_event_device *evt;
+	struct resource res;
+	unsigned long rate = 0;
+	struct clk *clk;
+	int ret;
+	u32 val;
+
+	evt = kzalloc(sizeof(*evt), GFP_KERNEL);
+	if (!evt)
+		panic("Can't allocate mtk clock event driver struct");
+
+	evt->dev.name = "mtk_tick";
+	evt->dev.rating = 300;
+	evt->dev.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT;
+	evt->dev.set_mode = mtk_clkevt_mode;
+	evt->dev.set_next_event = mtk_clkevt_next_event;
+	evt->dev.cpumask = cpu_possible_mask;
+
+	if (of_address_to_resource(node, 0, &res))
+		panic("Failed to parse resource\n");
+
+	if (!request_mem_region(res.start, resource_size(&res), "mtk-timer"))
+		panic("Registers are a busy IO resource");
+
+	evt->gpt_base = ioremap(res.start, resource_size(&res));
+	if (!evt->gpt_base)
+		panic("Can't map registers");
+
+	evt->dev.irq = irq_of_parse_and_map(node, 0);
+	if (evt->dev.irq <= 0)
+		panic("Can't parse IRQ");
+
+	clk = of_clk_get(node, 0);
+	if (IS_ERR(clk))
+		panic("Can't get timer clock");
+
+	clk_prepare_enable(clk);
+	rate = clk_get_rate(clk);
+
+	mtk_timer_global_reset(evt);
+
+	/* Configure clock source */
+	mtk_timer_reset(evt, GPT_CLK_SRC);
+
+	writel(TIMER_CLK_SRC(TIMER_CLK_SRC_SYS13M) | TIMER_CLK_DIV1,
+			evt->gpt_base + TIMER_CLK_REG(GPT_CLK_SRC));
+
+	writel(TIMER_CTRL_OP(TIMER_CTRL_OP_FREERUN) | TIMER_CTRL_ENABLE,
+			evt->gpt_base + TIMER_CTRL_REG(GPT_CLK_SRC));
+
+	clocksource_mmio_init(evt->gpt_base + TIMER_CNT_REG(GPT_CLK_SRC),
+			node->name, rate, 300, 32, clocksource_mmio_readl_up);
+
+	evt->ticks_per_jiffy = DIV_ROUND_UP(rate, HZ);
+
+	/* Configure clock event */
+	mtk_timer_reset(evt, GPT_CLK_EVT);
+
+	writel(TIMER_CLK_SRC(TIMER_CLK_SRC_SYS13M) | TIMER_CLK_DIV1,
+			evt->gpt_base + TIMER_CLK_REG(GPT_CLK_EVT));
+	writel(0, evt->gpt_base + TIMER_CMP_REG(GPT_CLK_EVT));
+
+	writel(TIMER_CTRL_OP(TIMER_CTRL_OP_REPEAT) | TIMER_CTRL_ENABLE,
+			evt->gpt_base + TIMER_CTRL_REG(GPT_CLK_EVT));
+
+	ret = request_irq(evt->dev.irq, mtk_timer_interrupt,
+			IRQF_TIMER | IRQF_IRQPOLL, "mtk_timer", evt);
+	if (ret)
+		pr_warn("failed to setup irq %d\n", evt->dev.irq);
+
+	/* Enable timer0 interrupt */
+	val = readl(evt->gpt_base + GPT_IRQ_EN_REG);
+	writel(val | GPT_IRQ_ENABLE(GPT_CLK_EVT),
+			evt->gpt_base + GPT_IRQ_EN_REG);

Could you encapsulate in well named functions the different 'writel' above ?

+	clockevents_config_and_register(&evt->dev, rate, 0x3,
+					0xffffffff);
+}
+CLOCKSOURCE_OF_DECLARE(mtk_mt6589, "mediatek,mtk6577-timer", mtk_timer_init);
+

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