Re: [PATCH 3/6] Clocksource: add nuc970 clocksource driver
From: Daniel Lezcano
Date: Mon Jun 27 2016 - 15:46:15 EST
On 06/25/2016 12:37 PM, Wan Zongshun wrote:
This patch is to add nuc970 clocksource driver support.
Hi Wan,
add a detailed description of how works this timer and its general
design. If there is a pointer or a reference to a manual that would be
awesome.
Signed-off-by: Wan Zongshun <mcuos.com@xxxxxxxxx>
---
.../mach-w90x900/include/mach/nuc970-regs-timer.h | 44 +++++
drivers/clocksource/Kconfig | 8 +
drivers/clocksource/Makefile | 1 +
drivers/clocksource/timer-nuc900.c | 207 +++++++++++++++++++++
4 files changed, 260 insertions(+)
create mode 100644 arch/arm/mach-w90x900/include/mach/nuc970-regs-timer.h
create mode 100644 drivers/clocksource/timer-nuc900.c
diff --git a/arch/arm/mach-w90x900/include/mach/nuc970-regs-timer.h b/arch/arm/mach-w90x900/include/mach/nuc970-regs-timer.h
new file mode 100644
index 0000000..43d7e8b
--- /dev/null
+++ b/arch/arm/mach-w90x900/include/mach/nuc970-regs-timer.h
@@ -0,0 +1,44 @@
+/*
+ * Copyright 2016 Wan Zongshun <mcuos.com@xxxxxxxxx>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#ifndef __ASM_ARCH_REGS_TIMER_H
+#define __ASM_ARCH_REGS_TIMER_H
+
+/* Timer Registers */
+
+#define TMR_BA 0x0
+
+#define REG_TMR_TCSR0 (TMR_BA+0x00)
+#define REG_TMR_TICR0 (TMR_BA+0x04)
+#define REG_TMR_TDR0 (TMR_BA+0x08)
+
+
+#define REG_TMR_TCSR1 (TMR_BA+0x10)
+#define REG_TMR_TICR1 (TMR_BA+0x14)
+#define REG_TMR_TDR1 (TMR_BA+0x18)
+
+
+#define REG_TMR_TCSR2 (TMR_BA+0x20)
+#define REG_TMR_TICR2 (TMR_BA+0x24)
+#define REG_TMR_TDR2 (TMR_BA+0x28)
+
+#define REG_TMR_TCSR3 (TMR_BA+0x30)
+#define REG_TMR_TICR3 (TMR_BA+0x34)
+#define REG_TMR_TDR3 (TMR_BA+0x38)
+
+#define REG_TMR_TCSR4 (TMR_BA+0x40)
+#define REG_TMR_TICR4 (TMR_BA+0x44)
+#define REG_TMR_TDR4 (TMR_BA+0x48)
+
+#define REG_TMR_TISR (TMR_BA+0x60)
Are these macros used only in the timer driver or somewhere else ?
+#endif /* __ASM_ARCH_REGS_TIMER_H */
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 47352d2..441c5ee 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -427,4 +427,12 @@ config CLKSRC_ST_LPC
Enable this option to use the Low Power controller timer
as clocksource.
+config NUC900_TIMER
+ bool "Clocksource timer for nuc900 platform" if COMPILE_TEST
+ depends on ARM
+ select CLKSRC_OF if OF
+ select CLKSRC_MMIO
+ help
+ Enables the clocksource for the NUC900 platform.
+
endmenu
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
index 473974f..fcc2cc7 100644
--- a/drivers/clocksource/Makefile
+++ b/drivers/clocksource/Makefile
@@ -67,3 +67,4 @@ obj-$(CONFIG_H8300_TMR16) += h8300_timer16.o
obj-$(CONFIG_H8300_TPU) += h8300_tpu.o
obj-$(CONFIG_CLKSRC_ST_LPC) += clksrc_st_lpc.o
obj-$(CONFIG_X86_NUMACHIP) += numachip.o
+obj-$(CONFIG_ARCH_W90X900) += timer-nuc900.o
obj-$(CONFIG_NUC900_TIMER)
diff --git a/drivers/clocksource/timer-nuc900.c b/drivers/clocksource/timer-nuc900.c
new file mode 100644
index 0000000..6ba025c
--- /dev/null
+++ b/drivers/clocksource/timer-nuc900.c
@@ -0,0 +1,207 @@
+/*
+ * Copyright 2016 Wan Zongshun <mcuos.com@xxxxxxxxx>
+ *
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ */
+
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/jiffies.h>
+#include <linux/clockchips.h>
+#include <linux/types.h>
+#include <linux/clk.h>
+
+#include <linux/io.h>
+#include <asm/mach/time.h>
+
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include <mach/mfp.h>
+#include <mach/map.h>
+#include <mach/nuc970-regs-timer.h>
+#include <mach/hardware.h>
+#include <mach/regs-clock.h>
Please do a cleanup with these headers.
+#define RESETINT 0x1f
+#define PERIOD (0x01 << 27)
PERIODIC
+#define ONESHOT (0x00 << 27)
+#define COUNTEN (0x01 << 30)
+#define INTEN (0x01 << 29)
+
+#define TICKS_PER_SEC 100
+/* Divider = prescale + 1 */
+#define PRESCALE 0x63
+
+#define TDR_SHIFT 24
+#define TDR_MASK ((1 << TDR_SHIFT) - 1)
+
+static unsigned int timer0_load;
+static void __iomem *tmr_base;
+
Structure and container_of:
struct nuc970_clockevents {
struct clock_event_device clkevt;
unsigned int timer0_load;
void __iomem *tmr_base;
};
struct nuc970_clockevents *clkevt_to_nuc970(
struct clock_event_device *ced)
{
return container_of(ced, struct nuc970_clockevents, clkevt);
}
+static int nuc970_clockevent_set_oneshot(struct clock_event_device *evt)
+{
+ unsigned int val;
struct nuc970_clockevents *nuc = clkevt_to_nuc970(evt);
val = __raw_readl(nuc->tmr_base + REG_TMR_TCSR0);
+
+
+ val &= ~(0x03 << 27);
(0x03 << 27) ==> #define BLABLA_MASK (0x03 << 27)
+
+ val |= (ONESHOT | COUNTEN | INTEN | PRESCALE);
+
+ __raw_writel(val, tmr_base + REG_TMR_TCSR0);
+ return 0;
+}
+
+static int nuc970_clockevent_set_periodic(struct clock_event_device *evt)
+{
+ unsigned int val;
+
+ val = __raw_readl(tmr_base + REG_TMR_TCSR0);
+ val &= ~(0x03 << 27);
+
+ __raw_writel(timer0_load, tmr_base + REG_TMR_TICR0);
+ val |= (PERIOD | COUNTEN | INTEN | PRESCALE);
+
+ __raw_writel(val, tmr_base + REG_TMR_TCSR0);
+
+ return 0;
+}
May be you can factour out:
static int nuc970_clockevent_set(bool periodic, void __iomem *addr)
{
unsigned int val;
val = __raw_readl(addr + REG_TMR_TCSR0);
val &= ULTRA_MASK;
val |= (COUNTEN | INTEN | PRESCALE);
val |= periodic ? PERIODIC : ONESHOT;
return __raw_writel(timer0_load, tmr_base + REG_TMR_TICR0);
}
+
+static int nuc970_clockevent_setnextevent(unsigned long evt,
+ struct clock_event_device *clk)
+{
+ unsigned int tcsr, tdelta;
+
+ tcsr = __raw_readl(tmr_base + REG_TMR_TCSR0);
+ tdelta = __raw_readl(tmr_base + REG_TMR_TICR0) -
+ __raw_readl(tmr_base + REG_TMR_TDR0);
+
+ __raw_writel(evt, tmr_base + REG_TMR_TICR0);
+
+ if (!(tcsr & COUNTEN) && ((tdelta > 2) || (tdelta == 0)))
+ __raw_writel(__raw_readl(tmr_base + REG_TMR_TCSR0) | COUNTEN,
+ tmr_base + REG_TMR_TCSR0);
+
+ return 0;
+}
+
+static int nuc970_clockevent_shutdown(struct clock_event_device *evt)
+{
+ unsigned int val = __raw_readl(tmr_base + REG_TMR_TCSR0) &
+ ~(0x03 << 27);
+
+ __raw_writel(val, tmr_base + REG_TMR_TCSR0);
+
+ return 0;
+}
+
+static struct clock_event_device nuc970_clockevent_device = {
+ .name = "nuc970-timer0",
+ .shift = 32,
+ .features = CLOCK_EVT_FEAT_PERIODIC |
+ CLOCK_EVT_FEAT_ONESHOT,
+ .set_state_shutdown = nuc970_clockevent_shutdown,
+ .set_state_periodic = nuc970_clockevent_set_periodic,
+ .set_state_oneshot = nuc970_clockevent_set_oneshot,
+ .set_next_event = nuc970_clockevent_setnextevent,
+ .tick_resume = nuc970_clockevent_shutdown,
+ .rating = 300,
+};
+
+/*IRQ handler for the timer*/
+static irqreturn_t nuc970_timer0_interrupt(int irq, void *dev_id)
+{
+ struct clock_event_device *evt = &nuc970_clockevent_device;
+
+ __raw_writel(0x01, tmr_base + REG_TMR_TISR);
+
+ evt->event_handler(evt);
+
+ return IRQ_HANDLED;
+}
+
+static struct irqaction nuc970_timer0_irq = {
+ .name = "nuc970-timer0",
+ .flags = IRQF_TIMER | IRQF_IRQPOLL,
+ .handler = nuc970_timer0_interrupt,
+};
+
+static void __init nuc970_clock_source_event_init(void __iomem *base, int irq,
+ struct clk *clk_timer0,
+ struct clk *clk_timer1)
+{
+ unsigned int val;
+ unsigned int rate = 0;
+
+ /* Get the timer base address */
+ tmr_base = base;
+
+ /*Clocksource init*/
+ WARN_ON(clk_prepare_enable(clk_timer1));
Error check, pr_err, return error
+
+ __raw_writel(0x00, tmr_base + REG_TMR_TCSR1);
+
+ rate = clk_get_rate(clk_timer1) / (PRESCALE + 1);
rate check ?
+
+ __raw_writel(0xffffffff, tmr_base + REG_TMR_TICR1);
+
+ val = __raw_readl(tmr_base + REG_TMR_TCSR1);
+ val |= (COUNTEN | PERIOD | PRESCALE);
+ __raw_writel(val, tmr_base + REG_TMR_TCSR1);
+
+ clocksource_mmio_init(tmr_base + REG_TMR_TDR1, "nuc970-timer1",
+ rate, 200, TDR_SHIFT,
+ clocksource_mmio_readl_down);
Error check, rollback previous actions and return error
+
+ /*Clockevents init*/
+ WARN_ON(clk_prepare_enable(clk_timer0));
+
+ __raw_writel(0x00, tmr_base + REG_TMR_TCSR0);
+
+ rate = clk_get_rate(clk_timer0) / (PRESCALE + 1);
+
+ timer0_load = (rate / TICKS_PER_SEC);
+
+ __raw_writel(RESETINT, tmr_base + REG_TMR_TISR);
+
+ setup_irq(irq, &nuc970_timer0_irq);
s/setup_irq/request_irq/
+ nuc970_clockevent_device.cpumask = cpumask_of(0);
+
+ clockevents_config_and_register(&nuc970_clockevent_device, rate,
+ 0xf, 0xffffffff);
return 0;
+}
+
+static void __init nuc970_timer_of_init(struct device_node *node)
+{
+ struct clk *clk_timer0, *clk_timer1;
+ void __iomem *base;
+ int irq;
+
+ base = of_iomap(node, 0);
+ if (!base)
+ panic("%s: Unable to map timer base\n", node->full_name);
No panic. Error checking, pr_err and then rollback.
I changed the init functions to return an error and will take care of
changing this driver but meanwhile please handle the errors and rollback.
+
+ clk_timer0 = of_clk_get_by_name(node, "timer0");
+ if (IS_ERR(clk_timer0))
+ panic("%s: Unable to get clk_timer0\n", node->full_name);
+
+ clk_timer1 = of_clk_get_by_name(node, "timer1");
+ if (IS_ERR(clk_timer1))
+ panic("%s: Unable to get clk_timer1\n", node->full_name);
+
+ irq = irq_of_parse_and_map(node, 0);
+ if (irq <= 0)
+ panic("%s: Unable to get irq\n", node->full_name);
+
+ nuc970_clock_source_event_init(base, irq, clk_timer0, clk_timer1);
+}
+
+CLOCKSOURCE_OF_DECLARE(nuc970, "nuvoton,tmr", nuc970_timer_of_init);
Thanks !
-- Daniel
--
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