[U-Boot] [PATCH 09/11] imx: system counter driver for imx7d and mx6ul

[Alonso Adrian]

Hi Nikolay,

> -----Original Message-----
> From: Nikolay Dimitrov [mailto:picmaster at mail.bg]
> Sent: Monday, July 20, 2015 3:43 PM
> To: Alonso Lazcano Adrian-B38018
> Cc: u-boot at lists.denx.de; sbabic at denx.de; Estevam Fabio-R49496;
> otavio at ossystems.com.br
> Subject: Re: [U-Boot] [PATCH 09/11] imx: system counter driver for imx7d and
> mx6ul
> 
> Hi Adrian,
> 
> On 07/16/2015 01:49 AM, Adrian Alonso wrote:
> > * The system counter driver for imx7d abd mx6ul, move
> >    this timer driver to imx-common and rename it as syscounter.c
> >
> >    For mx6ul and mx7, configurations are used for choose the GPT timer
> >    or system counter timer (default).
> >
> >    GPT timer:              CONFIG_GPT_TIMER
> >    System counter timer:   CONFIG_SYSCOUNTER_TIMER
> >
> >    For mx6dqp GPT timer is the default setting.
> >
> > Signed-off-by: Adrian Alonso <aalonso at freescale.com>
> > Signed-off-by: Ye.Li <B37916 at freescale.com>
> > ---
> >   arch/arm/imx-common/syscounter.c             | 126
> +++++++++++++++++++++++++++
> >   arch/arm/include/asm/imx-common/syscounter.h |  29 ++++++
> >   include/configs/mx6_common.h                 |   1 +
> >   3 files changed, 156 insertions(+)
> >   create mode 100644 arch/arm/imx-common/syscounter.c
> >   create mode 100644 arch/arm/include/asm/imx-common/syscounter.h
> >
> > diff --git a/arch/arm/imx-common/syscounter.c
> > b/arch/arm/imx-common/syscounter.c
> > new file mode 100644
> > index 0000000..f5e5cdc
> > --- /dev/null
> > +++ b/arch/arm/imx-common/syscounter.c
> > @@ -0,0 +1,126 @@
> > +/*
> > + * Copyright (C) 2014-2015 Freescale Semiconductor, Inc.
> > + *
> > + * SPDX-License-Identifier:	GPL-2.0+
> > + *
> > + * The file use ls102xa/timer.c as a reference.
> > + */
> > +
> > +#include <common.h>
> > +#include <asm/io.h>
> > +#include <div64.h>
> > +#include <asm/arch/imx-regs.h>
> > +#include <asm/arch/sys_proto.h>
> > +#include <asm/imx-common/syscounter.h>
> > +
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> > +/*
> > + * This function is intended for SHORT delays only.
> > + * It will overflow at around 10 seconds @ 400MHz,
> > + * or 20 seconds @ 200MHz.
> > + */
> > +unsigned long usec2ticks(unsigned long usec) {
> > +	ulong ticks;
> > +
> > +	if (usec < 1000)
> > +		ticks = ((usec * (get_tbclk()/1000)) + 500) / 1000;
> > +	else
> > +		ticks = ((usec / 10) * (get_tbclk() / 100000));
> > +
> > +	return ticks;
> > +}
> > +
> > +static inline unsigned long long tick_to_time(unsigned long long
> > +tick) {
> > +	unsigned long freq;
> > +
> > +	asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));
> > +
> > +	tick *= CONFIG_SYS_HZ;
> > +	do_div(tick, freq);
> > +
> > +	return tick;
> > +}
> > +
> > +static inline unsigned long long us_to_tick(unsigned long long usec)
> > +{
> > +	unsigned long freq;
> > +
> > +	asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));
> > +
> > +	usec = usec * freq  + 999999;
> > +	do_div(usec, 1000000);
> > +
> > +	return usec;
> > +}
> 
> Is it possible to use the same naming convention for usec2ticks(),
> tick_to_time() and us_to_tick() (e.g. choose either "2" or "_to_")?
> Thanks.

 [Adrian] usec2ticks follows the definition of prototype function in header file "include/common.h"
the comment in the header /* arch/$(ARCH)/lib/time.c */ implies that each platform should provide
that function; For iMX SoC's case usec2ticks is only used in drivers/crypto/fsl/jr.c and drivers/i2c/fsl_i2c.c
IMHO we should keep the same naming convention defined in the "include/common.h" file.

> 
> > +
> > +int timer_init(void)
> > +{
> > +	struct sctr_regs *sctr = (struct sctr_regs *)SCTR_BASE_ADDR;
> > +	unsigned long val, freq;
> > +
> > +	freq = CONFIG_SC_TIMER_CLK;
> > +	asm("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
> > +
> > +	writel(freq, &sctr->cntfid0);
> > +
> > +	/* Enable system counter */
> > +	val = readl(&sctr->cntcr);
> > +	val &= ~(SC_CNTCR_FREQ0 | SC_CNTCR_FREQ1);
> > +	val |= SC_CNTCR_FREQ0 | SC_CNTCR_ENABLE | SC_CNTCR_HDBG;
> > +	writel(val, &sctr->cntcr);
> > +
> > +	gd->arch.tbl = 0;
> > +	gd->arch.tbu = 0;
> > +
> > +	return 0;
> > +}
> > +
> > +unsigned long long get_ticks(void)
> > +{
> > +	unsigned long long now;
> > +
> > +	asm("mrrc p15, 0, %Q0, %R0, c14" : "=r" (now));
> > +
> > +	gd->arch.tbl = (unsigned long)(now & 0xffffffff);
> > +	gd->arch.tbu = (unsigned long)(now >> 32);
> > +
> > +	return now;
> > +}
> > +
> > +ulong get_timer_masked(void)
> > +{
> > +	return tick_to_time(get_ticks());
> > +}
> > +
> > +ulong get_timer(ulong base)
> > +{
> > +	return get_timer_masked() - base;
> > +}
> > +
> > +void __udelay(unsigned long usec)
> > +{
> > +	unsigned long long tmp;
> > +	ulong tmo;
> > +
> > +	tmo = us_to_tick(usec);
> > +	tmp = get_ticks() + tmo;	/* get current timestamp */
> > +
> > +	while (get_ticks() < tmp)	/* loop till event */
> > +		 /*NOP*/;
> > +}
> > +
> > +/*
> > + * This function is derived from PowerPC code (timebase clock frequency).
> > + * On ARM it returns the number of timer ticks per second.
> > + */
> > +ulong get_tbclk(void)
> > +{
> > +	unsigned long freq;
> > +
> > +	asm volatile("mrc p15, 0, %0, c14, c0, 0" : "=r" (freq));
> > +
> > +	return freq;
> > +}
> > diff --git a/arch/arm/include/asm/imx-common/syscounter.h
> > b/arch/arm/include/asm/imx-common/syscounter.h
> > new file mode 100644
> > index 0000000..ddb412e
> > --- /dev/null
> > +++ b/arch/arm/include/asm/imx-common/syscounter.h
> > @@ -0,0 +1,29 @@
> > +/*
> > + * Copyright (C) 2014-2015 Freescale Semiconductor, Inc.
> > + *
> > + * SPDX-License-Identifier:	GPL-2.0+
> > + */
> > +
> > +#ifndef _ASM_ARCH_SYSTEM_COUNTER_H
> > +#define _ASM_ARCH_SYSTEM_COUNTER_H
> > +
> > +/* System Counter */
> > +struct sctr_regs {
> > +	u32 cntcr;
> > +	u32 cntsr;
> > +	u32 cntcv1;
> > +	u32 cntcv2;
> > +	u32 resv1[4];
> > +	u32 cntfid0;
> > +	u32 cntfid1;
> > +	u32 cntfid2;
> > +	u32 resv2[1001];
> > +	u32 counterid[1];
> > +};
> > +
> > +#define SC_CNTCR_ENABLE		(1 << 0)
> > +#define SC_CNTCR_HDBG		(1 << 1)
> > +#define SC_CNTCR_FREQ0		(1 << 8)
> > +#define SC_CNTCR_FREQ1		(1 << 9)
> > +
> > +#endif
> > diff --git a/include/configs/mx6_common.h
> > b/include/configs/mx6_common.h index 86d7b16..690038d 100644
> > --- a/include/configs/mx6_common.h
> > +++ b/include/configs/mx6_common.h
> > @@ -30,6 +30,7 @@
> >
> >   #define CONFIG_MP
> >   #define CONFIG_MXC_GPT_HCLK
> > +#define CONFIG_GPT_TIMER
> >
> >   #define CONFIG_SYS_NO_FLASH
> >
> >
> 
> Regards,
> Nikolay