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Message-ID: <20160713210857.GA9500@roeck-us.net>
Date: Wed, 13 Jul 2016 14:08:57 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: Fu Wei <fu.wei@...aro.org>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Marc Zyngier <marc.zyngier@....com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Sudeep Holla <sudeep.holla@....com>,
Hanjun Guo <hanjun.guo@...aro.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linaro-acpi@...ts.linaro.org" <linaro-acpi@...ts.linaro.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
rruigrok@...eaurora.org, harba@...eaurora.org,
Christopher Covington <cov@...eaurora.org>,
Timur Tabi <timur@...eaurora.org>,
G Gregory <graeme.gregory@...aro.org>,
Al Stone <al.stone@...aro.org>, Jon Masters <jcm@...hat.com>,
wei@...hat.com, Arnd Bergmann <arnd@...db.de>,
Wim Van Sebroeck <wim@...ana.be>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Suravee Suthikulanit <Suravee.Suthikulpanit@....com>,
Leo Duran <leo.duran@....com>,
"linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
David Miller <davem@...emloft.net>,
Andrew Morton <akpm@...ux-foundation.org>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
kvalo@...eaurora.org, mchehab@...nel.org,
Jiri Slaby <jslaby@...e.cz>, christoffer.dall@...aro.org,
julien.grall@....com
Subject: Re: [PATCH v7 4/9] acpi/arm64: Add GTDT table parse driver
On Wed, Jul 13, 2016 at 10:30:37PM +0200, Rafael J. Wysocki wrote:
> On Wed, Jul 13, 2016 at 7:53 PM, <fu.wei@...aro.org> wrote:
> > From: Fu Wei <fu.wei@...aro.org>
> >
> > This patch adds support for parsing arch timer in GTDT,
> > provides some kernel APIs to parse all the PPIs and
> > always-on info in GTDT and export them.
> >
> > By this driver, we can simplify arm_arch_timer drivers, and
> > separate the ACPI GTDT knowledge from it.
> >
> > Signed-off-by: Fu Wei <fu.wei@...aro.org>
> > Signed-off-by: Hanjun Guo <hanjun.guo@...aro.org>
> > ---
> > drivers/acpi/Kconfig | 5 ++
> > drivers/acpi/Makefile | 1 +
> > drivers/acpi/arm64/Kconfig | 15 ++++
> > drivers/acpi/arm64/Makefile | 1 +
> > drivers/acpi/arm64/acpi_gtdt.c | 170 +++++++++++++++++++++++++++++++++++++++++
> > include/linux/acpi.h | 6 ++
> > 6 files changed, 198 insertions(+)
> >
> > diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
> > index b7e2e77..1cdc7d2 100644
> > --- a/drivers/acpi/Kconfig
> > +++ b/drivers/acpi/Kconfig
> > @@ -521,4 +521,9 @@ config XPOWER_PMIC_OPREGION
> >
> > endif
> >
> > +if ARM64
> > +source "drivers/acpi/arm64/Kconfig"
> > +
> > +endif
> > +
> > endif # ACPI
> > diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile
> > index 251ce85..1a94ff7 100644
> > --- a/drivers/acpi/Makefile
> > +++ b/drivers/acpi/Makefile
> > @@ -99,5 +99,6 @@ obj-$(CONFIG_ACPI_EXTLOG) += acpi_extlog.o
> > obj-$(CONFIG_PMIC_OPREGION) += pmic/intel_pmic.o
> > obj-$(CONFIG_CRC_PMIC_OPREGION) += pmic/intel_pmic_crc.o
> > obj-$(CONFIG_XPOWER_PMIC_OPREGION) += pmic/intel_pmic_xpower.o
> > +obj-$(CONFIG_ARM64) += arm64/
> >
> > video-objs += acpi_video.o video_detect.o
> > diff --git a/drivers/acpi/arm64/Kconfig b/drivers/acpi/arm64/Kconfig
> > new file mode 100644
> > index 0000000..ff5c253
> > --- /dev/null
> > +++ b/drivers/acpi/arm64/Kconfig
> > @@ -0,0 +1,15 @@
> > +#
> > +# ACPI Configuration for ARM64
> > +#
> > +
> > +menu "The ARM64-specific ACPI Support"
> > +
> > +config ACPI_GTDT
> > + bool "ACPI GTDT table Support"
>
> This should depend on ARM64.
>
> Also I wonder if it needs to be user-selectable? Wouldn't it be
> better to enable it by default when building for ARM64 with ACPI?
>
It is currently selected in patch 9, in the watchdog driver's Kconfig
entry. Not sure if I like that; maybe the watchdog driver should depend
on it instead ?
Guenter
> > + help
> > + GTDT (Generic Timer Description Table) provides information
> > + for per-processor timers and Platform (memory-mapped) timers
> > + for ARM platforms. Select this option to provide information
> > + needed for the timers init.
> > +
> > +endmenu
> > diff --git a/drivers/acpi/arm64/Makefile b/drivers/acpi/arm64/Makefile
> > new file mode 100644
> > index 0000000..466de6b
> > --- /dev/null
> > +++ b/drivers/acpi/arm64/Makefile
> > @@ -0,0 +1 @@
> > +obj-$(CONFIG_ACPI_GTDT) += acpi_gtdt.o
> > diff --git a/drivers/acpi/arm64/acpi_gtdt.c b/drivers/acpi/arm64/acpi_gtdt.c
> > new file mode 100644
> > index 0000000..9ee977d
> > --- /dev/null
> > +++ b/drivers/acpi/arm64/acpi_gtdt.c
> > @@ -0,0 +1,170 @@
> > +/*
> > + * ARM Specific GTDT table Support
> > + *
> > + * Copyright (C) 2016, Linaro Ltd.
> > + * Author: Daniel Lezcano <daniel.lezcano@...aro.org>
> > + * Fu Wei <fu.wei@...aro.org>
> > + * Hanjun Guo <hanjun.guo@...aro.org>
> > + *
> > + * 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.
> > + */
> > +
> > +#include <linux/acpi.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +
> > +#include <clocksource/arm_arch_timer.h>
> > +
> > +#undef pr_fmt
> > +#define pr_fmt(fmt) "GTDT: " fmt
>
> I would add "ACPI" to the prefix too if I were you, but that's me.
>
> > +
> > +typedef struct {
> > + struct acpi_table_gtdt *gtdt;
> > + void *platform_timer_start;
> > + void *gtdt_end;
> > +} acpi_gtdt_desc_t;
> > +
> > +static acpi_gtdt_desc_t acpi_gtdt_desc __initdata;
> > +
> > +static inline void *next_platform_timer(void *platform_timer)
> > +{
> > + struct acpi_gtdt_header *gh = platform_timer;
> > +
> > + platform_timer += gh->length;
> > + if (platform_timer < acpi_gtdt_desc.gtdt_end)
> > + return platform_timer;
> > +
> > + return NULL;
> > +}
> > +
> > +#define for_each_platform_timer(_g) \
> > + for (_g = acpi_gtdt_desc.platform_timer_start; _g; \
> > + _g = next_platform_timer(_g))
> > +
> > +static inline bool is_timer_block(void *platform_timer)
> > +{
> > + struct acpi_gtdt_header *gh = platform_timer;
> > +
> > + if (gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK)
> > + return true;
> > +
> > + return false;
>
> This is just too much code. It would suffice to do
>
> return gh->type == ACPI_GTDT_TYPE_TIMER_BLOCK;
>
> > +}
> > +
> > +static inline bool is_watchdog(void *platform_timer)
> > +{
> > + struct acpi_gtdt_header *gh = platform_timer;
> > +
> > + if (gh->type == ACPI_GTDT_TYPE_WATCHDOG)
> > + return true;
> > +
> > + return false;
>
> Just like above.
>
> > +}
> > +
> > +/*
> > + * Get some basic info from GTDT table, and init the global variables above
> > + * for all timers initialization of Generic Timer.
> > + * This function does some validation on GTDT table.
> > + */
> > +static int __init acpi_gtdt_desc_init(struct acpi_table_header *table)
> > +{
> > + struct acpi_table_gtdt *gtdt = container_of(table,
> > + struct acpi_table_gtdt,
> > + header);
> > +
> > + acpi_gtdt_desc.gtdt = gtdt;
> > + acpi_gtdt_desc.gtdt_end = (void *)table + table->length;
> > +
> > + if (table->revision < 2) {
> > + pr_info("Revision:%d doesn't support Platform Timers.\n",
> > + table->revision);
>
> Is it really useful to print this message (and the one below) at the
> "info" level? What about changing them to pr_debug()?
>
> > + return 0;
> > + }
> > +
> > + if (!gtdt->platform_timer_count) {
> > + pr_info("No Platform Timer.\n");
> > + return 0;
> > + }
> > +
> > + acpi_gtdt_desc.platform_timer_start = (void *)gtdt +
> > + gtdt->platform_timer_offset;
> > + if (acpi_gtdt_desc.platform_timer_start <
> > + (void *)table + sizeof(struct acpi_table_gtdt)) {
> > + pr_err(FW_BUG "Platform Timer pointer error.\n");
>
> Why pr_err()?
>
> > + acpi_gtdt_desc.platform_timer_start = NULL;
> > + return -EINVAL;
> > + }
> > +
> > + return gtdt->platform_timer_count;
> > +}
> > +
> > +static int __init map_generic_timer_interrupt(u32 interrupt, u32 flags)
> > +{
> > + int trigger, polarity;
> > +
> > + if (!interrupt)
> > + return 0;
> > +
> > + trigger = (flags & ACPI_GTDT_INTERRUPT_MODE) ? ACPI_EDGE_SENSITIVE
> > + : ACPI_LEVEL_SENSITIVE;
> > +
> > + polarity = (flags & ACPI_GTDT_INTERRUPT_POLARITY) ? ACPI_ACTIVE_LOW
> > + : ACPI_ACTIVE_HIGH;
> > +
> > + return acpi_register_gsi(NULL, interrupt, trigger, polarity);
> > +}
> > +
> > +/*
> > + * Map the PPIs of per-cpu arch_timer.
> > + * @type: the type of PPI
> > + * Returns 0 if error.
> > + */
> > +int __init acpi_gtdt_map_ppi(int type)
> > +{
> > + struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
> > +
> > + switch (type) {
> > + case PHYS_SECURE_PPI:
> > + return map_generic_timer_interrupt(gtdt->secure_el1_interrupt,
> > + gtdt->secure_el1_flags);
> > + case PHYS_NONSECURE_PPI:
> > + return map_generic_timer_interrupt(gtdt->non_secure_el1_interrupt,
> > + gtdt->non_secure_el1_flags);
> > + case VIRT_PPI:
> > + return map_generic_timer_interrupt(gtdt->virtual_timer_interrupt,
> > + gtdt->virtual_timer_flags);
> > +
> > + case HYP_PPI:
> > + return map_generic_timer_interrupt(gtdt->non_secure_el2_interrupt,
> > + gtdt->non_secure_el2_flags);
> > + default:
> > + pr_err("ppi type error.\n");
> > + }
> > +
> > + return 0;
> > +}
> > +
> > +/*
> > + * acpi_gtdt_c3stop - got c3stop info from GTDT
> > + *
> > + * Returns 1 if the timer is powered in deep idle state, 0 otherwise.
> > + */
> > +int __init acpi_gtdt_c3stop(void)
>
> Why not bool?
>
> > +{
> > + struct acpi_table_gtdt *gtdt = acpi_gtdt_desc.gtdt;
> > +
> > + return !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON);
> > +}
> > +
> > +int __init gtdt_arch_timer_init(struct acpi_table_header *table)
> > +{
> > + if (table)
> > + return acpi_gtdt_desc_init(table);
> > +
> > + pr_err("table pointer error.\n");
>
> This message is totally unuseful.
>
> > +
> > + return -EINVAL;
> > +}
>
> What is supposed to be calling this function?
>
> > diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> > index 288fac5..8439579 100644
> > --- a/include/linux/acpi.h
> > +++ b/include/linux/acpi.h
> > @@ -532,6 +532,12 @@ void acpi_walk_dep_device_list(acpi_handle handle);
> > struct platform_device *acpi_create_platform_device(struct acpi_device *);
> > #define ACPI_PTR(_ptr) (_ptr)
> >
> > +#ifdef CONFIG_ACPI_GTDT
> > +int __init gtdt_arch_timer_init(struct acpi_table_header *table);
> > +int __init acpi_gtdt_map_ppi(int type);
> > +int __init acpi_gtdt_c3stop(void);
>
> The __init thing is not necessary here.
>
> > +#endif
> > +
> > #else /* !CONFIG_ACPI */
> >
> > #define acpi_disabled 1
> > --
>
> Thanks,
> Rafael
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