Re: [PATCH 7/8] efi: clocksoure: use event for timer

[Michael Olbrich <m.olbrich@pengutronix.de>]

On Mon, Feb 27, 2017 at 11:19:29AM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> with this we can be hw generic
> 
> If the EFI implement timestamp protocol we could use instead of event
> but even EDK2 Never Ever compile it for any target.
> 
> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
> ---
>  common/efi/efi.c             |   8 ++++
>  drivers/clocksource/Kconfig  |   4 ++
>  drivers/clocksource/Makefile |   1 +
>  drivers/clocksource/efi.c    | 110 +++++++++++++++++++++++++++++++++++++++++++
>  4 files changed, 123 insertions(+)
>  create mode 100644 drivers/clocksource/efi.c
> 
> diff --git a/common/efi/efi.c b/common/efi/efi.c
> index 4b589b600..05c58250f 100644
> --- a/common/efi/efi.c
> +++ b/common/efi/efi.c
> @@ -353,6 +353,14 @@ efi_status_t efi_main(efi_handle_t image, efi_system_table_t *sys_table)
>  	return EFI_SUCCESS;
>  }
>  
> +static int efi_core_init(void)
> +{
> +	struct device_d *dev = device_alloc("efi-cs", DEVICE_ID_SINGLE);
> +
> +	return platform_device_register(dev);
> +}
> +core_initcall(efi_core_init);
> +
>  static int efi_postcore_init(void)
>  {
>  	char *uuid;
> diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
> index 9b7f0a9d7..b12a85403 100644
> --- a/drivers/clocksource/Kconfig
> +++ b/drivers/clocksource/Kconfig
> @@ -34,6 +34,10 @@ config CLOCKSOURCE_DUMMY_RATE
>  	  The option CONFIG_CLOCKSOURCE_DUMMY_RATE is used to adjust this clocksource.
>  	  The bigger rate valuest makes clocksource "faster".
>  
> +config CLOCKSOURCE_EFI
> +	bool "Generic EFI Driver"
> +	depends on EFI_BOOTUP
> +
>  config CLOCKSOURCE_EFI_X86
>  	bool "EFI X86 HW driver"
>  	depends on EFI_BOOTUP && X86
> diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
> index 1fd18296e..f69b33d0b 100644
> --- a/drivers/clocksource/Makefile
> +++ b/drivers/clocksource/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_ARM_SMP_TWD) += arm_smp_twd.o
>  obj-$(CONFIG_CLOCKSOURCE_BCM283X) += bcm2835.o
>  obj-$(CONFIG_CLOCKSOURCE_CLPS711X) += clps711x.o
>  obj-$(CONFIG_CLOCKSOURCE_DIGIC)   += digic.o
> +obj-$(CONFIG_CLOCKSOURCE_EFI) += efi.o
>  obj-$(CONFIG_CLOCKSOURCE_EFI_X86) += efi_x86.o
>  obj-$(CONFIG_CLOCKSOURCE_MVEBU)   += mvebu.o
>  obj-$(CONFIG_CLOCKSOURCE_NOMADIK) += nomadik.o
> diff --git a/drivers/clocksource/efi.c b/drivers/clocksource/efi.c
> new file mode 100644
> index 000000000..df65dd86c
> --- /dev/null
> +++ b/drivers/clocksource/efi.c
> @@ -0,0 +1,110 @@
> +/*
> + * Copyright (C) 2012 Jean-Christophe PLAGNIOL-VILLARD <plagnio@jcrosoft.com>
> + *
> + * Under GPL v2
> + */
> +#include <common.h>
> +#include <init.h>
> +#include <driver.h>
> +#include <clock.h>
> +#include <efi.h>
> +#include <efi/efi.h>
> +#include <efi/efi-device.h>
> +#include <linux/err.h>
> +
> +static uint64_t ticks = 1;
> +static void *efi_cs_evt;
> +
> +static uint64_t efi_cs_read(void)
> +{
> +	return ticks;
> +}
> +
> +static void efi_cs_inc(void *event, void *ctx)
> +{
> +	ticks++;
> +}
> +
> +/* count ticks during a 1dms */
> +static uint64_t ticks_freq(void)
> +{
> +	uint64_t ticks_start, ticks_end;
> +
> +	ticks_start = ticks;
> +	BS->stall(1000);
> +	ticks_end = ticks;
> +
> +	return (ticks_end - ticks_start) * 1000;
> +}
> +
> +/* count ticks during a 20ms delay as on qemu x86_64 the max is 100Hz */
> +static uint64_t ticks_freq_x86(void)
> +{
> +	uint64_t ticks_start, ticks_end;
> +
> +	ticks_start = ticks;
> +	BS->stall(20 * 1000);
> +	ticks_end = ticks;
> +
> +	return (ticks_end - ticks_start) * 50;
> +}
> +
> +static int efi_cs_init(struct clocksource *cs)
> +{
> +	efi_status_t efiret;
> +	uint64_t freq;
> +
> +	efiret = BS->create_event(EFI_EVT_TIMER | EFI_EVT_NOTIFY_SIGNAL,
> +			EFI_TPL_CALLBACK, efi_cs_inc, NULL, &efi_cs_evt);
> +
> +	if (EFI_ERROR(efiret))
> +		return -efi_errno(efiret);
> +
> +	efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, 10);
> +	if (EFI_ERROR(efiret)) {
> +		BS->close_event(efi_cs_evt);
> +		return -efi_errno(efiret);
> +	}
> +
> +	freq = 1000 * 1000;
> +	if (ticks_freq() < 800 * 1000) {
> +		uint64_t nb_100ns;
> +
> +		freq = ticks_freq_x86();

This needs a sanity ckeck. On one hardware that I have here 'freq' is often
(but not always) zero.

Michael

> +		nb_100ns = 10 * 1000 * 1000 / freq;
> +		pr_warn("EFI Event timer too slow freq = %llu Hz\n", freq);
> +		efiret = BS->set_timer(efi_cs_evt, EFI_TIMER_PERIODIC, nb_100ns);
> +		if (EFI_ERROR(efiret)) {
> +			BS->close_event(efi_cs_evt);
> +			return -efi_errno(efiret);
> +		}
> +	}
> +
> +	cs->mult = clocksource_hz2mult(freq, cs->shift);
> +
> +	return 0;
> +}
> +
> +static struct clocksource efi_cs = {
> +	.read   = efi_cs_read,
> +	.mask   = CLOCKSOURCE_MASK(64),
> +	.shift  = 0,
> +	.init   = efi_cs_init,
> +};
> +
> +static int efi_cs_probe(struct device_d *dev)
> +{
> +	return init_clock(&efi_cs);
> +}
> +
> +static struct driver_d efi_cs_driver = {
> +	.name = "efi-cs",
> +	.probe = efi_cs_probe,
> +};
> +
> +static int efi_cs_initcall(void)
> +{
> +	return platform_driver_register(&efi_cs_driver);
> +}
> +/* for efi the time must be init at core initcall level */
> +late_initcall(efi_cs_initcall);
> -- 
> 2.11.0
> 
> 
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