From: Geert Uytterhoeven <geert@linux-m68k.org> To: Jisheng Zhang <Jisheng.Zhang@synaptics.com> Cc: Geert Uytterhoeven <geert+renesas@glider.be>, Mark Rutland <mark.rutland@arm.com>, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, Linux-Renesas <linux-renesas-soc@vger.kernel.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org> Subject: Re: [PATCH 1/2] drivers: firmware: psci: Add psci_is_available() Date: Thu, 12 Oct 2017 08:58:42 +0200 [thread overview] Message-ID: <CAMuHMdVuEtXYGL5FL4e-_GMNSmRNyodfFvhdNi6ZHaAVcDEUEA@mail.gmail.com> (raw) In-Reply-To: <20171012105801.0bb643eb@xhacker.debian> Hi Jisheng, On Thu, Oct 12, 2017 at 4:58 AM, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > On Wed, 11 Oct 2017 10:03:01 +0200 Geert Uytterhoeven wrote: > >> PSCI support may be disabled at build time (by configuration) or at >> run-time (PSCI firmware not present). While CONFIG_ARM_PSCI_FW can be >> used to check for build time enablement, there is currently no simple >> way to check if PSCI is actually available and used. >> >> Hence add a helper function to check if PSCI is available. >> >> This is useful for e.g. drivers that are used on platforms with and >> without PSCI. Such drivers may need to take provisions for proper >> operation when PSCI is used, and/or to implement functionality that is >> usually provided by PSCI. > > the psci_ops is a global var, why not check psci_ops.mmnn members > individually in each drivers? check IS_ENABLED(CONFIG_ARM_PSCI_FW) for > building time ennoblement. While psci_ops is a global var, it only exists if CONFIG_ARM_PSCI_FW=y, so typical code like if (IS_ENABLED(CONFIG_ARM_PSCI_FW) && psci_ops.cpu_suspend) { ... } won't link. So having a helper is useful. The alternative is #ifdef. >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> --- >> drivers/firmware/psci.c | 5 +++++ >> include/linux/psci.h | 2 ++ >> 2 files changed, 7 insertions(+) >> >> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c >> index da469c972b503f83..a3a11e2d8ffffaaa 100644 >> --- a/drivers/firmware/psci.c >> +++ b/drivers/firmware/psci.c >> @@ -670,6 +670,11 @@ int __init psci_dt_init(void) >> return init_fn(np); >> } >> >> +bool psci_is_available(void) >> +{ >> + return psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend; > > IIRC, for PSCI 0.1, cpu_suspend is optional, we can't say the PSCI isn't > available if cpu_suspend is missing. Hmm... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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From: geert@linux-m68k.org (Geert Uytterhoeven) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH 1/2] drivers: firmware: psci: Add psci_is_available() Date: Thu, 12 Oct 2017 08:58:42 +0200 [thread overview] Message-ID: <CAMuHMdVuEtXYGL5FL4e-_GMNSmRNyodfFvhdNi6ZHaAVcDEUEA@mail.gmail.com> (raw) In-Reply-To: <20171012105801.0bb643eb@xhacker.debian> Hi Jisheng, On Thu, Oct 12, 2017 at 4:58 AM, Jisheng Zhang <Jisheng.Zhang@synaptics.com> wrote: > On Wed, 11 Oct 2017 10:03:01 +0200 Geert Uytterhoeven wrote: > >> PSCI support may be disabled at build time (by configuration) or at >> run-time (PSCI firmware not present). While CONFIG_ARM_PSCI_FW can be >> used to check for build time enablement, there is currently no simple >> way to check if PSCI is actually available and used. >> >> Hence add a helper function to check if PSCI is available. >> >> This is useful for e.g. drivers that are used on platforms with and >> without PSCI. Such drivers may need to take provisions for proper >> operation when PSCI is used, and/or to implement functionality that is >> usually provided by PSCI. > > the psci_ops is a global var, why not check psci_ops.mmnn members > individually in each drivers? check IS_ENABLED(CONFIG_ARM_PSCI_FW) for > building time ennoblement. While psci_ops is a global var, it only exists if CONFIG_ARM_PSCI_FW=y, so typical code like if (IS_ENABLED(CONFIG_ARM_PSCI_FW) && psci_ops.cpu_suspend) { ... } won't link. So having a helper is useful. The alternative is #ifdef. >> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> >> --- >> drivers/firmware/psci.c | 5 +++++ >> include/linux/psci.h | 2 ++ >> 2 files changed, 7 insertions(+) >> >> diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c >> index da469c972b503f83..a3a11e2d8ffffaaa 100644 >> --- a/drivers/firmware/psci.c >> +++ b/drivers/firmware/psci.c >> @@ -670,6 +670,11 @@ int __init psci_dt_init(void) >> return init_fn(np); >> } >> >> +bool psci_is_available(void) >> +{ >> + return psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend; > > IIRC, for PSCI 0.1, cpu_suspend is optional, we can't say the PSCI isn't > available if cpu_suspend is missing. Hmm... Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
next prev parent reply other threads:[~2017-10-12 6:58 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-10-11 8:03 [PATCH 0/2] drivers: firmware: psci: Extract psci_is_available() helper Geert Uytterhoeven 2017-10-11 8:03 ` Geert Uytterhoeven 2017-10-11 8:03 ` [PATCH 1/2] drivers: firmware: psci: Add psci_is_available() Geert Uytterhoeven 2017-10-11 8:03 ` Geert Uytterhoeven 2017-10-12 2:58 ` Jisheng Zhang 2017-10-12 2:58 ` Jisheng Zhang 2017-10-12 6:58 ` Geert Uytterhoeven [this message] 2017-10-12 6:58 ` Geert Uytterhoeven 2017-10-12 6:58 ` Geert Uytterhoeven 2017-10-25 15:45 ` [1/2] " Lorenzo Pieralisi 2017-10-25 15:45 ` Lorenzo Pieralisi 2017-10-11 8:03 ` [PATCH 2/2] drivers: firmware: psci: checker: Use psci_is_available() Geert Uytterhoeven
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